Category Archives: fish

Episode 212: The River of Giants

Thanks to Pranav for his suggestion! Let’s find out what the river of giants was and what lived there!

Further reading:

King of the River of Giants

Spinosaurus was a swimming dinosaur and it swam in the River of Giants:

A modern bichir, distant relation to the extinct giants that lived in the River of Giants:

Not actually a pancake crocodile:

A model of Aegisuchus and some modern humans:

Show transcript:

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

A while back, Pranav suggested we do an episode about the river of giants in the Sahara. I had no idea what that was, but it sounded interesting and I put it on the list. I noticed it recently and looked it up, and oh my gosh. It’s amazing! It’s also from a part of the world where it’s really hot, as a break for those of us in the northern hemisphere who are sick of all this cold weather. I hope everyone affected by the recent winter storms is warm and safe or can get that way soon.

The Sahara is a desert in northern Africa, famous for its harsh climate. Pictures of the Sahara show its huge sand dunes that stretch to the horizon. This wasn’t always the case, though. Only about 5,500 years ago, it was a savanna with at least one lake. Lots of animals lived there and some people too. Before that, around 11,000 years ago, it was full of forests, rivers, lakes, and grasslands. Before that, it was desert again. Before that, it was forests and grasslands again. Before that, desert.

The Sahara goes through periodic changes that last around 20,000 years where it’s sometimes wet, sometimes dry, caused by small differences in the Earth’s tilt which changes the direction of the yearly monsoon rains. When the rains reach the Sahara, it becomes green and welcoming. When it doesn’t, it’s a desert. Don’t worry, we only have 15,000 more years to wait until it’s nice to live in again.

This wet-dry-wet pattern has been repeated for somewhere between 7 and 11 million years, possibly longer. Some 100 million years ago, though, the continents were still in the process of breaking up from the supercontinent Gondwana. Africa and South America were still close together, having only separated around 150 million years ago. The northern part of Africa was only a little north of the equator and still mostly attached to what is now Eurasia.

Near the border of what is now Morocco and Algeria, a huge river flowed through lush countryside. The river was home to giant animals, including some dinosaurs. Their fossilized remains are preserved in a rock formation called the Kem Kem beds, which run for at least 155 miles, or 250 km. A team of paleontologists led by Nizar Ibrahim have been working for years to recover fossils there despite the intense heat. The temperature can reach 125 degrees Fahrenheit there, or 52 Celsius, and it’s remote and difficult to navigate.

For a long time researchers were confused that there were so many fossils of large carnivores associated with the river, more than would be present in an ordinary ecosystem. Now they’ve determined that while it looks like the fossils were deposited at roughly the same time from the same parts of the river, they’re actually from animals that lived sometimes millions of years apart and in much different habitats. Bones or even fossils from one area were sometimes exposed and washed into the river along with newly dead river animals. This gives the impression that the river was swarming with every kind of huge predator, but it was probably not quite so dramatic most of the time.

Then again, there were some really fearsome animals living in and around the river in the late Cretaceous. One of the biggest was spinosaurus, which we talked about in episode 170. Spinosaurus could grow more than 50 feet long, or 15 m, and possibly almost 60 feet long, or 18 m. It’s the only dinosaur known that was aquatic, and we only know it was aquatic because of the fossils found in the Kem Kem beds in the last few years.

Another dinosaur that lived around the river is Deltadromeus, with one incomplete specimen found so far. We don’t have its skull, but we know it had long, slender hind legs that suggests it could run fast. It grew an estimated 26 feet long, or 8 meters, including a really long tail. At the moment, scientists aren’t sure what kind of dinosaur Deltadromeus was and what it was related to. Some paleontologists think it was closely related to a theropod dinosaur called Gualicho, which lived in what is now northern Patagonia in South America. Remember that when these dinosaurs were still alive, the land masses we now call Africa and South America had been right in the middle of a supercontinent for hundreds of millions of years, and only started separating around 150 million years ago. Gualicho looked a lot like a pocket-sized Tyrannosaurus rex. It grew up to 23 feet long, or 7 meters, and had teeny arms. Deltadromeus’s arms are more in proportion to the rest of its body, though.

Some of the biggest dinosaurs found in the Kem Kem beds are the shark-toothed dinosaurs, Carcharodontosaurus, nearly as big as Spinosaurus and probably much heavier. It grew up to 40 or 45 feet long, or 12 to almost 14 meters, and probably stood about 12 feet tall, or 3 ½ meters. It had massive teeth that were flattened with serrations along the edges like steak knives. The teeth were some eight inches long, or 20 cm.

Researchers think that Carcharodontosaurus used it massive teeth to inflict huge wounds on its prey, possibly by ambushing it. The prey would run away but Carcharodontosaurus could take its time catching up, following the blood trail and waiting until its prey was too weak from blood loss to fight back. This is different from other big theropod carnivores like T. rex, which had conical teeth to crush bone.

Dinosaurs weren’t the only big animals that lived in and around the River of Giants, of course. Lots of pterosaur fossils have been found around the river, including one species with an estimated wingspan of as much as 23 feet, or 7 meters. There were turtles large and small, a few lizards, early snakes, frogs and salamanders, and of course fish. Oh my goodness, were there fish.

The river was a large one, possibly similar to the Amazon River. In the rainy season, the Amazon can be 30 miles wide, or 48 km, and even in the dry season it’s still two to six miles wide, or 3 to 9 km. The Amazon is home to enormous fish like the arapaima, which can grow up to 10 feet long, or 3 m. Spinosaurus lived in the River of Giants, and that 50-foot swimming dinosaur was eating something. You better bet there were big fish.

The problem is that most of the fish fossils are incomplete, so paleontologists have to estimate how big the fish was. There were lungfish that might have been six and a half feet long, or 2 meters, a type of freshwater coelacanth that could grow 13 feet long, or 4 meters, and a type of primitive polypterid fish that might have been as big as the modern arapaima. Polypterids are still around today, although they only grow a little over three feet long these days, or 100 cm. It’s a long, thin fish with a pair of lungs as well as gills, and like the lungfish it uses its lungs to breathe air when the water where it lives is low in oxygen. It also has a row of small dorsal fins that make its back look like it has little spikes all the way down. It’s a pretty neat-looking fish, in fact. They’re called bichirs and reedfish and still live in parts of Africa, including the Nile River.

There were even sharks in the river of giants, including a type of mackerel shark although we don’t know how big it grew since all we have of it are some teeth. Another was a type of hybodont shark with no modern descendants, although again, we don’t know how big it was.

The biggest fish that lived in the River of Giants, at least that we know of so far, is a type of ray that looked like a sawfish. It’s called Onchopristis numidus and it could probably grow over 26 feet long, or 8 meters. Its snout, or rostrum, was elongated and spiked on both sides with sharp denticles. It was probably also packed with electroreceptors that allowed it to detect prey even in murky water. When it sensed prey, it would whip its head back and forth, hacking the animal to death with the sharp denticles and possibly even cutting it into pieces. Modern sawfish hunt this way, and although Onchopristis isn’t very closely related to sawfish, it looked so similar due to convergent evolution that it probably had very similar habits.

The modern sawfish mostly swallows its prey whole after injuring or killing it with its rostrum, although it will sometimes eat surprisingly large fish for its size, up to a quarter of its own length. A 26-foot long Onchopristis could probably eat fish over five feet long, or 1.5 meters. It wouldn’t have attacked animals much larger than that, though. It wasn’t eating fully grown Spinosauruses, let’s put it that way, although it might have eaten a baby spinosaurus from time to time. Spinosaurus might have eaten Onchopristis, though, although it would have to be pretty fast to avoid getting injured.

But there was one other type of animal in the River of Giants that could have tangled with a fully grown spinosaurus and come out on top. The river was full of various types of crocodylomorphs, some small, some large, some lightly built, some robust. Kemkemia, for instance, might have grown up to 16 feet long, or 5 meters, but it was lightly built. Laganosuchus might have grown 20 feet long, or 6 meters, but while it was robust, it wasn’t very strong or fast. It’s sometimes called the pancake crocodile because its jaws were long, wide, and flattened like long pancakes. Unlike most pancakes, though, its jaws were lined with lots and lots of small teeth that fit together so closely that when it closed its mouth, the teeth formed a cage that not even the tiniest fish could escape. Researchers think it lay on the bottom of the river with its jaws open, and when a fish swam too close, it snapped it jaws closed and gulped down the fish. But obviously, the pancake crocodile did not worry spinosaurus in the least.

Aegisuchus, on the other hand, was simply enormous. We don’t know exactly how big it is and estimates vary widely, but it probably grew nearly 50 feet long, or 15 meters. It might have been much longer, possibly up to 72 feet long, or 22 meters. It’s sometimes called the shield crocodile because of the shape of its skull.

We don’t have a complete specimen of the shield crocodile, just part of one skull, but that skull is weird. It has a circular raised portion called a boss made of rough bone, and the bone around it shows channels for a number of blood vessels. This is unique among all the crocodilians known, living and extinct, and researchers aren’t sure what it means. One suggestion is that the boss was covered with a sheath that was brightly colored during the mating season, or maybe its shape alone attracted a mate. Modern crocodilians raise their heads up out of the water during mating displays.

