Category Archives: invertebrates

Episode 108: Strange Things Found in Amber

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Thanks to Nicholas for suggesting this week’s episode topic! Lots of strange and fascinating insects and other animals are found trapped in amber. So what is amber, how does it preserve animal parts, and most importantly, what have scientists found in amber?

A millipede preserved in amber, one of 450 millipedes discovered in Myanmar amber. Somebody had to count them:

A newly described insect that got its own order because it’s so weird. Look at that triangular head with giant eyeballs!

A mushroom, a hair, and a tiny phasmid exoskeleton, all caught in amber:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

Last month I released an episode about trace fossils, and listener Nicholas wrote me to suggest I also do an episode about amber—specifically, the animals and other items that were trapped in amber and preserved inside it when the amber fossilized. Nicholas also sent me lots of links to really interesting articles!

Amber is the term for fossilized tree resin. If you’ve ever climbed a pine tree and ended up with pine sap all over your hands, which is impossible to get off by just washing your hands and is super sticky and picks up every bit of dirt, you’ll have an idea of what amber starts out as and why it sometimes has insects and other stuff in it. Despite the name pine sap, it’s not actually sap. Sap is the fluid that carries nutrients around to a plant’s cells, sort of like plant blood. Resin is secreted by certain trees and other plants for various reasons, including to protect it from insect damage, to kill fungus, to seal off a broken branch or other injury, and to taste bad so herbivores won’t eat it.

There are different types of amber, because there are different plants that produce resin. We don’t always know what species of plant a particular type of amber comes from, since many are now extinct and can’t be directly studied. Conifer trees evolved around 300 million years ago but became really successful during the Mesozoic around 250 million years ago, spreading throughout the world and dripping resin all over the place. Conifers include pine trees, fir trees, hemlocks, yews, larches, junipers, cedars, redwoods, spruces, and lots of other trees and shrubs that are still widespread today. Some flowering plants, mostly trees, also produce resins. But before conifers evolved and outcompeted them, plants called medullosales lived around the world and produced resin too. Medullosales first appear in the fossil record around 360 million years ago and mostly died out around 298 million years ago. They’re all extinct now.

If your name is Amber, by the way, you are named for fossilized tree resin. That sounds gross, but amber has been prized for millennia as a gemstone. When polished, it can be a gorgeous yellow, gold, or brown, often the color of honey. But some amber is other colors, including red, blue, or green. It all depends on what tree originally produced the resin, its chemical makeup, and how it was fossilized.

So how does the resin fossilize? Sometimes it would drip onto the ground, become buried, and fossilize along with the ground around it. Sometimes the resin-producing tree would fall, become buried, and the resin inside would fossilize along with the wood. Sometimes the resin would drip into water, float to a quiet area or sink to the bottom of the pool or lagoon, and fossilize along with the sand and other sediment that covered it. This is why so much amber is found in the ocean, by the way. Once fossilized, amber floats in salt water—just barely, but enough that on some beaches it’s commonly washed up with the tide. People collect the pieces of amber to polish and sell. Amber can also be burned and often gives off a musky, piney scent that has been used in religious ceremonies.

The reason we’re talking about fossilized plant material in an animal podcast is that amber sometimes has insects or other small animals or animal parts inside it. This happened when it was still resin, which is really sticky. If an ant or bee was in the wrong place at the wrong time, it could be covered with resin and die. Then, if that particular dollop of resin ended up getting protected by sediment at just the right time, instead of weathering away and decaying it might fossilize over millions of years with the ant or bee or whatever inside it. And because the ant or bee was protected from air, water, and bacteria by the resin, and kept in place, the things found in amber are usually mostly intact and include parts of the body that ordinarily never fossilize. It may even help preserve DNA, which ordinarily decays after a matter of thousands of years, although there’s still conflicting evidence about whether this is the case. All this helps researchers study animals that went extinct millions of years ago almost as though those animals were still around.

Substances inside amber are called inclusions, whether they’re something exciting like a spider or just a piece of dirt. Well preserved inclusions, especially pretty ones like flowers, can make the piece of amber extremely valuable. If you want to buy polished amber with an inclusion, though, keep in mind that there are a lot of fakes out there. Make sure to have an expert examine an expensive piece before you spend money on it.

So let’s learn about some insects and other things that have been discovered in amber. I’m going to mention Myanmar repeatedly because it’s a big amber-producing region and the subject of an intensive ongoing study of animals found in the amber. Myanmar is in southeast Asia and was once called Burma.

The oldest organism found in amber are two tiny mites and a fly dated to 230 million years ago. The amber in question is very small, droplets no more than about six millimeters across, found in the Italian Alps. The mites are two different species, both new to science although they have living relations that resemble the ancient mites closely. Both of them ate plants. The fly isn’t as well preserved so researchers aren’t sure what species it was.

A 3 millimeter beetle found in amber dated to 99 million years ago was found in Myanmar. It’s an ancient relative of the modern flat rove beetle that lives under tree bark. But the flat rove beetle lives in South America, with one species from southwestern North America. Comparing the modern beetles with their ancestor gives researchers a closer idea of when the supercontinent Gondwana started to split apart into smaller continents as the landmasses moved slowly across the Earth to their current positions.

The amber found in Myanmar has yielded a lot of interesting information during recent studies. For instance, 450 millipedes! Not all in one piece, of course. The research team used a new type of analysis called micro-CT, which scans the inclusion and creates a highly detailed 3D image which can then be studied without damaging or even touching the amber. This is helpful when the amber pieces are privately owned and only on loan to scientists. Some of the millipede specimens were newly hatched, some fully grown, and include many species new to science.

Another insect found in Myanmar amber dated to 99 million years ago is so unusual that researchers placed it in its own order. To illustrate how rare this is, there are over a million insects described by scientists but they all fit into 31 orders. But now there’s 32 orders. The insect had a triangular head with big bulging eyes, a long flat body, long legs, and no wings. It also had glands on its neck that secreted chemicals that probably helped repel predators. Because of its large eyes and the unusual head shape, it could see almost all the way around it without turning its head. Two specimens of the extinct insect have been found in amber. One of the researchers who described the insect, amber expert and entomologist George Poinar, Jr, said that he thought it looked like an alien’s head so he made a Halloween mask that looked like it. As you do. He said “when I wore the mask when trick-or-treaters came by, it scared the little kids so much I took it off.”

It’s not just insects that are found preserved in amber. One foot and part of a tail from a 100 million year old gecko were found in amber about a dozen years ago. Researchers think the rest of the gecko was probably eaten, possibly by a dinosaur. Even though there isn’t a lot of the gecko to study, there’s enough to determine that it was a genus and species new to science, and that it was probably a juvenile gecko that would have grown up to a foot long if it had lived, or 30 cm. It was only about an inch long when it died, or a bit over two cm. It was stripey and had the same type of toe pads that modern geckos have that allow them to walk up walls.

Another foot, this one from a frog, was discovered in more of the Myanmar amber that’s the subject of ongoing studies. It was a tiny juvenile frog that lived in a tropical forest around 100 million years ago. It’s only the third frog ever found in amber, and is by far the oldest in addition to being the best preserved. Its skull, forelegs, part of its backbone, and the partial hind leg and foot are all preserved, together with a beetle. The problem is, some of the details researchers need to determine what kind of frog it is are missing, like the pelvis. They have just enough information to tantalize them since what they can see indicates that it might be related to some species of toad that live in temperate climates today, but not enough to tell for sure. You know they have to be tearing their hair out in frustration. Hopefully they’ll find another frog with all the bits and pieces they need.

Another surprise from the Myanmar amber is a baby snake only about two inches long, or 5 cm. At first researchers thought it was yet another millipede—I mean, when you’ve found 450 millipedes in amber you probably start to think everything is a millipede—but a scan determined that it was way different. It’s well preserved and even shows some features that modern snakes no longer have, like V-shaped bone spurs on the tail vertebrae that probably helped with stability when snakes first evolved to be limbless. Unfortunately the specimen is missing its skull.

Only one salamander has been found in amber, and it came from a surprising place. The amber was mined from the mountains of the Dominican Republic, which is in the Caribbean near Haiti. But there are no salamanders in the Caribbean today. The salamander in amber dates to around 25 million years ago and proves that salamanders did once live in the Caribbean. Not only that, the amber itself comes from an extinct tree that’s related to a tree native to East Africa. The salamander was a tiny juvenile that fell into a glob of resin after a predator bit one of its legs off. So, you know, it was doomed either way. Poor little salamander.

One really exciting discovery is part of an actual dinosaur tail trapped in amber. It came from a juvenile dinosaur that a scientist found at a market in Myanmar in 2015. The seller thought the tail was a plant, because—you’ll like this—it’s covered in FEATHERS that looked like bits of leaf. It’s dated to 99 million years ago. The feathers were chestnut brown on the tail’s upper surface and white underneath. They’re also very different from modern bird feathers. Researchers aren’t sure which dinosaur species the tail is from, but they do note that the dinosaur died, probably because it couldn’t get free from the resin. It wasn’t like some modern lizards that can drop their tails to escape predators.

Lida Xing, the same researcher who acquired the dinosaur tail in amber also managed to buy a bird in amber in the same Myanmar amber market. Only a few birds have been found in amber and they sell for ridiculous amounts of money—like half a million dollars—to private collectors. As a result, they’re rarely studied. Fortunately, Lida Xing was able to buy the bird in amber and it’s been studied ever since. It’s a young bird that was partially weathered away and squished after it died. It’s about 2 ½ inches long, or 6 cm, and is a type of primitive bird that went extinct at the same time as the non-avian dinosaurs 66 million years ago. It was dark brown and had teeth and clawed fingers on its wings, although both the beak and the finger-wings are missing from the specimen.

Sometimes marine or freshwater organisms are found in amber. For a long time no one understood how this happened, but in 2007 a team of researchers conducted a simple study to find out how it worked. One of the researchers owned some swampy property in central Florida. The team went there and cut pieces out of some pine trees growing in the swamp. Resin flowed from the trees’ injuries, down the trunk, and into the water. The researchers then collected the resin from the water and took it to a lab to examine it. They found water beetles, nematodes, small freshwater crustaceans, mites, even bacteria found in swampy water, all stuck in the blobs of resin. In other words, it’s not a bit unusual for water animals to get caught in resin. The unusual part is when they’re preserved in the resin long enough for the resin to fossilize into amber, and then the really rare part is when they’re found by a human who understands what they’re looking at and realizes it’s important.

Some of the most useful information preserved in amber concerns animal behavior. For instance, the recent discovery of a tick wrapped in spider silk. Spiders don’t usually eat ticks, but occasionally they do, and this tick in amber had been wrapped up in spider silk to immobilize it. Researchers aren’t sure whether the spider planned to eat the tick or was just stopping it from tearing up its web. Either way, it fell out of the web and plopped right into resin, which fossilized and was then found around 100 million years later. From this little piece of amber, we have direct evidence of a spider wrapping up its prey the same way they do today.

Another example is dated to 130 million years ago, when some green lacewing eggs hatched and the larvae and eggs were trapped in resin almost immediately. The green lacewing is a type of flying insect that’s still around today, although the ones found in resin are a species new to science. Since the babies were covered in resin during the act of hatching, researchers have learned a lot about how they emerged from the eggs.

There’s even a piece of amber dated to around 100 million years ago, also found in Myanmar, that shows a dragonfly with a missing head, together with the foot and tail of a tiny lizard. Researchers think the lizard may have caught the dragonfly and decapitated it to kill it, but before it could eat it, both predator and prey were trapped in resin. It’s too bad we don’t have the lizard’s head, because it would be really awesome if it had the dragonfly’s head in its mouth.

Some pieces of amber tell a story like this, like a photograph from millions of years ago. About 50 million years ago near what is now the Baltic Sea, a small mammal, possibly a rodent, bit a mushroom off at its base. A tiny insect, specifically a phasmid, or walking stick, was feeding on the mushroom and jumped away. All this happened just as a blob of resin dropped on the scene. The mammal fled, leaving behind a hair. The insect was trapped but was able to wriggle out of its exoskeleton in an early molt and escape, leaving its exoskeleton behind. The mushroom did nothing, because it was a mushroom. That particular phasmid species is now extinct, as is the mushroom species. Researchers don’t know much about the mammal. They know that the exoskeleton was literally shed moments before it was enveloped in resin because it still shows tiny filaments that would have crumbled away otherwise.

Even more dramatically, another piece of amber, again from Myanmar and about 100 million years old, shows a spider in the act of attacking a wasp. Both the spider, a bristly orb-weaver, and the parasitic wasp are still around today.

Other things are also preserved in amber, from pollen and plant spores to feathers and spiderwebs. It’s mined and gathered in various parts of the world for jewelry, so new amazing specimens could be discovered any day.

I could literally just keep going with this episode for hours talking about what’s been found so far, but I have to stop somewhere so I’ll leave you with one last amber inclusion.

It’s another strange insect new to science, also found in Myanmar amber dated to about 100 million years ago. It was tiny but really weird-looking. Researchers have been referring to it as a unicorn fly because it had a sort of horn sticking up from the top of its head that had three eyes at its tip. Researchers think its specialized horn with eyes on it gave it an advantage when flowers were tiny, as they were back in the early Cretaceous when it lived. Flowering plants had only recently emerged and were diversifying rapidly. It probably ate pollen and nectar. But when flowers evolved to be larger, it lost its evolutionary advantage and went extinct. It also had tiny mandibles that meant it could only eat very small particles of food, long legs, and weirdly shaped antennae.

The unicorn fly was described by our friend George Poinar, who described the weird insect with the triangular head too. And true to form, Dr. Poinar is up to his same tricks. He’s reported as saying that he was “thinking of making some masks based on it for Halloween.”

George, no! The children are frightened! Stop making Halloween masks!

One note about listener suggestions. I’ve been getting a lot of them lately, which is awesome, but I don’t necessarily use the suggestions in order. Which one I pick out for the next episode depends on a lot of things, including how much time I have for research, what strikes me as neat on any given day, and whether I can work a suggestion in to a planned episode about a larger topic. But I promise I do keep all suggestions in a list, and I will eventually get to them all! I’m always delighted to get more, too, so don’t feel like I’m telling you not to send any. Some of the best episodes I’ve done have been from listener suggestions, about animals I’d never heard of before.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

 

Episode 105: The Hagfish and the Sea Spider

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This week’s episode is about two strange animals of the sea: the hagfish, which isn’t a fish, and the sea spider, which isn’t a spider.

A curled-up hagfish:

The sea spider is actually quite pretty as long as I don’t have to touch it:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

A long long long time ago, and I can’t even remember which episode it was, I mentioned that one day I would do an episode about the hagfish because it’s such a weird animal.

Well, that day is today.

The hagfish isn’t a fish. It looks more like an eel and is sometimes called a slime eel. But it’s not an eel either. In fact, it’s so weird that scientists are still trying to figure out exactly where the hagfish fits in the animal world.

The only living animal that is similar to the hagfish is the lamprey, and current research suggests that they are fairly closely related. We talked about the sea lamprey way back in episode three.

There are a number of hagfish species. The biggest is the goliath hagfish (Eptatretus goliath), which can grow more than four feet long, or 127 cm, but most species are much smaller. As mentioned, it looks sort of like an eel, with a tail that’s flattened like a paddle. It doesn’t have true fins, it doesn’t have a jaw, and it only has a single nostril. It usually breathes by swallowing water, which runs through gill pouches inside the body, but some researchers think it can also absorb oxygen through its skin. It can survive for hours without oxygen.

The hagfish is considered a vertebrate because it has a rudimentary spine, called a notochord. It has eyespots instead of true eyes, which can only detect light, but fossilized ancestors of living hagfish seem to have had more complex eyes. I guess they just didn’t need them.

