Episode 402: The Hoop Snake and Friends

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Thanks to Nora and Richard from NC this week as we learn about some scary-sounding reptiles, including the hoop snake!

Further reading:

The Story of How the Giant “Terror Skink” Was Presumed Extinct, Then Rediscovered

San Diego’s Rattlesnakes and What To Do When They’re on Your Property

Snake that cartwheels away from predators described for the first time

Giant new snake species identified in the Amazon

The terror skink, AKA Bocourt’s terrific skink [photo by DECOURT Théo – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=116258516]:

The hoop snake according to folklore:

The sidewinder rattlesnake [photo taken from this article]:

The dwarf reed snake [photo by Evan Quah, from page linked above]:

The green anaconda [photo by MKAMPIS – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=62039578]:

Show transcript:

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

As monster month continues, we’re going to look at some weird and kind of scary, or at least scary-sounding, snakes and lizards. Thanks to Nora and Richard from NC for their suggestions this week!

We’ll start with the terror skink, whose name should inspire terror, but it’s also called Bocourt’s terrific skink, which is a name that should inspire joy. Which is it, terror or joy? I suppose it depends on your mood and how you feel about lizards in general. All skinks are lizards but not all lizards are skinks, by the way.

The terror or possibly terrific skink lives on two tiny islets, which are miniature islands. These islets are themselves off the coast of an island called the Isle of Pines, but in French, which I cannot pronounce. The Isle of Pines is only 8 miles wide and 9 miles long, or 13 by 15 km, and is itself off the coast of the bigger island of New Caledonia. All these islands lie east of Australia. Technically the islets where the skink lives are off the coast of another islet that is itself off the coast of the Isle of Pines, which is off the coast of New Caledonia, but where exactly it lives is kept a secret by the scientists studying it.

The skink was described in 1876 but only known from a single specimen captured on New Caledonia around 1870, and after that it wasn’t seen again and was presumed extinct. Colonists and explorers brought rats and other invasive animals to the New Caledonian islands, which together with habitat loss have caused many other native species to go extinct.

But in December 2003, a scientific expedition studying sea snakes around the New Caledonian islands caught a big lizard no one recognized. Once the expedition members realized it was a terror skink, alive and well, they took lots of pictures and videos of it and then released it back into the wild. Since then, more specimens have been discovered during four different expeditions, but only on the islets, not on any of the bigger islands. It’s so critically endangered that its location has to be kept secret, because if someone captures some of the lizards to sell on the illegal pet market, the species could easily be driven to extinction.

The terror skink is gray-brown with darker stripes, a long tail, and a slightly downturned mouth that makes it look grumpy. It grows about 20 inches long, or 50 cm, including its tail. This is really big for a skink, so technically it’s a giant skink.

It gets the name terror skink from its size and from its teeth, which are large and curved like fangs. It mainly eats one particular species of land crab, which is why its jaws are so strong and its teeth are so sharp, so it can bite through the crab’s exoskeleton.

Another lizard with a spooky name that has been presumed extinct is the gray ghost lizard, suggested by Richard from NC. It’s more properly called the giant Tongan ground skink, and it’s native to some more South Pacific islands—specifically, the Tongan Islands. These islands are even farther east from Australia than the New Caledonian islands, and are actually closer to New Zealand than to Australia, although they’re not really very close to either.

The giant Tongan ground skink was described in 1839 from two specimens collected in the late 1820s on Tongatapu Island. They’re the only two specimens known and the lizard is considered extinct, especially considering that these days, the island is almost completed deforested and rats, dogs, and cats have been introduced to it, which has driven many species to extinction.

But after the terror skink was rediscovered, scientists started to wonder if the gray ghost might still be around. It was called the gray ghost because it was so hard to see, since it was dark gray in color. The native Tongan people considered it a good omen if someone saw one, since it was so rare.

A paper published in early 2024 suggests that the gray ghost might be living on some smaller islands where forests still remain, and also suggested that it might be nocturnal and a burrowing skink. That would explain why it was so rarely seen by the people who lived on its island when it was still alive.

We know basically nothing about the gray ghost. Hopefully an expedition to the smaller Tongan islands will rediscover it so we can learn more about it and protect it.

Richard from NC also suggested we talk about the hoop snake, an animal of folklore. I remember reading about it as a kid in a book about American folklore animals, most of which were clearly jokey and not meant to seem real. The hoop snake sounded more realistic.

The hoop snake was supposed to be a long, slender snake that slithered around normally most of the time, but when it needed to move faster, it would grab the end of its tail in its mouth and roll like a wheel, or a hoop. Some versions of the story had the snake rolling along with the tip of its tail pointed forward, and since the tail was supposed to be sharp and venomous, it would roll after you so fast that when its tail stabbed you, you’d drop dead. The only way to escape would be to jump behind a tree. The tail would stab the tree instead and you could run away while the hoop snake was trying to unstick its tail. The venom in its tail was supposed to be so deadly that the tree would turn black and die. Other versions of the story said you had to jump through the snake’s hoop to confuse it, which would allow you to get away safely.

All this is weird, to say the least, but some snakes do have ways of traveling that are unusual. The sidewinder, for instance, is a real species of rattlesnake from the southwestern United States and northwestern Mexico. It grows around 2 ½ feet long, or 80 cm, and has pointy scales, called keeled scales, including a pair above its eyes that make it look like it has little horns. Since it’s a type of rattlesnake, it has a rattle that it can shake to make a loud warning noise. It’s mostly brown in color, or sometimes pinkish, yellowish, or even whitish, with darker stripes or blotches down its back. Its coloration helps camouflage it against the ground, and it will actually change color slightly depending on the temperature. This is something other rattlesnakes can do too.

The sidewinder lives in desert conditions where it has to travel through loose sand, and the sand is also extremely hot. While the snake can travel normally when it wants to, it sidewinds to move quickly over loose sand or very hot sand that might burn it. It lifts most of its body up so that it’s only touching the ground in two places, then undulates its body so that the sections touching the ground constantly move. That way no part of its body has to stay in contact with hot sand for more than a split second. It travels in a path that runs diagonal to the direction its body is pointing. That sounds complicated, but it’s easy for the snake. It’s not even the only snake that can travel by sidewinding. Other desert-living snakes travel across hot sand by sidewinding, including several species from Africa, but just about any snake can do it if they need to. It allows a snake to travel over surfaces that are too slippery for its belly scales to get a grip.

The story of the hoop snake might be based on garbled reports of sidewinders, but it might just be a completely invented animal. The hoop snake story is found in other parts of the world too, especially Australia, although it dates back to at least the late 18th century in the United States.

No snake in the world has the anatomy to allow it to roll like a hoop without hurting itself. But there is one other snake that does something very similar, called cartwheeling. It’s the dwarf reed snake that lives in Malaysia and other parts of southeast Asia. Reed snakes aren’t very well known to science, so this cartwheeling activity wasn’t documented scientifically until recently, with the study published in 2023. Reed snakes are nocturnal and spend most of the daytime hiding under rocks or logs, or buried in dead leaves or sand, so they’re not seen very often by people. The dwarf reed snake is slender and only grows about 10 inches long, or 25 cm.

Some small snakes can jump short distances by pushing their tails against the ground. The dwarf reed snake does something similar, but more complicated. It pushes off with its tail, with its body curved in a sort of S shape. It lands on its head and rolls over completely, head to tail, and then pushes off the ground again with its tail. It can move extremely fast in this way to get away from predators, but it takes a whole lot of energy. But when it’s moving downhill, with gravity on its side, it can continue to cartwheel longer.

Cartwheeling isn’t something the snake does often, and it’s rare that a human would ever observe it. But just like sidewinding, some scientists think cartwheeling might be a motion that more snakes can do if they really need to. Maybe that’s where the hoop snake legend started.

Let’s finish with a suggestion from Nora, who wanted to learn more about the green anaconda. That’s a scary snake for sure, because it happens to be the biggest snake alive today, and almost the longest, as far as we know.

The green anaconda lives throughout much of South America, although not in Patagonia because like most reptiles, it needs warm weather to function. It’s a beautiful olive green with black blotches, and it’s a big, bulky snake. It spends a lot of time in the water, which helps it stay cool in hot weather and helps support its weight comfortably, and its eyes are near the top of its head so it can watch for prey while it’s mostly submerged.

The anaconda is a member of the boa family and is a constrictor. It’s not venomous, but you really don’t want a hug from a hungry anaconda. Its body is bulky because it’s incredibly strong, and once it starts to contract its muscles, whatever it’s constricting has only minutes left to live. It can kill animals as large as caimans, which are a type of crocodile, tapirs, capybaras, deer, and even jaguars. For the most part, though, an anaconda doesn’t want to bother with prey that could potentially hurt it, so it will stick with smaller animals that are still big enough to make it worth the effort. And yes, it is possible that an anaconda in the wild could kill and eat a human, but there’s no reliable evidence that it’s ever happened.

It’s hard to know exactly how long and how heavy an anaconda can get. There are lots of stories of 30-foot, or 9-meter snakes, but that seems to be a wild exaggeration. Snakes are stretchy, and a healthy live snake doesn’t really want to stretch out straight to be measured. A dead snake is even stretchier than a live snake. A shed snakeskin is the stretchiest of all, and usually has stretched out quite a bit when the snake was shedding. A good estimate is that a big female anaconda can grow about 20 feet long, or 6 meters, and can weigh around 250 lbs, or 114 kg. Males are smaller on average, and a wild snake will weigh less than one kept in captivity.

There are definitely larger individual anacondas, especially considering that reptiles continue to grow throughout their lives, but they’re probably not that much longer. This is only a little shorter than the reticulated python, which can definitely grow up to 23 feet long, or 7 meters.

One important detail about the size of the green anaconda is that the biggest snakes live in the Amazon rainforest–but the Amazon rainforest is really hard for humans to navigate safely and most anacondas killed or kept in captivity lived in other parts of South America. So there might easily be anacondas in the rainforest that are much bigger than the ones scientists have been able to measure so far.

In February of 2024, a journal article was published about a 2022 National Geographic nature documentary and scientific expedition to the Amazon basin to find a rumored population of extra-large anacondas. The expedition was led by hunters from the Waorani people, who consider the snakes sacred, and the hunters and their chief were credited as co-authors of the paper, as they should be since they provided so much information.

The scientists were able to examine several fully grown anacondas and take tiny tissue and blood samples to test later. They were astounded at the size of the snakes they found, including one that measured 20 and a half feet long, or 6.3 meters. The hunters reported seeing snakes that they estimated as over 24 feet long, or 7.5 meters, that might have weighed as much as 500 pounds, or 226 kg.

Beyond mere size, though, is something very interesting, which the scientists learned when they got home and ran genetic tests. The anacondas are actually quite different genetically from other anacondas known to science, that live farther south. They described the snake as a new species, which they refer to as the northern green anaconda, but it has actually resulted in a lot of controversy. Some scientists agree that the northern green anaconda is a separate species, others think it’s only a subspecies of the green anaconda, while others think the genetic differences are minor and separating the northern green anaconda from other anacondas isn’t justified by the evidence.

Obviously scientists need to follow up and learn more about the anacondas, but one thing is clear. There are some really, really big snakes out there in the Amazon.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 401: El Gran Maja and Other Giant Eels

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Thanks to Murilo for suggesting El Gran Maja for our first monster month episode of 2024!