The shield crocodile had a flattened head other than this boss, and its eyes may have pointed upward instead of forward. If so, it might have rested on the bottom of the river, looking upward to spot anything that passed overhead. Then again, it might have floated just under the surface of the water near shore, looking up to spot any dinosaurs or other land animals that came down to drink. Watch out, dinosaur! There’s a crocodilian!

Could the shield crocodile really have taken down a fully grown spinosaurus, though? If it was built like modern crocodiles, yes. Spinosaurus was a dinosaur, and dinosaurs had to breathe air. If the shield crocodile hunted like modern crocs, it was some form of ambush predator that could kill large animals by drowning them. You’ve probably seen nature shows where a croc bursts up out of the water, grabs a zebra or something by the nose, and drags it into the water, quick as a blink. The croc can hold its breath for up to an hour, while most land animals have to breathe within a few minutes or die. The shield crocodile and spinosaurus also lived at the same time so undoubtedly would have encountered each other.

Then again, there’s a possibility that the shield crocodile wasn’t actually very fearsome, no matter how big it was. It might have been more lightly built with lots of short teeth like the pancake crocodile’s to trap fish in its broad, flattened snout. Until we have more fossils of Aegisuchus, we can only guess.

Fortunately, palaeontologists are still exploring the Kem Kem beds for more fossils from the river of giants. Hopefully one day soon they’ll find more shield crocodile bones and can answer that all-important question of who would win in a fight, a giant crocodile or a giant swimming dinosaur?

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at if you’d like to support us that way and get twice-monthly bonus episodes as well as stickers and things.

Thanks for listening!

Episode 209: Animals Discovered in 2020

Here’s a 2020 retrospective episode that looks at the bright side of the year! Thanks to Page for the suggestion! Let’s learn about some animals discovered in 2020 (mostly).

Further reading:

Watch This Giant, Eerie, String-Like Sea Creature Hunt for Food in the Indian Ocean

Rare Iridescent Snake Discovered in Vietnam

An intrusive killer scorpion points the way to six new species in Sri Lanka

What may be the longest (colony) animal in the world, a newly discovered siphonophore:

New whale(s) just dropped:

A newly discovered pygmy seahorse:

A newly discovered pipefish is extremely red:

So tiny, so newly discovered, Jonah’s mouse lemur:

The Popa langur looks surprised to learn that it’s now considered a new species of monkey:

The newly rediscovered devil eyed frog. I love him:

The newly discovered Lilliputian frog looks big in this picture but is about the size of one of your fingernails:

This newly discovered snake from Vietnam is iridescent and shiny:

A new giant scorpion was discovered in Sri Lanka and now lives in our nightmares:

The Gollum snakehead was technically discovered in 2019 but we’re going to let that slide:

Show transcript:

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

Very recently, Page suggested the topic “animals discovered in 2020.” Since I was already thinking of doing something like this, I went ahead and bumped his suggestion to the top of the list and here we go!

You’d think that with so many people in the world, there wouldn’t be too many more new animals to discover, especially not big ones. But new scientific discoveries happen all the time! Many are for small organisms, of course, like frogs and insects, but there are still unknown large animals out there. In fact, 503 new animals were officially discovered in 2020. Every single one is so amazing that I had a hard time deciding which ones to highlight. In most cases we don’t know much about these new animals since studying an animal in the wild takes time, but finding the animal in the first place is a good start.

Many of the newly discovered species live in the ocean, especially the deep sea. In April of 2020, a deep-sea expedition off the coast of western Australia spotted several dozen animals new to science, including what may be the longest organism ever recorded. It’s a type of siphonophore, which isn’t precisely a single animal the way that, say, a blue whale is. It’s a colony of tiny animals, called zooids, all clones although they perform different functions so the whole colony can thrive. Some zooids help the colony swim, while others have tiny tentacles that grab prey, and others digest the food and disperse the nutrients to the zooids around it. Many siphonophores emit bioluminescent light to attract prey.

Some siphonophores are small but some can grow quite large. The Portuguese man o’ war, which looks like a floating jellyfish, and which we talked about way back in episode 16, is actually a type of siphonophore. Its stinging tentacles can be 100 feet long, or 30 m. Other siphonophores are long, transparent, gelatinous strings that float through the depths of the sea, snagging tiny animals with their tiny tentacles, and that’s the kind this newly discovered siphonophore is.

The new siphonophore was spotted at a depth of about 2,000 feet, or 625 meters, and was floating in a spiral shape. The scientists estimated that the spiral was about 49 feet in diameter, or 15 meters, and that the outer ring alone was probably 154 feet long, or 47 meters. The entire organism might have measured 390 feet long, or almost 119 meters. It’s been placed into the genus Apolemia although it hasn’t been formally described yet.

Another 2020 discovery off the coast of Australia was an entire coral reef a third of a mile tall, or 500 meters, and almost a mile across, or 1.5 km. It’s part of the Great Barrier Reef but isn’t near the other reefs. A scientific team mapping the seafloor in the area discovered the reef and undoubtedly did a lot of celebrating. I mean, it’s not every day that you find an entirely new coral reef. They were able to 3D map the reef for study and take video too. Best of all, it’s a healthy reef with lots of other animal life living around it.

Another big animal discovered in 2020 is one Patreon subscribers already know about, because we started out the year with an episode all about it. It’s a new whale! In 2018 scientists recording audio of animal life around Mexico’s San Benito Islands in the Pacific Ocean heard a whale call they didn’t recognize. They thought it probably belonged to a type of beaked whale, probably a little-known species called Perrin’s beaked whale.

In late 2020 a team went back to the area specifically to look for Perrin’s beaked whales. They did see three beaked whales and got audio, video, and photographs of them, but they weren’t Perrin’s beaked whales. The whale specialists on the expedition didn’t know what these whales were. They don’t match any species of known cetacean and appear to be a species new to science.

And speaking of new species of whale, guess what. Don’t say chicken butt. You can say whale butt, though, because the discovery of another new whale species was just announced. This one’s a 2021 discovery but there’s no way I was going to wait until next year to talk about it. It lives in the Gulf of Mexico and can grow over 41 feet long, or more than 12 meters. It’s a baleen whale, not a beaked whale, and it was hiding in plain sight. It looks a lot like the Bryde’s whale and was long thought to be a subspecies, but new genetic testing shows that it’s much different. It’s been named Rice’s whale, and unfortunately it’s extremely rare. There may only be around 100 individuals alive. It’s mostly threatened by pollution, especially oil spills like the 2010 Deepwater Horizon oil spill, and by collisions with ships. Hopefully now that scientists know more about it, it can be further protected.

Let’s move on from new gigantic animal discoveries to a much, much smaller one. A new pygmy seahorse was discovered off the coast of South Africa in May 2020. It’s brownish-yellow with pinkish and white markings and is only 20 mm long at most. A dive instructor who had seen the fish but didn’t know what it was told researchers about it and they organized a team to look for it. Its closest known relation lives in southeast Asia almost 5,000 miles away, or 8,000 km. Like other seahorses, it lives in shallow water and uses its flexible tail to hang onto underwater plants, but the area where it lives is full of huge waves rolling in from the ocean. It’s called the Sodwana Pygmy Seahorse after the bay where it was discovered, and officially named Hippocampus nalu. “Nalu” means “here it is” in the local Zulu and Xhosa languages, and it also happens to mean “surging surf” in Hawaiian, and it also happens to be the middle name of the dive instructor who spotted the fish, Savannah Nalu Olivier. Sometimes fate just says “this is the right name.”

A new species of pipefish, which is closely related to the seahorse, was also described in 2020, Stigmatopora harastii. It lives off the coast of New South Wales, Australia and can grow up to 5 ½ inches long, or 14 cm. It was first spotted by scuba divers in 2002. These divers know their fish. It lives among a type of red algae and is the same color red for camouflage. It’s surprising how long it took for scientists to discover it, because it’s not exactly hard to confuse with anything else. Except, you know, algae.

Not all newly discovered animals live in the ocean. In August of 2020 researchers discovered a new mouse lemur in Madagascar. We talked about a different type of mouse lemur in episode 135, that one discovered in 1992 and only growing to 3.6 inches long, or 9 cm, not counting its long tail. The newly discovered Jonah’s mouse lemur is only a little bigger than that. Mouse lemurs are the smallest members of the primate family. They’re also super cute but endangered due to habitat loss.

Another primate discovered in 2020 is one that researchers already knew about for more than a hundred years, but no one realized it was its own species, just like Rice’s whale. In 2020, genetic analysis finally determined that the Popa langur is a new species. It’s a beautiful fuzzy gray monkey with bright white markings around its eyes like spectacles. It lives on an extinct volcano in Myanmar and is critically endangered, with only an estimated 250 individuals left in the wild.

A 2020 expedition to the Bolivian Andes in South America led to the discovery of twenty new species of plant and animal, plus a few re-discoveries of animals that were thought to be extinct. The rediscoveries include a species of satyr butterfly not seen for 98 years, and a frog seen only once before, twenty years ago. The frog is called the devil-eyed frog because of its coloring. It’s purplish or brownish black with red eyes and only grows about an inch long, or 29 mm.