The hagfish has a lot of blood for its size. Its skin is loose and only attached to the rest of the body along its back and at its slime glands. Since its skin is thick and contains about a third of the body’s blood, the hagfish actually looks kind of like a fluid-filled sock with a tail. If you’ve ever bought an eelskin wallet or other item, it was probably actually made from hagfish skin. Because the hagfish has such low blood pressure, the lowest recorded in any animal, and because its skin is so loose and it only has a few bones, it can squeeze through incredibly small openings. When it does, the blood in its skin is pushed into the rear of its body. This would kill an ordinary animal, but it doesn’t affect the hagfish at all.

There’s so much weirdness about the hagfish that it’s hard to know where to start. Its mouth, for instance. Instead of jaws, its skull has a piece of cartilage that can move forward and backward, with two pairs of comb-shaped teeth attached to the plate. This sounds like it would be an awkward way to bite into food, but it works so well for the hagfish that it hasn’t changed in some 300 million years. It’s more like a toothed tongue or a radula than anything resembling vertebrate jaws. The hagfish also has short tentacles around its mouth.

The hagfish eats anything, but the main part of its diet is probably marine worms that live on the sea floor. It also scavenges carcasses that sink to the bottom of the sea. If you’ve seen that amazing time-lapse video of a blue whale carcass, you’ve seen hagfish. They’re the ones that burrow into the carcass to bite pieces of meat off from the inside, and the ones that will actually tie their body into a knot to help yank food off the carcass. Since the hagfish lives on or near the sea floor, trawlers who drag nets along the sea floor to fish often catch hagfish by accident. Sometimes they catch so many hagfish that by the time they haul the net up, the hagfish have eaten all the fish in the net.

But the hagfish also hunts fish actively, especially the red bandfish that lives off the coast of New Zealand. The red bandfish digs a burrow, and the hagfish will slither into the burrow and drag the fish out to eat it. It may actually suffocate the fish first by smothering its gills with slime.

And that brings us to another weird thing about the hagfish, its slime. The hagfish is famous for its slime. It has something like a hundred slime glands along its sides, and if it feels threatened it will release massive amounts of slime through the glands. It only takes a fraction of a second to release slime. This doesn’t just make it slippery, the slime actually absorbs water and increases in volume, and it’s sticky. If a fish grabs a hagfish, suddenly the hagfish has secreted more than five gallons of slime—that’s 20 liters—which contains thin fibers that help clog the fish’s gills. Meanwhile, the hagfish will tie itself into a knot and push the knot from its head to its tail, which pushes the slime off of its own body and leaves it behind. The hagfish swims away, leaving the predator dealing with copious amounts of slime sticking to its gills. Basically, almost nothing eats the hagfish, not even sharks. But exuding so much slime does cost the hagfish energy. It can take weeks to recover.

One really interesting thing about hagfish slime is those fibers that make up part of its volume. When dried out, the fibers look like silk and are almost as strong and thin as spider silk. They’re also produced from cells that are genetically smaller than those in spiders. Researchers are trying to figure out how to take the DNA for hagfish fiber production and implant it into bacteria that would then produce quantities of silk. Because it’s so strong and lightweight, the silk could then be used to make cloth that could take the place of petroleum-based fibers like nylon. This is so exciting. My guess is it’ll be marketed as eel silk, because that sounds way better than hagfish slime fibers.

We don’t have many hagfish fossils since the hagfish only has a few bones and the rest of its body is rarely preserved in the fossil record. But we do have one really good fossil dated to 100 million years old. Recently, it was imaged using a method called synchrotron scanning, which identifies chemical traces of soft tissues left in the stone. The scan revealed the chemical signature of keratin along the fossil’s sides, and since the slime fibers are made of keratin, researchers think that 100 million years ago the hagfish was already producing slime.

An interesting side note about the synchrotron scanning is that it can be used to detect glue or paint used to make a fossil look more complete than it really is. Fossil forgers beware.

Researchers still don’t know a lot about how hagfish reproduce. We do know that hagfish eggs take a long time to hatch, something like eleven months. The eggs have hooked hair-like structures at the ends and usually stick together in bunches. Hagfish don’t hatch into larvae like lampreys do, but instead hatch into little hagfish. Some hagfish species appear to be hermaphroditic, which means an individual contains both eggs and sperm, but they probably don’t lay eggs until they’re older.

The hagfish also has three hearts. Happy Valentine’s Day.

Another weird and fascinating ocean creature is the sea spider. Honestly, despite its name, after the hagfish, the sea spider seems positively normal.

The sea spider isn’t actually a spider, but it’s also not a crab. Like the hagfish, researchers aren’t sure where the sea spider belongs taxonomically. Traditionally it’s been grouped with the group of arthropods known as chelicerata [kelisserate-a], which includes true spiders, scorpions, ticks, and their relatives, and horseshoe crabs. But some researchers think the sea spider is more closely related to our old friend Anomalocaris, a stem arthropod that lived during the Cambrian. Recent genetic studies so far indicate that the traditional chelicerata classification is probably correct.

The sea spider has four pairs of legs, although a few species have five or six pairs of legs instead. Some species have one or two pairs of simple eyes, but other species have no eyes at all. The body is quite small in relation to the legs, which are extremely long, which means the digestive tract is actually partly in the legs, because the body is too small for it. It walks along the bottom of the ocean or may swim by pulsing its long legs like a jellyfish with legs instead of a bell. In species that swim, the legs may be lined with long bristles. Males take care of the eggs until they hatch, so male sea spiders have a pair or two of small legs called ovigers that are used to carry eggs.

Like true spiders, the sea spider doesn’t breathe in a way we think of breathing. It absorbs oxygen through pores in its exoskeleton, and the oxygen is then absorbed into a substance called hemolymph. This is basically invertebrate blood. The hemolymph is moved around its body to the cells that need it—not by its heart, which is relatively weak and only moves hemolymph around the small body, but by the digestive system. Since the digestive system goes all the way down into the legs and already moves digestive fluids around, that makes sense.

Some species have mouthparts, but most eat using a proboscis that it uses to suck hemolymph and other fluids out of its prey. Some species have spines at the tip of the proboscis. It sticks its proboscis into a sponge, worm, jelly, sea anemone, or other invertebrate, injects digestive fluids that liquefy the surrounding tissues, and slurp the fluids up. Sometimes this kills the prey animal, sometimes it doesn’t.

Sea spiders live throughout the world’s oceans and there are well over a thousand known species. Most are small and live in shallow water, but a few live in water up to 23,000 feet deep, or 7,000 meters. The biggest species live in the cold waters around Antarctica, with the very largest individual ever found having a legspan of about 27 inches, or 70 cm. So no, they’re not dangerous to humans at all and while they may look scary because those legs are so long, they’re harmless unless you happen to be a soft-bodied invertebrate that can’t run away.

That doesn’t mean there aren’t actual spiders that live in the ocean. Marine spiders are actual spiders, and they’re intertidal, which means they live in the typically small area between high tide and low tide. During high tide they hide underwater in shells, coral, or plants, and they can breathe because they build air chambers from silk. When the tide goes out, the spiders run onto the sand and hunt small insects and other invertebrates. A new species of marine spider was discovered in Queensland, Australia in 2009 that grows to almost 9 mm in size. That’s almost a centimeter long, or half an inch! Males are smaller, though. It was named Desis bobmarleyi after the Bob Marley song “High Tide or Low Tide.”

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 100: The Centipede of Episodes!

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It’s our 100th episode! Thanks to my fellow animal podcasters who sent 100th episode congratulations! Thanks also to Simon and Julia, who suggested a couple of animals I used in this episode.

An Amazonian giant centipede eating a mouse oh dear god no:

The kouprey:

The Karthala scops owl:

A sea mouse. It sounds cuter than it is. Why are you touching it? Stop touching it:

A sea mouse in the water where it belongs:

Mother and baby mountain goats. Much cuter than a sea mouse:

A hairy octopus:

Further reading:

Silas Claiborne Turnbo’s giant centipede account collection

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

This is our 100th episode! I’ll be playing clips from some of my favorite animal podcasts throughout the show, and I highly recommend all of them if you don’t already listen!

For our big 100 show, I’ve decided to cover several animals, some mysterious, some not so mysterious, and all weird. But we’ll start with one that just seems to fit with the 100th episode, the centipede—because centipedes are supposed to have 100 legs.

So do they have 100 legs? They don’t, actually. Different species of centipede have different numbers of legs, from only 30 to something like 300. Centipedes have been around for some 430 million years and there are thousands of species alive today.

A centipede has a flattened head with a pair of long mandibles and antennae. The body is also flattened and made up of segments, a different number of segments depending on the centipede’s species, but at least 15. Each segment has a pair of legs except for the last two segments, which have no legs. The first segment’s legs project forward and end in sharp claws with venom glands. These legs are called forcipules, and they actually look like pincers. No other animal has forcipules, only centipedes. The centipede uses its forcipules to capture and hold prey. The last pair of legs points backwards and sometimes look like tail stingers, but they’re just modified legs that act as sensory antennae. Each pair of legs is a little longer than the pair in front of it, which helps keep the legs from bumping into each other when the centipede walks.

Like other arthropods, the centipede has to molt its exoskeleton to grow larger. When it does, some species grow more segments and legs. Others hatch with all the segments and legs they’ll ever have.

The centipede lives throughout the world, even in the Arctic and in deserts, which is odd because the centipede’s exoskeleton doesn’t have the wax-like coating that other insects and arachnids have. As a result, it needs a moist environment so it won’t lose too much moisture from its body and die. It likes rotten wood, leaf litter, soil, especially soil under stones, and basements. Some centipedes have no eyes at all, many have eyes that can only sense light and dark, and some have relatively sophisticated compound eyes. Most centipedes are nocturnal.

Many centipedes are venomous and their bites can cause allergic reactions in people who also react to bee stings. Usually, though, a centipede bite is painful but not dangerous. Small centipedes can’t bite hard enough to break the skin. I’m using bite in a metaphorical way, of course, since scorpions “bite” using their forcipules, which as you’ll remember are actually modified legs.

The largest centipedes alive today belong to the genus Scolopendra. This genus includes the Amazonian giant centipede, which can grow over a foot long, or 30 cm. It’s reddish or black with yellow bands on the legs, and lives in parts of South America and the Caribbean. It eats insects, spiders, including tarantulas, frogs and other amphibians, small snakes, birds, mice and other small mammals, and lizards. It’s even been known to catch bats in midair by hanging down from cave ceilings and grabbing the bat as it flies by. Because it’s so big, its venom can be dangerous to children. A four-year-old in Venezuela died in 2014 after being bitten by one, but this is unusual, and bites generally only lead to a few days of pain, fever, and swelling.

You’ll often hear that the Amazonian giant centipede is the longest in the world, but this isn’t actually the case. Its close relation, the Galapagos centipede, is substantially longer. The Galapagos Islands have EVERYTHING. The Galapagos centipede can grow 17 inches long, or 43 cm, and is black with red legs.

Another member of Scolopendra is the waterfall centipede, which grows a mere 8 inches long, or 20 cm, but which is amphibious. The waterfall centipede was only discovered in 2000, when entomologist George Beccaloni was on his honeymoon in Thailand. Naturally he was poking around looking for bugs, and I trust his spouse was aware that that’s what he would do on his honeymoon, when he spotted a dark greenish-black centipede with long legs. It ran into the water and hid under a rock, which he knew was extremely odd behavior for a centipede. They need moisture but they avoid entering water. Beccaloni noted that the centipede was able to swim in an eel-like manner. He captured it and later determined it was a new species. Only four specimens have been found so far in various parts of South Asia. Beccaloni hypothesizes that it eats insects and other small animals found in the water.

There are stories of huge centipedes found in the depths of jungles throughout the world, centipedes longer than a grown man is tall. These are most likely tall tales, since centipedes breathe through tiny notches in their exoskeleton like other arthropods and don’t have proper lungs. As we learned in the spiders episode a few months ago, arthropods just can’t get too big or they can’t get enough oxygen to live. But some of the stories of huge unknown centipedes have an unsettling ring of truth.

There are stories from the Ozark Mountains in North America about centipedes that grow as long as 18 inches, or almost 46 cm. Historian Silas Claiborne Turnbo collected accounts of giant centipede encounters in the 19th century, which are available online. I’ll put a link in the show notes.

All the accounts come across as truthful and not exaggerated at all. I think it’s worth it to read the last few paragraphs of the centipedes chapter of Turnbo’s manuscript verbatim, because they’re really interesting and I kept finding garbled accounts of the stories in various places online. Whenever possible, go to the primary source.

“R. M. Jones, of near Protem, Mo., tells of finding a centipede once imprisoned in a hollow tree. Mr. Jones said that after his father, John Jones, settled on the flat of land on the east side of Big Buck Creek in the southeast part of Taney County, his father told him one day in the autumn of 1861 to split some rails to build a hog pen. Going out across the Pond Hollow onto the flat of land he felled a post oak tree one and one-half feet in diameter. There was a small cavity at the butt of the tree. After chopping off one rail cut he found that the hollow extended only four or five feet into the rail cut, and was perfectly sound above it. After splitting the log open he was astonished at finding a centipede eight inches in length, coiled in a knot in the upper part of the cavity. At first there appeared to be no life about it. ‘I took two sticks,’ said he, ‘and unrolled it and found that it was alive. It was wrapped around numerous young centipedes which were massed together in the shape of a little ball. The old centipede was almost white in color. After a thorough examination of the stump and the ground around it, I found no place where the centipede could have crawled in. Neither, in the log, was there any place where it could enter. How it got there I am not able to explain and how long it had been an inhabitant there is another mystery to me.’

“William Patton, who settled on Clear Creek in Marion County, Ark., in 1854 and became totally blind and is dead now, says that one day while his eyesight was good he was in the woods on foot stock hunting. When about 1 ½ miles west of where the village of Powell now is, he noticed something a short distance from him crawl into a hollow tree at the ground. ‘On approaching the tree to identify the object,’ remarked Mr. Patton, ‘I saw a monster centipede lying just on the inside of the hollow which was the object I had just observed crawl into the tree. I placed the muzzle of my rifle near the opening and shot it nearly in twain, and taking a long stick I pulled it out of the hollow and finished killing it with stones. I had no way of measuring it accurately, but a close estimation proved that it was not less than 14 inches long and over an inch wide.’

“The biggest centipede found in the Ozarks that I have a record of was captured alive by Bent Music on Jimmies Creek in Marion County in 1860. Henry Onstott an uncle of the writer and Harvey Laughlin who was a cousin of mine kept a drugstore in Yellville and collected rare specimens of lizards, serpents, spiders, horned frogs and centipedes and kept them in a large glass jar which sat on their counter. The jar was full of alcohol, and the collection was put in the jar for preservation as they were brought in. Amongst the collection was the monster centipede mentioned above. It was of such unusual size that it made on almost shudder to look at it. Brice Milum, who was a merchant at Yellville when Mr. Music brought the centipede to town, says that he assisted in the measuring of it, before it was put in the alcohol and its length was found to be 18 inches. It attracted a great deal of attention and was the largest centipede the writer ever saw. The jar with its contents was either destroyed or carried off during the heat of the war. Henry Onstott died in Yellville and is buried in the old cemetery one half a mile west of town.”

There are large centipedes around the Ozarks, including the red-headed centipede that can grow over eight inches long, or 20 cm. A hiker was bitten by a six-inch red-headed centipede a few years ago in Southwestern Missouri and had to be treated at a hospital. The red-headed centipede mostly stays underground during the day, although it will come out on cloudy days. It has especially potent venom and lives in the southwestern United States and northern Mexico. And, interestingly, females guard their babies carefully for a few days after they hatch. Since the red-headed centipede is a member of the genus Scolopendra, the ones that grow so long, I wouldn’t be a bit surprised if individuals sometimes grow much longer than eight inches.