Further reading:

The Loch Ness Monster: If It’s Real, Could It Be an Eel?

Further watching:

Borisao Blois’s YouTube channel [I have not watched very many of his videos so can’t speak to how appropriate they all are for younger viewers]

El Gran Maja, YouTube star:

The European eel [photo by GerardM – http://www.digischool.nl/bi/onderwaterbiologie/, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=284678]:

A supposed 21-foot eel, a product of trick photography:

The slender giant moray eel [photo by BEDO (Thailand) – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=40262310]:

Show transcript:

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

It’s monster month, where we talk about weird, mysterious, and sometimes spooky creatures! This year I’ve decided to be less spooky and more weird, so let’s kick off the month with an episode all about gigantic eels. Thanks to Murilo for suggesting our first giant eel, El Gran Maja.

El Gran Maja is an eel that is supposed to live off the coast of northern Puerto Rico, and it’s supposed to grow 675 meters long. That’s 2,215 feet, or almost half a mile. That is an excessive amount of eel.

Obviously, an eel that big couldn’t actually exist. By the time its front end noticed danger, its back end could already be eaten by a whole family of sharks. But maybe it was based on a real eel that grows really long. Let’s take a look at some eels we know exist, and then we’ll return to El Gran Maja and learn some very interesting things about it.

Eels are fish, but not every animal that’s called an eel is actually an eel. Some are just eel-shaped, meaning they’re long and slender. Electric eels aren’t actually eels, for instance, but are more closely related to catfish. Most eels live in the ocean at the beginning and end of their lives, and freshwater in between.

For example, the European eel has a life cycle that’s pretty common among eels. It hatches in the ocean into a larval stage that looks sort of like a transparent leaf. Over the next six months to three years, the larvae swim and float through the ocean currents, closer and closer to Europe, feeding on plankton and other tiny food. Toward the end of this journey, they grow into their next phase, where they resemble eels instead of leaf-shaped tadpoles, but are still mostly transparent. They’re called glass eels at this point. The glass eels make their way into rivers and slowly migrate upstream. Once a glass eel is in a good environment it metamorphoses again into an elver, which is basically a small eel. As it grows it gains more pigment until it’s called a yellow eel. Over the next decade or two it grows and matures, until it reaches its adult length—typically around 3 feet, or about a meter. When it’s fully mature, its belly turns white and its sides silver, which is why it’s called a silver eel at this stage. Silver eels migrate more than 4,000 miles, or 6500 km, back to the Sargasso Sea to spawn, lay eggs, and die.

One place where European eels live is Loch Ness in Scotland, and in the 1970s the idea that sightings of the Loch Ness Monster might actually be sightings of unusually large eels became popular. A 2018 environmental DNA study brought the idea back up, since the study discovered that there are a whole, whole lot of eels in Loch Ness. The estimate is a population of more than 8,000 eels in the loch, which is good since the European eel is actually critically endangered. But most of the eels found in Loch Ness are smaller than average, and the longest European eel ever measured was only about 4 feet long, or 1.2 meters.

An eel can’t stick its head out of the water like Nessie is supposed to do, but it does sometimes swim on its side close to the water’s surface, which could result in sightings of a string of many humps undulating through the water.

But the Loch Ness monster aside, the European eel isn’t very big compared to many species of eel. The European conger eel is the heaviest eel known, although not the longest. It lives off the coast of Europe down to northern Africa, and also in the Mediterranean Sea. An exceptionally large female might be as much as 10 feet long, or 3 meters, but it’s also chonkier than other eels. The largest conger ever measured reportedly weighed 350 lbs, or almost 159 kg, and was caught in a net off the coast of Iceland, although that report isn’t very reliable.

In 2015, a lot of newspaper reports talked about a huge eel caught off the coast of Devon, England. They printed pictures of a massively huge eel hung up in front of the fishermen who caught it. The articles said the eel was as much as 21 feet long, or 6.4 meters, and weighed 160 lbs, or just over 72 kg.

But if you think about it, there’s something fishy (sorry) about the story. If you picture a big man, say a football player who’s fit and strong, he might be about six feet tall, or 1.8 meters, and weigh a bit more than 200 lbs, or maybe 95 kg. But the eel weighed a lot less than that hypothetical man, and eels are strongly muscled even though they’re slender in shape. A 21 foot eel should weigh much more than a football player.

Most likely, reporters looked at the photo and compared it to the fishermen, and came up with the 21 foot length themselves. But it’s a trick photo, even if the trick wasn’t planned, because the eel was hung up very close to the camera while the fishermen were much farther back, which makes the eel look huge in comparison. Not only that, but when you hang a dead eel up by its head, it stretches so that it looks longer than it really was when it was alive. Other pictures of the eel make it look much shorter.

As it turns out, the fishermen who caught the eel didn’t even measure it. They thought it might have been up to 10 feet long, but it might have been closer to 7, or 2 meters. That’s still a big eel, and the weight may be close to a reliable record of heaviest eel, but it’s nowhere near the longest eel ever measured.

That record goes to the slender giant moray eel, which lives in muddy coastal water of the Pacific Ocean. It’s brown and isn’t especially exciting to look at unless you’re an eel enthusiast or an actual eel yourself, but the longest eel ever reliably measured was a slender giant moray. That was in 1927 in Queensland, Australia. The eel measured just shy of 13 feet long, or 3.94 meters.

In other words, the longest eel ever measured is approximately 2,202 feet, or 671 meters, shorter than El Gran Maja. But to learn more about El Gran Maja we have to talk about something called the bloop.

The bloop is a sound recorded in 1997 off the tip of South America by the National Oceanic and Atmospheric Administration, AKA NOAA. The sound itself came from the middle of the South Pacific Ocean, and was so loud that it was recorded by sensors 3,000 miles away, or 5,000 km. But it was also an ultra-low-frequency sound, so that humans and most other animals wouldn’t be able to hear it at all.

This is what the bloop sounds like, sped up 16 times so that people can hear it:

[bloop sound]

It turns out that the bloop was made by a big iceberg breaking into pieces, and similar sounds have been recorded since by NOAA and other researchers. But when the bloop was first made public, its source was still a mystery, and pretty much everyone on the internet lost their minds with excitement thinking it was a deep-sea creature far bigger than a blue whale. People speculated about the size of the bloop monster and estimated it had to be about 705 feet long, or 215 meters, for it to make such a loud call.

A film-maker and artist named Borisao Blois was interested in the bloop monster and wanted to animate it, but decided it needed a rival to fight—and he wanted the rival to be even bigger. He invented El Gran Maja and animated a fight between the two. Because Blois wanted his monster to be exciting to look at during his films, he gave it a huge wide mouth filled with sharp, comb-like teeth, and six all-white eyes. The first video was released in 2001 and has more than 89 million views. Many more videos followed, along with creations made by other artists who were inspired by the original.

The videos Blois has made about El Gran Maja are popular, and some people even think it might be a real monster. Considering that an eel that big would need to eat an astounding amount of food every day to survive, and it’s big enough to swallow entire ships whole, it’s probably a good thing that it’s just a made-up monster.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 400: Four no wait Five Mysteries!

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To donate to help victims of Hurricane Helena:

Day One Relief – direct donation link

World Central Kitchen – direct donation link

It’s the big 400th episode! Let’s have a good old-fashioned mystery episode! Thanks to Richard from NC for suggesting two of our animal mysteries today.

Further reading:

A 150-Year-Old Weird Ancient Animal Mystery, Solved

The Enigmatic Cinnamon Bird: A Mythical Tale of Spice and Splendor

First ever photograph of rare bird species New Britain Goshawk

Scientists stumbled onto toothy deep-sea “top predator,” and named it after elite sumo wrestlers

Bryde’s whales produce Biotwang calls, which occur seasonally in long-term acoustic recordings from the central and western Pacific

A stylophoran [drawing by Haplochromis – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10946202]:

A cinnamon flycatcher, looking adorable [photo by By https://www.flickr.com/photos/neilorlandodiazmartinez/ – https://www.flickr.com/photos/neilorlandodiazmartinez/9728856384, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=30338634]:

The rediscovered New Britain goshawk, and the first photo ever taken of it, by Tom Vieras:

The mystery fish photo:

The yokozuna slickhead fish:

The Biotwang maker, Bryde’s whale:

Show transcript:

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

We’ve made it to the big episode 400, and also to the end of September. That means monster month is coming up fast! To celebrate our 400th episode and the start of monster month, let’s have a good old-fashioned mysteries episode.

We’ll start with an ancient animal called a stylophoran, which first appears in the fossil record around 500 million years ago. It disappears from the fossil record around 300 million years ago, so it persisted for a long time before going extinct. But until recently, no one knew what the stylophoran looked like when it was alive, and what it could possibly be related to. It was just too weird.

That’s an issue with ancient fossils, especially ones from the Cambrian period. We talked about the Cambrian explosion in episode 69, which was when tiny marine life forms began to evolve into much larger, more elaborate animals as new ecological niches became available. In the fossil record it looks like it happened practically overnight, which is why it’s called the Cambrian explosion, but it took millions of years. Many of the animals that evolved 500 million years ago look very different from all animals alive today, as organisms evolved body plans and appendages that weren’t passed down to descendants.

As for stylophorans, the first fossils were discovered about 150 years ago. They’re tiny animals, only millimeters long, and over 100 species have been identified so far. The body is flattened and shaped sort of like a rectangle, but two of the rectangle’s corners actually extend up into little points, and growing from those two points are what look like two appendages. From the other side of the rectangle, the long flat side, is another appendage that looks like a tail. The tail has plates on it and blunt spikes that stick up, while the other two appendages look like they might be flexible like starfish arms.

Naturally, the first scientists to examine a stylophoran decided the tail was a tail and the flexible appendages were arm-like structures that helped it move around and find food. But half a billion years ago, there were no animals with tails. Tails developed much later, and are mainly a trait of vertebrates.

That led to some scientists questioning whether the stylophoran was an early precursor of vertebrates, or animals with some form of spinal cord. The spikes growing from the top of the tail actually look a little bit like primitive vertebrae, made of calcite plates. That led to the calcichordate hypothesis that suggested stylophorans gave rise to vertebrates.

Then, in 2014, scientists found some exceptionally well preserved stylophoran fossils in the Sahara Desert in Africa. The fossils dated to 478 million years ago and two of them actually had soft tissue preserved as the mineral pyrite. Pyrite is also called fool’s gold because it looks like gold but isn’t, so these were shiny fossils.

When the soft tissue was observed through electron microscopes in the lab, it became clear that the tails weren’t actually tails. Instead, they were more like a starfish arm, with what may be a mouth at the base. The arm was probably the front of the animal, not the back like a tail, and the stylophoran probably used it to grab food and maybe even to crawl around.

Most scientists today agree that stylophorans are related to modern echinoderms like starfish and urchins, but there is one big difference. Echinoderms show radial symmetry, but no stylophoran found so far does. It doesn’t really even show bilateral symmetry, since the two points aren’t really symmetrical to each other. We’re also not sure what the points were for and how such an unusual body plan really worked, so there are still a lot of mysteries left regarding the stylophoran.

Next let’s talk about a mythical bird, called some variation of the word cynomolgus, or just the cinnamon bird. Naturalists from the ancient world wrote about it, including Pliny the Elder and Aristotle, and it appeared in medieval bestiaries. It was said to be from Arabia and to build its nest of cinnamon sticks in the tops of very tall trees or on the sides of cliffs.

