Category Archives: invertebrates

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!

Episode 063: The Hammerhead Worm and the Ichthyosaur

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This week we’re learning about the hammerhead worm and the ichthyosaur, two animals that really could hardly be more different from each other. Thanks to Tania for the hammerhead worm suggestion! They are so beautifully disgusting!

Make sure to check out the podcast Animals to the Max this week (and always), for an interview with yours truly. Listen to me babble semi-coherently about cryptozoology and animals real and maybe not real!

Here are hammerhead worms of various species. Feast your eyes on their majesty!

An ichthyosaur:

More ichthyosaurs. Just call me DJ Mixosaurus:

Show transcript:

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

This week we’re looking at a couple of animals that have nothing in common. But first, a big thank you to the podcast Animals to the Max. The host, Corbin Maxey, interviewed me recently and the interview should be released the same day this episode goes live. If you don’t already subscribe to Animals to the Max, naturally I recommend it, and you can download the new episode and listen to me babble about cryptozoology, my favorite cryptids, and what animal I’d choose if I could bring back one extinct species. There’s a link to the podcast in the show notes, although it should be available through whatever app you use for podcast listening.

This week’s first topic is a suggestion from Tania, who suggested hammerheaded animals. We’ve covered hammerhead sharks before way back in episode 15, but Tania also suggested hammerhead worms. I’d never heard of that one before, so I looked it up. I’ve now been staring at pictures of hammerhead worms in utter fascination and horror for the last ten minutes, so let’s learn about them.

There are dozens of hammerhead worm species. They’re a type of planarian, our old friend from the regenerating animals episode, and like those freshwater planarians, many hammerhead worms show regenerative abilities. They’re sometimes called land planarians. Most are about the size of an average earthworm or big slug, with some being skinny like a worm while others are thicker, like a slug, but some species can grow a foot long or more. Unlike earthworms, and sort of like slugs, a hammerhead worm has a flattened belly called a creeping sole. Some hammerhead worms are brown, some are black, some have yellow spots, and some have stripes running the length of their bodies. Hmm, it seems like I’m forgetting a detail in their appearance. …oh yeah. Their hammerheads! Another name for the hammerhead worm is the broadhead planarian, because the head is flattened into a head plate that sticks out like a fan or a hammerhead depending on the species.

The hammerhead worm’s head contains a lot of sensory organs, especially chemical receptors and some eye-like spots that probably can only sense light and dark. Researchers think the worms’ heads are shaped like they are to help the worm triangulate on prey the same way many animals can figure out where another animal is just by listening. That’s why most animals’ ears are relatively far apart, too.

One species of hammerhead worm, Bipalium nobile, can grow over three feet long, or one meter, although it’s as thin as an earthworm. It has a fan-shaped head and is yellowish-brown with darker stripes. It’s found in Japan, although since it wasn’t known there until the late 1970s, researchers think it was introduced from somewhere else. That’s the case for many hammerhead worms, in fact. They’re easily spread in potted plants, and since they can reproduce asexually, all you need is one for a species to spread and become invasive.

While hammerhead worms do sometimes reproduce by mating, with all worms able to both fertilize other worms and also lay eggs, when they reproduce without a mate it works like this. Every couple of weeks a hammerhead worm will stick its tail end to the ground firmly. Then it moves the rest of its body forward. Its body splits at the tail, breaking off a small piece. The piece can move and acts just like a new worm, which it is. It takes about a week to ten days for the new worm to grow a head. Meanwhile, the original worm is just fine and is busy growing another tail piece that will soon split off again into another worm.

One common hammerhead worm accidentally introduced to North America from Asia is frequently called the landchovy. It’s slug-like, tan or yellowish, with a thin brown stripe and a small fan-shaped head. It looks like a leech and if I saw one I would assume that I was about to die. But I would be safe, because hammerhead worms only eat invertebrates, mostly earthworms but also snails, slugs, and some insects.

When a hammerhead worm attacks its prey, say an earthworm, it hangs on to it with secretions that act like a sort of glue. The earthworm can’t get away no matter what it does. The hammerhead worm’s mouth isn’t on its head. It’s about halfway down its body. Once it’s stuck securely to the earthworm, the hammerhead worm secretes powerful enzymes from its mouth that start to digest the earthworm. Which, I should add, is still alive, at least for a little while. The enzymes turn the worm into goo pretty quickly, which the hammerhead worm slurps up. The hammerhead worm’s mouth is also the same orifice that it expels waste from. I’m just going to leave that little factoid right there and walk away.