Another frog the team found is one of the smallest frogs in the world. It’s been identified as a frog in the genus Noblella and it only grows about ten mm long. As one article I read pointed out, that’s the size of an aspirin. It’s a mottled brown and black and it lives in tunnels it digs in the leaf litter and moss on the forest floor. It’s being referred to as the Lilliputian frog because of its small size.

In the summer of 2019, a team of scientists surveying the karst forests in northern Vietnam spotted an unusual snake. It was so unusual, in fact, that they knew it had to be new to science. It was dark in color but its small scales shone an iridescent purplish, and it was about 18 inches long, or almost 46 cm. It belongs to a genus referred to as odd-scaled snakes, and we don’t know much about them because they’re so hard to find. They mostly burrow underground or under leaf litter on the forest floor. The new species was described in late 2020.

A new species of giant scorpion was discovered in Sri Lanka in 2020. It lives in the forests of Yala National Park and is nocturnal. The female is jet black while the male has reddish-brown legs, and a big female can grow up to 4 inches long, or a little over 10 cm. It’s called the Yala giant scorpion after the park and is the sixth new scorpion species discovered in the park.

One thing I should mention is that all these scientific expeditions to various countries are almost always undertaken by both local scientists and experts from other places. Any finds are studied by the whole group, resulting papers are written with all members contributing, and any specimens collected will usually end up displayed or stored in a local museum or university. The local scientists get to collaborate with colleagues they might never have met before, while the visiting scientists get the opportunity to learn about local animals from the people who know them best, who also happen to know the best places to eat. Everybody wins!

Let’s finish with an astonishing fish that was technically discovered in 2018 and described in 2019, but was further studied in 2020 and found to be even more extraordinary than anyone had guessed. In 2018, after a bad flood, a man living in the village of Oorakam in Kerala, South India, spotted a fish in a rice paddy. He’d never seen a fish like it before and posted a picture of it on social media. A fish expert saw the picture, realized it was something new, and sent a team to Oorakam to retrieve it before it died or something ate it. It turned out to be a new type of snakehead fish.

There are lots of snakehead species that live in rivers and streams throughout parts of Africa and Asia. But this snakehead, which has been named the Gollum snakehead, lives underground. Specifically, it lives in an aquifer. An aquifer is a layer of water that occurs underground naturally. When rain soaks into the ground, some of it is absorbed by plant roots, some seeps out into streams, and some evaporates into the air; but some of it soaks deeper into the ground. It collects in gravel or sand or fractured rocks, or in porous rocks like sandstone. Sometimes an aquifer carves underground streams through rock, creating caves that no human has ever seen or could ever see, since there’s no entrance to the surface large enough for a person to get through. In this case, the heavy rain and floods in Oorakam had washed the fish out of the aquifer and into the rice paddy.

The Gollum snakehead resembles an eel in shape and grows abound four inches long, or 10 cm. Unlike fish adapted for life in caves, though, it has both eyes and pigment, and is a pale reddish-brown in color. This may indicate that it doesn’t necessarily spend all of its life underground. Aquifers frequently connect to springs, streams, and other aboveground waterways, so the Gollum snakehead may spend part of its life aboveground and part below ground.

When it was first described, the researchers placed the fish in its own genus, but further study in 2020 has revealed that the fish is so different from other snakeheads that it doesn’t just need its own genus, it needs its own family. Members of the newly created family are referred to as dragonfish.

Other snakeheads can breathe air with a structure known as a suprabranchial organ, which acts sort of like a lung, located in the head above the gills. Not only does the Gollum snakehead not have this organ, there’s no sign that it ever had the organ. That suggests that other snakeheads developed the organ later and that the Gollum snakehead is a more basal species. It also has a small swim bladder compared to other snakeheads.

Researchers think that the dragonfish family may have separated from other snakehead species as much as 130 million years ago, before the supercontinent of Gondwana began breaking up into smaller landmasses. One of the chunks that separated from Gondwana probably contained the ancestor of the Gollum snakehead, and that chunk eventually collided very slowly with Asia and became what we now call India.

The Gollum snakehead isn’t the only thing that lives in the aquifer, of course. Lots of other species do too, but it’s almost impossible to study them because they live underground with only tiny openings to the surface. The only time we can study the animals that live there is when they’re washed out of the aquifers by heavy rain. It turns out, in fact, that there’s a second species of dragonfish in the aquifer, closely related to the Gollum snakehead, with a single specimen found after rain.

So, next time you’re outside, think about what might be under the ground you’re walking on. You might be walking above an aquifer with strange unknown animals swimming around in it, animals which may never be seen by humans.

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, or just want a sticker, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at if you’d like to support us that way.

Thanks for listening!

Episode 193: Beebe’s Mystery Deep-Sea Fish

This week we’ll learn about five mystery fish that William Beebe spotted from his bathysphere in the early 1930s…and which have never been seen again. Thanks to Page for suggesting deep-sea fish!

Further reading:

How some superblack fish disappear into the darkness of the deep sea

The Fine Art of Exploration

Further listening:

99% Invisible “Bathysphere”

The Gulper Eel unlocked patreon episode

These two guys crammed themselves into that little bathysphere together. Sometimes they got seasick and puked in there. Also, they didn’t like each other very much:

The Pacific blackdragon is hard to photograph because it’s SUPERBLACK:

A larval blackdragon. Those eyestalks!

A painting (by Else Bostelmann) of Bathysphaera intacta (left) and an illustration from Beebe’s book Half Mile Down:

The pallid sailfish, also painted by Bostelmann:

A (dead) stoplight loosejaw. Tear your surprised eyeballs away from its weird jaws and compare its tail to the pallid sailfish’s:

A model of a loosejaw (taken from this site) to give you a better idea of what it looks like when alive. Close-up of the extraordinary jaws (seen from underneath) is on the right:

Show transcript:

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

This week we’re going to descend metaphorically into the depths of the ocean and learn about some mystery fish spotted once from a bathysphere by famous naturalist William Beebe and never seen again. Deep-sea fish is a suggestion by Page, so thank you, Page, for a fascinating and creepy addition to monster month.

William Beebe was an American naturalist born in 1877 who lived until 1962, which is amazing considering he made repeated dives into the deep sea in the very first bathysphere in the early 1930s. We talked about bathyspheres way back in episode 27–you know, the one where I scream about them imploding and kind of freak out a little. Even today descending into the deep sea is dangerous, and a hundred years ago it was way way way more dangerous.

Beebe was an early conservationist who urged other scientists to stop shooting so many animals. Back then if you wanted to study an animal, you just went out and killed as many of them as you could find. Beebe pointed out the obvious, that this was wasteful and didn’t provide nearly as much information as careful observation of living animals in the wild. He also pioneered the study of ecosystems, how animals fit into their environment and interact with it and each other.

While Beebe mostly studied birds, he was also interested in underwater animals. Really, he seems to have been interested in everything. He studied birds all over the world, was a good taxidermist, and especially liked to study ocean life by dredging small animals up from the bottom and examining them. He survived a plane crash, was nearly killed by an erupting volcano he was observing, and fought in WWI. Once when he broke his leg during an expedition and had to remain immobilized, he had his bed carried outside every day so he could make observations of the local animals as they grew used to his presence.

In the 1920s, during an expedition to the Galapagos Islands, he started studying marine animals more closely. First he just dangled from a rope over the surface of the ocean, which was attached to a ship’s boom, but eventually he tried using a diving helmet. This was so successful that he started thinking about building a vessel that could withstand the pressures of the deep sea.

With the help of engineer Otis Barton, the world’s first bathysphere was invented and Barton and Beebe conducted dozens of descents in Bermuda, especially off the coast of Nonsuch Island. The bathysphere had two little windows and a single light that shone through one of the windows, illuminating the outside just enough to see fish and other animals. The bathysphere couldn’t descend all that deeply, although it set records repeatedly. The deepest they descended was 3,028 feet, or 923 meters, but Beebe made careful notes of all the animals he observed and published many articles and books about them. Many of these articles and books were illustrated by an artist named Else Bostelmann, who worked closely with Beebe and his team of scientists. Bostelmann even painted underwater while wearing a diving helmet, because she needed to know how colors were affected by underwater light. She used oil paints, since oil and water don’t mix so the paints wouldn’t wash away, and she tied strings to her paintbrushes so they wouldn’t float off.

Incidentally, if you’re interested in reading a really interesting article about Bostelmann or learning more about the bathysphere and William Beebe, check the show notes. I’ve included links to the article and to a 99% Invisible episode about the bathysphere.

Many of the animals Beebe saw from the bathysphere have since been identified and described by later scientists. But there are five fish that Beebe observed that have never been seen since.

Before we talk about them, let’s learn about Page’s suggestion, the Pacific blackdragon, for reasons that will shortly become clear. The Pacific blackdragon is a type of fish that lives in the Pacific, which you probably figured out without me telling you. It prefers tropical and temperate water, although since it’s a deep-sea fish the water where it lives is mostly very cold.

If you remember episode 155 about extreme sexual dimorphism, where the males and females of a species look radically different, this fish is a good example. The male never eats. He can’t eat. He doesn’t have a functioning digestive system. He survives on the yolk from the egg he develops from and never grows any larger than his larval form, about three inches long, or 8 cm. He lives long enough to mate and then he dies.