Cinnamon comes from the inner bark of cinnamon trees, various species of which are native to southern Asia and Oceania. It’s an evergreen tree that needs a tropical or subtropical climate to thrive, and it smells and tastes really good to humans. You might have seen cinnamon sticks, which are curled-up pieces of dried cinnamon bark, and that’s the same type of cinnamon people used in the olden days. Ground cinnamon is just the powdered bark. Like many other spices, it was highly prized in the olden days and cost a fortune for just a little bit of it. Ancient Egyptians used it as part of the embalming process for mummies, ancient Greeks left it as offerings to the sun god Apollo, ancient Romans burnt it during the funerals of nobility, and it was sought after by kings throughout the world.

One interesting thing is that if you live in the United States, the cinnamon in your kitchen cupboard is probably actually cassia, also called Chinese cinnamon because it’s native to southern China. Cassia is often mentioned alongside cinnamon in old writings, because they’re so similar, but true cinnamon comes from a tree native to Sri Lanka. It’s usually marketed as Ceylon cinnamon and is more expensive, but cassia is actually better for baking. True cinnamon has a more subtle flavor that’s especially good with savory dishes, but it loses a lot of its flavor if you bake with it.

Anyway, back in the olden days, no one outside of subtropical Asia and Oceania knew where cinnamon came from. The traders who bought it from locals to resell definitely weren’t going to tell anyone where it was from. They made up stories that highlighted just how hard cinnamon was to find and harvest, to discourage anyone from trying to find cinnamon on their own and to keep prices really high. As Pliny the Elder pointed out 2,000 years ago, the cinnamon bird was one of those stories.

The cinnamon bird was supposedly the only animal that knew where cinnamon trees grew, and it would peel pieces of the bark off with its beak, then carry them to the Arabian desert or somewhere just as remote, where it would build a nest of the bark. The birds were supposed to be enormous, sometimes so big that their open wings stretched from horizon to horizon. Their nests were equally large, but so hard to reach that no human could hope to climb up and collect the cinnamon. Instead, cinnamon hunters left dead oxen and other big animals near the area where the birds had nests. The birds would swoop down and carry the oxen back to their nests to eat, and the extra weight would cause the nests to fall. In other stories, cinnamon hunters would shoot at the nests with arrows with ropes attached. Once several arrows were lodged into a nest, the hunters would pull the ropes to dislodge the nest and cause it to fall, so they could collect the cinnamon.

Of course none of that is true. Some scholars think the cinnamon bird is probably the same mythical bird as the phoenix, but without any magical abilities. Others agree with Pliny the Elder that it was just a way for traders to raise their prices for cinnamon even more. Either way, the cinnamon bird is probably not a real animal.

There are birds with cinnamon in their name, but that’s just a reference to their coloration. Cinnamon is generally a reddish-brown in color, and in animals that color is often referred to as rufous, chestnut, or cinnamon. For example, the cinnamon flycatcher, which lives in tropical and cloud forests along the Andes Mountains in South America. It’s a tiny round bird, only about 5 inches long including its tail, or 13 cm. It’s dark brown and red-brown in color with black legs and beak, and a bright cinnamon spot on its wings. It eats insects, which you could probably guess from the name.

This is what a cinnamon flycatcher sounds like:

[tiny bird sound]

Next, we need to talk about the New Britain goshawk, which Richard from NC told me about recently. It lives in tropical forests of Papua New Guinea, and is increasingly threatened by habitat loss. In fact, it’s so rare that it was only known from four specimens, and it hadn’t been officially spotted since 1969 and never photographed—until March of 2024.

During a World Wide Fund for Nature expedition, a wildlife photographer named Tom Vierus took lots of pictures of birds. One bird he photographed was a hawk sitting in a tree. He didn’t realize it was a bird that hadn’t been seen by scientists in 55 years, until later when he and his team were going through his photographs.

The goshawk is large, and is gray and white with an orange face and legs. We know very little about the bird, naturally, but now that scientists know it’s alive and well, they can work with the local people to help keep it safe. It’s called the keango or kulingapa in the local languages.

Next, we have a bona fide mystery animal, and a deep-sea mystery animal at that—the best combination!

In 1965, the U.S. Navy teamed up with Westinghouse to build a submersible designed by the famous diver and naturalist Jacques Cousteau. The craft was called Deepstar 4000 and between 1965 and 1972 when it was retired, it conducted hundreds of dives in different parts of the world, allowing scientists to learn a lot about the ocean. It could safely dive to 4000 feet, or 1200 meters, which isn’t nearly as deep as many modern submersibles, but which is still impressive.

This was long before remotely operated vehicles, so the submersible had to have a crew inside, both scientists and pilots. One of the pilots of Deepstar 4000 was a man named Joe Thompson. In 1966 Thompson maneuvered the craft to the ocean floor off the coast of California to deploy water sensors, in an area called the San Diego Trough. They touched down on the ocean floor and Thompson looked out of the tiny porthole, only to see something looking in at him.

Thompson reported seeing a fish with mottled gray-black skin and an eye the size of a dinner plate. He estimated it was 25 feet long, or over 7 ½ meters, which was longer than the Deepstar 4000 itself. Within seconds, the fish swam away into the darkness.

But that’s not the end of the story, because the water sensors the craft had already placed sensed the animal’s movement. There was definitely something really big near the craft. Even more interesting, an oceanographer had placed some underwater cameras in the area, and soon after Thompson’s sighting, the cameras took pictures of a huge gray fish.

While Thompson was positive the fish had scales, which he described as being as big around as coffee cups, the photo shows a more shark-like skin criss-crossed with scars. The oceanographer consulted with an ichthyologist, who identified the fish as a Pacific sleeper shark. We’ve talked about other sleeper sharks in episode 74. We don’t know a lot about these sharks, but they are gray, live in deep water, and can grow over 23 feet long, or 7 meters.

But Thompson was never satisfied with the identification of his mystery fish as a big Pacific sleeper shark. He was adamant that his fish had scales, a much larger eye than sharks have, and a tail that was more reminiscent of a coelacanth’s lobed tail than a shark’s tail.

One suggestion is that Thompson saw a new species of slickhead fish. Slickheads are deep-sea fish that can grow quite large, but we don’t know much about them since they live in such deep waters. The largest known species grows at least 8 feet long, or 2.5 meters, and possibly much longer. That’s the yokozuna slickhead, which was only discovered in 2021 by a scientific team studying cusk eels off the coast of Japan.

Most slickheads are small and eat plankton. This one was purplish in color, had lots of small sharp teeth, and was a strong, fast swimmer. When it was examined later, its stomach contents consisted of other fish, so it’s definitely a predator. Its eyes are also proportionately larger than a shark’s eyes. The slickhead gets its name because it doesn’t have scales on its head, but it does have scales on the rest of its body.

The yokozuna slickhead was discovered in a bay that’s well-known to both scientists and fishers, so the team didn’t believe at first that they could possibly have found a new species of fish there, especially one that was so big. But it definitely turned out to be new to science. More individuals have since been spotted, but they live very deep in the ocean, which explains why no one had seen one before. Interestingly, when the scientists first pulled the slickhead out of the water, they thought it looked a little like a coelacanth.

This episode was going to end there, but Richard from NC sent me another article about a whale mystery I’ve been talking about for years! It’s the so-called biotwang that we covered way back in episode 27.

In 2016 and early 2017, NOAA, the U.S. Coast Guard, and Oregon State University dropped a titanium-encased ceramic hydrophone into Challenger Deep. To their surprise, it was noisy as heck down there in the deepest water on earth. The hydrophone picked up the sounds of earthquakes, a typhoon passing over, ships, and whalesong—including the call of a whale researchers couldn’t identify. This is what it sounds like:

[biotwang whale call]

Well, as of September 2024, we now know what animal produces the biotwang call. It’s a whale, and one already known to science, although we don’t know much about it. It’s Bryde’s whale, a baleen whale that can grow up to 55 feet long, or almost 17 meters. The calls have all been associated with groups of Bryde’s whales, or a mother with a calf, so the scientists think the whales might use the unusual call to communicate location with its podmates. Bryde’s whales make lots of other sounds, and the scientists also think they might be responsible for some other mystery whale calls.

If you remember episode 193, about William Beebe’s mystery fish, he reported spotting a massive dark fish from his bathysphere a few decades before the Deepstar 4000 was built. He didn’t see it well enough to identify it and never saw it again. It just goes to show that there are definitely mystery animals just waiting to be discovered, whether it’s in the deep sea or perched in a treetop.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 399: Bears

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Thanks to Anbo, Murilo, Clay, and Ezra for their suggestions this week! Let’s learn about some bears!

Further reading:

Snack attack: Bears munch on ants and help plants grow

Extinct vegetarian cave bear diet mystery unravelled

Ancient brown bear genomes sheds light on Ice Age losses and survival

The sloth bear has shaggy ears and floppy lips [photo from this site]:

An absolute unit of a Kodiak bear in captivity [photo by S. Taheri – zoo, own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1118252]:

A polar bear:

Show transcript:

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

This week we’re revisiting a popular topic, bears! We’ll talk about some bears we’ve never covered before, with suggestions from Anbo, Clay, Ezra, and Murilo. We’ll even discuss a small bear mystery which has mostly been solved by science.

To start us off, Anbo wanted to learn about bears in general. We’ve had bear episodes before, but our last episode all about bears was way back in 2017, in episode 42. Some of our listeners weren’t even born back then, which makes me feel super old.

Bears live throughout much of the world today, but they evolved in North America around 38 million years ago. These ancestral bears were small, about the size of a raccoon, but they were successful. They spread into Asia via the land bridge Beringia, where they were even more successful than in North America, so successful that by around 30 million years ago, descendants of those earliest bear ancestors migrated from Asia back into North America. But it wasn’t until the Pleistocene around 2 ½ million years ago that bears really came into their own.

That’s because bears are megafauna, and megafauna evolved mainly as an adaptation to increasingly cold climates. As the ice ages advanced, a lot of animals grew larger so they could stay warm more easily. Predators also had to grow larger as their prey became larger, since if you want to hunt an animal the size of a bison or woolly rhinoceros, you’d better be pretty big and strong yourself.

Bears mostly weren’t hunting animals that big, though. Modern studies suggest that overall, bears are omnivores, not fully carnivorous. Bears eat a lot of plant material even if you don’t count the panda, which isn’t very closely related to other bears. Even when a bear does eat other animals, they’re not usually very big ones.

Let’s take Murilo’s suggestion as an example, the sloth bear. The sloth bear lives in India and is increasingly vulnerable due to habitat loss and poaching. It’s probably most closely related to the sun bear that we talked about in episode 234, which also lives in parts of South Asia. Both the sun bear and the sloth bear have long black hair and a white or yellowish V-shaped marking on the chest. The sloth bear’s hair is especially long on its neck and shoulders, like a mane, and its ears even have long hair.

The sloth bear stands around 3 feet high at the shoulder at most, or 91 cm, and a big male can be over 6 feet tall, or almost 2 meters, when he stands on his hind legs. This isn’t gigantic for bears in general, but it’s not small either. Scientists think the V-shaped marking on its chest warns tigers to leave the sloth bear alone, and tigers mostly do. If tigers think twice about attacking an animal, you know that animal has to be pretty tough.