One story of a giant centipede called the upah turned out to have a much different solution. Naturalist Jeremy Holden was visiting a village in western Sumatra in the early 2000s when he heard stories of the upah. It was supposed to be a green centipede that grew up to about a foot long, or 30 cm, and had a painful bite. It was also supposed to make an eerie yowling sound like a cat. Holden discounted this as ridiculous, since no centipedes are known to make vocalizations of any kind, until he actually heard one. He was in the forest with a guide, who insisted that this was the upah. The sound came from high up in the treetops so Holden couldn’t see what was making it. But on a later trip to Sumatra with a birdwatcher friend, Holden heard the same sound, but this time the friend knew exactly what was making it. It wasn’t a centipede at all but a small bird called the Malaysian honeyguide. The honeyguide has a distinctive catlike call followed by a rattling sound, but is extremely hard to spot even for seasoned birdwatchers with powerful binoculars. This is what a Malaysian honeyguide sounds like, if you’re curious:

[honeyguide call]

The worst kind of centipede is the house centipedes. I hate those things. I’d rather have a pet spider that lives in my hair than touch a house centipede. House centipedes are the really fast ones that have really long legs that sort of make them look like evil feathers running around on the walls.

Next, let’s take a look at the kouprey, a bovine that is rare and possibly extinct. Thanks to Simon who suggested this ages ago, after the mystery cattle episode, or at least he mentioned it to me while we were talking on Twitter.

The kouprey is a wild ox from Southeast Asia and may be closely related to the aurochs. It’s big and can stand over six feet tall at the shoulder, or almost two meters. It has long legs, a slightly humped back, and a long tail. Males have horns that look like typical cow horns, but females have horns that spiral upward like antelope horns. Cows and calves are gray with darker bellies and legs, while grown bulls are dark brown with white stockings. It lives in small bands led by a female and eats grass and other plants. Males are usually solitary or may band together in bachelor groups. It likes open forest and low, forested hills. Sometimes it grazes with herds of buffalo and other types of wild ox.

The kouprey wasn’t known to science until 1937, when a bull was sent to a zoo in Paris from Cambodia. It was already rare then. A 2006 study that showed the kouprey was actually a hybrid of a domestic cow and another species of wild ox, the banteng, was later rescinded by the researchers as inaccurate. Genetic studies have since proven that the hybrid hypothesis was indeed wrong.

Unfortunately, if the kouprey still exists, there are almost none left. In the late 1960s only about 100 were estimated to still remain. While it’s protected, it’s poached for meat and horns, and is vulnerable to diseases of domestic cattle and habitat loss. The last verified sighting of a kouprey was in 1983, and there are no individuals in captivity. But conservationists haven’t given up yet. They continue to search for the kouprey in its historical range, including setting camera traps. Since the kouprey looks very similar to other wild oxen, it’s possible there are still some hiding in plain sight.

Next up, let’s look at a rare owl. Thanks to Julia who suggested the Karthala scops owl, which only lives in one place in the world. That one place in the world happens to be an active volcano. Specifically, it lives on the island of Grande Comore between Africa and Madagascar, in the forest on the slopes of Mount Karthala.

It’s a small owl with a wingspan of only 18 inches, or 45 cm. Some of the owls are greyish-brown and some are dark brown. It probably eats insects and small animals, but not much is known about it. It’s critically endangered due to habitat loss, as more and more of its forest is being cut down to make way for farmland. It sounds like this, and if you don’t think this is adorable I just can’t help you:

[owl call]

The Karthala scops owl wasn’t discovered by science until 1958, when an ornithologist named C.W. Benson found a feather living a sunbird nest. He thought it might be a nightjar feather, but it turned out to belong to an unknown owl. At first researchers thought it was a subspecies of the Madagascar scops owl, but it’s now considered to be a new species. Unlike many other scops owl species, the Karthala scops owl doesn’t have ear tufts.

That’s pretty much all that’s known about the Karthala scops owl right now. Researchers estimate there are around 1,000 pairs living on the volcano, and hopefully conservation efforts can be put into place to protect their habitat.

The sea mouse has been on my ideas list from the beginning, so let’s learn a little bit about it today too. It’s not a mouse, although it does live in the sea. It’s actually a genus of polychaete worm that lives along the coasts of the Mediterranean Sea and the Atlantic Ocean, although it doesn’t really look like a worm. It looks kind of mouse-like, if you’re being generous, mostly because it has setae, or hairlike structures, on its back that look sort of like fur. Some species grow up to a foot long, or 30 cm, but most are usually smaller, maybe half that size or less. It’s shaped roughly like a mouse with no head or tail, and is about three inches wide, or 7.5 cm, at its widest.

The sea mouse is usually a scavenger, although at least one species hunts crabs and other polychaete worms. It spends a lot of its time burrowing in the sand or mud on the ocean bed, looking for decaying animal bodies to eat. It also has gills and antennae, although these aren’t readily noticeable because of the setae covering the animal’s back.

Underneath the setae, the sea mouse is segmented. It doesn’t have real legs but it does have appendages along its sides called parapodia, which it uses like little leglets to push itself along. Sometimes a sea mouse is found washed ashore after a storm. Often it scurries through the wet sand and looks even more like a mouse.

The most interesting thing about the sea mouse is its setae. The setae are about an inch long and are dark red, yellow, black, or brown under ordinary circumstances, depending on species. But when light shines on them just right, they glow with green and blue iridescence. The setae are hollow and made of chitin. The setae are much thinner than a human hair, and nanotech researchers have used them to create nanowires.

Here’s a sweet little mystery animal I got from one of my favorite books, Karl Shuker’s Search for the Last Undiscovered Animals. In 1858, French missionary Emmanuel Domenech published a book called Missionary adventures in Texas and Mexico. A personal narrative of six years’ sojourn in those regions, and in that book he mentions an interesting animal. This event apparently took place in or near Fredericksburg, Texas, sometime before about 1850. The woman in question may have been Comanche. I’ll quote the relevant passage, from pages 122 and 123 of the book.

“An American officer assured me that he had seen an Indian woman, dressed in the skin of a lion which she had killed with her own hand—a circumstance which manifested on her part no less strength than courage, for the lion of Texas, which has no mane, is a very large and formidable animal. This woman was always accompanied by a very singular animal about the size of a cat, but of the form and appearance of a goat. Its horns were rose-coloured, its fur was of the finest quality, glossy like silk and white as snow; but instead of hoofs this little animal had claws. This officer offered five hundred francs for it; and the commandant’s wife, who also spoke of this animal, offered a brilliant of great value in exchange for it; but the Indian woman refused both these offers, and kept her animal, saying that she knew a wood where they were found in abundance; and promised, that if she ever returned again, she would catch others expressly for them.”

So what could this strange little animal be? It sounds like a mountain goat. Mountain goats live in mountainous areas of western North America, but might well have been unknown elsewhere in the mid-19th century. They’re pure white with narrow black horns and hooves, but an albino individual might have horns that appear to be pinkish, at least at the base where the horn core is, due to lack of pigment in the horns allowing blood to show through the surface. While male mountain goats can grow more than three feet tall at the shoulder, or 1 meter, females are much smaller and have smaller horns. Most tellingly, mountain goats have sharp dewclaws as well as cloven hooves that can spread apart to provide better traction on rocks. To someone not familiar with mountain goats, this could look like claws rather than feet. My guess is the woman had a young mountain goat she was keeping as a pet, possibly an albino one, which would explain its size and appearance. It’s nice to think that she cared so much for her little pet that she refused huge amounts of money for it.

Let’s finish up with a rare and tiny cephalopod called the hairy octopus. It’s tiny, only two inches across, or five centimeters, and covered with strands of tissue that give it its name. The so-called hair of the hairy octopus camouflages it by making it look like a piece of seaweed or algae. It can also change colors like other octopuses, to blend in even more with its surroundings. It can appear red, brown, cream, or white, with or without spots and other patterns. It’s only ever been seen in the Lembeh Strait off the coast of Indonesia, and then only rarely.

It’s so rare, in fact, that it still hasn’t been formally described by science. So if you’re thinking about becoming a biologist and you find cephalopods like octopus and squid interesting, this might be the field for you. You might get to give the hairy octopus its official scientific name one day!

Thanks so much to all of you, whether you’re a fellow podcaster, a Patreon subscriber, a regular listener, or someone who just downloaded your first episode of Strange Animals Podcast to see if you like it. I’m having a lot of fun making these episodes, and I’m always surprised at how many people tell me they enjoy listening. I tend to forget anyone listens at all, so whenever I get an email or a review or someone tweets to me about an episode, I’m always startled and pleased. I’ve been trying hard to make the show’s sound quality better, and while I don’t always have the time to do as much research for each episode as I’d like, I do my best to make sure all the information I present is up to date and as accurate as possible.

As always, you can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening, and happy new year!

Episode 099: Island Life

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Those of us in the northern hemisphere are thinking a lot about island life right about now, where it’s warm and sunny. But there are islands everywhere, not just the tropics, and the animals on islands often evolve to look strange and different from their mainland cousins. Thanks to Richard E. and Lucy for their suggestions this week!

A fossa:

A tamaraw, miniature water buffalo:

A Socotra starling, my new favorite bird:

Adorable little Galapagos penguin:

A dragonblood tree, good grief!

A blue baboon. It’s not a baboon but it is blue:

A ground dragon:

Further listening:

The unlocked Patreon bonus episode about vampire finches on the Galapagos Islands

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

In a lot of episodes, we talk about animals from islands like the Galapagos and the Canaries. There’s a reason why islands give rise to strange animals. This week we’ll focus on island life—how island habitats lead to unique animals and how introduced animals can destroy an entire island ecosystem in a matter of a few years. Massive thanks to listener Richard E., who suggested the topics of introduced animals and island life!

Islands, of course, are surrounded by water and isolated from larger landmasses as a result. Some are close to the mainland so it’s easy for animals to swim or float across to the island. In cold areas, animals can sometimes walk across ice to islands. But other islands are more remote, or used to be close to the mainland but were pushed farther away by tectonic forces.

Once a piece of land is cut off from the mainland, the animals and plants on that piece of land start to evolve independently of the larger population of animals and plants on the mainland. If the island is isolated enough that potential predators can’t get to it, the animals already living on the island start to adapt to life with no or few predators. As a result, they may appear tame when humans arrive.

And that is where the problems start. Humans don’t just arrive alone. We bring other animals with us, either on purpose, like dogs, cats, and livestock, or by accident, like rats and mice. And these animals, along with humans, can destroy an entire island habitat really easily.

I’ll use one of Richard’s examples, since it’s a good one and not one you’d think of when thinking of islands. The red squirrel is native to Europe and parts of Asia, but it also lives in the UK and Ireland. It’s usually red-brown in color, although some populations can be brown, gray, or even black. The belly is white. It has long ear tufts and a poofy tail. It lives in trees and eats seeds, nuts, berries, fungi, and occasionally eggs or baby birds.

But remember, Ireland and the UK are islands. And in the 1870s, someone thought it would be really great to import eastern gray squirrels from North America and release them in parks in the UK. In Ireland, in 1911 someone gave a bunch of gray squirrels as a wedding gift, which is not a great gift, honestly, and they got loose because of course they did. They’re squirrels.

Grey squirrels are larger than red squirrels and don’t have ear tufts. They eat the same foods red squirrels do. They also carry a disease called squirrel parapoxvirus that doesn’t bother them but which kills red squirrels. The population of red squirrels has dropped substantially as introduced gray squirrel populations climb in the UK and Ireland. The red squirrel is now protected, with conservation efforts in place that are making a difference. But that just goes to show how easy it is to lose even a well-established species on large islands when an outside species is introduced.

On islands, especially smaller islands, small animals tend to grow larger overall and big animals tend to grow smaller overall. This is called Foster’s rule. It comes about partly because there are fewer predators but limited resources. Small animals don’t need to hide as carefully from predators, large animals may not be able to get enough to eat, but medium-sized animals are able to survive short famines without starving and can take advantage of some resources smaller or larger animals couldn’t use.

One example of island gigantism is the fossa, a predator from Madagascar. If you’ve seen the Madagascar movies, you might remember the fossa as a scary predator that looks something like a big cat. Well, the fossa is a real animal, but it’s not related to cats. It’s related to the mongoose, which is a weasel-like animal, but the fossa is generally much larger than a mongoose. It grows some five feet long, or 1.5 meters, including its tail, although its legs are short compared to those of a similarly-sized cat. It spends a lot of time in trees, where it uses its long tail to help it balance. It’s reddish-brown with a paler belly and eats lemurs and other mammals, birds, insects, crabs, lizards, and even fruit.

An example of island dwarfism is the tamaraw from the island of Mindoro in the Philippines, also called a Mindoro dwarf buffalo. It looks like its close relative, the water buffalo, but is much smaller, only about three and a half feet tall at the shoulder, or 105 cm. It’s like a pocket-sized water buffalo. It has V-shaped horns and is black with some white markings on the legs. It prefers to live in mountainous forested areas with water nearby, and it eats grass, young bamboo shoots, and wild sugarcane. It’s a solitary, shy animal.

Famously, Charles Darwin worked out the theory of evolution after examining the differences in finches living on the various Galapagos Islands. He had actually already started thinking along these lines before he’d really examined the finches, but they supported his ideas and helped him work out the details. Basically, as Darwin eventually determined, a type of finch had colonized the islands at some point in the far distant past. Each island had slightly different ecology, so although the finches could fly, over the years populations living on separate islands began to adapt to better fit the resources available on those islands. For instance, the large ground finch has developed a short, heavy bill to crack nuts, while the closely related vampire ground finch has a thinner, sharper bill that it uses to eat insects, seeds, and the BLOOD OF OTHER BIRDS. I am totally not making this up. In fact, I covered the vampire finch in a patreon bonus episode earlier this year. It’s already unlocked for anyone to listen to, so if you haven’t listened to it and want to, I’ll put a link in the show notes.

Remember that squirrel disease I mentioned earlier? There’s a bird disease called avipoxvirus, or avian pox, that has affected the Galapagos finches since 1898. Researchers think it was probably spread by humans who brought infected domestic birds with them on ships. Fortunately, it hasn’t driven any finches or other birds to extinction.

Another problem brought to the Galapagos Islands by humans, this one spread more recently by tourist boats, is a parasitic nest fly that kills baby birds. Researchers have started leaving cotton balls treated with a mild insecticide where the flies are known to attack endangered finches. The parent finches use the cotton balls to line their nests, which helps protect the babies once they hatch. The nest flies lay their eggs in the nests, and the larvae bite babies and mother birds and drink their blood, which can kill the babies. So far the treatment has helped reduce the number of larvae that hatch.

There’s another bird that lives on the Galapagos that is unique to the islands, and that’s the Galapagos penguin. Thanks to Lucy, who suggested it as a topic, and a shout-out to Lucy’s sister Willa too!

Lucy also wanted to hear about King and Gentoo penguins, so let’s start with them. Both species mostly nest on islands.

The King penguin is almost as big as the Emperor penguin and looks very similar, not surprising since they’re closely related. It stands over three feet tall, or 100 cm. It eats small fish, squid, and krill. Females lay one egg at a time and after the egg hatches, the baby spends its first month or so of life sitting on one parent’s feet while the other parent forages. After that both parents leave the baby in a communal nest, called a crèche, while both go foraging. A young king penguin won’t be able to fish for itself until it’s more than a year old.

The Gentoo penguin lives off the southern tip of South America, and it’s almost as tall as the king penguin, but it’s not closely related to the king and emperor penguins. The Gentoo penguin has a reddish bill and a white stripe on its head above its eyes. The female usually lays two eggs in a nest made of round stones. Gentoo penguins value good nesting stones, and a male may court a female by offering her high-quality stones. Sometimes he has stolen those good stones from other penguin nests. Watch out, ladies. The Gentoo penguin eats krill and other small crustaceans for the bulk of the diet, and also eats fish and squid.