The female, however, grows up to about two feet long, or 61 cm. Her body is long and thin, and her mouth is full of sharp teeth that she uses to grab anything she can catch. She especially likes to eat fish and small crustaceans, but she’s not picky.

Her body is black, and not just regular black. It’s called superblack or ultrablack. In episode 186 we talked about the eyed click beetle and velvet asity who both have superblack markings that absorb most of the light that hits them. Well, the Pacific blackdragon is superblack almost all over to help hide in the darkness of the water, since it’s an ambush predator. Just under the fish’s skin, there’s a layer of closely packed pigment-containing structures called melanosomes, which can absorb up to 99.95% of light. As if that wasn’t enough, because a lot of the animals the blackdragon eats emit bioluminescent light, her stomach is also black to block any light from the prey she’s swallowed. But although she’s basically invisible to other animals, she does have several rows of light-emitting cells called photophores along her sides. Scientists think she uses the lights to attract a mate, but she only flashes the photophores occasionally and only for brief moments. She also has a barbel that hangs from her chin with a luminescent lure at the end, which she uses to attract prey.

While the Pacific blackdragon is a deep-sea fish, at night she migrates upward nearer the surface to catch more prey, although she still stays below about 1,300 feet deep, or 400 m. She has large eyes as a result to take advantage of any moonlight and starlight that shines down that far. During the day she stays deeper, up to 3,200 feet deep, or 1,000 m.

Speaking of the Pacific blackdragon’s eyes, larval blackdragons have eyes on long stalks—really long stalks, nearly half their body length. As the larva matures, it absorbs the stalks until the adult fish has ordinary fish eyes. The larvae are also mostly transparent.

There are two other blackdragon species known, both of them a little smaller than the Pacific blackdragon. But in 1932 William Beebe spotted a fish that he thought might be related to the blackdragons, except that he estimated it was six feet long, or 1.8 m.

Beebe named the fish Bathysphaera intacta, but there’s no type specimen so no one can study it and verify whether it’s a species of blackdragon or something else. Beebe said the fish he saw had large eyes, lots of teeth, and photophores along its sides that glowed blue, and had a barbel with a light under its chin just like the Pacific blackdragon and its cousins. But it also had another, smaller barbel with a light near the tail. Beebe saw two of the fish together. They circled the bathysphere a few times, probably attracted to its light.

Another of Beebe’s mystery fish is one he named the pallid sailfin, Bathyembryx istiophasma. He saw it twice on the same descent in 1934, and described it as about two feet long, or 61 cm, shaped like a cigar with triangular fins and a tiny tail. In fact, in his book Half Mile Down Beebe described the fish this way:

“The strange fish was at least two feet in length, wholly without lights or luminosity, with a small eye and good-sized mouth. Later, when it shifted a little backwards I saw a long, rather wide, but evidently filamentous pectoral fin. The two most unusual things were first, the color, which, in the light, was an unpleasant pale olivedrab, the hue of water-soaked flesh, an unhealthy buff. It was a color worthy of these black depths, like the sickly sprouts of plants in a cellar. Another strange thing was its almost tailless condition, the caudal fin being reduced to a tiny knob or button, while the vertical fins, taking its place, rose high above and stretched far beneath the body, these fins also being colorless.”

Beebe assigned the pallid sailfish into the family Stomiidae, the same family that Bathysphaera intacta is assigned to as well as the other blackdragons. As a group, the fish in this family are called barbeled dragonfish. Some species in this family do show a similar tail arrangement that Beebe noted, with a very small tail fin but enlarged anal and dorsal fins that are set well back on the body. This includes a weird fish with various names, including black hinge-head, black loosejaw, or lightless loosejaw, which maybe gives you an idea of what it looks like. It’s a deep-sea fish like all the barbeled dragonfish, and it’s black in color. It grows about 10 inches long, or almost 26 cm. It’s also sometimes called the stoplight loosejaw because it has two photophores on its head, one of which shines green, the other which shines red. Unlike most deep-sea fish, it can see in the red spectrum, so the green photophore may attract prey and the red photophore allows the loosejaw to see its prey even though the prey can’t see the loosejaw. But mainly, it has remarkable jaws.

The loosejaw’s jaws are hinged and extremely large compared to the body, which is fairly thin. The jaws are so large that they’re not even attached to its body, just to its head. They aren’t even connected to the body with skin. It’s hard to describe, but I have some good pictures of a model of the fish in the show notes. Basically, the jaws are just bones covered with a thin layer of skin, but no skin or muscle in between the bones. If you put your thumb under your chin, you can feel your chin bone, then move your thumb backwards and instead of bone, you feel skin over layers of fat and muscle and other tissues that make up the soft part of your jaw. Well, the loosejaw doesn’t have those soft parts. It just has the chin bone and there’s literally nothing between the jaws. It doesn’t have a throat or cheeks or anything like that. Its jaws aren’t big because it needs to swallow big things, its jaws are big so it has a longer reach to snag the small fish and crustaceans it eats. It has a lot of needlelike teeth that it uses to keep its prey from wriggling away while it maneuvers it into its gullet. It mostly eats very small animals, but it’s not going to let anything get away once it gets within jaw range.

While I was researching this episode, I spent a ridiculous amount of time trying to find the episode where I talked about the umbrellafish, thinking it might be related to the loosejaw. It’s not, and I finally realized the umbrellafish episode was for patrons. I’ve unlocked that Patreon episode and linked to it in the show notes if you want to go listen to it. The umbrellafish, also called the gulper eel, looks superficially like the loosejaw, but it has skin over its huge hinged jaws.

After my inability to properly describe the loosejaw’s amazing jaws, let’s move on to Beebe’s other mystery fish. One he named the three-starred anglerfish, Bathyceratias trilychnus, which he estimated was about six inches long, or 15 cm. It had three bioluminescent illicia on its head that it probably used as lures, since that’s something that other deep-sea anglerfish do and Beebe was pretty sure it was actually a species of anglerfish. Since there are over 200 known species of anglerfish, it’s not surprising that there are more that aren’t known.

Another was the five-lined constellation fish, Bathysidus pentagrammus, named for the five rows of photophores on its sides. Beebe thought it looked kind of like a surgeonfish, which is a flat, round fish shaped sort of like a pancake with fins and a tail. But surgeonfish are mostly found in shallow, tropical waters around coral reefs. They’re often brightly colored. Beebe didn’t assign his constellation fish to the surgeonfish’s family, and in fact didn’t assign it to any family since he didn’t know where it belonged.

The last of Beebe’s mystery fish was the rainbow gar, which he didn’t give a scientific name to since he had no idea what kind of fish it might be. He thought it was shaped like a gar, but it was so extraordinary he didn’t know what to think. He actually saw four of them swimming almost vertically, heads up and tails down, at about 2,500 feet deep, or 760 m. He named them rainbow gar because of their coloring: bright red head and jaws, a light blue body, and a yellow tail. They were about four inches long, or a little over 10 cm, with long, pointed jaws. They moved by fanning the dorsal fin, sort of like a seahorse.

Beebe wrote scientific articles about some of these fish and included them all in his book Half Mile Down. But it wasn’t long before other scientists started doubting the sightings. Some people thought he’d made up the fish to make his expeditions more exciting, some thought he was just mistaken. One irate ichthyologist wrote in 1933 that the constellation fish was probably just light reflecting off Beebe’s own breath fogging the window, because no fish had photophores like the ones he described. Because I guess in 1933 everything was known about fish that would ever be known, right?

Beebe seems to have been an honest scientist, though, and he didn’t really need to make anything up. He discovered dozens, if not hundreds, of fish new to science, many of which have either been found and properly described later, or which Beebe himself managed to later catch. Whenever he and Barton came up from a descent in the bathysphere, Beebe had his team on the boat send down nets, and sometimes they caught some of the animals he had seen. This allowed Bostelmann to add details to her paintings that Beebe wouldn’t have known about from just a look through the bathysphere’s windows.

Not only that, if Beebe wanted to make up a fish that would excite the general public and make them want to buy his books, he would have made up something huge and frightening. His mystery fish are mostly quite small. Only Bathysphaera intacta was large, and he only said they were about six feet long. That’s big for a deep-sea fish, but remember that the bathysphere never made it to the really crushing depths of the abyss. It descended into the mesopelagic zone, which is extremely dark but not completely lightless. There’s also a lot of life in this zone, and many fish that spend the day here migrate nearer the surface at night where they can find more food while still remaining hidden. The long-snouted lancetfish lives in this zone and it can grow seven feet long, or 2.15 m.

Plus, Beebe didn’t need to convince anyone to buy his books. They were already runaway bestsellers and he was quite famous, although it seems not to have gone to his head. He just wanted to have fun and do science. He actually seems to have been a good person by modern standards too, which is always refreshing. He disagreed with people who claimed to have scientific proof that women were inferior to men or that some races were inferior to others. He insisted that his team members work hard, but he worked hard too, and if he thought everyone was feeling too stressed, he’d announce that his birthday was coming up and they should take a few days off to celebrate. Some years he had several birthdays.