The sloth bear has massive claws on big paws. The claws can measure 4 inches long, or 10 cm, although they’re not very sharp. The bear has an especially long muzzle but its teeth aren’t very large. Like most bears, it’s good at climbing trees and can run quite fast, and it swims well too. It even has webbed toes.

With all this in mind, what do you think the sloth bear eats? I’ll give you some more hints. It has loose, kind of flappy lips, especially the lower lip. It doesn’t have any teeth in the front of its upper jaw. It mainly uses its huge claws to dig.

If you guessed that the sloth bear eats ants, termites, and other insects, you are right! It digs into termite and ant nests and uses its long, flexible lips to slurp up as many insects as it can, giving them a quick crunch with its back teeth before swallowing them down.

Insects are actually quite nutritious, and the sloth bear isn’t the only bear that eats them. All bears snack on ants and other insects sometimes. You may have heard that bears love honey and will tear open beehives to get it, and while that’s true, the bear is mainly after the larval bees because they’re so nutritious. The honey is just, you know, dessert.

Next, Clay wanted to learn about the Kodiak bear, which may be the largest bear in the world. It’s a subspecies of brown bear and is sometimes called the Alaskan brown bear since it lives on some Alaskan islands called the Kodiak Archipelago. It’s light brown or rusty-red in color.

The Kodiak bear has been restricted to these islands for at least 10,000 years, since the end of the Pleistocene when the sea levels rose as glaciers melted. It demonstrates island gigantism, which is actually quite unusual. Because islands have limited resources, but are relatively protected from large numbers of predators, small animals are the ones that generally adapt to island life by growing larger. Animals that start off large generally adapt by growing smaller, called island dwarfism. That’s why some islands have been home to dwarf elephants but giant rodents.

In the case of the Kodiak bear, it has a source of protein that helps it grow so incredibly large, salmon. Five species of salmon spawn in the freshwater on the islands, and the bears are able to put on lots of weight to survive the harsh winter by eating as much salmon as they can catch. They also have lots of nutritious plants to eat. They actually prefer some plants to eating salmon, which makes sense when you think about it. A wild animal needs to conserve energy, and it can take a lot of energy to catch fish. It’s a lot easier to eat berries, which can’t swim away.

So how big can a Kodiak bear get? A big male can stand up to 10 feet tall on his hind legs, or 3 meters, and be 5 feet tall, or 1.5 meters, when standing on all fours. Bears kept in captivity can grow even larger. That’s much bigger than a grizzly and about the same size as the closely related polar bear, which brings us to Ezra’s suggestion.

Ezra wanted to learn about the polar bear, which lives in the Arctic and areas near the Arctic. It doesn’t live near the Antarctic, or south pole, which means polar bears don’t eat penguins, because penguins live around the Antarctic. The polar bear does eat a whole lot of other animals, though, and is the most carnivorous of all bears. It especially likes eating seals, and will also catch and kill walruses, caribou, and beluga whales. That’s right, the polar bear can actually kill an entire whale. The beluga is fairly small for a whale and relies on breathing holes in the ice, and sometimes when it comes up to breathe, there’s a polar bear waiting for it. Most of the time, though, the polar bear eats much smaller animals.

The polar bear spends a lot of its time on sea ice, and a lot of the time in the sea. It swims incredibly well and spends so much time in the water that some people consider it a marine animal. It’s certainly semi-aquatic. Its kidneys are adapted to filter excess salt out of its blood from seawater, and its small eyes are closer to the top of its head than in other bears. This helps it see above water while swimming.

The polar bear is closely related to the brown bear and will sometimes interbreed with the brown bear where their ranges overlap. The resulting hybrid bear is usually light brown in color. The polar bear is famously white, although its fur becomes yellowish as the year goes on. It sheds its winter coat in the spring and the new hair that grows in is white.

Actually, the polar bear’s fur is transparent, but it looks white because of the way it scatters light. The guard hairs are long and coarse, protecting a shorter, softer undercoat that helps keep the bear warm even on bitterly cold nights. Unlike other bears, the polar bear doesn’t hibernate, except for pregnant females.

There used to be a bear of similar size that lived in Europe and Asia during the Pleistocene and only went extinct about 24,000 years ago. The cave bear gets its name because so many of its remains have been found in caves. It may have hibernated in caves like some bears do today, or it might have used caves as shelters year-round.

Scientists think the cave bear was most closely related to brown bears and polar bears. The males were much larger than females, and a big male was as big as a Kodiak or polar bear. But this giant bear probably wasn’t too much of a problem for our ancient ancestors and Neandertal relations, because it was almost entirely vegetarian.

Scientists have studied the wear pattern on cave bear teeth and determined that it was eating a whole lot of fruit, especially berries. It probably did eat at least some meat, but it’s likely that most of it came from scavenged carcasses. The cave bear didn’t even have all the teeth that other bears have.

All this talk about huge bears brings us to a mystery. It may even be a mystery you were wondering about yourself. How did bears survive the end of the Pleistocene when so many other megafauna went extinct, from the mammoth and giant ground sloth to the dire wolf and sabertooth cat?

A team of scientists from Denmark and Japan decided to examine the genetics of ancient brown bears, to learn how individuals were related and therefore how bears migrated across the world over time. They extracted genetic material from the remains of bears that lived as much as 60,000 years ago and as recently as 3,800 years ago and compared them to each other and to bears alive today.

Scientists already knew that brown bears used to live in more parts of the world than they do today. The prevailing view was that as the climate warmed after the ice ages, the bears retreated into colder parts of the world where they were more comfortable. But the team learned something surprising from the study, which was published in January of 2024.

Brown bears that lived before the end of the Pleistocene, approximately 11,000 years ago, had much broader genetic diversity than the bears that lived more recently. That means that bears that lived as far south as Japan and Ireland during the Pleistocene didn’t move to colder parts of the world, they died out. Each population that went regionally extinct made the brown bear gene pool that much smaller.

Most likely it was a combination of luck and adaptability that allowed bears to survive the end-Pleistocene extinctions. Just think how sad it would be if I ended this episode by saying that bears went extinct 11,000 years ago. Instead, we can still go to the zoo and see all kinds of bears whenever we want to.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 398: Repeating Scientific Names

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Thanks to Alexandra, Pranav, Eilee, Conner, and Joel for their suggestions this week!

Velella velella, or by-the-wind-sailor [photo from this page]:

Porpita porpita, or the blue button [photo from this page]:

Cricetus cricetus, or the European hamster, next to a golden hamster:

Nasua nasua, or the South American coati [photo from this page]:

Mola mola, or the ocean sunfish:

Quelea quelea, or the red-billed quelea [photo from this page]:

Show transcript:

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

This week we’re going to learn a little bit about scientific names, and along the way we’re going to learn about several animals. Thanks to Alexandra, Eilee, Conner, Joel, and Pranav for their suggestions!

Alexandra inspired this episode by suggesting two animals, the by-the-wind-sailor and the blue button. Both are marine invertebrates that look superficially like jellyfish, but they’re actually colonial organisms. That means that although they look like a single animal, they’re actually made up of lots of tiny animals that live together and function as one organism.

The blue button is closely related to the by-the-wind-sailor and both are related to siphonophores. Both the blue button and the by-the-wind-sailor spend most of the time near or on the ocean’s surface and have a gas-filled chamber that helps keep them afloat, with stinging tentacles that hang down into the water, but both are made up of a colony of tiny animals called hydroids. Different hydroids have different functions, and all work together to find tiny food that will benefit the entire colony.

The blue button gets its name because its float is round and flat like a button, and often blue or teal in color. It’s quite small, only a little over an inch across, or about 3 cm, and its tentacles are not much longer. The by-the-wind-sailor is a little larger than the blue button, with a blue sail-shaped float that’s only a few inches across, or maybe 7 cm, with stinging tentacles of about the same size. The stings of both organisms aren’t very strong and aren’t dangerous to humans, but they do hurt, so it’s a good idea not to touch one. Since both can be very common in warm ocean waters and they sometimes get blown ashore by the wind in large numbers, it can be hard to avoid them if you’re visiting the beach at the wrong time. They can still sting you if they’re dead, too.

The by-the-wind sailor has the scientific name of Velella velella while the blue button’s scientific name is Porpita porpita. The term for a scientific name that contains the same words is a repeating scientific name, also called a tautonym or tautonymous name, and that’s the subject of this episode.

A scientific name is something we mention a lot but if you’re not sure what it means, it can sound confusing. Every organism with a scientific name has been described by a scientist, meaning it’s been studied and placed somewhere in the great interconnected web of life. The system of giving organisms scientific names is called binomial nomenclature. The first word of the name indicates which genus the organism belongs to, while the second word indicates what species it is. These are called generic and specific names. Some organisms also have a third word in their scientific name which indicates its subspecies.

The reason scientists use a complicated naming system is to make it easier for other scientists to know exactly what organism is being discussed. For example, let’s say a scientist has been studying hamsters in the wild to learn more about them, and publishes a paper about her observations. If she just calls the animal a hamster, someone reading it might assume she was talking about the hamster found in their part of the world, when the paper is actually about a totally different, although closely related, hamster that lives somewhere else. And that brings us to Pranav’s suggestion, the European hamster, whose scientific name is Cricetus cricetus [cry-SEE-tus].

The hamster most of us are familiar with is actually the golden hamster, also called the Syrian hamster, more properly called Mesocricetus auratus. That’s the most common species kept as a pet. We can learn from the different scientific names that the European hamster is in a different genus from the golden hamster, which usually means it’s pretty different in some significant ways.

The European hamster lives throughout parts of Eurasia, especially eastern Europe through central Asia, and used to be extremely common. It’s also called the black-bellied hamster because the fur on its underside is black, while the fur on its upper side is tan or brown with white markings. These days it’s critically endangered due to habitat loss and being killed by farmers who think it hurts their crops. It does eat seeds, vegetables, and some roots, but it also eats grass and many other plants that are considered weeds, as well as insects, including insects that farmers also don’t want in their gardens.

In many respects, the European hamster is a lot like the golden hamster. It carries food home to its burrow in its cheek pouches and stores food in a larder. It hibernates in cold weather but wakes up around once a week to have a snack from its larder, which honestly sounds like the best way to spend the winter. But the European hamster is larger than the golden hamster. Like, a lot larger. The golden hamster is maybe 5 inches long, or 13 cm, which is small enough that you can easily hold it in your hand. The European hamster grows up to 14 inches long, or 35 cm. That’s the size of a small domestic cat, but with a short little hamster tail and short little hamster legs.

Even though an organism’s scientific name only designates genus and species, and subspecies when applicable, it allows scientists to look up a more detailed family tree. Every genus is classified in a family and every family is classified in an order, and every order in a class, and every class in a phylum, and every phylum in a kingdom, and every kingdom in a domain. Almost all of the organisms we talk about in this podcast belong to the kingdom Animalia. The more of these categories an organism shares with another organism, the more closely related they are.

Conner suggested we learn more about the coati, which we talked about in episode 302. The South American coati’s scientific name is Nasua nasua [NAH-sue-uh]. It grows almost four feet long, or 113 cm, which makes it sound enormous, but half of its length is its long ringed tail. It lives in much of South America, especially the northern part of the continent.

The coati is related to the raccoon of North America, and the two animals’ scientific names can help us determine how closely they’re related. The common raccoon’s scientific name is Procyon [PROSE-eon] lotor, so we already know it belongs to a different genus than the coati. But both the genus Procyon and the genus Nasua are classified in the family Procyonidae. So we know they’re closely related, because they belong to the same family, but not as closely related as they’d be if they belonged to the same genus, so we can expect to see some fairly significant differences between the two animals.