So that gives us a sort of baseline of ordinary penguins to compare to the Galapagos penguin. All other penguins all live in the southern hemisphere, usually not all that far from Antarctica. Part of the Galapagos Islands are in the northern hemisphere, although just barely. Penguins are adapted to severe cold, so how do Galapagos penguins thrive near the equator? As it happens, the waters around the Galapagos are actually quite cold, with various oceanic currents bringing cold water north from the Antarctic and bringing cold water from the depths to the surface in the area. Unlike other penguin species, which often travel widely to find food, the Galapagos penguin stays near the islands where the water is comfortably cool and there’s enough food. On hot days, penguins go into the water to stay cool.

The Galapagos penguin is only about 19 inches tall, or 49 cm. It’s almost the smallest penguin and is definitely the rarest penguin, with only about 1,000 breeding pairs. It mates for life and females lay one or two eggs, making sure to lay eggs in the shade so they won’t get too hot in the sun. If both eggs hatch, the weaker baby usually dies as the parents concentrate on feeding the stronger one. Then again, in good years, grown babies who have moved out of the nest may continue to beg their parents for food and sometimes get fed. I know some people like that. In addition to ordinary predators like seals and hawks, the Galapagos penguin is also vulnerable to introduced predators like cats.

We’ve talked a lot about the Galapagos Islands, but every island has its own unique ecosystem. For example, the island of Socotra lies in the Arabian Sea off the coast of Yemen. It’s only 82 miles long, or 132 km, and 31 miles wide, or 50 km. There are three other, smaller islands nearby. It’s been so isolated for so long that even its trees are bizarre-looking, like the dragon’s blood tree that has dense branches with leaves sticking up at the very top so that it looks like grass growing on top of a weird tree-shaped cliff. The tree also has red sap that has been traditionally used as a dye or varnish.

Humans have lived on the Socotra for 2,000 years, so many endemic species have gone extinct due to habitat loss, hunting, and competition or predation by introduced animals like cats and cattle. But there are still a lot of unusual animals that are found nowhere else in the world. The island has only one native mammal species, a bat, and no amphibians, but it has lots of reptiles and some birds found nowhere else in the world. For instance, the Socotra starling. It’s a large, beautiful songbird with a black body and soft gray head and neck, a heavy black bill, and a black eye with a thin white eye ring. It eats insects and fruit. Socotra is also surrounded by coral reefs with lots of unique fish and crabs.

One interesting animal that lives on Socotra Island is called the blue baboon. But it’s not a baboon or any other kind of primate. It’s not even a mammal. It’s a tarantula, and it’s beautiful! It’s a lovely indigo blue in color with white hairs on the abdomen and the top joints of the legs. Its legspan is about five inches across, or 12 cm, and males are smaller than females. Unlike most other tarantula species, it tolerates others instead of being solitary, so people often keep them as pets. Fortunately, it’s become so popular in captivity that there are lots of captive-bred blue baboons readily available, so the market for illegally collected wild specimens has diminished.

I’ve talked a lot about how animals in island habitats can be driven to extinction very easily, but there are success stories too. For instance, the island of Redonda. It’s a tiny island in the Caribbean, only about a mile long, or 1.6 km, with no source of fresh water and land that’s basically just rock. For centuries no one bothered Redonda because no one wanted to live there, but in the late 19th century it was mined for bird guano, or bird poop, which was used as fertilizer. This went on until 1914, and then in 1929 a hurricane destroyed what was left of the mining equipment. The few people who lived there left, but there were still rats and feral goats that ate everything they could find.

Redonda might have become a wasteland with nothing but rats, goats, and a few birds, but an ambitious conservation effort is paying off. First, the rats and goats were trapped and removed from the island. The rats were mostly killed, but the goats were taken to nearby Antigua where they’ve found homes. Then—and this is important—people left the island alone. Without introduced species and without human interference, the population of endemic animals have begun to rebound. Native plants and trees have started growing back. Rare seabirds nest there again. Instead of a big rock, the island now appears green again.

And the population of lizards on the island is rebounding like crazy. In just a year, the number of ground dragons has almost doubled. Ground dragons are lizards only found on the island. They’re shiny black with long tails and eat pretty much anything they can catch, including young ground dragons.

Sometimes all it takes for nature to be set right is to just leave it alone to do what it does best. Sometimes humans have to help by restoring keystone species to a habitat. This has happened with giant Aldabra tortoises, which were once common on the island of Mauritius, the same island where the dodo once lived. A species of ebony tree had nearly been driven extinct by logging, but even after logging was stopped in the 1980s, the trees hadn’t rebounded. Researchers determined that giant tortoises had once eaten the ebony tree fruit and pooped out the seeds, much like the dodo and the rare dodo tree palm. When giant tortoises were reintroduced to Mauritius, new ebony trees started to sprout.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 093: Insects Large and Small, mostly large

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Many thanks this week to listeners Bob, Nicholas, and Damian, who all suggested insects of one kind or another! So this week is an insect extravaganza, or at least we learn about some gigantic insects, the rarest insect in the world, and a tiny ant.

The Lord Howe Island phasmid:

The longest insect in the world:

The Queen Alexandra’s birdwing butterfly:

The Hercules beetle with random frog. Onward, my steed!

Further reading:

An article about phasmid eggs

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

I’ve received a bunch of excellent topic suggestions this year and I’m getting behind on addressing them, so the next few weeks will mostly be listener suggestions. This week we’re going to look at a topic several listeners have suggested…insects.

Now, you know insects are not my favorite, but they are definitely interesting. So thanks to listeners Bob, Nicholas, and Damian, we’re going to learn about various horrifying, I mean fascinating, insects!

We’ll start with some very small insects. I could probably do a whole episode just about ants, and maybe one day I will, but right now let’s look at a type of ant suggested by Bob. Bob lives in California and mentioned that the type of ant common in that part of the United States is the Argentine ant. It’s native to South America, specifically lowlands around the Paraná River, but it’s spread to many other parts of the world.

The Argentine ant is only about 2 to 3 mm long and are brownish in color. The queen ants are about twice the size of the worker ants, and each colony has many queens, unlike other ant species that may only have one queen per colony. Queen ants are the only ones that lay eggs. Worker ants find food and bring it back to the colony, tend the queen and her eggs, and dig the shallow nest where the colony lives.

Argentine ants are omnivorous, eating pretty much anything, and are definitely pests. They get into people’s kitchens to find food and will even make nests inside houses. Because a colony has more than one queen, the colonies are hard to eradicate. They also displace native ant species, which can impact the entire ecosystem since other animals that depend on native ants as their primary food won’t be able to find enough to eat. Argentine ants also cause problems for farmers, partly because they eat the larvae of pollinating insects, partly because they tend aphids for the honeydew that aphids secrete. Aphids are a pest to many crops, and the last thing farmers want is more aphids around—but Argentine ants want all the aphids they can get.

Researchers have found out something really unusual about Argentine ants. The ants that still live in their native habitat are genetically diverse and territorial, with different colonies fighting each other for nesting sites and hunting grounds. This keeps the population under control naturally. But outside of its native habitat, all the Argentine ants in the world are so genetically similar that in many cases, ants from different colonies act as though they were from the same colony. They don’t fight for territory, and instead act like a supercolony that can stretch for hundreds of miles, killing off or displacing native ants and other insect species.

But in some parts of North America, the Argentine ant is facing an ant species that may end up beating it at its own game. The Asian needle ant has started taking territory from the Argentine ant, helped by its resistance to cold weather. Both species of ant become less active in winter, but the Asian needle ant starts reproducing and foraging much earlier in the spring than the Argentine ant. This gives it a head start every year. Plus, the Asian needle ant is aggressive and has a venomous sting. Unfortunately, the Asian needle ant is just as bad an invasive species as the Argentine ant, driving out native ant species—and, in fact, it’s worse because some people are allergic to its sting.

Now let’s go from tiny ants to an insect I was terrified of as a kid, the stick insect, also called walking sticks or phasmids. I like the word phasmid. I don’t know why the idea of a stick insect was so scary to kid me, except that I liked to climb trees and I think I thought one day I’d climb a tree and discover that some of those sticks were not actually part of the tree. Nicholas suggests the Lord Howe Island phasmid in particular, which isn’t just a stick insect, it’s the rarest insect in the world. AND it’s enormous! In fact, it’s sometimes called the land lobster or tree lobster.

The Lord Howe Island phasmid can grow eight inches long, or 20 cm, and can weigh a full ounce, or 25 grams. Males are smaller than females. It has a round head with short antennae, sort of like a cricket, but its body is long and heavy with big legs. It’s black in color with no wings. It’s thicker than most stick insects and doesn’t so much resemble a stick as a cricket on steroids. I’m looking at a picture right now of someone holding one on the palm of their hand, and the insect is literally longer than their palm and almost as long as their palm and fingers. Put it down. Don’t touch it.

These days the Lord Howe Island phasmid lives in one place. That place is not Lord Howe Island off the coast of Australia. That’s where it used to live, and it was so common and so large that fishermen used it as bait. But rats and mice invaded the island in 1918, and by 1920 they’d eaten all the phasmids, which were declared extinct in 1960. But in 1964, someone found a dead phasmid on Ball’s Pyramid, a volcanic islet 12 miles, or 20 km, away from Lord Howe Island.

Ball’s Pyramid is what’s known as a volcanic stack, the eroded remnant of a volcano which is part of the submerged continent of Zealandia. It’s basically a cliff rising straight up out of the ocean. It’s the tallest volcanic stack in the world, 1,844 feet high, or 562 meters, 3,600 feet long, or 1,100 meters, and 980 feet wide, or 300 meters. It’s surrounded by rough seas and barely submerged rocks, and there’s pretty much nothing on it, so not very many people have ever tried to land on the islet. A group of mountain climbers scaled it in 1965 and again in 1979, but in 1982 access to the islet was restricted. It’s now part of the Lord Howe Island Marine Park.

During the successful climbs of Ball’s Pyramid, and a few unsuccessful climbs, dead phasmids were photographed but no live ones found. In 2001, a couple of entomologists landed to make a survey of the islet, primarily to determine whether the Lord Howe Island phasmid was alive on the island or actually extinct. They were pretty sure it was extinct. They found some Melaleuca howeana shrubs growing in a few cracks in the rock, and incidentally that’s a subspecies of tea tree that only grows on Ball’s Pyramid and Lord Howe Island. It grows up to ten feet tall, or 4 meters, and almost as wide. And in one of the shrubs they found 24 live Lord Howe Island phasmids.

Since then, eggs have been collected from the wild and relocated to a captive breeding program, which has been successful so far. Hopefully Lord Howe Island phasmids will be rereleased onto Lord Howe Island, once the rats and mice are eradicated.

Researchers think the Lord Howe Island phasmid was able to survive in such low numbers because females are able to reproduce without being fertilized by males, called parthenogenesis. Researchers have compared DNA taken from the Ball’s Pyramid insects to museum specimens gathered from Lord Howe Island prior to 1920 and determined that they are the same species.

The term phasmid, of course, refers to an order of insects that are mostly camouflaged to look like twigs or leaves, and it contains the longest insects in the world. And that’s good, because listener Damian wants to know about the biggest insects alive today.

The longest insect is Phryganistria chinensis Zhao, a stick insect only discovered in 2014 by researcher Zhao Li of the Insect Museum of West China. Locals in the mountains had told him about a massively long phasmid and he finally tracked one down. He brought it back alive to the museum, where it laid six eggs. Can you possibly imagine how excited he must have been by those eggs? When they hatched, the smallest of the babies was 26 centimeters long, or over ten inches. The adult female measured 62.4 cm, or just over two feet long. HOLY CRAP. TWO FEET LONG. That’s more of a walking branch than a walking stick. Not only that, its legs are almost as long as its body.

Since then, the babies have grown up and one of them, another female, is now the longest living insect ever measured, at 64 cm, or 25 inches. So you know what this means. It means there are some of them in the wild that are probably even longer.

Before the discovery of Zhao’s phasmid, the longest insect known was called Chan’s megastick, which was 22.3 inches long, or 56.7 cm. It was discovered in 2008 in Borneo in Southeast Asia, and only six specimens have ever been found. That means it too probably has even longer individuals living in the wild.

Many stick insects lay eggs that look like seeds. For a long time researchers weren’t sure why. After all, birds eat seeds. Why would an insect lay eggs that might attract hungry birds? But it turns out that the eggs contain a deposit of fat that attracts seed-eating ants, and the ants carry the eggs back to their nest and bury them. The eggs are then safe from birds, parasitic wasps, and other predators. We have come full circle back to ants, notice? Not only that, but researchers in Japan tested whether the protective coating on some seed-mimicking phasmid eggs would protect the eggs if they were eaten by birds. Sure enough, when they fed the eggs to the brown-eared bulbul, a bird known to eat phasmids, a few of the eggs survived and hatched. So it’s likely that phasmid eggs resemble seeds to attract ants but it’s okay if they also attract birds—in fact, it might even be a good thing since the birds would spread the eggs to new areas. Special thanks to Nicholas, who sent me links to several articles about stick insects, including the article about phasmid eggs. I’ll put a link in the show notes if you want to read the article, because it’s really interesting.

So the longest insects are phasmids, but what is the heaviest insect alive? That would be the Little Barrier Island giant weta from New Zealand, also called the wetapunga, which has weighed in at 72 grams, or over 2 ½ ounces. That’s heavier than some songbirds and mice. The wetapunga is basically an enormous cricket and somewhat resembles a gigantic, rather elongated version of one of my least favorite bugs, the cave cricket. It’s that same sort of sickly orangey tan color. If you look at it from the right angle it looks kind of like a lobster, which I also don’t like. Not only can the wetapunga be really heavy, it’s also long—not stick insect long, but a respectable four inches or so long, or 10 cm, and even longer if you count the stretched-out legs.

It eats plants and is mostly nocturnal.

Like the Lord Howe Island phasmid, the wetapunga is vulnerable to introduced predators. It only survives in the wild on Little Barrier Island, and is now the subject of a successful captive breeding program. It’s been around for 190 million years so it would be a shame to let it go extinct now.

The insect with the biggest wingspan is a butterfly called Queen Alexandra’s birdwing, which can have a wingspan almost a foot across, or over 25 cm. Its body is just over 3 inches long, or 8 cm. The female is larger than the male and has brown wings with pretty white and yellow markings. The male looks much different, with iridescent blue-green wings and a bright yellow abdomen. The butterfly is a strong flyer that spends a lot of time flying much higher that typical butterflies do. Males court females with a spectacular aerial dance.

The Queen Alexandra’s birdwing lives in eastern Papua New Guinea in a coastal rainforest, a habitat that is only about 40 square miles total, or 100 square km. Not only is it threatened by habitat loss due to palm oil plantations, which are absolutely insidious and seriously, you should stop buying products that use palm oil, but a volcanic eruption in the 1950s destroyed part of its habitat too. It’s protected and no one is supposed to buy, sell, or trade individuals, live or dead. Hopefully conservationists can work out a way to breed the butterfly in captivity.

The biggest beetle alive today is probably the Hercules beetle, which lives in the rainforests of Central and South America. It’s only longer than the titan beetle that lives in the Amazon rainforest because of its long rhinoceros-like horns, which push its length to 7 inches, or 17 cm. A male uses his horns to fight by grabbing another male with his horns and throwing him. The male Hercules beetle is black with yellowish or yellow-green wing cases. Females are usually all black and don’t have horns. Hercules beetle larvae are humongous and weigh a whopping 100 grams, or 3.5 ounces. So technically the Hercules beetle larva is the heaviest insect, but I’ve disqualified it because it’s not fully grown and anyway, it eats rotting wood. I wouldn’t be surprised if half its weight is just all the rotten wood it’s eaten. The adult beetles eat fruit.