Hammerhead worms haven’t been studied a whole lot, but some recent studies have found a potent neurotoxin in a couple of species. That could explain why hammerhead worms don’t have very many predators. Or many friends.

[gator sound]

Our next animal is a little bit bigger than the hammerhead worm, but probably didn’t have a hammerhead. We don’t know for sure because we don’t have a complete skeleton, just a partial jawbone. It’s the giant ichthyosaur, and its discovery is new. In May of 2016 a fossil enthusiast named Paul de la Salle came across five pieces of what he suspected was an ichthyosaur bone along the coast of Somerset, England. He sent pictures to a couple of marine reptile experts, who verified that it was indeed part of an ichthyosaur’s lower jawbone, called a surangular. They got together with de la Salle to study the fossil pieces, and after doing size comparisons with the largest known ichthyosaur, determined that this new ichthyosaur probably grew to around 85 feet long, or 26 meters.

So what is an ichthyosaur? Ichthyosaur means fish-lizard, which is a pretty good name because they are reptiles that adapted so well to life in the ocean that they came to resemble modern fish and dolphins. This doesn’t mean they’re related to either—they’re not. But if you’ve heard the phrase convergent evolution, this is a prime example. Convergent evolution describes how totally unrelated animals living in similar habitats often eventually evolve to look similar due to similar environmental pressures.

The first ichthyosaurs appear in the fossil record around 250 million years ago, with the last ones dated to about 90 million years ago. In 1811, a twelve-year-old English girl named Mary Anning took her little brother Joseph to the nearby seashore to look for fossils they could sell to make a little money, and they discovered the first ichthyosaur skeleton. That sounds pretty neat, but Mary’s story is so much more interesting than that. First of all, when Mary Anning was barely more than a year old, a neighbor was holding her and standing under a tree with two other women, when the tree was struck by lightning. The three women all died, but Mary survived. She had been considered a sickly child before that, but after the lightning strike she was healthy and grew up strong.

Mary’s family was poor, so anything she and her brother could do to make money helped. At the time, no one quite understood what fossils were, but people liked them and a nice-looking ammonite or other fossilized shell could bring quite a bit of money when sold as a curio. Mary’s father was a carpenter, but the whole family was involved in collecting fossils from the nearby cliffs at Lyme Regis in Dorset, where they lived, and selling them to tourists. After her father died, selling fossils was the only way the family could make money.

As Mary and her brother became more proficient at finding and preparing fossils, geologists became more and more interested. She made detailed drawings and notes of the fossils she found, and read as many scientific papers as she could get her hands on. At the time, women weren’t considered scholars and certainly not scientists, but Mary taught herself so much about fossils and anatomy that she literally knew more about ichthyosaurs than anyone else in the world.

When Mary was 27 years old, she opened her own shop, called Anning’s Fossil Depot. Fossil collectors and geologists from all over the world visited the shop, including King Frederick Augustus II of Saxony, who bought an ichthyosaur skeleton from her. Collecting fossils could be dangerous, though. In 1833 she almost died in a landslide. Her little dog Trey was just in front of her, and he was killed by the falling rocks. Probably Trey had not heard about the lightning incident or he wouldn’t have stuck so close to Mary.

Although Mary Anning was an expert, and every collection and museum in Europe contained fossil specimens she had found and prepared, she got almost no credit for her work. She was not happy about this, either. Her discoveries were claimed by others, just because they were men. Mary was the one who figured out that the common conical fossils known as bezoar stones were fossilized ichthyosaur poops, called coproliths. Her expertise wasn’t just with ichthyosaurs, either. She was also an expert on fossil sharks and fishes, pterosaurs, and plesiosaurs, and she discovered ink sacs in belemnite fossils. Her friends Anna Pinney and Elizabeth Philpot frequently accompanied Mary on collecting expeditions. I picture them frowning and kicking scientific butt.

Okay, back to ichthyosaurs. Ichthyosaurs were warm-blooded, meaning they could regulate their body temperature internally, without relying on outside sources of heat. They breathed air and gave birth to live babies the way dolphins and their relations do. They had front flippers and rear flippers along with a tail that resembled a shark’s except that the lower lobe was larger than the upper lobe. Some species had a dorsal fin too. They had huge eyes, which researchers think indicated they dived for prey. Many ichthyosaur bones show damage caused by decompression sickness, when an animal surfaces too quickly from a deep dive—called the bends by human scuba divers. Not only were their eyes huge, they were protected by a bony eye ring that would help the eyes retain their shape even under deep-sea pressures.