Beebe did spot one other mystery animal, but he didn’t get a good enough view to make a guess as to what it might be. This is what he wrote about it:

“…I saw its complete, shadow-like contour as it passed through the farthest end of the beam [of light]. Twenty feet is the least possible estimate I can give to its full length, and it was deep in proportion. The whole fish was monochrome, and I could not see even an eye or a fin. For the majority of the ‘size-conscious’ human race this marine monster would, I suppose, be the supreme sight of the expedition. In shape it was a deep oval, it swam without evident effort, and it did not return. That is all I can contribute, and while its unusual size so excited me that for several hundred feet I kept keenly on the lookout for hints of the same or other large fish, I soon forgot it in the (very literal) light of smaller, but more distinct and interesting organisms.

“What this great creature was I cannot say. A first, and most reasonable guess would be a small whale or blackfish. …[O]r, less likely, it may have been a whale shark, which is known to reach a length of forty feet. Whatever it was, it appeared and vanished so unexpectedly and showed so dimly that it was quite unidentifiable except as a large, living creature.”

Twenty feet is six meters, by the way. It might easily have been a whale, since many species of whale routinely dive much farther than the bathysphere descended at its deepest. Whatever it was, and whatever Beebe’s other five mystery fish were, hopefully one day a modern deep-sea vehicle will find them again.

You can find Strange Animals Podcast online at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at if you’d like to support us that way. Don’t forget to enter our book giveaway if you haven’t already, too! Details are on the website.

Thanks for listening!

Episode 191: Masters of Disguise!

Thanks to Nicholas and Pranav for their suggestions which led to this episode about animals that are especially good at disguising themselves!

If you’d like to listen to the original Patreon episode about animal mimics, it’s unlocked and you can listen to it on your browser!

Don’t forget to contact me in some way (email, comment, message me on Twitter or FB, etc.) if you want to enter the book giveaway! Deadline is Oct. 31, 2020.

Further watching:

An octopus changing color while asleep, possibly due to her dreams

Crows mobbing an owl!

Baby cinereous mourner and the toxic caterpillar it’s imitating:

The beautiful wood nymph is a moth that looks just like bird poop when it sits on a leaf, but not when it has its wings spread:

The leafy seadragon, just hanging out looking like seaweed:

This pygmy owl isn’t looking at you, those are false eyespots on the back of its head:

Is it a ladybug? NO IT’S A COCKROACH! Prosoplecta looks just like a (bad-tasting) ladybug:

The mimic octopus:

A flower crab spider with lunch:

Show transcript:

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

This week let’s look at some masters of disguise. This is a suggestion from Nicholas, but we’ll also learn about how octopuses and other animals change colors, which is a suggestion from Pranav. Both these suggestions are really old ones, so I’m sorry I took so long to get to them. A couple of years ago we had a Patreon episode about animal mimics, so I’ll be incorporating parts of that episode into this one, but if you want to listen to the original Patreon animal mimics episode, it’s unlocked so anyone can listen to it. I’ll put a link to it in the show notes.

Most animals are camouflaged to some degree so that they blend in with their surroundings, which is also called cryptic coloration. Think about sparrows as an example. Most sparrows are sort of brownish with streaks of black or white, which helps hide them in the grass and bushes where they forage. Disruptive coloration is a type of camouflage that breaks up the outlines of an animal’s body, making it hard for another animal to recognize it against the background. Many animals have black eye streaks or face masks that help hide the eyes, which in turn helps hide where their head is.

But some animals take camouflage to the extreme! Let’s learn about some of these masters of disguise.

We’ll start with a bird. There’s a bird that lives in parts of South America called the cinereous mourner that as an adult is a pretty ordinary-looking songbird. It’s gray with cinnamon wing bars and an orange spot on each side. It mostly lives in the tropics. In 2012, researchers in the area found a cinereous mourner nest with newly hatched chicks. The chicks were orangey-yellow with dark speckles and had long feather barbs tipped with white. While the researchers were measuring the chicks and making observations, they noticed something odd. The chicks started moving their heads back and forth slowly. If you’ve ever seen a caterpillar moving its head back and forth, you’d recognize the chicks’ movements. And, as it happens, in the same areas of South America, there’s a large toxic caterpillar that’s fluffy and orange with black and white speckles.

It’s rare that a bird will mimic an insect, but mimicry in general is common in nature. We’ve talked about some animal mimics in earlier episodes, including the orchid mantis in episode 187 that looks so much like a flower that butterflies sometimes land on it…and then get eaten. Stick insects, also known as phasmids, which we talked about in episode 93, look like sticks. Sometimes the name just fits, you know? Some species of moth actually look like bird poop.

Wait, what? Yes indeed, some moths look just like bird poop. The beautiful wood nymph (that’s its full name; I mean, it is beautiful, but it’s actually called the beautiful wood nymph) is a lovely little moth that lives in eastern North America. It has a wingspan of 1.8 inches, or 4.6 cm, and its wings are quite lovely. The front wings are mostly white with brown along the edges and a few brown and yellow spots, while the rear wings are a soft yellow-brown with a narrow brown edge. It has furry legs that are white with black tips. But when the moth folds its wings to rest, suddenly those pretty markings make it look exactly like a bird dropping. It even stretches out its front legs so they resemble a little splatter on the edge of the poop.

But it’s not just insects that mimic other things. We’ve talked about frogfish before in episode 165. It has frills and protuberances that make it look like plants, rocks, or coral, depending on the species. The leafy seadragon, which is related to seahorses and pipefish, has protrusions all over its body that look just like seaweed leaves. It lives off the coast of southern and western Australia and grows over nine inches long, or 24 cm, and it moves quite slowly so that it looks like a piece of drifting seaweed. Not only are the protuberances leaf-shaped, they’re green with little dark spots, or sometimes brown, while the body can be green or yellowish or brown like the stem of a piece of seaweed.

Many animals have false eyespots, which can serve different purposes. Sometimes, as in the eyed click beetle we talked about in episode 186, the false eye spots are intended to make it look much larger and therefore more dangerous than it really is. Sometimes an animal’s false eyespots are intended to draw attention away from the animal’s head. A lot of butterflies have false eyespots on their wings that draw attention away from the head so that a predator will attack the wings, which allows the butterfly to escape. Some fish have eyespots near the tail that can make a predator assume that the fish is going to move in the opposite direction when startled.

Even some species of birds have false eyespots, including many species of pygmy owl. The Northern pygmy owl is barely bigger than a songbird, just six inches tall, or 15 cm. It lives in parts of western North America, usually in forests although it also likes wetlands. It’s mostly gray or brown with white streaks and speckles, but it has two black spots on the back of its head, fringed with white, that look like eyes. Predators approaching from behind think they’ve been spotted and are being stared at.

But some larger birds of prey have false eyespots too, including the American kestrel and northern hawk owl. What’s going on with that?

You’ve probably seen or heard birds mobbing potential predators. For instance, where I live mockingbirds will mob crows, while crows will mob hawks. The mobbing birds make a specific type of angry screaming call while divebombing the predator, often in groups. They mostly aim for the bird’s face, especially its eyes, in an attempt to drive it away. This happens most often in spring and summer when birds are protecting their nests. Researchers think the false eyespots that some birds of prey have help deflect some of the attacks from other birds. The mobbing birds may aim for the false eyespots instead of the real eyes. Despite its small size, the northern pygmy owl will eat other birds, and it’s also a diurnal owl, meaning it’s most active during the day, and it does sometimes get mobbed by other birds.

Sometimes, instead of blending in to its surroundings, an animal’s appearance jumps out in a way that you’d think would make it easy to find and eat. But like the cinereous mourner chicks mimicking toxic caterpillars, something in the mimic’s appearance makes predators hesitate.

A genus of cockroaches from the Philippines, Prosoplecta, have evolved to look like ladybugs, because ladybugs are inedible to many predators. But cockroaches don’t look anything like ladybugs, so the modifications these roaches have evolved are extreme. Their hind wings are actually folded up and rolled under their carapace in a way that has been found in no other insect in the world. The roach’s carapace is orangey-red with black spots, just like a ladybug.

In the case of a lot of milkweed butterfly species, including the monarch butterfly, which are all toxic and which are not related to each other, researchers couldn’t figure out at first why they all look pretty much alike. Then a zoologist named Fritz Müller suggested that because all the butterflies are toxic and all the butterflies look alike, predators who eat one and get sick will afterwards avoid all the butterflies instead of sampling each variety. That’s called Mullerian mimicry.

A lot of insects have evolved to look like bees, wasps, or other insects with powerful stings. The harmless milksnake has similar coloring to the deadly coral snake. And when the mimic octopus feels threatened, it can change color and even its body shape to look like a more dangerous animal, such as a sea snake.

And that brings us to the octopus. How do octopuses change color? Is it the same in chameleons or is that a different process? Let’s find out and then we’ll come back to the mimic octopus.

We’ve talked about the octopus in many episodes, including episodes 100, 142, and 174, but while I’ve mentioned their ability to change color before, I’ve never really gone into detail. Octopuses, along with other cephalopods like squid, have specialized cells called chromatophores in their skin. A chromatophore consists of a sac filled with pigment and a nerve, and each chromatophore is surrounded by tiny muscles. When an octopus wants to change colors, its nervous system activates the tiny muscles around the correct chromatophores. That is, some chromatophores contain yellow pigment, some contain red or brown. Because the color change is controlled by the nervous system and muscles, it happens incredibly quickly, in just milliseconds.