The South American coati is diurnal, unlike the nocturnal raccoon. While female raccoons often live in small groups of a few animals that share the same territory, female coatis live in groups of up to 30 animals who forage for food together and are very social. The coati also doesn’t have a set territory. The male coati is completely solitary, while the male raccoon will also live in small groups of three or four animals. Both are omnivorous but the coati eats more fruit and insects than the raccoon does, and the coati doesn’t dunk its food in water the way the raccoon famously does.

The system of binomial nomenclature that we use today was developed by the Swedish botanist Carolus Linnaeus in 1735. We talked about some of his mistakes in episode 123. Linnaeus built on a system developed by a zoologist almost a century before him, but streamlined it and made it easier to use. In the 300 years since Linnaeus came up with his system, many other scientists have made changes to reflect increased knowledge about the natural world and how best to denote it.

I keep saying “organism” instead of “animal,” and that’s because all living organisms may be given a scientific name as they are described. This includes everything from humans to maple trees, from earthworms to harpy eagles, from bumblebees to mushrooms. Linnaeus originally included minerals in his classification system, but minerals don’t evolve the way living organisms do. One group that wasn’t given scientific names until 2021 are viruses. There’s still a lot of controversy as to whether viruses are technically alive or not, but giving them scientific names helps organize what we know about them.

Eilee suggested the ocean sunfish, which has the scientific name Mola mola. Because its scientific name is easy to say, and because there’s also a freshwater sunfish that isn’t related to the ocean sunfish, a lot of people just call it the mola-mola, or just the mola. We talked about it way back in episode 96, so we’re definitely due to revisit it.

The ocean sunfish doesn’t look like a regular fish. It looks like the head of a fish that had something humongous bite off its tail end. It has one tall dorsal fin and one long anal fin, and a little short rounded tail fin that’s not much more than a fringe along its back end. This isn’t even a real tail but part of the dorsal and anal fins. The sunfish uses the tail fin as a rudder and progresses through the water by waving its dorsal and anal fins the same way manta rays swim with their pectoral fins. Pectoral fins are the ones on the sides, while the dorsal fin is the fin on a fish’s back and an anal fin is a fin right in front of a fish’s tail. Usually dorsal and anal fins are only used for stability in the water, not propulsion. The ocean sunfish does have pectoral fins, but they’re tiny.

The ocean sunfish lives mostly in warm oceans around the world, and it eats jellies, small fish, squid, crustaceans, plankton, and even some plants. It has a small round mouth that it can’t close and four teeth that are fused to form a sort of beak. It also has teeth in its throat, called pharyngeal teeth. Its skin is thick and rough like sandpaper with a covering of mucus, and its bones are mostly cartilaginous. It likes to sun itself at the water’s surface, and it will float on its side like a massive fish pancake and let sea birds stand on it and pick parasites from its skin. This also helps it absorb heat from sunlight after it’s been hunting in deeper water.

The female ocean sunfish can lay up to 300 million eggs at a time. That is the most eggs known to be laid by any vertebrate. When the eggs hatch, the larval sunfish are only 2 ½ mm long. Once they develop into their juvenile form, they have little spines all around their thin end, which kind of make them look like tiny stars. If that seems weird, consider that the ocean sunfish is actually related to the pufferfish, although not very closely. The largest adult ocean sunfish ever reliably measured was 14 feet tall, or 4.3 meters, including the long fins, which is a whole lot bigger than 2 ½ mm.

Sometimes after an organism is initially described and named, later scientists learn more about it and determine that it doesn’t actually belong in the genus or family where it was initially placed. If it gets moved to a different genus, its scientific name also needs to change. Some organisms get moved a lot and their scientific names change a lot. But typically, the species name doesn’t change. That’s the case for a little bird from Africa.

Joel suggested a bird called the red-billed quelea [QUEE-lee-ya], whose scientific name is Quelea quelea. When Linnaeus described it in 1758, he thought it was a type of bunting, so he named it Emberiza quelea. Another scientist moved it into a new genus, Quelea, in 1850.

I’d never heard of the red-billed quelea, which is native to sub-Sarahan Africa, but it may actually be the world’s most numerous non-domesticated bird, with an estimated 1.5 billion birds alive at any given moment.

The red-billed quelea mainly eats grass seeds, and unlike the European hamster, it is actually a problem to farmers. The bird doesn’t know the difference between yummy grass seeds and yummy wheat, barley, milt, oats, sunflowers, and other food that humans eat. In fact, some researchers suggest that the bird has become incredibly numerous because it has all this great food to eat that was planted by people.

A flock of red-billed quelea birds can number in the millions. The flock flies until they find grassland or fields with food they like. The first birds land, the birds behind them land a little bit farther along, and so on until all the birds have landed and are eating. But by the time the last birds of the flock land, the first ones have eaten everything they can find, so they fly up and over the rest of the birds until they find fresh grass to land in again. This is happening constantly with the entire flock of millions of birds, so that from a distance the flock’s movement looks like a cloud of smoke rolling across a field.

The red-billed quelea also eats insects, mostly during nesting season. Insects and other small invertebrates like spiders are especially nutritious for nestlings.

The quelea is about the size of a sparrow, which it resembles in many ways, although it’s actually a member of the weaver bird family, Ploceidae. It grows less than five inches long, or about 12 cm, including its tail, and it’s mostly brown and gray. Its beak and legs are orangey-red, and during breeding season the male has a rusty-red head with a black mask on his face.

One subspecies of red-billed quelea is native to western and central Africa. Since it’s a subspecies, it has three words in its scientific name: Quelea quelea quelea.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 397: Some Colorful Fishies

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Thanks to Cosmo, William, and Silas for their fishy suggestions this week!

You have until Sept. 13, 2024 to back the enamel pin Kickstarter!

Further reading:

The Handfish Conservation Project

Researchers Look in Tank and See Promising Cluster of Near-Extinct Babies

The unique visual systems of deep sea fish

A red handfish:

Another red handfish. This one is named Hector:

The black dragon fish:

The white-edged freshwater whipray [photo by Doni Susanto]:

Show transcript:

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

This week we return to the vertebrate world, specifically some strange and colorful fishies. Thanks to William, Cosmo, and Silas for their suggestions!

We’ll start with Silas’s suggestion, the red handfish. We talked about it before back in episode 189, but it’s definitely time to revisit it. When we last discussed it, scientists estimated there were fewer than 100 red handfish left in the wild, meaning it was in imminent danger of extinction. Let’s find out how it’s doing now, four years later.

The handfish gets its name because its pectoral fins look like big flat hands. It spends most of its time on the sea floor, and it uses its hands to walk instead of swimming. It can swim, although it’s not a very strong swimmer, and anyway if you had great big hands you might choose to walk on them too. It doesn’t have a swim bladder, which helps most fish stay buoyant.

All species of handfish are small, only growing to about 6 inches long at most, or 15 cm. This is surprising considering the handfish is closely related to anglerfish, and some anglerfish can grow over 3 feet long, or about a meter.

As for the red handfish specifically, it generally only grows about 4 inches long at most, or 10 cm, and it once lived in shallow water around much of Australia. These days, it’s only found on two reefs southeast of Tasmania. Some populations are bright red while some are pink with red spots. It has a wide downturned mouth that makes it look like a grumpy red toad with big hands.

So how is the red handfish doing? Four years ago it was almost extinct in wild, with fewer than 100 individuals alive. These days the Handfish Conservation Project estimates that the wild population is probably about the same, although because the red handfish is so small and hides so well among sea grass, algae, and rocks that make up its home, it’s hard to get a good count of how many are really alive. It’s also under even more pressure than before as an overpopulation of urchins is overgrazing the plants where it lives, which may sound familiar to you if you listened to episode 395 a few weeks ago. But there is one fantastic change that gives conservationists hope that the red handfish won’t go extinct after all.

The red handfish is so endangered, and its remaining habitat is so small, that a few years ago scientists decided they needed to start a captive breeding program. But even though the fish did just fine in captivity, they didn’t breed at first. Then, in November 2023, one of the fish laid 21 eggs and all 21 hatched safely. Hopefully it won’t be long until the babies are old enough to release into the wild.

The red handfish is one of very few fish that hatch into tiny baby fish instead of into a larval form. Newly hatched babies are only about 5 mm long. Most fish colonize new habitats after they float around aimlessly as larvae, until they grow enough to metamorphose into adults. Since the red handfish doesn’t have this larval stage, and babies just walk around on the sea floor finding tiny worms and other food, it’s hard for the fish to expand its range. Hopefully, as the captive breeding program continues and more young fish are released into the wild, scientists can start releasing red handfish into areas where they used to live.

Next, William asked about the dragon fish. We’ve talked about a few dragonfish before, in episodes 193 and 231, but there are lots of species in many genera in the family Stomiidae. Many have barbels with photophores at the end that lure prey, and most have long needle-like teeth and jaws that can open incredibly wide. They also have stretchy stomachs so they can hold whatever they manage to catch. As you may have guessed from these traits, the dragon fish lives in the deep sea where there’s little or no light from the surface.

You may wonder why deep-sea fish even have eyes if there’s no light. Fish that live in cave systems eventually evolve to be eyeless, since they don’t need their eyes to see and growing eyes is just a waste of their energy. It’s because even though there’s no sunlight in the deep sea, there is light from lots of different organisms. Many, many deep-sea animals produce bioluminescent light to attract mates or trick smaller animals into coming closer.

Any sunlight that does find its way to the depths of the ocean is blue, because blue has the shortest wavelength and can travel farther. Red wavelengths are longest so that red is the first color lost when you start descending into the water. One article that I’ve linked to in the show notes mentions that if a diver gets a cut, the blood looks brown or even black if the water is deep enough. That’s creepy.

As a result, deep-sea fish are most sensitive to the color blue. Most of them can’t perceive red at all because there just isn’t any red in their environment. And that’s where the dragon fish comes in, because some species of dragon fish can not only see red, they produce red light that illuminates everything around them. A fish or other animal swimming along has no idea that it’s lit up like it’s under a red spotlight because it can’t even see that color.

At least one species, the black dragon fish, perceives red light very differently from the way other animals do. As far as we know it’s unique among all animals. Its eyes contain a photosensitizer derived from chlorophyll, which allows it to see shorter lightwaves. Chlorophyll is found in plants and some bacteria, and it’s actually a specialized pigment that absorbs energy from light. It’s the reason why plants are green. But the black dragonfish uses the chlorophyll it digests to perceive red light.

But remember how dragon fish have giant sharp fangs and will eat pretty much anything they can swallow? Where does the black dragon fish get the chlorophyll it needs? There aren’t any plants in the deep sea anyway.

The answer seems to be that the black dragon fish eats a whole lot of copepods, tiny crustaceans that live throughout the world. The particular species of copepods that the black dragon fish prefers contain a type of chlorophyll.

Finally, Cosmo wanted to learn about the freshwater stingray. We talked about it in episode 296, but mostly we concentrated on the South American fish in that episode. There are freshwater stingrays that live in other parts of the world, such as Asia. This includes the white-edge freshwater whipray, which is extremely rare and only found in four rivers in Southeast Asia.