Ichthyosaurs had long jaws full of teeth, but different species ate different things. Many ate fish and cephalopods like squids, while other specialized in shellfish, and others ate larger animals. We have a good idea of what they ate because we have a lot of high quality fossils, so high quality that we can see the contents of the animals’ stomachs. We also have all those coproliths that paleontologists cut open to see what ichthyosaur poop contained.

Ichthyosaurs lived before plesiosaurs and weren’t related to them. Plesiosaurs are usually depicted with long skinny necks, but more recent reconstructions suggest their necks were actually thick, protected by muscles and fat. Ichthyosaurs appear to have been outcompeted by plesiosaurs once they began to evolve, but ichthyosaurs were already on the decline at that point, although we don’t know why.

Until very recently, the biggest known species of ichthyosaur was Shonisaurus sikanniensis, which grew to almost 70 feet long, or 21 meters. It was discovered by Elizabeth Nicholls, continuing Mary Anning’s legacy of kicking butt and finding ichthyosaurs, and described in 2004. But the new ichthyosaur just discovered was even bigger.

In the mid-19th century, some fragments of fossilized bones were found near the village of Aust in England. They were assumed to be dinosaur bones, but now researchers think they may have been from giant ichthyosaurs, maybe even ones bigger than the one whose jawbone was recently found.

As a comparison, the biggest animal ever known to have lived is the blue whale. It’s alive today. Every time I think about that, it blows my mind. A blue whale can grow almost 100 feet long, or 30 meters. Until very recently, researchers didn’t think any animal had ever approached its size. Even megalodon, the biggest shark known, topped out at about 60 feet, or 18 meters. If the estimated size of the giant ichthyosaur, 85 feet or 26 meters, is correct, it’s possible there were individuals that were bigger than the biggest blue whale, or it’s possible that the jawbone we have of the giant ichthyosaur was actually from an individual that was on the small side of average. Let’s hope we find more fossils soon so we can learn more about it.

Mary Anning would have been out there looking for more of its fossils, I know that.

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 057: Horseshoe Crabs and Cone Snails

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Let’s learn about horseshoe crabs and cone snails! The former is harmless, the latter is deadly. Both are interesting!

This episode’s animals are inspired by the podcast Animals to the Max and by the book Strange Survivors by Dr. Oné R. Pagán. Check both out because they are awesome!

A horseshoe crab will never hurt you and just wants to be left alone to be a horseshoe crab:

A trilobite fossil:

A cone snail just wants to be left alone to be a cone snail but it will kill you if it has to:

Above: the stripey tube thing is the snail’s siphon, the pink tube thing is the snail’s proboscis, or VENOM DUCT.

The Glory of the Sea has a pretty shell:

More cone snail shells:

The rarest seashell in the world:

Show transcript:

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

This week we’re going to look at animals inspired by a book I recently read and a podcast I recently discovered.

The podcast is called Animals to the Max, and it’s one of several new animal podcasts that I’ve been enjoying lately. In most episodes, the host Corbin Maxey interviews someone who works with animals. Recently I was listening to episode 15, and the subject of horseshoe crabs came up briefly. Those things are awesome and well deserving of the term living fossil, so let’s start there.

First of all, horseshoe crabs are not actually crabs. They’re not even crustaceans. In fact, they’re more closely related to spiders and scorpions than to crustaceans. There are four species of horseshoe crabs alive today, three from Asia and one from the Gulf of Mexico and American Atlantic coast. Females are larger than males and depending on the species, may be about a foot long including the tail, or 30 cm, or twice that length.

The horseshoe crab gets its name from its rounded, slightly domed carapace that’s kinda sorta the shape of a horse’s hoof, with a long spike of a tail sticking out from its rear. It has a ridiculous number of eyes—seriously, it has nine eyes plus some photoreceptors on its tail. But it doesn’t see very well. Mostly it just senses light, although it can also see into the ultraviolet range.

It also has five pairs of legs tipped with little claws, and its mouth is in the middle of the base of its legs. Its legs act as shredders to cut up its food into tiny pieces. It eats worms and other invertebrates, and will eat fish if it can get it. Most of the time it swims upside-down. It can breathe air on land for short periods of time as long as its gills stay damp. Oh, and it can regenerate legs if one is injured.