But that’s not all, because some species of octopus also have other cells called iridophores and leucophores. Iridophores are layers of extremely thin cells that can reflect light of certain wavelengths, which results in iridescent patches of color on the skin. While the octopus can control these reflections, it takes a little longer, several seconds or sometimes several minutes.

Leucophores are cells that scatter light, sort of like a mirrored surface, which doesn’t sound very helpful except when you remember how light changes as it penetrates the water. Near the surface, with full spectrum light from sunshine, the leucophores just appear like little white spots. But water scatters and absorbs the longer wavelengths of light more quickly than the shorter wavelengths. We’ve talked about this before here and there, mostly when talking about deep-sea animals.

To make it a little simpler, think of a rainbow. A rainbow is caused when there are a lot of water droplets in the air. Light shines through the droplets and is scattered, and the colors are always in the same pattern. Red will always be on the top of the rainbow because it has the longest wavelength, while violet, or purple, will always be on the bottom because it has the shortest wavelength. The same thing happens when sunlight shines into the water, but it doesn’t form a rainbow that we can see. Red light is absorbed by the water first, which is why so many deep-sea animals are unable to perceive the color red. There’s no reason for them to see it, so there’s no need for the body to put effort into growing receptors for that color.

Blue, by the way, penetrates water the deepest. That’s why clear, deep water looks blue. Solid particles in the water also affect how light scatters, so it can get complicated. But to get back to an octopus with leucophores, the leucophores reflect the color of the light that shines on them. So if an octopus is deeper in the water and the light shining on it is mostly in the green and blue spectrum, the leucophores will reflect green and blue, helping make the octopus look sort of invisible.

But wait, it gets even more complicated, because some octopuses can also change the texture of the skin. Sometimes that just means it can make its skin bumpy to help it blend in with rocks or coral, but some species can change the shape of the skin more drastically.

We still don’t fully understand how cephalopods know what colors they should change to. While octopuses mostly have good eyesight, at least some species are colorblind. But they can still match the background colors exactly. Some preliminary research into cuttlefish skin appears to show that the cuttlefish has a type of photosensor in the skin that allows it to sense light wavelengths and brightness without needing to use its eyes. Basically the skin acts like its own eye. This is getting weirder and weirder, but that happens when we talk about cephalopods because they are peculiar and fascinating animals. In 2019, marine biologists released footage of a captive octopus changing colors in her sleep. Some researchers think she may have been dreaming, and her dream prompted the color changes.

Let’s get back to the mimic octopus now that we’ve learned the basics of how octopuses change color. The mimic octopus lives throughout much of the Indo-Pacific, especially around Indonesia, and has an armspan of about two feet across, or 60 cm. It generally lives in shallow, murky water, where it forages for small crustaceans and occasionally catches small fish. It’s usually light brown with darker brown stripes, but it’s good at changing both its color and its shape to mimic other animals.

So far, researchers have documented it mimicking 15 other animals, including a sea snake where it hides all but two of its legs, a lion fish where it holds its legs out to look like spines, jellyfish, sting rays, frogfish, starfish, sponges, tube-worms, flatfish, and even a crab. It actually imitates a crab in order to approach other crabs, which it then grabs and eats. So obviously it’s not using its mimicry ability randomly. It will imitate a sea snake if it feels threatened by an animal that is eaten by sea snakes, for instance. And it was only discovered in 1998 and hasn’t been studied very well yet.

Unfortunately, the mimic octopus is rare to start with and threatened by pollution and habitat loss. Once it was discovered, people immediately wanted to own them. But the mimic octopus doesn’t do well in captivity, usually dying within weeks or even days. Even octopus experts have trouble keeping them alive for very long. One expert reported that the mimic octopus is incredibly shy and spends most of its time hiding deep under the sand. It’s mostly active at night and doesn’t like bright light. It’s incredibly sensitive to temperature changes, water quality, and even the type of salt used in saltwater aquariums, and most importantly, he reported that in captivity, it doesn’t do any imitating.

Chameleons are also famous for their ability to change color and pattern, but not every species can do so. The ones who can use a very different process for color changing compared to octopuses. The chameleon has a layer of skin that contains pigments with a layer beneath that contains crystals of guanine, a reflective molecule that’s used in cosmetics to make things look shimmery, like nail polish. The chameleon can move the crystals to change the way light reflects off them, which affects the color, especially when combined with the pigments in the upper layer of skin. The color change takes about 20 seconds and different species are able to change into different colors and patterns.

Not all mimics use appearance. A number of moths are toxic to bats, but it’s no use evolving bright colors to advertise their toxicity to predators who use echolocation to hunt. Instead, the moths generate high-pitched clicks that the bats hear, recognize, and avoid. And naturally, some non-toxic moths also generate the same sounds to mimic the toxic moths.

Let’s finish with a tiny spider that also changes color. It’s called the white crab spider or the goldenrod crab spider or the banana crab spider, or just the flower spider. It’s a small, common spider that lives throughout the northern hemisphere. You’ve probably seen a few of them in your time, probably when you’re leaning down to sniff a flower. It hangs out on flowers and can be white or yellow in color. A big female can be 10 mm long, not counting her legs, while males are barely half that size. They’re called crab spiders because they often run sideways like a crab. The flower spider doesn’t build a web. Instead, it just sits on a flower.

The male flower spider climbs around from flower to flower, looking for a mate. The female generally stays put on a particular flower until it fades, and then she’ll find a new one. If she moves from a yellow flower to a white one, or vice versa, she can change color to match, but it’s not a quick process. It takes at least ten days and sometimes up to 25 days to change from white to yellow, since the spider has to secrete yellow pigment into its cells, while changing from yellow to white usually takes less than a week. If she’s on a flower that is another color, she’ll usually remain white. Only the female can change color, and some females may have small red or pink markings that don’t change color. The male is usually yellow or off-white in color.

The flower spider is so well camouflaged that it can be hard to spot even if you’re looking for it. It eats butterflies and moths, bees, and other insects that visit the flowers. Males will also eat pollen. Its venom is especially toxic to bees, although it’s harmless to humans. It really likes to eat bumblebees. Its first pair of legs are longest and curve forward to make it easier for the spider to grab a bumblebee and sink its fangs into it. Meanwhile, the bumblebee has black and yellow stripes to advertise to potential predators that it will sting, but that doesn’t help it when it comes to the little crab spider. Danger in the bee world!

You can find Strange Animals Podcast online at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at We also have a Patreon if you’d like to support us that way.

Don’t forget to contact me if you want to enter the book giveaway contest, which will run through October 31, 2020! If you want to enter, just let me know by any means you like.

Thanks for listening!

Episode 189: The Handfish and the Lumpsucker

This week we have two more listener suggestions, so thanks to Rosy and Simon! They both suggested small but intensely interesting fish!

Further reading:

The Handfish Conservation Project – Name a Fish!

Further watching:

Pacific Spiny Lumpsucker making adorable faces

The only smooth handfish specimen in the whole world:

In case you were wondering why it’s called a handfish (this one is a spotted handfish):

A red handfish. You’d be angry too if there were fewer than 100 individuals left in your species (photo by Rick Stuart-Smith):

A Pacific spiny lumpsucker:

HOW IS THIS REAL? I AM GOING TO DIE. These are real lumpsuckers on a real balloon in an aquarium. Apparently it’s a birthday party thing to do in Japan:

The sucker part of the lumpsucker:


Show transcript:

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

This week we’re going to learn about two interesting fish, but first a CORRECTION!

In the hyena episode last week I called the hyena a canid, and it’s not! Yikes, that was a major blunder on my part. Thanks to Bal for the correction. Hyenas aren’t even very closely related to canids at all. They’re in the family Hyaenidae while canids are in the family Canidae, although both are in the order Carnivora along with cats and walruses and raccoons and weasels, etc. AND thanks to Simon who also let me know that the striped hyena lives in the Middle East and Asia as well as Africa. Sorry, y’all. I hate when I make mistakes.

Anyway, back to the fish! We’ll start with the handfish, which happens to be a suggestion by Simon. Simon sent me an article about the smooth handfish specifically, and it’s a sad article because the smooth handfish has been declared extinct.

The smooth handfish used to be a common fish that lived off the coast of Tasmania in warm, shallow water. It was reddish-brown with darker brown markings, and it grew to about 1 3/4 inches long, or 4.4 cm. But the area where it lived was dredged so intensively for oysters and scallops up until 1967 that the fish’s habitat was destroyed. It was described in 1802 from a single specimen caught by a French naturalist, but that’s the only smooth handfish anyone ever bothered to collect for science. And now it’s the only specimen we have to study.

The reason the smooth handfish was so vulnerable to habitat loss is that it didn’t have a larval stage where newly hatched fish could disperse to new areas by floating on currents. Handfish eggs hatch into teeny baby handfish, not larval handfish. As a result, it was restricted to only specific areas and when those areas were destroyed by dredging, the fish was driven extinct. And the really awful thing is, the only reason people stopped dredging for oysters and scallops is because they’d been so overfished that there basically weren’t any left. The smooth handfish is actually the first marine fish known that has gone extinct in modern times.