So what about extinct insects? Were there ever insects even bigger than the ones alive today? The answer, as you may already know, is a big loud YES. Back in the early Permian era, around 290 million years ago, two species of flying insect called a griffinfly, which resembled a dragonfly, had a wingspan of almost two feet across, or 71 cm, and a body length of 17 inches, or 43 cm. Researchers estimate they may have weighed as much as a pound, or 450 grams.

If you were brave enough to listen to the spiders episode a few weeks ago, you may remember that spiders, and insects, can’t grow too big or they literally can’t get enough oxygen to function. So how did a huge active flying insect of that size manage?

One theory is that the atmosphere in the Permian contained more oxygen than the current level, which made it easier for insects to get the oxygen they needed. Air today is made of about 21% oxygen, with the other 80% made up of other gases, mostly nitrogen, but in the early Permian oxygen content was around 30%, although that was down from a peak of 35% only ten million years before. By the late Permian oxygen content had plunged to 16% and even reached as low as 12% at the beginning of the Triassic, killing off many animals and fragmenting populations of the ones that survived. Because the oxygen content was so low, animals could only survive at or near sea level. Even the lowest mountains were deadly because the air at higher elevations naturally contains less oxygen. Researchers estimate that breathing air with only 12% oxygen at sea level would be like breathing air at 17,400 feet, or 5,300 meters. Humans can’t survive at elevations above about 19,500 feet, or 5,950 meters. The reduction of oxygen in the atmosphere led to a massive extinction event called the Great Dying, where 90% of all marine life and almost 75% of all life on land went extinct around 251 million years ago.

Researchers aren’t sure what caused the de-oxygenation of the atmosphere, but it’s possible the massive volcanic activity near the end of the Permian played a part by releasing carbon dioxide and other gases into the atmosphere. The rock record during the Permian shows the results in stark detail: limestone in the older rock strata that’s full of fossils and the fossilized burrows of little animals that lived in the soft mud at the bottom of shallow oceans. Then there’s a mineralized layer of rock full of pyrite, which forms in low atmospheric conditions. Above this are bands of clay full of minerals from volcanic eruptions but with no fossils present. Above that are mudstone layers where fossils finally start appearing again in small numbers as life rebounded after the extinction event.

I’ve sort of gotten away from huge insects here, so I’ll finish by pointing out that clearly the phasmids of today aren’t having any issues with growing really big. So, you know, watch out where you put your hands when you’re climbing trees.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 090: Spiders! NO COME BACK, IT’S SAFE TO LISTEN

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As we get closer and closer to Halloween, the monsters get scarier and scarier! Okay, spiders are not technically monsters, but some people think they are. Don’t worry, I keep descriptions to a minimum so arachnophobes should be okay! This week we learn about some spider friends and some spider mysteries.

I stole the above cartoon from here. I am sorry, Science World.

A cape made from golden silk orbweaver silk:

Further reading and listening:

Blue spiders

Varmints! Podcast scorpions episode

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

It’s almost Halloween! I’m on the third bag of gummi spiders, although they’ve changed the flavor from last year so I only eat the orange and yellow ones. The purple and green ones are in the bucket to give out to unsuspecting children.

Speaking of spiders…yes, I’m going there. I realize a lot of people are scared of spiders, but they’re beautiful, fascinating animals that are associated with Halloween. Don’t worry, I will try hard not to say anything that will set off anyone’s arachnophobia. Besides, there are some mysterious spiders out there that I think you’ll find really interesting.

First off, you don’t have to worry about gigantic spiders like in the movies. Spiders have an exoskeleton like other arthropods, and if a spider got too big, some researchers think its exoskeleton would weigh so much the spider wouldn’t be able to move. Not only that, spiders have a respiratory system that isn’t nearly as efficient as that of most vertebrates, so giant spiders couldn’t exist because they wouldn’t be able to get enough oxygen to function.

Specifically, some spiders have a tracheal system of breathing, like most insects and other arthropods also have. These are breathing tubes that allow air to pass through the exoskeleton and into the body, but it’s a passive process and spiders don’t actually breathe in and out. Other spiders have what are called book lungs. The book lung is made up of a stack of soft plates sort of like the pages of a book. Oxygen passes through the plates and is absorbed into the blood, which by the way is pale blue. This is also a passive process.

In other words, that picture that’s forever popping up on facebook of the enormous spider on the side of someone’s house, it’s photoshopped. In fact, pretty much any photo you see of a gigantic spider or insect or other arthropod is either photoshopped or made to look bigger by forced perspective. Also, spiders with wings are photoshopped, because no spider has ever had wings, even fossil spiders all the way back to the dawn of spider history, over 300 million years ago. So that’s one less thing to worry about.

Spiders live all over the world, everywhere except in the ocean and in Antarctica. The smallest spider known is .37 mm, so basically microscopic. It lives in Colombia and basically lives out its whole life not knowing most things about the world, like what whales are and how to operate a smart phone. On the other hand, the largest spider in the world is a tarantula called the goliath birdeater, and it probably also doesn’t know what whales are and how to use a smartphone. The goliath birdeater is the heaviest spider at a bit over 6 ounces, or 175 g, and has a legspan of 11inches, or 28 cm. Despite its name, it mostly eats insects but it will occasionally eat frogs, small rodents, small snakes, and worms. It lives in swampy areas in the rainforests of northeastern South America.

The spider with the biggest legspan—yes, I know, some of you are freaking out but I can’t do an episode about spiders and not talk about the biggest spiders. The spider with the biggest legspan is the giant huntsman, which lives around cave entrances in Laos, a country in southeast Asia. And it’s not much bigger than the goliath birdeater, with a legspan of one foot, or 30 cm.

All spiders produce silk but not all of them make webs. I won’t go into the process of how a spider generates silk, because it’s complicated and I just read about it and have already forgotten all the details, but spiders use silk to wrap up their eggs safely, line the walls of burrows to make a comfortable home, wrap up prey so it can’t escape, and of course make webs and get around without falling off tall things.

Most spider silk appears white, but the golden silk orb-weaver produces golden silk. The spider itself is gorgeous, with striped legs and a body that can be yellow, red, greenish, or brown, often with white spots and delicate patterns. It lives all over the world in warm climates, especially Australia. It builds webs that can be several feet across, or over a meter, and it occasionally catches and eats small birds as well as insects. One was even spotted eating a small snake that had been caught in its web. Its silk has occasionally been used to make cloth, but spider silk is difficult to collect in the quantities needed for textiles.

Most spiders eat insects, although one spider eats plants. Just one. It lives in Central America. Some baby spiders eat nectar until they get big enough to catch prey. Some spiders will scavenge on dead insects, some will eat fruit as well as insects, many eat pollen that gets caught on their webs, and some eat each other. Some spiders are adapted to swim in freshwater, and while they mostly eat aquatic insects, they will catch and eat small fish. Some spiders also catch and eat small birds and bats.

Basically, there are too many spiders to cover everything about them in one episode. Besides, what we all really want to know about are the mystery spiders. Because it’s almost Halloween!

Our first mystery spider is from Africa, specifically the jungles of central Africa. In 1938, an English couple, Reginald and Margurite Lloyd, were driving through the jungle when what looked like a monkey or cat stepped onto the dirt road. They stopped the car so it could cross the road, at which point they saw it was a spider. It looked like a tarantula but was huge, with a legspan of up to three feet, or almost a meter. Before Reginald Lloyd could grab his camera, the spider disappeared into the undergrowth.

Supposedly, the same giant spider was reported in the 1890s by a British missionary named Arthur John Simes. Some of his men got tangled in a huge web and a pair of spiders came out and attacked them. The larger of the spiders, presumably the female, was four feet across, or 1.2 meters. Simes was bitten but shot one of the spiders and was able to escape. He ultimately died of the bite.

This seems less than believable, to put it gently. The largest spider that catches prey with a web is our friend the golden silk orbweaver, but its legspan is only five inches across, or 12 cm. The biggest spiders in the world are tarantulas and other spiders that hunt actively, none of which build webs.

A more believable giant-spider mystery is called the up-island spider, which is supposed to be an extra-large variety of wolf spider from parts of Maine in the United States. Its legspan is supposed to be as much as 8 inches across, or 20 cm. Wolf spiders are common throughout the world, and while they look scary, they bite people very rarely and their venom is weak, no worse than a bee sting. The wolf spider with the biggest legspan is Hogna ingens, with a legspan less than 5 inches, or 12 cm. Hogna ingens lives on one island in the Maderia archipelago, and is a beautiful soft grey with white stripes on the legs. It’s critically endangered, but Bristol Zoo in England has a successful captive breeding program underway so it won’t go extinct. The species of wolf spider most commonly found in Maine is probably Tigrosa helluo, but it’s not very big, only a couple of inches across at most, or maybe five cm. It’s likely that the up-island spider is actually the Carolina wolf spider, which can have a legspan of four inches, or 10 cm, but I can tell you from personal experience that they look a whole lot bigger if you see one in your garage or basement when you flip on the light. The Carolina wolf spider does live in Maine, but it’s not very common in the area.

Zoologist Karl Shuker has a blog post from 2010, with some later updates, about spiders that are normal sized except for being blue, in species that aren’t normally blue. It’s an interesting post and I’ll link to it in the show notes if you want to read it and look at the pictures he posts. He discusses a number of blue spiders readers have reported to him, and while one seems to have been spraypainted blue, the rest appear naturally colored blue.

As it happens, there are lots of reports of blue spiders out there—and other blue invertebrates like woodlice. According Shuker’s post, some of these have been studied and found to be suffering from a virus called invertebrate iridovirus, or IIV. This infects invertebrates and sometimes is so highly concentrated in the animal’s tissues that it forms crystalline aggregations that emit blue iridescence and make the animal look blue. I should stress that you can’t catch IIV if you are a mammal, bird, reptile, fish, or anything else with a backbone, which I am assuming is most of my listeners.

The ancestors of spiders evolved around 380 million years ago, although those animals probably couldn’t generate silk. They did have eight legs, though. True spiders date to around 300 million years ago. Those spiders had silk spinnerets in the middle of the abdomen instead of at the end, and modern spiders appeared around 250 million years ago. We have fossil spiders and we also have spiders preserved in amber, the resin of certain trees that later fossilizes but remains at least partly transparent. We even have a spider web preserved in amber and dated to 110 million years ago, along with several insects that had been trapped in the web.

Spiders are closely related to whip scorpions, also called whip spiders because they look superficially similar to spiders in some ways except that they are HORRIFYING and I cannot look at pictures of them right now, I just can’t. While whip scorpions have eight legs, they only walk on six of them. The front pair are more like feelers and are elongated. Other whip scorpions have long, thin tails and are sometimes called vinegaroons, because if they’re disturbed they squirt a liquid that smells like vinegar. Some whip scorpions look a lot like scorpions. I don’t want to talk about scorpions. In fact, I’m just going to stop talking entirely, because while spiders don’t bother me, scorpions do and I cannot look at these pictures anymore, okay? If you want to learn about scorpions, Varmints! Podcast just released a scorpions episode. I’ll put a link in the show notes. Eventually I’ll manage to listen to it myself.

Happy Halloween?

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 082: Animals with Face Tentacles

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This week we’re going to learn about animals with TENTACLES ON THEIR FACES oh my gosh

Thanks to Llewelly for the topic suggestion!

Don’t forget to come see me on the panel How to Start Your Own Indie Podcast at DragonCon 2018, at 4pm on Sunday, September 2, 2018 in the Hilton Galleria 6.

A tentacled snake:

A star-nosed mole. Hello, nose star!

A caecilian, with its tiny tentacle circled:

A squidworm:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

I’m back from Paris this week and definitely jet-lagged, but this episode should wake everyone up. It’s about animals with TENTACLES ON THEIR FACES

A big thanks to Llewelly who sent me an article about the tentacled snake, which turned into this episode. I love it when people send me links to articles or suggestions for topics. I have a bunch of suggestions I haven’t gotten to yet, but I promise I will as soon as possible. I’m like a dog in a park full of squirrels. There are so many exciting animals to chase, it’s hard to know which one to follow.

That reminds me. If you go to the strangeanimalspodcast.com website, there’s a page with a list of animals that I’ve covered in various episodes. If you don’t see your favorite animal on that list, feel free to email me with your suggestion!

Also, if you’re listening to this episode the week it comes out, this coming weekend I’ll be at DragonCon in Atlanta. If you’re going to be there too, I’m on a panel about how to start your own podcast, part of the podcasting track. It’ll be at 4pm on Sunday in the Hilton Galleria 6.

Now, on to the tentacles.

We’ll start with the tentacled snake, which lives in parts of southeast Asia. It lives in both fresh and ocean water and doesn’t come on land very often. When it does, it has trouble getting around since it’s adapted for swimming. It grows up to three feet long, or about 90 cm, and is brown or gray, sometimes with stripes, sometimes with blotches. Its body and head are flattened and its scales are rough. Basically it looks a lot like an old stick with lichen on it. If something disturbs it, it holds its body completely rigid even if it’s lifted out of the water, which makes it look even more like a stick.

Its nose is squared-off with nostrils at the top so it can more easily grab breaths at the water’s surface. And it has a pair of short tentacles at the corners of its snout that it uses to help it sense the fish and frogs it eats. It has weak venom, but its fangs are in the back of its mouth and not dangerous to humans.

It likes slow-moving water, murky water, or water with a lot of vegetation in it because it doesn’t rely on its eyes to sense fish, although it has good eyesight. The tentacles are finely attuned to movement in the water and the snake can sense when a fish is approaching even if it can’t see the fish.

The tentacled snake is an ambush predator. It uses its tail to anchor itself in the water, and holds its body in a J shape, either head down or head up. When a fish swims nearby, the snake moves the looped section of its body extremely quickly without moving its head, which creates a pressure wave in the water that makes the fish think there’s a predator approaching. The fish doubles back and tries to flee, but in the wrong direction—basically right into the snake’s face.

Another animal with tentacles on its face is the star-nosed mole. It’s a mammal that lives in parts of northeastern North America, especially in marshy areas. Like other moles, it’s not very big, only about six inches long, or 15 cm. Its fur is dense and velvety, it has tiny eyes and ears that are mostly hidden under its fur, and its tail is short. It spends a lot of time in the water but it also digs shallow tunnels. It eats worms, insects, mollusks, and small animals of various kinds, including frogs.

The star-nosed mole has eyes, but they’re tiny and don’t function very well. Instead, it senses prey and navigates using the unique structure at the tip of its snout: 22 tiny tentacles containing over 25,000 sensory receptors. The structure is roughly star-shaped so is usually called a nose star. It actually is more starfish-shaped, if you ask me, like it has a tiny pink starfish growing out of the tip of its nose, with two little nostrils in the middle.

Mammals are not known for their tentacles. The star-nosed mole is the only mammal with tentacles, in fact—at least as far as I can find out. And the star-nosed mole has tons of weird adaptations as a result. The tentacles of its nose star are the most sensitive organ of touch in any mammal. Think about how sensitive your fingertips are and how much information you can learn from just touching something with a fingertip. The star-nosed mole’s star has five times the number of nerve fibers than your entire hand contains, and the star is smaller than your pinky fingernail. It’s so sensitive and the mole can gain so much information from it that researchers compare it more to a sense of sight than of touch. The mole’s nervous system is also extremely efficient in order to process all the information coming from the star, literally just about at the physiological limit of neurons. That means the star-nosed mole can identify prey and decide whether to eat it in only 8 milliseconds.

You know how long it takes you to blink your eyes? About 350 milliseconds. A star-nosed mole could have examined and made eating decisions about 44 things in that same time. And since it can also eat most small prey like bugs in only 200 milliseconds, it could have also eaten one and a half things in the time you blink your eyes. This is blowing my mind, everyone, especially since I am the slowest eater in the world.