Horseshoe crab blood is blue because instead of hemoglobin, its blood contains hemocyanin to transport oxygen throughout the body. Hemoglobin contains iron, which is red, while hemocyanin contains copper, which is blue. Its blood also contains amebocytes instead of white blood cells, and amebocytes have medical applications for humans, specifically as a way to detect bacteria in medical equipment. That means horseshoe crab blood is valuable. Half a million horseshoe crabs are caught every year, up to 30% of their blood is harvested, and the crabs released back into the wild none the worse for wear. At least, that’s how it’s supposed to go. In fact, almost 30% of the horseshoe crabs released just up and die due to stress, and some companies don’t even release them. They just quietly sell them as bait. Horseshoe crabs have been used as commercial fishing bait and ground up as fertilizer for years. Because of all these pressures, along with pollution and the development of beaches where they lay their eggs, the horseshoe crab has gone from being one of the most numerous animals in the ocean to threatened in a matter of decades. Fortunately, many places have put protections and harvesting limits in place to help the population rebound.

Horseshoe crabs first appear in the fossil record 450 million years ago, near the end of the Ordovician Period, back when most life lived in the oceans and fish with jaws were only just evolving. This was well before dinosaurs. This was well before any animals were living on land at all, although probably some marine animals had discovered that if they laid their eggs on the beach, nothing much would eat them, and some other marine animals had discovered that if they could haul themselves out onto the beach for short periods of time, they might find some eggs to eat. The horseshoe crabs alive today are basically identical to the horseshoe crabs found throughout the fossil record. They hit on a successful body plan hundreds of millions of years ago and have stuck with it ever since.

Trilobites were also everywhere during the Ordovician as well as before and after, until they died out 252 million years ago. Trilobite fossils are really common so you’ve probably seen them, but they looked sort of like big roly-polies, or pill bugs, or sow bugs, depending on what you call them. Horseshoe crabs are actually related to trilobites, and one of the big questions is why trilobites died out after being so incredibly successful for so long—270 million years—while horseshoe crabs didn’t. It was probably just luck. The Great Permian Extinction event wiped out almost 90% of all life on earth, and even before then trilobites were already in decline, while the horseshoe crab was chugging along just fine.

If you’re on the beach and see a horseshoe crab on its back, trying to get right side up, help it by flipping it onto its feet. It won’t hurt you, and you might very well save its life.

The other animal I want to look at today is the cone snail, inspired by a brand new book called Strange Survivors by Oné Pagán. Dr. Pagán kindly sent me an advance copy and it is definitely a book a lot of you would find interesting. It’s about evolutionary forces and how things like venom developed in various animals. I’ll put a link in the show notes if you want to order a copy for yourself. One of the animals Dr. Pagán talks about in the book is the cone snail. I’d never heard of it before but it’s fascinating.

There are something like 800 species of cone snail, in fact. They live in tropical oceans and their shells often have beautiful geometric patterns, the kind collectors spend big bucks for. But all cone snails are venomous and some can be fatal. Cone snails are snails and therefore not exactly known for their speed, but the larger ones hunt and kill fish. How do snails hunt fish? Usually it’s the other way round.

Well, let me just tell you. You are not even going to believe this, but you should, because it is a real thing that actually happens. I’ll use the geographic cone snail as an example, because it’s been well studied. It’s about 6 inches long, or 15 cm, and is common throughout shallow reefs in the Indian Ocean and the Red Sea. It’s also the most toxic of cone snails, and there is no antidote to its venom.

So, imagine a cone snail on the bottom of a shallow, warm ocean. Small fish are swimming around. The cone snail has a mottled brown and white shell, quite pretty, and the snail itself is somewhat similar in color with a siphon sticking out of the bottom of its shell. It’s not bothering anything and some little fish ignore it because hey, they’re fast fish and it’s just a slow snail.

But when the little fish get close to the snail, something odd happens. They just sort of slow down. They stop moving and sink to the bottom, but they don’t act panicked. That’s because the snail has released venom into the water, venom containing insulin that mimics the insulin found in fish. When a fish absorbs the venom through its gills, it goes into hypoglycemic shock, which stuns it. The snail then fires a modified hollow tooth called a harpoon into the fish, injecting more venom and killing the fish. The harpoon is attached to the snail’s body by a proboscis, or venom duct, which the snail uses to winch the fish into its mouth to digest.