The white-edge freshwater whipray grows up to two feet across, or 60 cm, with a thin tail about two and a half times longer than the body itself so that technically it can grow around 6 and a half feet long, or 2 meters. Most of that length is tail, though. It’s mostly brown so it can hide in the sandy mud at the bottom of the river, with black dermal denticles down the middle of its back. The tail is mostly white, though, and has two long stinging spines that can be over 3 inches long, or 8 cm.

While the white-edged whipray lives in rivers, it can also tolerate brackish water where the ocean and the river waters mix. It eats small animals it finds on the bottom of the river, including crustaceans and mollusks. It’s endangered due to habitat loss, overfishing, and pollution.

The white-edged whipray is so rare these days that it’s unlikely that anyone would accidentally step on one in the water. But if they did, the ray would whip its long tail up and jab the spines into the person’s leg or foot. The spines can do a lot of damage on their own, but the venom they inject makes the wound incredibly painful and can even potentially kill the person.

If you plan to do some wading in a South Asian river anytime soon, make sure to shuffle your feet as you walk to scare away any potential whiprays before you step right on it.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

 

Episode 396: Moths!

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Thanks to Joel and an anonymous listener for their suggestions this week!

Further reading:

Dieback and recovery in poplar and attack by hornet clearwing moth

The enormous and beautiful Atlas moth:

A male hairy tentacle moth without and with coremata extended [photos from this site]:

The hornet moth looks like a hornet but can’t sting:

Show transcript:

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

Welcome to September, where we’re mere weeks away from Monster Month! Invertebrate August is over for another year, but what’s this? An episode about moths?! Hurrah for one extra invertebrate episode, because they don’t get enough attention on this podcast! Thanks to Joel and an anonymous listener for their suggestions.

First, a listener who wants to remain anonymous suggested that we talk about moths in general, and the Atlas moth in particular. I like the Atlas moth because you can catch it in Animal Crossing. It’s also beautiful and one of the largest moths in the entire world. Its wingspan can be well over 10 inches across, or about 27 cm, which is bigger than a lot of bird wingspans.

The Atlas moth’s wings are mostly cinnamon brown with darker and lighter spots. The upper wings have a curved sort of hook at the top that’s lighter in color and has an eyespot. It looks remarkably like a snake head, and in fact if a predator approaches, the moth will move its wings so that it looks like a snake is rearing its head back to strike.

Despite having such huge wings, atlas moths don’t fly very well. That’s okay because they only need to be able to fly for a few days, which they mostly do at night. They’re only looking for a mate, not food, because they don’t even have fully formed mouthparts. They don’t eat as adults. Like many moths, they mate, lay eggs, and die.

A few weeks later, the eggs hatch and the baby caterpillars emerge. The caterpillar is pale green with little spikes all over, and it eats plants until it grows to around 4 and a half inches long, or about 11 and a half cm. At that point it spins a cocoon attached to a twig, hidden from potential predators by dead leaves that the caterpillar incorporates into the cocoon’s outside.

The Atlas moth lives in forests in southern Asia, including China, India, Indonesia, and Malaysia, with a subspecies native to Japan. Its cocoons are sometimes collected to use for silk. The silk isn’t as high a quality as the domesticated silk moth’s, but it’s very strong and since the cocoons are so big, they produce lots of silk. Sometimes people will collect a cocoon after the moth has emerged and use it as a little purse.

Next, Joel suggested two interesting moths. The first is often called the hairy tentacle moth, which sounds absolutely horrifying. Its scientific name is Creatonotos gangis, and it lives in parts of Australia and southeast Asia.

The hairy tentacle moth is also called the Australian horror moth and other names that inspire fear and disgust. But why? The moth is really pretty. Its wings are pale brown and white with dark gray stripes in the middle, and it has a black spot on its head. The abdomen is usually red with black spots in a row. The wingspan is about 40 mm.

The issue comes with the way the male attracts a female. Inside his abdomen the male has four coremata, which are glands that emit pheromones. Pheromones are chemicals that other moths can detect, much like smells. When a male is ready to advertise for a mate, he perches on the edge of a leaf or somewhere similar and inflates the coremata so that they unfurl from inside the abdomen, like blowing up a balloon. Sometimes he only extends two of the coremata, sometimes all of them. Either way, the coremata are surprisingly large, sometimes longer than the entire abdomen. They’re dark gray with feathery hairs and they do actually look like hairy tentacles. They’re sometimes called hair pencils, but the term coremata is actually Greek for feather dusters.

If you don’t know what they are, the coremata really do look weird and unpleasant. But the moth is just doing his best to get his pheromones picked up on the breeze so a female will find him. The pheromone also repels other males.

The hairy tentacle moth can only develop his coremata and the pheromones he needs if he eats enough of plants that contain pyrrolizidine alkaloids. These are intensely bitter compounds that are also toxic to many animals. When he’s a caterpillar, the male eats plants that contain these alkaloids and retains them in his body, chemically modifying them later into pheromones, but if he doesn’t eat enough of them, he’s not able to grow coremata either.

Finally, Joel also suggested the hornet moth, which lives in Europe and the Middle East. It’s a moth, but it genuinely looks exactly like a yellow and black striped hornet. It even has clear wings like a hornet or wasp and flies like one too, and it’s about the size of a hornet. Even though it’s harmless, it looks like it would give you a bad sting, which protects it from potential predators who know better than to mess with a hornet. It’s a great example of what’s called Batesian mimicry, but it has one big drawback. The moth lives in some areas where there aren’t any hornets, and in those areas birds and other animals soon learn that those brightly striped insects are yummy and easy to catch.

The female hornet moth lays her eggs in the plants around the base of a tree or on its bark, especially the poplar tree. When the eggs hatch, the larvae spend the next two or three years in and around the tree, mostly around its roots. It eats the wood of the roots, and when it’s ready to pupate it burrows into the tree trunk and spins its cocoon in the burrow. The problem is that it needs the cocoon to be protected inside the tree, not near the entrance of the burrow, but when it emerges from the cocoon it needs to be near the entrance or its newly metamorphosed body will be too large for it to crawl out. To solve the problem, when it’s getting close to emerging, the moth will wriggle around in its cocoon so energetically that it manages to push the pupa up the burrow to the entrance. You can imitate this action by zipping yourself into a sleeping bag and trying to crawl across a room.

For a long time people thought the hornet moth was damaging poplar trees by this behavior, causing them to die. It turns out that the moths aren’t hurting the trees, they’re just more noticeable when poplars are already injured by drought.

There’s also an American hornet moth that lives in some parts of the Midwest and western areas of North America. It’s closely related to the hornet moth of Europe and adults look an awful lot like hornets, but they don’t sting. So the next time you’re about to run from a hornet, take a moment to determine if the hornet is actually a harmless moth. Or at least don’t run, just walk away quickly and safely. Just in case.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 395: Crinoids and Urchins

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Thanks to Sy and Finn for their suggestions this week!

Further reading:

Creeping Crinoids! Sea Lilies Crawl to Escape Predators, New Video Shows

New and Unusual Crinoid Discovered

Sea otters maintain remnants of healthy kelp forest amid sea urchin barrens

Sea urchins see with their feet

A sea lily [photo from this page]:

A feather star [still from a video posted on this page]:

Purple urchins [photo by James Maughn]:

Show transcript:

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

This week as we bring invertebrate August to a close, we’re going to cover some animals suggested by Finn and Sy.

We’ll start with Sy’s suggestion, crinoids, also called feather stars or sea lilies depending on what body plan a particular species has. We talked about them in episode 79 but it’s definitely time to revisit them.

Crinoids are echinoderms, a really old phylum of animals. Fossils of ancient echinoderms date back to the Cambrian half a billion years ago and they’re still incredibly common throughout the world’s oceans.

Ancient crinoids had five arms the way many starfish do, which makes sense because crinoids are related to starfish. At some point each arm developed into two, so many crinoids have ten arms or even more, and many have arms that branch. The arms are used for feeding and have feathery appendages lined with sticky mucus that traps tiny bits of food floating in the water.

There are two big divisions of crinoids today, the feather stars and the sea lilies. Feather stars are more common and can swim around as adults if they want to, although most stick to crawling along the sea floor. They swim by waving their feathery arms. Sea lilies look like flowers as adults, with a slender stem-like structure with the small body and long feathery arms at the top. I specify that sea lilies have stems as adults because a lot of feather stars also have stems as juveniles, but when they reach maturity they become free-swimming.

Even though the sea lily looks like a plant, and some species even have root-like filaments that help it anchor itself to the sea floor or to rocks, it’s still an animal. For one thing, it can uproot itself and move to a better location if it wants to, crawling with its arms and pulling its stem behind it, which is not something a plant can do except in cartoons. If a predator attacks it, the sea lily will even shed its stem completely so it can crawl away much faster. Since echinoderms in general are really good at regenerating parts of the body, losing its stem isn’t a big deal.

The biggest sea lilies today are deep-sea species, but even they only grow a stem up to about three feet long at most, or about a meter. This wasn’t the case in the ancient past, though. The longest crinoid stem fossil ever discovered was 130 feet long, or 40 meters.

Crinoids filter food particles from the water that flows through the feathery arms. Even though they look like feathers or petals, a crinoid’s arms are actually arms. They have tiny tube feet on them that act sort of like fingers to help the crinoid hold onto pieces of food, and to do a better job of holding the food, the tube feet are covered with a sticky mucus. The mouth is in the middle of the arms on the top of the body.

Crinoids absorb oxygen directly from the water. Its body contains a system of chambers and pores that are full of water, and by contracting special muscles, the crinoid moves water around in its body to transport nutrients and oxygen and to collect waste material.

Crinoids are closely related to starfish, sea cucumbers, sand dollars, and sea urchins, which brings us to Finn’s suggestion. Finn suggested urchins, which are also echinoderms. In fact, at the end of episode 79 I mentioned that one day I’d do an episode about urchins, and it only took me six years to get here!

Many urchins look like living pincushions because they’re covered in spines. That’s where the name urchin comes from, in fact. Hedgehogs, which are little round mammals with spiny backs that we talked about in episode 126, were called urchins in the olden days. Some people call the echinoderm type of urchin the sea urchin to distinguish it from the mammal type of urchin, and some people call the echinoderm urchin the sea hedgehog.

Urchins live throughout the world’s oceans, in shallow water or deep water, warm water and cold water, and there are almost a thousand species known to science. There are undoubtedly many more species yet to be discovered.

The typical urchin has a body shaped sort of like a little ball, but unlike most balls it has spines growing all over it. Depending on the species, the spines may be thin and sharp or thick and blunt. Some species even have venomous spines. Underneath, the urchin has a small area of its body that isn’t protected by spines. This is where its mouth is and its little tube feet that allow it to move around. Like crinoids and other echinoderms, it pumps water in and out of its tube feet to move them. It can also push itself off of surfaces with its spines to help it maneuver.

You may be wondering if, under its spines, an urchin has a soft body like a bouncy ball or a hard body like a baseball. Its body is actually hard, but not due to an exoskeleton. Echinoderms have an endoskeleton, meaning the hard parts of its body are on the inside like our bones are, not on the outside like a lobster’s armor. Instead of bones, echinoderms have tiny plates called ossicles that fit together like puzzle pieces and are covered with tough skin. The ossicles fit together to make the stem of a sea lily or a spiky ball in urchins, called a test.