You know what else the star-nosed mole can do? It can smell underwater. It blows tiny bubbles into the water and breathes them back in to examine them for scents. The tentacles of the mole’s star keep the bubbles from floating away before the mole can breathe them back in. The star-nosed mole is a good swimmer and the tunnels it digs often start and end underwater. Researchers think that hunting underwater and in swampy soil helps keep the mole’s sensitive nose star from damage. If you rub your fingertips lightly over sandpaper or a brick’s surface, after only a few seconds you’ll feel some discomfort, but soft mud doesn’t hurt fingertips or nose stars.

Another animal with face tentacles is the caecilian. Caecilians are legless amphibians that look like worms or snakes, but are more closely related to frogs and salamanders. Probably. We don’t know a lot about how caecilians developed, and some researchers think they may actually be more closely related to reptiles than amphibians.

The longest caecilian, Thompson’s caecilian, grows to some five feet long, or 1.5 meters. It lives in Colombia in South America and is gray or black. The smallest species only grow to about four inches long, or 10 cm. There are some 180 species of caecilian that we know of, which live in tropical regions in many parts of the world. Many dig burrows and spend most of their time underground, while some live in the water. Most eat small animals like worms and insects. Even though all caecilians are long, unlike worms and snakes, most don’t actually have a tail, or may only have a short tail. It’s just hard to tell because they also don’t have legs. Some species appear snakey while some have what look like body segments like an earthworm, which helps it wriggle its way through soil like a worm. It even moves in what’s called an accordion-type fashion like a worm where it bunches up parts of its body and stretches other parts out to advance.

The caecilian has a pair of tiny tentacles between its eyes and nostrils that grow out of an opening in the snout. The tentacles appear to have developed from the tear duct and eye muscles. Some caecilian species have tiny eyes, although they may be hard to see. Some species have no eyes at all. Some species have eyes, but they’re actually beneath the skull bones. In two species from Africa, the eyes are under the skull but are connected to the tentacles, and the caecilian can extend its tentacles and actually move its eyes out of the skull and into the tentacle. The tentacle tips lack pigment so light can pass through. You see what’s going on here? EYE STALKS. Eye stalks aside, researchers think that the tentacles mostly contain chemical receptors that the caecilian uses to find prey.

Caecilians are really interesting animals. Different species are sometimes radically different from each other in very basic ways. For instance, how babies develop. Some caecilian species lay eggs that hatch into larvae, like tadpoles. Some lay eggs that hatch into miniature caecilians, like certain species of frog whose eggs hatch into tiny frogs instead of tadpoles. Three caecilian species give birth to up to four live babies that are already developed, and those babies grow within the mother by eating a special oviduct lining of her body, which they scrape off with teeth modified for this purpose. Two egg-laying species have a similar process for feeding babies, but in this case the mother caecilian develops a thickened skin that’s full of nutrients, which her babies scrape off with modified teeth. It doesn’t hurt the mother, who grows more of the skin as the babies eat it.

One species of caecilian doesn’t even have lungs, Atretochoana eiselti. Some salamanders don’t have lungs either, and instead absorb oxygen through the skin. But salamanders that breathe this way are either very small or live in cold, fast-flowing water with high oxygen content. Atretochoana grows nearly three feet long, or 80 cm, but seems to prefer warmer, slower water. So researchers aren’t sure how it breathes. Not a lot is known about it in general, but it does have muscles that attach to the skull that aren’t found in any other organism studied. Its head is broad and flat. We don’t even know what it eats.

The caecilian has two sets of jaw muscles, if you were wondering. Researchers aren’t sure why, but they suspect it has something to do with keeping the head and neck rigid while the caecilian pushes its way through the soil. Some caecilians are toxic, and since many species are brightly colored, it’s a good bet that those species probably contain at least some toxins. But again, we don’t know for sure because there haven’t been very many studies on caecilians.

There are other animals with tentacles on their faces, but those are the big three that are alive today. Catfish whiskers, properly called barbels, aren’t technically tentacles, and I have a whole episode on catfish planned eventually so I’ll skip them this time. Snails and slugs have four head appendages that are tentacle-like, two of them eyestalks and the other pair for smell and touch. Back in the Cambrian, the eel-like Pikaia gracilens had a pair of long tentacles on its head and rows of shorter bristles along the sides of its head that may have acted as gills. Some species of modern lancelet look very similar to Pikaia and even have similar sensory appendages, but these are more similar to cilia than actual tentacles.

But another living animal, a deep-sea polychaete worm called the squidworm, has actual tentacles on its head—ten of them. It grows around 4 inches long, or 10 cm, not counting its tentacles, which are as long or longer than the body. It lives in the depths up to 2800 meters down, or almost 1.75 miles below the ocean’s surface. Two of its tentacles are yellowish and usually held in a curled-up position, and those are the ones the worm uses to collect food—probably plankton and detritus that sinks from the upper ocean. The other tentacles are used for breathing, and it also has feathery sensory organs growing from its head.

But the awesome thing is, the squidworm was only discovered in 2007 off the coast of the Philippines. And it’s not rare. In fact, it seems to be really common, which means there are probably other species of squidworm that haven’t been discovered yet. And there might be other tentacled things down there too, who knows?

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 081: Little Yard Animals

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This week we’re staying at home and looking around our own yards and gardens to learn about some of the little critters we see every day but maybe never pay attention to. Thanks to Richard E. for the topic suggestion, and thanks also to John V. and Richard J. for other animal suggestions I used in the episode!

The common or garden snail:

A couple of robins:

A brown-eared bulbul nomming petals:

An Eastern hognose snake. srsly, no one believes ur dead snek:

The hognose in happier times:

An Australian water dragon. Stripey!!

The edible dormouse. I think you mean the ADORABLE dormouse:

The eastern chipmunk:

A guppy with normal eyes:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

I’m out of the country this week, visiting Paris, France and undoubtedly eating my weight in pastries and cheese as you listen to this. Since I’m away from home, though, I’m probably feeling a little homesick. So this week’s episode is all about the ordinary-seeming little animals found in gardens and yards, a suggestion from Richard E. This is also a perfect opportunity to feature some listener-suggested animals that aren’t really complex enough for a full episode but are still really interesting.

But I’m not going to just look at the animals in my yard. Depending on where you live, hopefully I’ll touch on one or two animals you might be able to see for yourself just by going outside and looking around.

It sounds corny, but no matter how boring you think the nearest patch of greenery is, if you look closely enough you’ll see a world of activity. The other day I was sitting on a bench outside the library, enjoying a breeze and the shade of an oak tree, and because I am sort of disgusting and was wearing flip-flops, I was picking at one of my toenails that was partly broken. I pulled the broken part off and flipped it into the grass nearby. A few minutes later I noticed that a couple of ants had found that piece of toenail and were working hard to wrestle it over the grass and twigs and presumably back to their home. Why? Why did they want my toenail? It’s just a piece of keratin, and while keratin is a type of protein, it’s not digestible by most animals.

I looked it up, and guess what. I am not the first person to notice this. No one’s sure why ants take toenail and fingernail clippings, either. They’re not interested in hair, just nails. Hair and nails have different properties so it’s possible the ants are able to digest the keratin in nails but not the keratin in hair.

That was probably not the best story to start with. Try to forget that picture of me and remember that I’m sipping wine at a sidewalk café in Paris right now, or touring the Louvre.

Let’s move on to a small invertebrate that is sometimes eaten as a delicacy in France and other parts of Europe, the common or garden snail. That’s Cornu aspersum, which is native to the Mediterranean and western Europe, but which has been introduced in other parts of the world. It’s pretty big for a snail, with a shell almost 2 inches across, or 5 cm. The shell varies in color and pattern, but it’s usually brown with yellow markings.

The shells almost always coil to the right, or clockwise, but the occasional rare snail will have a left-coiling shell. Researchers have found that left-coiling shells are due to a genetic mutation and only occur about once in a million snails. A famous lefty snail was called Jeremy, who died in October 2017 at the ripe old age of two years. Since snails are hermaphrodites who both fertilize other snails’ eggs and lay their own, a boy name seems like a random choice. Jeremy was discovered by a retired scientist in his London garden, who gave the snail to the University of Nottingham for study. After a public appeal, two other left-handed snails were found by the public, but while the three snails all laid eggs, all the babies had clockwise shells.

The garden snail mostly eats plants, but will sometimes scavenge on small dead animals like drowned worms and squished slugs. When it’s threatened, it can pull itself all the way into its shell, and if it’s too dry out, it will pull itself into its shell and secrete a thin layer of mucus, which dries out to form a seal.

Snails raised to be eaten are kept in special cages, traditionally made from wine-grape vines. I am probably not going to eat any snails while I’m in France, but you never know. I will let you know if I do.

One animal Richard E. suggested as a topic is the robin, specifically the difference between the American robin and European robin. That’s a good one for this episode, because in both North America and Britain, the robin is a really common bird—so common that most people barely pay any attention to it.

The American robin is a type of thrush. It lives year-round in most of the United States and part of Mexico, spends summers in much of Canada, and winters in parts of Mexico. It’s big for a songbird, around 10 inches long, or 25 cm. It’s dark gray on its back, with a rusty red breast, white undertail coverts, and a long yellow bill. It also has white markings around its eyes. Young birds are speckled. It mostly eats insects, worms, and berries. If you see a bird on the ground, running quickly and then stopping, it’s probably a robin. Mostly the robin hunts bugs by sight, but it has good hearing and can actually hear worms moving around underground. You can sometimes see a robin with its head cocked, listening for a worm, before pouncing and pulling it out of the ground, just like in a cartoon.

American robin eggs are a light teal blue, so common and well-known that robin’s-egg-blue is a typical description of that particular color. In the spring after eggs hatch, the mother robin will carry the eggshells away from the nest to drop them, so predators won’t see the shells and know there’s a nest nearby. That’s why you’ll sometimes see half a robin eggshell on the sidewalk. It doesn’t mean something bad happened to the baby, just that the mother bird is doing her job. Both parents feed the chicks, and the parents also carry off the babies’ droppings to scatter them away from the nest.

This is what an American robin’s song sounds like. If you live in North America, you’ve probably heard this song a million times without noticing it.

[robin song]

The American robin was named after the European robin, also called the robin redbreast, but while the European robin does have a rusty red breast, it doesn’t look much like the American robin. The European robin is much smaller, only around 5 inches long, or 13 cm, with a brown back, streaked gray or buff belly, and orange face and breast. It has a short black bill and round black eyes. It eats insects, worms, berries, and seeds. The eggs are pale brown with reddish speckles.

It lives throughout much of Eurasia, but robins in Britain tend to be fairly tame, probably because they were traditionally considered beneficial in Britain and Ireland, so farmers and gardeners wouldn’t hurt them. In other parts of Europe they were hunted and are much more shy. European robins are also common on Christmas cards in Britain and Ireland, possibly because in the olden days, postmen used to wear red jackets. They started to be called robins as a result, and since postmen bring Christmas cards, the bird robin became linked with card delivery and finally just ended up on Christmas cards. Plus, their orange markings are cheerful in winter. And, of course, in the traditional story Babes in the Wood, which is often associated with Christmas pantomimes, robins cover the children’s dead bodies with leaves. Because nothing says Christmas spirit like a story about dead children.

This is what the European robin sounds like. If you live in Britain or parts of Europe, you’ve probably heard this song a million times without noticing it.

[other robin song]

Another common bird in gardens, this one from Japan and other parts of Asia, is the brown-eared bulbul. It’s about the size of the American robin, around 11 inches long, or 28 cm, including its long tail. It’s gray or gray-brown all over, with a speckled breast and belly, a sharp black bill, and a dark brown spot on the sides of its head that gives it its name. It mostly eats plants, including fruit, seeds, flowers, and even leaves. I have a picture in the show notes of one chowing down on a flower, just swallowing petals like it’s in a video game and petals give it a power-up. It likes nectar too, and in spring and summer especially will look like it has a yellow head or yellow markings because of all the pollen on its feathers. It helps pollinate plants as a result. It also sometimes eats insects. It gathers in large flocks at times and many farmers consider it a pest, especially fruit farmers.

It has a loud song and call that many people dislike. I’ll let you decide, if you’re not already familiar with it. I kind of like it, to be honest. This is what a brown-eared bulbul sounds like:

[brown-eared bulbul call]

Listener John V. recently suggested the Eastern Hognose snake for an episode, and tickled me because he referred to it as the “dramatic hognose snake.” The hognose is a common snake in many parts of North America, and can grow almost four feet long, or 116 cm, although about half that length is much more average. Its snout turns up like a little snub nose. It varies in color and pattern, and some snakes are black or gray, some orange, brown, even greenish. Some snakes have no pattern, some snakes have various colored blotches or even a checkered pattern. The belly is usually yellowish but is sometimes gray or almost white. It has a big head that makes some people believe it’s venomous, but it’s actually harmless to humans and most animals.

The only animals that really need to worry about the Eastern hognose are amphibians, like toads and frogs. As it happens, the hognose does have mild venom, but it’s only effective on amphibians. It especially likes to eat toads, and while some toads are toxic, the hognose snake is resistant to toad toxins. A toad will frequently puff itself up to make it appear larger and make it hard for a snake to eat, but the Eastern hognose has a solution for that too. It has big teeth at the rear of its upper jaws, like fangs in the back of its mouth. It uses those teeth to puncture puffed-up toads so they deflate.

But the most memorable thing about the Eastern hognose, and the thing that earns it the drama snake award, is what it does when it feels threatened. Phase one of the dramatics is aggression. The snake will flatten its neck to look more threatening, raise its head like a cobra, and hiss and strike—but without biting. It’s just trying to scare you away. If that doesn’t work, the snake puts phase two into effect. It will flop down and roll onto its back, its tongue hanging out, and emit a foul musky smell from its cloaca, and play dead. If you call its bluff and roll drama queen snake onto its belly, it will turn onto its back again. It is really insistent that it is dead.

A common reptile visitor to yards in Australia is the water dragon. Of course Australia would have a little dragon running around in suburban neighborhoods. Males can grow up to three feet long, or a little over a meter, with females smaller, but those lengths include a tail that’s almost twice the length of the body. Males are more brightly patterned than females. It’s a long-leggedy lizard with a spiky crest along its head and spine. It’s generally a pale greeny-grey with dark stripes, especially on the tail and legs, or gray with white stripes. Depending on the species and individual, it may also have a colorful blotch on the throat, usually white or yellow, but sometimes orange or red.

It’s a fast runner and can even run on its hind legs if it really needs to hurry. It climbs trees well, but it especially likes water and is semi-aquatic. Its long tail helps it swim. It likes to bask on branches overhanging the water, and if something threatens it, it drops into the water, where it hides. It can stay underwater without needing to take another breath for over half an hour. It eats small animals like frogs and worms, crustaceans and mollusks, insects, fruit, and plants.

In areas where it gets cold in winter, such as Sydney, the water dragon will dig a burrow if it doesn’t already have one, close the entrance off with dirt, and hibernate until spring, when it emerges and starts searching for a mate. Males sometimes fight each other, biting and scratching. Once the weather is warm, the female lays 6 to 18 eggs in a hole she digs in sandy soil.

Water dragons will visit yards if there’s cover and a water source nearby, whether it’s a creek or just a dog’s water bowl. Don’t try to pet one, though. Dragons bite.

Now let’s look at a couple of common rodents. The edible dormouse lives throughout much of western Europe and is big, about the size of a squirrel, which it also roughly resembles. It’s grey or grey-brown with paler underparts. In autumn when it’s preparing for hibernation it gets very fat, which is why it’s also called the fat dormouse. The name edible dormouse comes from the Romans, who used to farm them in captivity and eat them as a delicacy. In some parts of Europe, especially Slovenia, wild edible dormice are still trapped and eaten.