So far researchers have found two snails that stun fish with venom released into the water, the geographic and the tulip cone snails, but all cone snails have the harpoon contraption to shoot fish with. And the harpoon is fast. It travels at about 400 miles per hour, or 644 km per hour, and special muscles at the base of the venom duct can pump venom into the fish just as fast. Sometimes a snail will hide in the mud or sand and wiggle its proboscis like a worm, and when a fish comes to investigate, the snail harpoons it. It takes the snail a week or two to digest a fish, and during that time it also grows a new harpoon.

Cone snails also use their harpoons defensively, and they can penetrate right through clothes and even divers’ wetsuits. And the venom can kill a human in a matter of hours. The problem is that many cone snail shells are really pretty, so people pick them up to look at. The snail thinks it’s about to be eaten, defends itself, and the person thinks, “Ow, that felt funny. And my hand is going numb. Hmm. Now my whole body is going numb, how strange.” And then they die. Well, it takes longer than that, but you get the idea. Of course, only 36 people have actually died from cone shell stings in the last 90 years, but just a reminder that if you don’t get in the water you are probably safe from venomous marine snails.

On the other hand, researchers are very interested in the cone snail’s toxins. They could lead to painkillers that don’t cause dependency, better treatments for diabetes, and even treatments for nervous system disorders like Parkinson’s disease and Alzheimer’s. At least one painkiller developed from peptides in a cone snail toxin is already on the market.

One cone snail, the Glory of the Sea, was at one time thought to be the rarest shell in the world. In 1970 its habitat was discovered by divers, in various places throughout the Indo-Pacific but mostly near the Solomon Islands. Before then, though, collectors would spend thousands of U.S. dollars on a specimen. These days they can still go for around one or two hundred bucks just because they’re really pretty and still not terribly common. I’ll put a picture of one in the show notes.

This episode is a little short so let’s just plunge down this rare shell rabbit hole. The rarest shell in the world is arguably that of Sphaerocypraea incomparabilis, and its story is pretty awesome. In 1963 a trawler dredged up a dark brown cowrie type shell that made its way to a Russian shell collector. Rumors of the shell leaked out and in the 1990s, a collector named Donald Dan flew to Moscow and managed to buy the shell. It turned out to be the shell of a snail that had been thought extinct for 20 million years. It’s still extremely rare, though. Only six of the shells are known to be in collections and the living snail still hasn’t been examined by scientists or formally described.

I don’t want to get in the water more than about ankle deep, but I do enjoy beachcombing. Apparently there’s some money to be made in shell collecting, too, but don’t pick up any cone snail shells unless you’re 100% certain the shell is empty.

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 054: Regenerating Animals

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This week we’re going to learn about animals that can regenerate parts of their body. What animals can do it, how does it work, and can humans figure out how to make it work for us too?

Thanks to Maxwell of the awesome Relic: The Lost Treasure podcast for suggesting this week’s topic!

The planarian, not exciting to look at but you can get a lot of them easily:

A starfish leg growing a new starfish, or possibly a slightly gross magic wand. Ping! You’ve been turned into a magical starfish:

The adorable axolotl:

The almost as adorable African spiny mouse:

A hydra. Not really very adorable except possibly to other hydras but kind of pretty:

Show transcript:

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

This week’s episode was going to be about lungfish, but I had to postpone it because I ran across some conflicting information about a mystery lungfish, which required me to order a book that probably won’t arrive for a week or two. So when I tweeted about needing a new topic quick, Maxwell of the Relic: The Lost Treasure podcast suggested animals that can regenerate parts of their bodies.

We’ve touched on regenerative abilities before in one or two episodes. Some lizards can drop their tail if threatened, which then regrows later—but a lizard can only do that once. The fish-scaled gecko from episode 20 can lose its scales and regenerate them repeatedly. But other animals can regenerate not just bits and pieces, but entire organs and even their brains. The sea lamprey can even regenerate spinal cord cells. You better believe researchers are trying to figure out how regeneration works and if it can be adapted for human application.