If you look at an urchin, it’s pretty obvious it has no head or face. It’s just a little spiky ball with feet and a mouth underneath. But urchins can not only sense light and dark, at least some species can see images to some degree, and they see without eyes. Instead they have light-sensitive cells in their tube feet. Since the tube feet aren’t just for walking, and most urchins have tube feet in between spines as well as underneath, it can keep a lookout for danger with some of its feet while it’s walking around or eating with its other feet.

Unlike its crinoid cousins, the urchin isn’t a filter feeder. It mainly it eats algae and kelp but it will also eat lots of small animals, including crinoids. Its spines help keep it safe from being eaten by larger predators, but lobsters, crabs, and some kinds of starfish aren’t very worried about the spines and will eat urchins without any trouble.

One animal that specializes in eating urchins is the sea otter. The sea otter loves to eat urchins, and is good at flipping them over and biting them on their unprotected underside, or just hitting them with a rock to break off the spines. It cracks the poor urchin open like a nut and gobbles up the insides.

Because urchins like to eat kelp, and otters like to eat urchins, the kelp forests off the coast of California have always had a lot of both animals. But about a decade ago now, starting in about 2013, several things happened to alter the balance of kelp and urchin and otter. First, a disease caused the sunflower sea star to die off in great numbers, and in fact it’s still critically endangered as a result. Since that’s a type of starfish that eats a whole lot of urchins, the urchin population exploded. The next year, 2014, a heatwave over the west coast of North America caused a lot of kelp to stop growing. Kelp needs cold water to thrive. The hordes of urchins started chomping down on as much kelp as they could find, decimating more than 80% of the kelp forests in northern California before scientists even realized what was happening.

The urchin in question is the purple urchin, which lives along the eastern coast of North America. Its spines are purple and it can grow up to 4 inches across, or 10 cm. Sea otters love purple urchins so much that sometimes their teeth turn purplish in color from eating so many.

The sea otters responded to the population explosion by turning into urchin-eating maniacs, eating up to four times as many urchins as usual. The problem is that the sea otter population is still rebounding from being hunted nearly to extinction in the early 20th century, and they’re still an endangered species. There just weren’t enough otters to eat all the urchins.

Scientists studying the situation noticed something strange. The otters were only eating urchins where the kelp forests were still healthy. They ignored all the millions of urchins where the kelp forests had been eaten down to the ground, even though the urchins didn’t have anywhere to hide from hungry otters. The scientists discovered that the urchins in what they called urchin barrens were basically starving to death. There were far too many urchins and no food left for them to eat. That meant they weren’t as nutritious, so the otters didn’t bother to eat them.

The result was actually positive. The balance of urchins and sea otters and healthy kelp was maintained, so the urchin barrens didn’t get any worse. The kelp forests will rebound, although it will take a long time. Everybody say hello to the otters, and goodbye to all the extra urchins.

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 394: Mantis Shrimp!

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Thanks to Anbo and Siya for suggesting the mantis shrimp this week!

The Kickstarter for some animal-themed enamel pins is still going on!

Further reading:

Rolling with the punches: How mantis shrimp defend against high-speed strikes

The magnificent peacock mantis shrimp [picture by Cédric Péneau, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=117431670]:

Show transcript:

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

As invertebrate August continues, this week we have a topic suggested by Anbo and Siya. They both wanted to learn about the mantis shrimp!

The mantis shrimp, which is properly called a stomatopod, is a crustacean that looks sort of like a lobster without the bulky front end, or a really big crayfish. Despite its name, it’s not a shrimp although it is related to shrimps, but it’s more closely related to lobsters and crabs. It can grow as much as 18 inches long, or 46 cm, but most are about half that size. Most are brown but there are hundreds of different species and some are various brighter colors like pink, blue, orange, red, or bright green, or a rainbow of colors and patterns.

There are two things almost everyone knows about the mantis shrimp. One, it can punch so hard with its claws that it breaks aquarium glass, and two, it has 12 to 16 types of photoreceptor cells compared to 3 that humans have, and therefore it must be able to see colors humans can’t possibly imagine.

One of those things is right, but one is wrong, or at least partially wrong. We’ll discuss both in a minute, but first let’s learn the basics about these fascinating animals.

The mantis shrimp lives in shallow water and spends most of its time in a burrow that it digs either in the sea floor or in crevices in rocks or coral, which it enlarges if necessary. Some species will dig elaborate tunnel systems while others just wedge themselves into any old crack that will hide them. It molts its exoskeleton periodically as it grows, like other crustaceans, and after that it either has to expand its burrow or move to a larger one. Most species live in tropical or subtropical areas, but some prefer more temperate waters.

It has eight pairs of legs, which includes three pairs of walking legs, four pairs with claws that help it grasp items, and its front pair, which are hinged and look a little like the front legs of a praying mantis. That’s where the “mantis” in mantis shrimp comes from, although of course it has lots of other names worldwide. In some places it’s called the thumb splitter.

The mantis shrimp has two eyes on stalks that move independently. Its brain extends into the eye stalks, and the section of the brain in the eye stalks, called the reniform body, is what processes vision. This allows it to process a lot of visual information very quickly. Reniform bodies have also been identified in the brains of some other crustaceans, including shrimp, crayfish, and some crabs. Scientists also think that the eyes themselves do a lot of visual processing before that information gets to the reniform body or the brain at all. In other words, part of the reason the mantis shrimp’s eyes are so complicated and so unusual compared to other animals’ eyes is because each eye is sort of a tiny additional brain that mainly processes color.

The typical human eye can only sense three wavelengths of light, which correspond to red, green, and blue. The mantis shrimp has twelve different photoreceptors instead of three, meaning it can sense twelve wavelengths of light, and some species have even more photoreceptors. But while our brains are really good at synthesizing the three wavelengths of light we can see, combining them so that we see incredibly fine gradations of color in between red, green, and blue, the mantis shrimp doesn’t process color the same way we do. So while its eyes can sense colors we can’t, its brain doesn’t seem to do anything with the color information. The eyes themselves process the colors to determine if an object is important or dangerous or food or whatever, and the determination of the object is the part that’s important to the brain, not what the actual color is.

Maybe by the year 2124, you can go into an eye clinic and have those extra sensors added to your eyes so you can see more colors, because a human brain knows exactly what to do with extra color information. We use it to make art.

Mantis shrimp can see ultraviolet light, which we talked about in episode 369. To be clear, we didn’t specifically talk about mantis shrimp in that episode, just UV light. At least six species of mantis shrimp can also see polarized light, with at least one species, the purple spot mantis shrimp, capable of dynamic polarization vision. (I don’t know what that means.) When sunlight reaches our earth’s atmosphere, the light waves are affected by earth’s magnetic field and the atmosphere itself. This scatters the light, causing it to travel in a sort of spiral. A lot of animals can sense light polarization, like bees and octopuses, which allows them to navigate more accurately. Mantis shrimp have patterns on their bodies that reflect polarized light in certain ways, so scientists think that’s one way mantis shrimp identify each other while staying hidden from most animals, which either can’t sense polarized light at all or can only sense it faintly.

So we must ask ourselves: If the mantis shrimp doesn’t use its multiple photoreceptors to see color, what does it use them for? We’re not fully sure yet, but scientists have some suggestions. The fertility of a female mantis shrimp depends on the tidal cycle, which is dependent on the phase of the moon, but if you live underwater and spend most of the time in a burrow, you can’t exactly look up at the moon easily or check how big the waves are. The female fluoresces when she’s fertile, though, and she fluoresces at a wavelength that the male can see but other animals can’t.

So it’s not completely accurate to say that the mantis shrimp can see colors we can’t even imagine, because there’s a difference in the eye seeing something and the brain processing it. But that means that the other mantis shrimp fact is completely true, that its claws are so strong that it can crack aquarium glass. But it’s more complicated than it sounds, because different mantis shrimp species have different abilities.

Mantis shrimp that hunt fish are called spearers, because the ends of their front pair of legs have a barbed spike that the mantis shrimp uses to spear the fish. Mantis shrimp that eat clams and other animals with hard shells are called smashers, and instead of spikes, the ends of their front pair of legs have a hammer-like club that the mantis shrimp uses to punch its prey. Both spearers and smashers can move their front legs incredibly fast, literally at the speed that a bullet leaves the barrel of a gun, with a correspondingly strong amount of force when the leg connects with something.

Moving the legs so fast also causes a small shock wave in the water, which can kill a small animal even if the mantis shrimp misses hitting it. The shock wave is actually what the mantis shrimp uses to smash the shells of clams and other hard-shelled prey, and it also uses the shock wave to smash pieces of coral or rock when it wants to enlarge its burrow. Its body has multiple layers of tissue that absorb the shock wave so it won’t damage the mantis shrimp itself.

Smashing or spearing so fast costs the mantis shrimp a lot of energy, so if it feels threatened by a potential predator it will spread its arms wide to look intimidating before it actually resorts to striking. That’s when it earns the name thumb splitter. That’s also the main reason why it isn’t very common for people to eat mantis shrimp even though they’re perfectly edible to humans and reportedly taste like lobster. They’re just too hard to catch and kill safely.

Some species of mantis shrimp mate for life, with some bonded pairs staying together for decades. Depending on the species, both parents take care of the eggs, or the female takes care of the eggs and the male brings her food. In one species, the female lays two bunches of eggs. She takes care of one bunch, while the male takes care of the other.

Many species of mantis shrimp are territorial, and if one enters another’s territory, the two may end up fighting. When you can punch as hard as a mantis shrimp, you need a good defense. During fights, the mantis shrimp coils its tail in front of its body to act as a shield. The tail is well armored, but the armor is layered to absorb and dissipate energy from punches.

The peacock mantis shrimp is the one that most people have heard about. It’s even one of the creatures you can catch in Animal Crossing by diving. It’s metallic green and blue with orange legs, purple eyes, and white spots, so some aquarium keepers love having one on display. The problem is that they will kill and eat pretty much anything else kept in the same tank, will smash up any rocks or coral in the tank too, and yes, they will even smash the aquarium glass—which is exceptionally strong in big aquariums, more like a car window than a window in your house. Sometimes an aquarium keeper will use a rock from the ocean to decorate the aquarium, and only find out too late that there’s a peacock mantis shrimp already living in a crevice in the rock. Then all they can do is take the rock back to the ocean, because getting a mantis shrimp out of its rock safely is pretty much impossible.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 393: Little Spiders

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Thanks to Siya, Zachary, Khalil, and Eilee for their suggestions this week!

The enamel pin Kickstarter goes live on Wednesday, August 14, 2024!!

Further reading:

How spiders breathe under water: Spider’s diving bell performs like gill extracting oxygen from water

Aggressive spiders are quick at making accurate decisions, better at hunting unpredictable preys

Into the Spider-Verse: A young biologist shares her love for eight-legged creatures

A New Genus of Prodidominae Cave Spider from a Paleoburrow and Ferruginous Caves in Brazil

The diving bell spider [photo from this paper]:

Jumping spiders are incredibly cute, even the ones that eat other spiders [photo taken from this excellent site]:

The spoor spider’s web looks like a cloven hoofprint in the sand [photo by JMK – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=39988887]:

Show transcript:

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

I’m excited this week, because on Wednesday my little Kickstarter to fund getting more enamel pins made goes live, and also we’re talking about some weird and fascinating spiders! Thanks to Siya, Zachary, Khalil, and Eilee for their spider suggestions!