The edible dormouse lives in dense forests, caves, and people’s attics, where it can be a real pest. It eats plants, especially fruit and nuts, but will eat bark and leaves, and sometimes bird eggs and insects. It especially likes beech tree seeds. It’s mostly nocturnal. Unlike most rodents, it doesn’t always breed every year.

If a predator grabs the edible dormouse’s tail, the skin and fur will slide off, allowing the dormouse to escape. The exposed tail vertebrae later break off and the wound heals up, making the tail shorter. That is kind of horrifying.

Chipmunks are rodents common throughout North America, although the Siberian chipmunk lives in Asia. The Eastern chipmunk is the one I’m going to talk about today, primarily because I got audio of one calling this morning on my way to work. I spilled coffee all over myself to get the audio, so I definitely want to share it.

The chipmunk is larger than a mouse but smaller than a squirrel. It has reddish-brown fur with stripes down its sides, a white band in between two thinner black bands. It prefers woodlands with lots of brush and rocks to hide in, but it lives in parks, yards, and definitely all over the college campus where I work. It climbs trees well but mostly it stays on the ground. It digs complex burrows with tunnels that can be more than 11 feet long, or 3.5 meters. It even digs a special latrine burrow to keep droppings out of the rest of the burrow system, and will throw nut shells and other trash into the latrine too. When it’s digging a new tunnel or burrow, it carries the dirt it’s dug away from the tunnel entrance in its cheek pouches, so predators won’t notice newly dug soil and come to take a look.

The chipmunk is omnivorous, and eats everything from bird eggs, worms, snails, and insects to seeds, nuts, and mushrooms. It even eats small animals like baby mice and nestling birds. It carries food in its cheek pouches to store for the winter, and helps disperse some plants as a result. It doesn’t hibernate, but in winter it spends most of its time sleeping, which is pretty much what I like to do in winter too.

THIS is what an Eastern chipmunk sounds like! A cup of coffee died to bring you this audio:

[chipmunk sound]

Our final animal isn’t something you’d typically find in your yard or garden—but you might find it in your house, if you have a freshwater aquarium: the guppy. A different Richard suggested this animal, specifically my brother Richard. He texted me a while back about Poecilia reticulata, a “common aquarium fish that can turn its little eyes black.” Then we texted back and forth about how that would be a really neat superpower, and how we would apply it in our lives if we could turn our eyes black.

The guppy is a tropical fish native to parts of South America, although it’s been introduced into the wild in other parts of the world and is an invasive species in many places. In the wild it eats algae, insect larvae, and various tiny animals. It’s usually between one and two inches long, or 3 to 6 cm, with females being larger. Females are gray or silvery in color, while males are gray with spots of bright color. Aquarium enthusiasts breed different strains of guppy that may have bright colors and striking patterns.

So does the guppy turn its eyes black? Yes, it really does. Most of the time guppies have silver eyes, but some species can change their eye color in only seconds. In the wild, guppies that live in dangerous areas with many predators tend to group together and cooperate. But guppies that live in safer areas tend to be loners and more aggressive toward each other. When a guppy is angry at another guppy, it turns its eyes black to indicate that it’s willing to fight. Other guppies may back off at that point, or if the other guppy is bigger, it may attack. Researchers don’t know yet how guppies change their eye color.

Until next week, when I’m home from Paris and hopefully caught up on my sleep, remember to look around at the strange little animals in your own backyard. But watch out if their eyes turn black.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 079: Starfish and Friends

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This week’s episode is all about echinoderms, or at least the star-shaped echinoderms! Thanks to Llewelly for the suggestion about feather stars and crinoids!

A very pretty starfish:

Crown of thorns starfish. Do not touch:

Pumpkin starfish or orange throw pillow? YOU DECIDE:

Sea daisies. Not much to look at tbh:

A banded arm brittle star:

Ruby brittle stars:

Brittle stars riding around in a jelly:

A basket star:

Basket stars got TEETH THINGS:

A stemmed crinoid:

A lovely feather star:

Further reading:

Echinoblog, a really amazing resource and so much fun to browse

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

This week we’re going to look at some marine animals that most people barely think about, but which are really interesting. It was going to just be about starfish and maybe one other animal, but while I was still researching starfish, listener Llewelly suggested I cover feather stars and crinoids. They’re related to starfish, so I thought I’d tack them on. And if you talk about starfish, you really have to talk about brittle stars too, and if you talk about brittle stars you have to talk about basket stars. Basically, I had to stop myself from breaking this episode into two big episodes about echinoderms. It’s just the stars this time.

Before we get into echinoderms, though, a quick note about my schedule. Next week I’m going on a trip to Paris, France! I know it sounds like I’m rich and just travel as my whim takes me, but actually I just have really generous relatives. A week and a half after I return from Paris, I’ll be in Atlanta, Georgia for DragonCon, where I’ll be on a panel about podcasting. In other words, I won’t be around much on social media for the rest of August, but don’t worry, I’ll have episodes recorded and scheduled to run normally while I’m gone.

Okay, now let’s get into echinoderms. Echinoderms include sand dollars, sea urchins, starfish, and many others, and every single echinoderm lives in the ocean. Many of them can regenerate limbs and other body parts, and instead of blood they have a water vascular system. In most echinoderms, seawater enters the body through slits or pores, then travels through canals within the body to transport oxygen to cells and waste products out of cells. Echinoderms have internal skeletons made of calcium carbonate, but they’re invertebrates because they don’t have a backbone. Heck, technically they don’t even have a back.

Echinoderms show radial symmetry, which means their bodies are roughly the same in all directions instead of having a clear front and rear. The echinoderms we’re talking about this week are ones that also exhibit pentaradial symmetry, which means they have five sides. And the best-known echinoderms out there are starfish. There are about 1,500 species of starfish known, and some of them are really weird and some are only kind of weird. Most have five arms but some have a whole lot more.

Starfish are members of the class Asteroidea, which just delights me. A better name for them is sea star, since they’re not fish at all. Starfish have been around for at least 450 million years, but in 2012 paleontologists found a fossil of the oldest known ancestor of starfish in the mountains of Morocco. It’s about 515 million years old, from the Cambrian period. It was only about an inch and a half long, or 4 cm, and looked similar to the modern-day sea lily, or crinoid. If you recall, the Cambrian period was when life was expanding rapidly in the oceans and evolving sometimes quite strange body plans. You know, like things with FIVE LEGS.

Most starfish have ossicles in their skin, little hard beads of calcium carbonate that help protect the animal. In some starfish, the ossicles are more like spines or even spikes. Although cartoons of starfish usually make them look like their legs are always exactly star-shaped, the legs are actually quite flexible. If a starfish is flipped upside down, it bends a couple of its legs down to flip itself back over.

The starfish’s mouth is in the very center of its body, the part in the middle of the legs, known as the disc. Different starfish use their mouths differently. That sounds confusing, but just hang on, because things are about to get weird and gross.

Starfish are primarily predators. Some starfish just swallow their prey whole and digest it in the stomach. Pretty normal. But other starfish—look, I don’t know how to tell you this, so I’ll just say it. They turn their stomach inside out, called eversion, squish it around the prey, and start the digestive process. Part of the stomach stays inside the body, and when the prey has been digested enough that’s it sort of a lumpy soup, the starfish retracts its everted stomach and the food back into the body. This means that the starfish can eat prey that’s bigger than it is.

A lot of starfish eat bivalves of various kinds, like clams. Say a starfish finds a clam and wants to eat it. The clam is closed up tight and starfish don’t have teeth or claws to break the clam open. But starfish do have tiny tubes on the bottoms of their legs, called tube feet. These tubes act like suction cups, although they actually stick to things with a chemical reaction. So the starfish latches onto both shells of the bivalve with its tube feet and pulls. It probably isn’t strong enough to pull the clam open completely, but it doesn’t need to. It just needs a little space so it can evert its stomach and squish it into the clam’s shell. Then it releases digestive enzymes and the clam is doomed.

Starfish can’t move very fast, and lots of animals eat them. But they can regenerate lost legs if some of them are bitten off. The starfish doesn’t have a brain, although it does have a nerve net. Plus, it has sensory bundles at the ends of its arms that can detect smells, along with eye spots at the end of each leg. The eye spots basically just detect light and darkness and they don’t actually look like eyes, which is a good thing because that would be terrifying.

Starfish arms, or legs, are properly called rays. I will continue to confuse everyone by calling them arms or legs depending on which word sounds better to me at the time.

So let’s get down to the nitty-gritty. What is the biggest starfish? What is the weirdest starfish? Could a starfish actually kill you, and I don’t mean by making you faint with terror and drown, which is what would happen to me if I accidentally touched one.

Let’s start with the biggest starfish. Starfish don’t actually get all that enormous. Even the biggest ones are typically only about two feet across, or 60 cm. The sunflower star can grow more than three feet across, or over a meter, and can weigh up to 11 pounds, or 5 kilograms. AND it has a ridiculous number of arms, up to 24 of them.

Sunflower stars can be purple, red, pink, brown, orange, yellow, or even white. They live on the sea bed along the Pacific coast, usually where it’s shallow but sometimes nearly 1500 feet deep, or over 450 meters. Young sunflower stars only have five arms, but as they get older they grow more arms. One genus of starfish, commonly called Heliaster, looks similar to the sunflower star even though it’s not that closely related to it, but some individuals can have up to 50 legs.

Recently, a bed of 350 fossil starfish were found in Florida, so well preserved that paleontologists were able to identify them as Heliaster michrobachius, which is still around today. But it lives off the western coast of Central and South America, from Mexico all the way down to Chile—but it’s not found anywhere else. So what were they doing in Florida three million years ago?

Remember the Great American Interchange, where the isthmus of Panama formed, connecting North and South America and allowing animals from both places to spread into the other continents? Before then, North America was separate from South America, so Heliaster undoubtedly lived along North America’s southern coast. After the isthmus formed, currents, salinity, and many other factors changed, which probably led to Heliaster dying out in the Atlantic side of the continent. Fortunately, it survived in the Pacific side.

So, what is the weirdest starfish? It’s really hard to decide. All starfish are weird, frankly. Labidiaster annulatus can grow up to two feet across, or 60 cm, and has 40 to 45 long, thin legs with sharp spines that can actually grab prey. The starfish holds its legs out and wriggles them like fishing lines, and when a little fish or an amphipod comes close, the spines snag it. The starfish wraps its arms around the prey and pulls it to its mouth, where it everts its stomach and starts digesting.

The crown-of-thorns starfish mostly eats coral polyps and is covered with thorny spines that are venomous. It can have up to 21 arms and is the same size as Labidiaster, but with a thicker body and much shorter legs. It looks scary, but it’s actually delicate and rarely survives being lifted out of the water for even a short time. It lives in a lot of areas, including part of the Pacific Ocean, Red Sea, and along the east African coast, but it’s most common around Australia. At one point people worried that it was killing a lot of the coral in Australia’s great barrier reef, but under ordinary circumstances it actually helps maintain biodiversity in coral reefs by preying mainly on fast-growing coral. This allows slow-growing coral to flourish. Every so often, though, there’s a population boom among the crown-of-thorns starfish. Researchers aren’t sure why, and when it happens Australia has tried various population control measures to keep their numbers down and protect the reefs.

The pumpkin sea star is fat, thick, and orange. It’s big too, literally the size of a pumpkin. It’s also rare, and was only discovered in 1997. Even though it’s big, its skeleton is very small and it’s basically very meaty, which makes it look like a star-shaped orange throw pillow. Now I want a pumpkin starfish throw pillow. It lives in the Indo-Pacific up to about 650 feet deep, or 200 meters, but not much is known about it yet.

Luidia maculata has long, flattened arms that are brown and black striped above and white underneath, sometimes with a brown daisy pattern on its body disc. Seriously, who knew these things were so pretty? It lives in shallow water in the Indo-Pacific and often buries itself in the sand with the help of the long spines on the undersides of its legs. It doesn’t have an eversible stomach so it just swallows its prey whole, including sand dollars, sea urchins, clams, other starfish, sea cucumbers, and snails. Whatever’s left over after it has digested its prey, it spits out.

The sea daisy is a deep-sea animal described in 1986 after being discovered by accident. A team collecting samples of wood from the South Pacific seabed found nine of the strange creatures and didn’t know what they were. It’s small, only about 9 mm long, and is shaped roughly like an umbrella without a handle. Its upper surface is covered with plates with spines along the edges, and underneath it has a single row of tube feet and a membrane. Researchers at first decided the sea daisy was so different from other echinoderms that it needed its own class, but further study determined that it’s actually a type of starfish even though it has no arms and no stomach. In fact, it most closely resembles a juvenile starfish, but where starfish grow arms as they develop, the sea daisy never grows arms and instead grows outward along its circumference, like a wheel. It lives among wood that has sunk to the bottom of the ocean to a depth of at least 3300 feet, or 1,000 meters, and researchers think it may eat bacteria that grow on the wood. The membrane on its underside resembles an everted stomach.

Okay, one more. A starfish sometimes referred to as a slime star is covered with a soft, squishy, gelatinous surface. Its body is frequently almost transparent too. It usually lives in the deep sea, with new species found just about every time a deep-sea expedition scouts around on the sea floor. The largest are almost a foot across, or nearly 30 cm. Since they’re so delicate, it’s hard to study them, so not a lot is known about them. But there is a shallow-living species that has been studied a little more, and we know one important thing about them. If you pick up a slime star, it will secrete just ridiculous amounts of slime. This helps it keep from being eaten. The slime may also contain a soap-like toxin.

That brings us to our last question about starfish: can starfish kill you? No. No, they can’t. Even the crown-of-thorns starfish venom won’t kill you, just hurt like crazy for a few hours or as much as a week. The venom actually chemically resembles soap or detergent so isn’t very toxic to humans or other animals, but it does make the starfish taste bad.

Next, let’s look at brittle stars. Brittle stars look superficially like starfish and are closely related to them. Their legs are usually very long and slender, with the legs of some species growing up to two feet long, or 60 cm. The legs are supported by a skeleton made of plates called vertebral ossicles, which resembles a bike chain.

Brittle stars have five arms and a round central disc, with the legs much more differentiated from the disc than starfish legs are. They mostly scavenge for bits of food or eat worms and other small animals. They usually move slowly, but when they need to, they can really zoom around quickly. Their legs are extremely flexible and they can use them for swimming or crawling. Sometimes a brittle star will raise its body disc up and walk on its legs sort of like a spider, which is oddly creepy but also remarkably adorable. Look, I don’t mind telling you, I really like brittle stars. I barely knew what they were before I started researching them, but now I think they’re one of the best things ever.

Some brittle stars are bioluminescent, but only along their arms. Most species can regenerate their arms like starfish can, but not as well as starfish, and some species can’t regenerate at all.

Brittle stars are more freewheeling than their starfish cousins. For instance, one brittle star, Ophiocnemis marmorata, hitches rides on jellyfish. One 2017 study found that 79% of moon jellies examined hosted brittle stars, some riding inside the jellys’ bells, some riding in the tentacles near the oral arms. Larger jellies carry more brittle stars, while small ones usually only have a few. It turns out that the brittle stars steal food from the jellies, known as kleptoparasitism. They also gain some protection from living inside a jelly, and they get a free ride to new parts of the ocean. Researchers hypothesize that the brittle stars find their jelly hosts as larvae, ride around with it for a while, and drop off to live on the sea floor. Since the brittle star prefers tropical waters, it abandons its host jelly when it migrates into colder water.

Brittle stars are divided into two groups, brittle stars and basket stars. Brittle stars live all over and are especially common around coral reefs, but basket stars mostly live in deep water. While brittle stars have relatively simple, snakey arms, basket star arms are long and branched. Sometimes the branches of their arms are so elaborate, they look more like a kind of coral or like a tumbleweed sitting on the bottom of the ocean.