A lot of worms can regenerate lost pieces, including earthworms. Whenever I’m gardening and accidentally cut an earthworm in half with the shovel, I reassure myself that the worm will regenerate the end I cut off. Some species can even grow back from both cut pieces, effectively turning one earthworm into two, depending on where it is severed, although that’s rare. Some species of worm can only regrow the tail, but some can regrow the head. And some, of course, can’t regrow anything. Leeches are a type of worm but they can’t regenerate at all.

Planarians are flatworms. Some species live in water, some in damp areas on land, but they can all regenerate. If you cut a planarian in two, each half will regenerate into a new planarian. If you cut a planarian in three, you’ll get three planarians. Cut one into four, you get four planarians, and so on and on. Researchers with a lot of time and patience have determined that you can cut a planarian into as many as 277 pieces and you will get 277 planarians after a few weeks. But I guess if you cut a planarian into 278 or more pieces, some of the extra pieces won’t do anything.

Starfish are well-known to regenerate lost or injured legs, and may even drop a leg to escape from predators the way some lizards drop their tails. Some species of starfish can regrow an entire starfish from a single limb. That’s oddly creepy. I don’t know why I find it so creepy. I don’t find the planarians creepy. It’s like if I was run over by a motorboat that chopped my arms and legs off, and instead of dying I not only regrew my arms and legs, my severed arms and legs each grew a new me. I don’t think I’d like that. Although I’m not going to get in the water so I doubt I’ll be run over by a motorboat, and also if I was, sharks would probably eat me before we could see if any parts regrew.

Many starfish relations, such as sea urchins and sea cucumbers, can also regenerate body parts. When the sea cucumber is threatened, it can and will eject its internal organs. They’re sticky and full of toxins, which deters predators, and the sea cucumber just regenerates them.

Most crustaceans, such as crabs and krill, can regenerate legs. So can spiders, which may drop legs to escape from predators. That’s called autotomy, by the way, when an animal detaches a body part to escape from a predator. Spiders molt their exoskeletons every so often as they grow, and lost limbs grow back after molting. Sometimes it takes a few molts for the leg to be the same size as the other legs. Spiders can also regenerate other lost or damaged parts, including mouthparts and spinnerets.

Salamanders and newts can regenerate limbs, tail, some organs, jaws, even parts of their eyes. Frogs and other amphibians can’t. Likewise, some fish can regenerate injured tissue, such as the zebrafish which can regrow fins and eye retinas, and some species of sharks that can regenerate skin tissue, while others can’t. The axolotl, which is an adorable rare salamander found in Mexico, can regrow just about any part of its body, including its spinal cord and up to half of its brain.

So what about mammals? Do any mammals have regenerative capabilities? As a matter of fact, yes. The African spiny mouse is the big regenerator among mammals. It’s actually more closely related to gerbils, and it has stiff guard hairs all over its body that stick out and make it look fuzzy but which act as spines to help ward off predators. But if a predator attacks anyway, three species of the spiny mouse can autotomically drop off part of its skin, which later grows back. Some species of spiny mouse are kept as pets, even though they don’t do very well in captivity. The pet species don’t have regeneration abilities, incidentally. However, they do have delicate tails that are easily injured, which they then lose, and the tail does not grow back.

Those three species of African spiny mouse can also regenerate ear tissue. If a spiny mouse’s ear is damaged, even if it has a hole as big as four mm across, it can regenerate the ear as good as new rather than heal it with scar tissue. A number of mammals can regenerate small injuries to ear cartilage under the right circumstances, including cats. Rabbits can also regrow damaged ear tissue, and have some other regenerative abilities too.

It’s all well and good to point out that a whole lot of animals can regenerate lost or damaged body parts. But how does it work? And more to the point, why can’t humans do it?

Technically, humans and other animals are regenerating certain cells all the time, especially skin cells and blood cells. Small cuts and scrapes heal up without scarring and we don’t think about it at all. Fingertips will grow back after injury and the liver can regenerate. The endometrium, which is the lining of the uterus, is partially reabsorbed into the body and partially expelled from the body every month during menstruation, then regrows. Toenails and fingernails regrow after injury. We just don’t think about all these things because they seem normal to us, whereas we can’t regrow a whole finger if it’s been chopped off, for instance.

I won’t go too deeply into how regeneration works, mostly because it’s complicated and I don’t want to screw it up too badly. There are also different types of regenerative abilities with different processes. Basically, though, as an example, when a salamander loses a leg, the cells surrounding the wound dedifferentiate, basically turning from regular skin cells or what have you into stem cells that can grow into anything the body needs. These cells form what’s called a blastema, which is just the fancy name for a bundle of dedifferentiated cells. Then the blastemal cells start differentiating again, this time into the cells needed to regrow the leg, just as stem cells grew legs when the salamander was developing in its egg.