A lot of people are afraid of spiders, but don’t worry. All the spiders in this episode are small and completely harmless unless you are a bug. Also, they probably live very far away from you. Personally, I think most spiders are cute.

Let’s start with a spider suggested by Siya, who pointed out that we don’t actually have very many episodes about spiders. Siya suggested we learn about the diving bell spider, a tiny, remarkable animal that lives in parts of Europe and Asia.

The diving bell spider gets its name because it mostly lives underwater but still needs to breathe air, so it brings air with it into the water. A diving bell made by humans is a structure shaped sort of like a big bell that can be lowered straight down into the water on a cable. If the diving bell doesn’t tip to one side or another, the air inside it stays inside and allows a human diver to take breaths without coming to the surface. A diving bell made by spiders is made of silk but is shaped sort of the same, with an entrance at the bottom. The spider builds its bell among water plants to anchor it and keep it hidden. The spider brings air from the surface to replenish the supply of air inside the bell.

The spider does this by surfacing briefly. Its belly and legs are covered with tiny water-repellent hairs, and after surfacing the hairs trap air, so that when it dives back into the water it’s covered with little silvery bubbles. It swims down to its diving bell and rubs the bubbles off its body, which rise into the bell and are trapped there by the closely woven silk. Then it goes back to the surface for more air.

Once the bell is full of air, the spider only needs to replenish the air supply about once a day under normal circumstances. That’s because the bell itself acts as a sort of external gill. It’s able to absorb oxygen from the water quite efficiently, but it still loses volume slowly because nitrogen from the air diffuses into the water. If not for that, the spider probably wouldn’t need to come to the surface at all.

The diving bell is the spider’s home, especially for the female. Unlike most spiders, the female diving bell spider is much smaller than the male and she hunts differently. The male is an active hunter, swimming quickly to catch tiny animals like mosquito larvae, so he’s large and strong but only has a small diving bell. The female spends most of her time in her diving bell and only swims out to catch animals that come too close, or occasionally to replenish the air in her bell.

When the spider leaves its diving bell to hunt, air bubbles remain trapped on its abdomen, which allows it to breathe while it’s hunting too. Then it can dart back to its bell to get more air or hide if it needs to.

When a male finds a female, he will build his diving bell near hers. If she doesn’t object, he’ll build a little tunnel between the two bells so he can visit her more easily. The pair will mate in the female’s bell and she either attaches her egg sac to the inside wall of her bell or will build a little addition onto her bell that acts as a nursery.

The diving bell spider is gray or black in color and even a big male only grows about 15 mm long, head and body size together. His legs are longer. In the water the spiders appear silver because of the bubbles attached to their bodies.

The spider used to be common throughout much of Asia and Europe, but its numbers are in decline due to pollution and habitat loss, since it needs slow-moving streams, ponds, marshes, and other clean freshwater with aquatic plants to survive. It will bite if it feels threatened and some people claim that its bite is painful and leads to symptoms like fever, but there’s not a lot of evidence for the bite being dangerous or even all that painful to humans.

Next, Zachary suggested the Portia spider, and pointed out that it demonstrates “uniquely intelligent hunting.” If it weren’t such a tiny spider, it might be scary because it’s so smart. Fortunately for humans, not only is it even smaller than the diving bell spider, with even a big female no more than 10 mm long counting her head and body together, it’s a spider that eats other spiders.

There are 17 species of portia spider currently known, living in parts of Africa, Asia, Australia, and a lot of islands in southeast Asia. It’s a type of jumping spider and can jump as much as 6 inches, or 15 cm, from a complete standstill. It’s mostly brown with mottled darker and lighter markings that make it look like a bit of dead leaf when it’s standing still. It also has flaps on its legs that help it look less like a spider too.

Looking like a bit of dead leaf helps the Portia spider keep from being eaten by birds and frogs, but it also helps it when hunting prey spiders. Unlike almost all other spiders, the portia spider can travel on the webs of pretty much any species of spider without getting stuck. It will creep into another spider’s web and sneak up on it very slowly, or pretend to be a stuck insect to lure it closer. Most spiders don’t see very well, so they don’t identify the portia as a predatory spider. They either think it’s just a leaf stuck in its web or an insect, until it’s too late.

The portia spider will try many different ways to catch a spider. If one doesn’t work it will use another method, and will continue to try new methods and combinations of methods until it outsmarts the prey spider and can jump on it. The methods it uses can be incredibly complex and often require the portia spider to move away from the prey spider or even out of view of it, but it can remember exactly where the prey spider is and what it wants to do to approach it. Remember, this is an animal about the size of one of your fingernails. It has a teeny brain!

In captive studies, portia spiders are observed to be more or less aggressive depending on the individual. The more aggressive spiders tend to do a better job hunting prey with unpredictable behaviors, while the less aggressive spiders are more patient.

When the portia spider walks, it does so arrhythmically, which helps it imitate a dead leaf being moved by the wind. Some spiders are so nervous of portia spiders that if they sense an arrhythmic movement on their web, even if it’s not a portia spider, they’ll run and hide. For that matter, the portia spider will take advantage of wind and other natural occurrences to get closer to their prey.

In addition to active hunting, female portia spiders will also build funnel webs to catch insects. You know, kind of a side hustle. Any portia spider will spin a simple web to hide behind to rest. Portia spiders are also social, sharing food and even living together.

When the male portia spider wants to find a mate, he spins a little web near a female’s web and shakes his legs to attract the female. If she likes him, she’ll drum on his web to let him know. However, in most species, mating is a death sentence for the male. Remember how last week we talked about the praying mantis and how sometimes the female will actually eat the male after or even during mating? Well, that’s true for most species of portia spider too. In some species the female almost always eats the male. He gets to pass his genes along to the next generation, and she gets a good meal to help her grow healthy eggs.

Next, Leo’s friend Khalil suggested the wandering spider. This is the name given to a big family of spiders that live throughout much of the world. Most of them are quite large and look like tarantulas, especially the Brazilian wandering spider, also called the banana spider. It can have a head and body length of two inches, or about 5 cm, but a legspan of up to 7 inches, or 18 cm. That’s a lot of spider, and this week we’re talking about small spiders, but let’s take a quick detour and find out if the banana spider really is sometimes found in bunches of bananas sold in stores.

The banana spider lives in Brazil and other parts of northern South America and Central America, and that’s where a lot of the world’s bananas are grown. I couldn’t find any good estimates of how many bananas are exported every year, but the United States is the biggest importer of bananas. I’m going to switch completely to imperial measurements for a moment because the amounts I’m about to talk about make no logical sense anyway. About four bananas add up to one pound of weight, and 2000 pounds make up one ton. That means one ton of bananas is approximately 8,000 bananas. In 2023, over 5 million tons of bananas were imported to the United States. That is at least 40 billion bananas!

In comparison, no one seems to be tracking how many spiders are found hiding in banana bunches, but one paper from 2014 documented that of 135 spiders submitted to the scientists for study as having been found in all international shipments, of bananas and everything else, only seven were actually banana spiders. The rest were other kinds of spider, most of them completely harmless. When one is found it gets into the news because it’s so rare.

Spiders don’t live inside the banana peel anyway, and they don’t eat bananas. It’s just that bunches of bananas make good hiding places, and the spiders don’t know that people are going to chop the whole bunch down without even noticing a hidden spider. By the time the bananas get to the store, the big bunches have been cut up into little bunches of a few bananas each, which isn’t a great hiding space for a big spider. So your bananas are safe.

Anyway, the smallest wandering spider is probably in the genus Acanthonoctenus, which are native to Central and South America. A big female only grows about 15 mm long, head and body measured together, although her legspan is much larger. There are other wandering spiders with about the same body size in various genera. The problem is, there are hundreds of known species of wandering spider and probably a lot more that haven’t been discovered yet, but not a lot of people are studying them. We don’t know a whole lot about the smallest species because they’re harder to find and therefore harder to study. Many species have only ever had a single specimen collected. So if you want to become an arachnologist, you might look into wandering spiders for your specialization. Many of them are absolutely gorgeous, with striped legs and bright colors.

Like some other spiders, many Acanthonoctenus spiders will hide on a leaf or tree trunk by lying flat and stretching four of its legs out in front of it and the other four legs behind it. This makes it less spider shaped when a bird or lizard is looking around trying to find a snack.

Next, Eilee suggested the spoor spider, the name for Seothyra, a genus of spiders that live in sandy areas in southern Africa. Females grow up to 15 mm long, head and body together, while males grow up to 12 mm long and are usually considerably smaller than the females. The female can be brown, gray, or tan and may have stripes on her abdomen, while the male is more brightly colored. He can be yellow and black with a rusty-red head, sometimes with white spots on his abdomen.

The male spends most of his time running around finding food, and since he looks a lot like a type of wasp called the velvet ant, he’s in less danger than you’d think considering he’s active during the day. The female spends almost all of her life in an elaborate web that she builds into the sand.

The female excavates a burrow in the sand that can be as much as 6 inches deep, or 15 cm, lined with silk to keep it from collapsing. She gets sand out of the burrow as she constructs it by spinning little silk bags around the sand to carry it out. She leaves the bags of sand around the entrance, and once the burrow is finished, she incorporates the sandbags into the web itself. She spins web sheets and mixes them with sand to make mats around the burrow’s opening, which is hidden, and the spider can lift the web sheets to go in and out. Ideally she stays in the same burrow her whole life, repairing it as needed, because while it’s not an especially big web, it takes her a lot of energy to make.

The female puts sticky strands of silk around the edges of the web, then retreats to the underside of the web sheet or into the burrow if it’s too hot. When an insect gets stuck on the silk, she darts out and kills it, then takes it into her burrow to eat. Mostly she eats ants.

The name spoor spider, also called buck spoor spider, comes from the shape of the female’s web. In most species, the web sheet has two sides in a shallow depression in the sand. Since the web is also covered with and incorporates sand to hide it, the little depression with a rounded double shape at the bottom looks an awful lot like the footprint of an animal with a cloven hoof. The word “spoor” is a term indicating an animal’s track.

The spoor spider female only produces one egg sac in her life, and takes care of it in her burrow until the babies hatch. Then she takes care of the babies by gradually liquefying her own internal organs and regurgitating the liquid so the babies can eat it. When all her organs are gone she dies, naturally, and the babies eat the remainder of her body before venturing out into the world on their own.

Fossilized web sheets very similar to the modern spoor spider’s web have been found dating back 16 million years. Most spiderwebs can’t fossilize, but most spiderwebs aren’t built partly out of sand.

Finally, let’s finish up with a newly discovered spider from South America. I learned about it from Zeke Darwin, a science teacher who makes really interesting videos on TikTok. The spider has been described as a new species, named Paleotoca, and was discovered in Brazil. We know very little about it so far so I don’t have much information to share, but it’s so interesting that I just had to include it.

Paleotoca is pale yellow, although its abdomen has very little pigmentation, and its head and body together measure barely 2 mm. It doesn’t have eyes. You might be able to guess where it lives from its lack of eyes and lack of pigment in its body, but I bet I’m going to surprise you anyway. Paleotoca does live in caves, but technically these caves are burrows. It’s just that the burrows where it lives are extremely large, dug into the sides of hills thousands of years ago by giant ground sloths before they went extinct.

Luckily for the spider, there are also some natural caves in the area and at least one of the spiders has been found living in one. So little Paleotoca isn’t in danger of going extinct just because the burrow-builders are gone.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!