The biggest basket star we know of is probably Gorgonocephalus. There are at least ten species, and they can be hard to tell apart even by experts. Gorgonocephalus’s body disc can grow some 5 ½ inches across, or 14 cm, but its five net-like arms can grow over two feet long, or 70 cm. It’s white or yellowish in color, and its disc is often dark brown. During the day it hides among sponges and corals, but at night it comes out to hunt.

Basket stars mostly eat small animals like krill, jellyfish, and copepods that get tangled in their elaborately branched arms. The arms have hooks and spines all over them too. Basket stars will sit on a rock or a sponge or something similar, and extend their arms as though casting a net. When an animal strays into the net, the basket star carries it to the mouth on the underside of its body disc. And the mouth is full of spikes. Like many deep-sea animals, we don’t know a whole lot about basket stars and new species are discovered pretty frequently.

The last star we’ll look at this time is the feather star, but to learn about the feather star we also have to learn about the crinoid. If you’ve taken a geology class, you probably remember crinoid stem fossils. They’re incredibly common fossils, because crinoids used to be incredibly common animals. Pieces of crinoid stem fossils are sometimes called St. Cuthbert’s beads, and they’ve been used by humans to make jewelry for millennia.

In the past crinoids had five arms, but at some point each arm developed into two, so many modern crinoids have ten arms. In addition, some species have arms that branch. The arms have feathery appendages and tube feet coated with mucus, which helps trap tiny bits of food. Crinoids’ water vascular system is internal, unlike in starfish and brittle stars, which pump water in from outside.

Crinoids with stalks look like plants and are often called sea lilies. Some even have tiny rootlike filaments that help it attach to the sea floor or to rocks or other structures. The stem is slender with the cup-like body disc, called a calyx, and feathery arms at the top. Many species of crinoid have stems as juveniles, but become free-swimming when they reach maturity. Today some deep-sea crinoids can have stems a little over three feet long, or roughly a meter, but one fossil crinoid found had a stem 130 feet long, or 40 meters. But unlike true plants, crinoids can uproot themselves and move to a better location.

Most crinoids today are free-swimming, and these are the feather stars. They may have a vestigial stalk or may have no stalk at all. Most feather stars are sedentary, only crawling around for short distances, but some can swim with their arms. Many are brightly colored and absolutely beautiful.

I could keep talking about echinoderms for hours, but this episode is already getting long. Eventually I’ll do a follow-up episode about other echinoderms, like sea urchins. Until then, if you want to learn more about echinoderms I highly recommend a site called Echinoblog. It’s run by Dr. Chris Mah, a starfish expert, whose enthusiastic and informative posts about echinoderms really helped me learn to appreciate them. I’ll put a link in the show notes. Usually, the more I look at pictures of invertebrates, the more gross they seem, but the opposite is true for feather stars and brittle stars. They’re just gorgeous. Starfish, on the other hand, I would rather admire from afar.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 069: The Cambrian Explosion

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This week let’s find out a little something about the Cambrian explosion, where the relatively simple and tiny life on earth suddenly proliferated and grew much larger…and definitely stranger.

The Burgess shale area: beautiful AND full of fascinating fossils:

Anomalocaris, pre-we-figured-out-what-these-things-are:

What anomalocaris probably actually looked like, plus a couple of the “headless shrimp” fossils:

More “headless shrimp” fossils because for some reason I find them hilarious:

Marrella. Tiny, weird, looks sort of like those creepy house centipedes that freak me out so much, but with horns:

Hallucigenia, long-time mystery fossil:

What hallucingenia probably looked like, maybe:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

This week’s topic is one I’ve been fascinated by for years but I’ve never read much about it: the Cambrian explosion. That refers to the explosion of life forms in the Cambrian period, which started about 540 million years ago. That was long before the dinosaurs, long before fish, basically long before almost all life on earth that wasn’t simple squidgy things living in warm, shallow seas.

To learn about the Cambrian explosion, let’s go back even farther first and learn about the first life on earth.

Obviously, the more recently an animal lived, the more likely we are to find fossils and other remains: footprints in fossilized mud, gastroliths and coproliths, and so forth. The farther back we go, the fewer remains we have. The earth is continually changing, with mountains rising up and continents moving around, volcanoes erupting, old mountains being worn down by wind and weather. That’s good for the earth and therefore for life in general, since nutrients are cycled through the ecosystem and habitats are continually renewed. But it’s bad when paleontologists are trying to find out what lived a billion years ago, because most of those rocks are gone, either weathered into sand long ago, melted into magma, or buried under the ocean or otherwise out of our reach.

The Earth formed about 4.5 billion years ago, oceans formed 4.4 billion years ago, and the oldest rocks we can find are about 4 billion years old. The first life on earth, single-celled organisms, dates back to about 3.8 billion years ago, maybe earlier. By 3.5 billion years ago, complex single-celled microorganisms had evolved—we know because we’ve found eleven microscopic fossils in rocks from western Australia. Researchers have concluded that the fossils belonged to five different taxonomical groups, which means that by 3.5 billion years ago, life was already well established and diverse.

By 2.5 billion years ago, the earth had continents roughly the same size as the ones today, although not anything like the same shapes or in the same places. Land also didn’t have dirt on it, just sand and bare rock, since dirt is largely decomposed organic matter and nothing was living or dying on the land yet. Not long after, 2.45 billion years ago, oxygen started to make up a large part of the earth’s atmosphere. That’s right, before then we literally could not have breathed the air. I mean, we could have, but we would die of suffocation because the air contained only trace amounts of oxygen. While having oxygen in the air sounds great to us now, the single-celled organisms living then couldn’t process it and died off—probably the greatest extinction event in the earth’s history. Only organisms that were able to evolve quickly enough to use oxygen survived and thrived.

One particular type of microorganism dating back 2.3 billion years, sulfur bacteria, again known from ancient rocks from western Australia, is still around. Modern sulfur bacteria live in the deep sea off the coast of Chile, and they literally have not needed to change at all in 2.3 billion years. That’s what you call success.

The earliest multicellular organisms date to around 2.1 billion years ago, or at least those are the oldest fossils we’ve found. Algae and fungi evolved soon after. The earliest animal fossils date from about 580 million years ago and include small jellyfish and sea anemones, but all the oldest fossils we’ve found are of specialized animals so they probably arose much earlier. At about the same time, fossils of more complex shelled animals start appearing in the fossil record, animals which may have been the ancestors of arthropods, echinoderms, and mollusks. We also have fossils of burrows made in the sea floor, although we don’t know what kind of animal made them—some kind of wormy creature, but none have been found, just their burrows. Clearly a lot was going on back then, but it was all on a small scale: tiny worms, colonies of bacterial mats, and shelled animals measured in millimeters.

Then came the Cambrian explosion, starting about 540 million years ago, where diverse and often bizarre-looking animals suddenly appear in the fossil record, proliferating at a rate unheard-of in the previous eras. We’re not completely sure why, but it was probably a combination of factors, possibly including increased oxygen levels, the development of an ozone layer in earth’s atmosphere that protects cells from lethal UV radiation, an increase of calcium in ocean water, and many other factors, large and small. As animals grew larger and more diverse, more species could exploit more ecological niches; and when all the available niches were occupied, competition grew even more fierce, leading to even bigger and more specialized animals.

The first Cambrian fossils found were those of trilobites, first described in 1698 but not recognized as extinct fossil animals until the 18th century. By the 19th century so many forms of trilobite were known that geologists used them to help date rock strata. While trilobites had probably been around before the Cambrian, during the Cambrian they evolved exoskeletons and became much larger and more common.

You’ve probably heard of the Burgess shale, and you’ve probably heard of it because of the book Wonderful Life, published in 1989 by paleontologist Stephen Jay Gould. The book is out of date now, but when it was new it caused a lot of popular interest in the Cambrian explosion in general and the Burgess shale fossils in particular.

Shale, if you’re not familiar with the term, is a type of sedimentary rock formed from mud containing a lot of clay, generally mud from slow-moving water, floodplains, and quiet lagoons. It’s common, generally gray in color, and splits into flat pieces that you can draw on with other pieces of shale like a chalkboard. People sometimes confuse shale with slate, but slate is actually shale that’s been hardened by pressure and heat within the earth into a metamorphic rock. Because shale is formed from fine particles instead of sand, it can preserve fossils in incredible detail, although usually flattened.

So the Burgess shale is a large deposit of shale some 30 miles across, or 50 km, and 520 feet thick, or 160 meters. The area was once the bottom of a shallow sea next to a limestone cliff, around 505 million years ago, right in the middle of the Cambrian period. When the Rocky Mountains were created by tectonic forces around 75 million years ago, the Burgess shale was lifted 8000 feet above sea level, or 2500 meters. It’s in Canada, specifically Mount Stephen in Yoho National Park in British Columbia, and it’s properly called the Stephen Formation.

In the late 19th century a construction worker found some fossils in the loose shale weathered out of the formation. A geologist working for the Geological Survey of Canada heard reports of the fossils and in 1886 visited the area. He found trilobites and told his supervisor. Eventually paleontologist Joseph Whiteaves took a look and collected some Burgess shale fossils he thought were headless shrimps. They weren’t, by the way. We’ll come back to them in a minute.

In a nearby section of the Stephen Formation, paleontologist Charles Doolittle Walcott set up a fossil quarry in 1910. He and his team worked the quarry intermittently for the next few decades, collecting more than 60,000 specimens. But he didn’t publish very much about his findings, and after his death no one was very interested in the Burgess shale until the 1960s and 70s, when a couple of paleontologists started poking through Walcott’s collection. Their findings are what Gould writes about in Wonderful Life. Since then, paleontologists have continued to find amazing fossils in the Stephen Formation, and research continues on Walcott’s collection.

Part of the reason Gould’s book was such a sensation, apart from the fact that he’s a great writer and fossils are just interesting, was that he suggested the Cambrian explosion was caused by an unknown event that forced new evolutionary mechanisms into play, leading to many animals that are completely unrelated to those living today. He and some of the paleontologists working on the Burgess shale animals in the 1970s thought many of them belonged to phyla unknown today. There are only 33 designated phyla, although they do get looked at and changed around occasionally as new information comes to light. Humans and all other mammals, as well as reptiles, birds, amphibians, and fish, belong to the Chordata phylum. Gould suggested that if the Burgess shale animals had continued to evolve instead of dying out, life on earth today might look radically different.

That brings us to Whiteaves’s headless shrimp. Its name is Anomalocaris, which means abnormal shrimp. If you’re familiar with shrimp—you know, the things you eat, especially with rice or grits and I am so hungry right now—you have probably seen a headless one. The heads are typically removed before shrimp are sold, even though the rest of the shrimp may be intact, including shell, legs, and those little finny bits on the tail. That’s more or less what the fossil Whiteaves found looked like, except that its legs weren’t jointed. It was a little over 3 inches long, or around 8.5 cm. Whiteaves described it as a type of crustacean in 1892.

But to find out what it really was, we have to look at a couple of other discoveries. Walcott discovered what he identified as a type of jellyfish, around two inches across, or 5 cm, a circular segmented creature with a hole in the middle that looks a lot like a fossilized pineapple ring. Walcott also found what he thought was a feeding appendage or tail of an arthropod called Sidneyia, but didn’t realize it was the same anomalocaris Whiteaves had described. And paleontologist Simon Conway Morris discovered another of Walcott’s pineapple ring jellyfish, preserved together with what he took to be a sponge.

Harry Whittington, a paleontologist working on the Burgess shale fauna in the late 20th century, finally realized all these fossils belonged together—not as a crustacean, a sponge, and a jellyfish, but as one large animal. The shrimp tail was its feeding appendage, of which it had a pair in the front of its head, and the unjointed legs were spines. The pineapple ring jellyfish was its round mouthpiece consisting of plates that it contracted to crush prey. The sponge was its lobed body, which was softer and didn’t preserve as well as its other pieces.

Whiteaves’s feeding appendage came from a larger species, Anomalocaris canadensis, which grew some three feet long, or about a meter. It probably ate soft-bodied animals. Peytoia nathorsti was much smaller and may have used its feeding appendages to filter tiny prey from the mud.

In the 1990s anomalocaris and its relatives were identified as stem arthropods, ancestors of or at least relations to modern arthropods like insects, crustaceans, and spiders, and not belonging to a new phylum at all. Another anomalocarid was found in rocks 100 million years younger than the Burgess shale, which means at least some of the strange Cambrian animals persisted well into the Devonian.

Another confusing animal is called Marrella, a common fossil in the Burgess shale. Walcott found the first one in 1909 and called it a lace crab, then decided it was a strange trilobite. It’s small, less than an inch long, or under 2 cm, and has long antennae and legs, and head appendages that sweep back into rear-facing spikes that may have protected its gills. It was probably a scavenger that lived on the bottom of the ocean, and we know some interesting things about it. We have one Marrella fossil that shows an individual partly moulted, so we know it moulted its exoskeleton periodically. We also have some specimens so well preserved that researchers have found a pattern on them that would have diffracted light. In other words, its exoskeleton was iridescent and colorful. Charles Whittington examined Marrella in 1971 and determined that it wasn’t a trilobite, wasn’t a crab or other crustacean, and wasn’t any kind of horseshoe crab. Instead, it’s a stem arthropod like anomalocaris.

Hallucigenia may be the most famous Burgess shale animal, although it’s also been found in fossil beds in other parts of the world. It was first described by Walcott as a polychaete worm. Simon Conway Morris redescribed it in 1977, pointed out that it definitely was not a worm, and gave it its own genus. But no one was really sure what it would have looked like when alive, how it would move around and eat, or what it might be related to. Fossils show a thin, flexible worm-like body with long spines sticking out along its length on one side, and flexible tentacles sticking out along its length on the other side. One end of the body is sort of bulbous and the other blunt, but it’s not clear which is the head and which is the tail. It’s small, only an inch or so long at most, or a few centimeters. Conway Morris thought the animal walked on its stiff spikey legs and the tentacles were for feeding, and that each tentacle might even end in a mouth. Other paleontologists suggested the fossil might be part of a bigger animal, the way Anomalocaris feeding appendages were initially thought to be separate animals.

But after more and better fossils were discovered in China, paleontologists in 1991 realized Hallucigenia had been reconstructed upside down and backwards by Conway Morris. The tentacles were paired legs and the stiff spines probably protected the animal from other things that wanted to swallow it. The bulbous end seems to be a head with two simple eyes and a round mouth, possibly with teeth. Its closest living relation is probably a caterpillar-like land animal called a velvet worm or lobopodian worm, although it’s not actually a worm.

Other Burgess shale animals include a bristle worm, an actual relative of modern shrimp, a relative of the horseshoe crab, something that may be related to modern mantis shrimp, a rare mollusk ancestor that was an active swimmer, and a fishlike animal with short tentacles on its tiny head that may have been a primitive chordate.

Most of the Burgess shale animals that have been studied are now classified as arthropod ancestors. But there are hundreds, if not thousands, of fossil species that paleontologists are still puzzling over, with more yet to be discovered in the Stephen Formation and elsewhere. It’s always possible that some animals that evolved during the Cambrian will surprise us as belonging to a completely new group of animals, and that we really will need to add a couple of phyla to the list.

Another exciting thing to remember is that because life on earth is common and arose relatively soon after the earth was formed, it’s almost 100% certain that some other planets also have life—maybe not planets in our own solar system, although we don’t know for sure yet, but astronomers have discovered lots of planets outside of our solar system. They estimate the Milky Way galaxy alone may contain 100 billion planets. In the past researchers have insisted that only planets similar to ours can support life, but that’s not the right approach. Only planets similar to ours can support life like ours. That’s because we evolved to fit our planet. Life on other planets naturally will evolve to fit those planets. Even here on earth we have extremophiles that survive in environments where most other organisms would be destroyed immediately. So next time you’re outside at night, look up at the stars and give them a little wave. Some curious creature might be standing on a planet’s surface untold light years away, staring into the sky and waving a greeting too.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!