It sounds pretty simple, put like that. I mean, that’s how we all develop in the first place, from a fertilized egg into a person who can make podcasts and eat cupcakes. The main problem is figuring out how to get human cells to dedifferentiate into a blastema. Because it’s not just injuries that could be helped if scientists figure this out, it’s all sorts of problems. People who have lost their sight due to retinal diseases could regrow new retinas. People born with birth defects could have the nonstandard parts regrown so that they work the way they’re supposed to.

Researchers are working hard to figure all this out. Stem cell research is a big part of regenerative research. Unfortunately, at some point the rumor started that all stem cells come from babies, specifically embryonic stem cells. When a human egg is fertilized, after a couple of days a blastocyst is formed from the cells, which is similar to a blastema but made of cells that have never differentiated into anything else. They’re brand new cells with the capacity to make a brand new human. Naturally, people are squiffy about taking cells that might make a baby and using them for something else. But amniotic fluid, the fluid that surrounds the baby as it’s growing in its mother, also contains stem cells, and they can be harvested without hurting the baby or the mother. You can also get stem cells from the umbilical cord right after a baby is born, and the umbilical cord is just cut off and thrown away anyway so you might as well give it a little extra use. But most stem cells used in research and treatment these days come from bone marrow, lipid cells in fat tissue, and blood, all of which can be extracted without harming the person. They’re not as powerful as embryonic and amniotic stem cells, but they have the benefit of being from the patient’s own body, so no immunosuppression is required to make sure the body accepts them in stem cell treatment.

That was a lot of confusing medical information, so let’s talk about one more animal that can regenerate, the hydra. We’ve talked about the hydra before in the jellyfish episode, which for a long time was our most popular episode. It’s now our second-most downloaded episode, with our first episode inexplicably in the top spot. The hydra is a freshwater animal related to jellies that can regenerate so completely it’s essentially immortal.

The hydra is related to the so-called immortal jellyfish we talked about in episode 19. It can regenerate just about any injury, and like the planarian it can regenerate into more than one copy of itself if it’s cut up into tiny pieces. It’s only a few millimeters long but its tiny body is full of stem cells, and as long as stem cells are present in the body part that was cut off, an entirely new hydra can grow from it. Because of its amazing regenerative abilities, some admittedly controversial studies suggest the hydra doesn’t age. That’s a neat trick, if you can manage it.

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 046: The Other Loch Ness Monsters

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There’s more in Loch Ness than one big mystery animal. This week we look at a few smaller mystery animals lurking in the cold depths of the lake.

Further reading:

Here’s Nessie: A Monstrous Compendium from Loch Ness by Karl P.N. Shuker

The goliath frog:

The Wels catfish (also, River Monsters is the best):

An amphipod:

Show transcript:

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

Back in episode 29, I dismissed Nessie, the Loch Ness monster, as probably not a real animal. But this week we’re heading back to Loch Ness to see what other monsters might lurk in its murky depths.

WHAAAAA? Other Loch Ness monsters???

Yes, really! See, ever since the first sightings of Nessie in the 1930s, Loch Ness has been studied and examined so closely that it would be more surprising if no one had ever spotted other mystery animals.

The source of most of the information in this episode is from zoologist Karl Shuker’s book Here’s Nessie! A Monstrous Compendium from Loch Ness. Check the show notes for a link if you’re interested in buying your own copy of the book.

Our first non-Nessie mystery dates from 1934, but it happened, supposedly, sometime in the 1880s. It appeared in the Northern Chronicle, an Inverness newspaper, on January 31, 1934. The article relates that a ship in Loch Ness hit a submerged reef called Johnnie’s Point and sank one night. Luckily no one died. The next day a local diving expert named Duncan Macdonald was hired to determine if the wreck could be raised, but he couldn’t spot the wreck during his dive.

Later that evening, some of the ship’s crew who had heard stories about strange creatures living in Loch Ness asked Macdonald whether he’d seen anything unusual. After some urging, Macdonald finally admitted that he had seen a frog-like creature the size of a good-sized goat sitting on a rock ledge some 30 feet, or 9 meters, underwater. It didn’t bother him so he didn’t bother it.