There are 13 other species of handfish known in the world, but they’re all endangered due to pollution, habitat loss, and the spread of invasive species. Like the smooth handfish, other handfish species lay eggs that hatch into juvenile fish instead of larval fish, so they’re also especially vulnerable to habitat loss. For example, there are fewer than 100 red handfish alive in two small areas off the coast of Tasmania. We know because each fish has unique markings, which allows conservationists to identify individuals. A group called the Handfish Conservation Project has put together a database of living individuals, and if you donate at least $1,000 (in Australian dollars) you get to give one of the fish a name. I’ll put a link in the show notes so you can go look at the fish and see the names some of them have been given. The names include Ginger Ninja, Knuckles, Rosie Palm, and The Stalker.

The handfish is called that because its pectoral fins look like big flat hands that it uses to walk along the ocean floor. It’s actually related to the anglerfish, and like anglerfish it has an illicium above its mouth. Anglerfish use the illicium as a lure to attract animals that it then gulps down, but the handfish’s illicium is relatively small and researchers aren’t sure if all species use it as a lure. We’re not even completely sure what handfish eat, although there are reports of handfish eating polychaete worms, small fish, and crustaceans like amphipods and shrimp.

All the species live off the coast of Australia, especially around Tasmania. The largest species only grows to about 6 inches long, or 15 cm.

That is pretty much all we know about the handfish, so let’s move on to our other fish today, a suggestion by Rosy. Rosy wants us to talk about the lumpsucker, and I cannot argue with this because they are weirdly adorable fish.

The lumpsucker lives in cold waters near the Arctic. Most species live in the North Pacific but some also live in the North Atlantic. It doesn’t swim very well and, like the handfish, it spends most of its time on the sea floor. But unlike the handfish, which lives in shallow coastal water, some lumpsuckers live in the deep sea, up to 5,600 feet deep, or 1,700 meters. It eats small crustaceans, mollusks, polychaete worms, and other small animals, and the deep-sea species may also eat small jellyfish.

There are around 30 species of lumpsucker known, and we don’t know a whole lot about most of them. Most are small, but the biggest can grow 20 inches long, or 50 cm, and weigh as much as 11 lbs, or 5 kg. That’s Cyclopterus lumpus, which varies in color from blue or gray to yellowish or brown, and sometimes greenish, although during breeding season males turn orangey-red. The female’s eggs are eaten by people as imitation caviar, and it’s the only lumpsucker that is fished for as a result. Some people eat the fish itself too, especially in Iceland, but usually only the males. The females reportedly taste bad.

Cyclopterus lumpus has become a helpful addition to salmon farming in a surprising way. It eats parasites called sea lice, which infest the salmon. The lumpsuckers do such a good job cleaning the salmon of sea lice that fish farmers don’t have to use parasiticides.

The lumpsucker gets its name because it’s a little round lump of a fish and it has modified pelvic fins that act as a little sucker on its belly that lets it stick to things. The lumpsucker also has little hard bumps on its body. It has big round eyes and a little round mouth. Basically what I’m trying to say is the best word to describe a lumpsucker is ROUND. So round.

The lumpsucker doesn’t have a swim bladder. Instead, it has jelly-like fat deposits that increase its buoyancy. The female lays her eggs in rock crevices and the male stays to guard the eggs. He uses his tail and tiny fins to push water over the eggs so they stay aerated, and remains with them until they hatch several weeks later. The larvae are well developed and already have suckers.

Probably the most well-loved species of lumpsucker is the Pacific spiny lumpsucker, which is the roundest and most adorable, and is often kept in aquariums. It grows to about three inches long, or 7.5 cm, and it varies in color. Females are usually greenish while males are orange or reddish, but individuals can be gray, brown, or yellow too. In the wild it lives around Japan, northern California, and many other areas, where it spends most of its time stuck to pieces of eel grass, kelp, or rocks, making adorable faces at things. There’s a link in the show notes to a little video of one sticking itself to a rock, looking around, moving slightly with its teeny fins, sticking itself back to the rock… You really need to watch it. It will make you feel very calm.

You can find Strange Animals Podcast online at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, or if you have a great idea for a red handfish name, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at if you’d like to support us that way.

Thanks for listening!

Episode 181: Updates 3 and a lake monster!

It’s our annual updates and corrections episode, with a fun mystery animal at the end!

Thanks to everyone who contributed, including Bob, Richard J. who is my brother, Richard J. who isn’t my brother, Connor, Simon, Sam, Llewelly, Andrew Gable of the excellent Forgotten Darkness Podcast, and probably many others whose names I didn’t write down!

Further reading:

Northern bald ibis (Akh-bird)

Researchers learn more about teen-age T. rex

A squid fossil offers a rare record of pterosaur feeding behavior

The mysterious, legendary giant squid’s genome is revealed

Why giant squid are still mystifying scientists 150 years after they were discovered (excellent photos but you have to turn off your ad-blocker)

We now know the real range of the extinct Carolina parakeet

Platypus on brink of extinction

Discovery at ‘flower burial’ site could unravel mystery of Neanderthal death rites

A Neanderthal woman from Chagyrskyra Cave

The Iraqi Afa – a Middle Eastern mystery lizard

Further watching/listening:

Richard J. sent me a link to the Axolotl song and it’s EPIC

Bob sent me some more rat songs after I mentioned the song “Ben” in the rats episode, including The Naked Mole Rap and Rats in My Room (from 1957!)

The 2012 video purportedly of the Lagarfljótsormurinn monster

A squid fossil with a pterosaur tooth embedded:

A giant squid (not fossilized):

White-throated magpie-jay:

An updated map of the Carolina parakeet’s range:

A still from the video taken of a supposed Lagarfljót worm in 2012:

An even clearer photo of the Lagarfljót worm:

Show transcript:

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

This is our third annual updates and corrections episode, where I bring us up to date about some topics we’ve covered in the past. We’ll also talk about an interesting mystery animal at the end. There are lots of links in the show notes to articles I used in the episode’s research and to some videos you might find interesting.

While I was putting this episode together, I went through all the emails I received in the last year and discovered a few suggestions that never made it onto the list. I’m getting really backed up on suggestions again, with a bunch that are a year old or more, so the next few months will be all suggestion episodes! If you’re waiting to hear an episode about your suggestion, hopefully I’ll get to it soon.

Anyway, let’s start the updates episode with some corrections. In episode 173 about the forest raven, I mentioned that the northern bald ibis was considered sacred by ancient Egyptians. Simon asked me if that was actually the case or if only the sacred ibis was considered sacred. I mean, it’s right there in the name, sacred ibis.

I did a little digging and it turns out that while the sacred ibis was associated with the god Thoth, along with the baboon, the northern bald ibis was often depicted on temple walls. It was associated with the ankh, which ancient Egyptians considered part of the soul. That’s a really simplistic way to put it, but you’ll have to find an ancient history podcast to really do the subject justice. So the northern bald ibis was important to the ancient Egyptians and sort of considered sacred, but in a different way from the actual sacred ibis.

In episode 146 while I was talking about the archerfish, I said something about how I didn’t fully understand how the archerfish actually spits water so that it forms a bullet-like blob. Bob wrote and kindly explained in a very clear way what goes on: “Basically, the fish spits a stream of water, but squeezes it so that the back end of the stream is moving faster than the front. So it bunches up as it flies and hits the target with one big smack. Beyond that, the water bullet would fall apart as the back part moves through the front part of the stream, but the fish can apparently judge the distance just right.” That is really awesome.

In another correction, Sam told me ages ago that the official pronouns for Sue the T rex are they/them, because that’s what Sue has requested on their Twitter profile. I forgot to mention this last time, sorry.

While we’re talking about Tyrannosaurus rex, researchers have IDed two teenaged T rex specimens found in Montana. Originally paleontologists thought the specimens might be a related species that grew to a much smaller size, Nanotyrannus, but the team studying them have determined that they were juvenile T rexes. To learn how old the specimens were and how fast they grew, they cut extremely thin slices from the leg bones and examined them under high magnification.

The study of fossil bone microstructure is called paleohistology and it’s a new field that’s helped us learn a lot about long-extinct animals like dinosaurs. We know from this study that T rex grew as fast as modern warm-blooded animals like birds and mammals, and we know that the specimens were 13 and 15 years old when they died. T rex didn’t reach its adult size until it was about twenty, and there are definite differences in the morphology of the juvenile specimens compared to an adult. The young T rexes were built for speed and had sharper teeth to cut meat instead of crush through heavy bones the way adults could. This suggests that juvenile T rexes needed to outrun both predators and smaller prey.

In other fossil news, Llewelly sent me a link about a pterosaur tooth caught in a squid fossil. We know pterosaurs ate fish because paleontologists have found fossilized fish bones and scales in the stomach area of pterosaur remains, but now we know they also ate squid. The fossil was discovered in Bavaria in 2012 and is remarkably well preserved, especially considering how few squid fossils we have. One of the things preserved in the fossil is a sharp, slender tooth that matches that of a pterosaur. Researchers think the pterosaur misjudged the squid’s size and swooped down to grab it from the water, but the squid was about a foot long, or 30 cm, and would have been too heavy for the pterosaur to pick up. One of its teeth broke off and remained embedded in the squid’s mantle, where it remains to this day 150 million years later.