There are a lot of problems with this account, of course. For one thing, we don’t know who wrote it—the article has no byline. It’s also a secondhand account. In fact, the article ends with this line: quote “The story, exactly as given, was told by Mr Donald Fraser, lock-keeper, Fort Augustus, who often heard the diver (his own grand-uncle) tell it many years ago.” unquote

Plus, of course, frogs don’t grow as big as goats. The biggest frog is the goliath frog, which can grow over a foot, or 32 cm, in length nose to tail, or butt I guess since frogs don’t have tails, which is pretty darn big but not anywhere near as big as a goat. The goliath frog also only lives in fast-moving rivers in a few small parts of Africa, not cold, murky lakes in Scotland, and its tadpoles only feed one one type of plant. In other words, even if someone did release a goliath frog into Loch Ness in the 1880s—which is pretty farfetched—it wouldn’t have survived for long.

The biggest frog that ever lived, as far as we know, lived about 65 million years ago and wasn’t all that much bigger than the goliath frog, only 16 inches long, or 41 cm. It had little horns above its eyes, which gives it its name, devil frog. Its descendants, South American horned frogs, also have little horns but are much smaller.

So what might Mr. Macdonald have seen, assuming he didn’t just make it all up? Some species of catfish can grow really big, but catfish aren’t native to Scotland. It’s always possible that a few Wels catfish, native to parts of Europe, were introduced into Loch Ness as a sport fish but didn’t survive long enough to establish a breeding population in the cold waters. Catfish have wide mouths, although their eyes are small, and might be mistaken for a frog if seen head-on in poor light. Plus, the Wels catfish can grow to 16 feet long, or 5 meters.

Then again, since the article was published during the height of the first Loch Ness monster frenzy, it might all have been fabricated from beginning to end.

A 1972 search for Nessie by the same team that announced that famous underwater photograph of a flipper, which later turned out to be mostly painted on, filmed something in the loch that wasn’t just paint. They were small, pale blobs on the grainy film. The team called them bumblebees from their shape.

Then in July of 1981, a different company searching not for Nessie but for a shipwreck from 1952 filmed some strange white creatures at the bottom of the loch. One of the searchers described them as giant white tadpoles, two or three inches long, or about 5 to 7 cm. Another searcher described them as resembling white mice but moving jerkily.

The search for the wreck lasted three weeks and the white mystery animals were spotted more than once, but not frequently. Afterwards, the company sent video of them to Dr. P Humphrey Greenwood, an ichthyologist at the Natural History Museum in London. Since this was the 1980s, of course, the film was videotape, not digital, but Dr. Greenwood got some of the frames computer enhanced. Probably on a computer that had less actual computing power than my phone. Anyway, the enhancement showed that the animals seemed to have three pairs of limbs. Dr. Greenwood tentatively identified them as bottom-dwelling crustaceans, but not ones native to Loch Ness.

Over the years many people have made suggestions as to what these mystery crustaceans might be. I’m going out on a limb here and declaring that they are not baby Loch Ness monsters. Karl Shuker suggests the white mice footage, at least, might be some kind of amphipod.

We’ve met amphipods before in a couple of episodes, mostly because some species exhibit deep-sea gigantism. Amphipods are shrimp-like crustaceans that live throughout the world in both the ocean and fresh water, and most species are quite small. While they do have more than three pairs of legs—eight pairs, in fact, plus two pairs of antennae—the 1981 videotape wasn’t of high quality and details might easily have been lost. Some of the almost 10,000 known species of amphipod are white or pale in color and grow to the right size to be the ones filmed in Loch Ness. But no amphipods of that description have ever been caught in Loch Ness.

New amphipods are discovered all the time, of course. They’re simply everywhere, and the smallest species are only a millimeter long. But because they’re so common, it’s also easy to transport them from one body of water to another. A rare amphipod discovered in Alpine lakes only a few years ago is already threatened by a different, more common species of amphipod introduced to one of the lakes by accident. So it’s possible that the white mice crustaceans in Loch Ness traveled there on someone’s boat.

That’s certainly the case with another creature found in Loch Ness in 1981, but we know exactly what this one is. It’s a flatworm native to North America, a bit over an inch long, or 3 cm, and only about 5 millimeters wide. It attaches its cocoons to boat bottoms, and in this case it was brought to Loch Ness by equipment used to hunt for Nessie. Spoiler alert: they didn’t find her.

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