And speaking of squid, the giant squid’s genome has been sequenced. Researchers want to see if they can pinpoint how the giant squid became so large compared to most other cephalopods, but so far they haven’t figured this out. They’re also looking at ways that the giant squid differs from other cephalopods and from vertebrates, including humans, to better understand how vertebrates evolved. They have discovered a gene that seems to be unique to cephalopods that helps it produce iridescence.

The Richard J. who is my brother sent me an article about giant squid a while back. There’s a link in the show notes. It has some up-to-date photos from the last few years as well as some of the oldest ones known, and lots of interesting information about the discovery of giant squid.

The Richard J. who is not my brother also followed up after the magpies episode and asked about the magpie jay. He said that the white-throated magpie jay is his favorite bird, and now that I’ve looked at pictures of it, I see why.

There are two species of magpie jay, the black-throated and the white-throated, which are so closely related that they sometimes interbreed where their ranges overlap. They live in parts of Mexico and nearby countries. They look a little like blue jays, with blue feathers on the back and tail, white face and belly, and black markings. Both species also have a floofy crest of curved feathers that looks like something a parrot would wear. A stylish parrot. Like other corvids, it’s omnivorous. It’s also a big bird, almost two feet long including the long tail, or 56 cm.

In other bird news, Connor sent me an article about the range of the Carolina parakeet before it was driven to extinction. Researchers have narrowed down and refined the bird’s range by researching diaries, newspaper reports, and other sightings of the bird well back into the 16th century. It turns out that the two subspecies didn’t overlap much at all, and the ranges of both were much smaller than have been assumed. I put a copy of the map in the show notes, along with a link to the article.

One update about an insect comes from Lynnea, who wrote in after episode 160, about a couple of unusual bee species. Lynnea said that some bees do indeed spin cocoons. I’d go into more detail, but I have an entire episode planned about strange and interesting bees. My goal is to release it in August, so it won’t be long!

In mammal news, the platypus is on the brink of extinction now more than ever. Australia’s drought, which caused the horrible wildfires we talked about in January, is also causing problems for the platypus. The platypus is adapted to hunt underwater, and the drought has reduced the amount of water available in streams and rivers. Not only that, damming of waterways, introduced predators like foxes, fish traps that drown platypuses, and farming practices that destroy platypus burrows are making things even worse. If serious conservation efforts aren’t put into place quickly, it could go extinct sooner than estimated. Conservationists are working to get the platypus put on the endangered species list throughout Australia so it can be saved.

A Neandertal skeleton found in a cave in the foothills of Iraqi Kurdistan appears to be a deliberate burial in an area where many other burials were found in the 1950s. The new skeleton is probably more than 70,000 years old and is an older adult. It was overlooked during the 1950s excavation due to its location deep inside a fissure in the cave. The research team is studying the remains and the area where they were found to learn more about how Neandertals buried their dead. They also hope to recover DNA from the specimen.

Another Neandertal skeleton, this one from a woman who died between 60,000 and 80,000 years ago in what is now Siberia, has had her DNA sequenced and compared to other Neandertal DNA. From the genetic differences found, researchers think the Neandertals of the area lived in small groups of less than 60 individuals each. She was also more closely related to Neandertal remains found in Croatia than other remains found in Siberia, which suggests that the local population was replaced by populations that migrated into the area at some point.

Also, I have discovered that I’ve been pronouncing Denisovan wrong all this time. I know, shocker that I’d ever mispronounce a word.

Now for a lizard and a couple of corrections and additions to the recent Sirrush episode. Last year, Richard J. and I wrote back and forth about a few things regarding one of my older episodes. Specifically he asked for details about two lizards that I mentioned in episode 21. I promised to get back to him about them and then TOTALLY FORGOT. I found the email exchange while researching this episode and feel really bad now. But then I updated the episode 21 show notes with links to information about both of those lizards so now I feel slightly less guilty.

Richard specifically mentioned that the word sirrush, or rather mush-khush-shu, may mean something like “the splendor serpent.” I totally forgot to mention this in the episode even though it’s awesome and I love it.

One of the lizards Richard asked about was the afa lizard, which I talked about briefly in episode 21. Reportedly the lizard once lived in the marshes near the Tigris and Euphrates rivers in what is now Iraq. Richard wanted to know more about that lizard because he wondered if it might be related to the sirrush legend, which is how we got to talking about the sirrush in the first place and which led to the sirrush episode. Well, Richard followed up with some information he had learned from a coworker who speaks Arabic. Afa apparently just means snake in Arabic, although of course there are different words for snake, and the word has different pronunciations in different dialects. He also mentioned that it’s not just the water monitor lizard that’s known to swim; other monitors do too, including the Nile monitor. I chased down the original article I used to research the afa and found it on Karl Shuker’s blog, and Shuker suggests also that the mysterious afa might be a species of monitor lizard, possibly one unknown to science. We can’t know for certain if the afa influenced the sirrush legend, but it’s neat to think about.

Next up, in cryptid news, Andrew Gable of the excellent Forgotten Darkness podcast suggested that some sightings of the White River Monster, which we talked about in episode 153, might have been an alligator—especially the discovery of tracks and crushed plants on the bank of a small island. This isn’t something I’d thought about or seen suggested anywhere, but it definitely makes sense. I highly recommend the Forgotten Darkness podcast and put a link in the show notes if you want to check it out.

And that leads us to a lake monster to finish up the episode. The Lagarfljót [LAH-gar-flote] worm is a monster from Iceland, which is said to live in the lake that gives it its name. The lake is a pretty big one, 16 miles long, or 25 km, and about a mile and a half wide at its widest, or 2.5 km. It’s 367 feet deep at its deepest spot, or 112 m. It’s fed by a river with the same name and by other rivers filled with runoff from glaciers, and the water is murky because it’s full of silt.

Sightings of the monster go back centuries, with the first sighting generally thought to be from 1345. Iceland kept a sort of yearbook of important events for centuries, which is pretty neat, so we have a lot of information about events from the 14th century on. An entry in the year 1345 talks about the sighting of a strange thing in the water. The thing looked like small islands or humps, but each hump was separated by hundreds of feet, or uh let’s say at least 60 meters. The same event was recorded in later years too.

There’s an old folktale about how the monster came to be, and I’m going to quote directly from an English translation of the story that was collected in 1862 and published in 1866. “A woman living on the banks of the Lagarfljót [River] once gave her daughter a gold ring; the girl would fain see herself in possession of more gold than this one ring, and asked her mother how she could turn the ornament to the best account. The other answered, ‘Put it under a heath-worm.’ This the damsel forthwith did, placing both worm and ring in her linen-basket, and keeping them there some days. But when she looked at the worm next, she found him so wonderfully grown and swollen out, that her basket was beginning to split to pieces. This frightened her so much that, catching up the basket, worm and ring, she flung them all into the river. After a long time this worm waxed wondrous large, and began to kill men and beasts that forded the river. Sometimes he stretched his head up on to the bank, and spouted forth a filthy and deadly poison from his mouth. No one knew how to put a stop to this calamity, until at last two Finns were induced to try to slay the snake. They flung themselves into the water, but soon came forth again, declaring that they had here a mighty fiend to deal with, and that neither could they kill the snake nor get the gold, for under the latter was a second monster twice as hard to vanquish as the first. But they contrived, however, to bind the snake with two fetters, one behind his breast-fin, the other at his tail; therefore the monster has no further power to do harm to man or beast; but it sometimes happens that he stretches his curved body above the water, which is always a sign of some coming distress, hunger, or hard times.”

The heath worm is a type of black slug, not a worm or snake at all, and it certainly won’t grow into a dragon no matter how much gold you give it. But obviously there’s something going on in the lake because there have been strange sightings right up to the present day. There’s even a video taken of what surely does look like a slow-moving serpentine creature just under the water’s surface. There’s a link in the show notes if you want to watch the video.

So let’s talk about the video. It was taken in February of 2012 by a farmer who lives in the area. Unlike a lot of monster videos it really does look like there’s something swimming under the water. It looks like a slow-moving snake with a bulbous head, but it’s not clear how big it is. A researcher in Finland analyzed the video frame by frame and determined that although the serpentine figure under the water looks like it’s moving forward, it’s actually not. The appearance of forward movement is an optical illusion, and the researcher suggested there was a fish net or rope caught under the water and coated with ice, which was being moved by the current.

So in a way I guess a Finn finally slayed the monster after all.

But, of course, the video isn’t the only evidence of something in the lake. If those widely spaced humps in the water aren’t a monstrous lake serpent of some kind, what could they be?

One suggestion is that huge bubbles of methane occasionally rise from the lake’s bottom and get trapped under the surface ice in winter. The methane pushes against the ice until it breaks through, and since methane refracts light differently from ordinary air, it’s possible that it could cause an optical illusion from shore that makes it appear as though humps were rising out of the water. This actually fits with stories about the monster, which is supposed to spew poison and make the ground shake. Iceland is volcanically and geologically highly active, so earthquakes that cause poisonous methane to bubble up from below the lake are not uncommon.

Unfortunately, if something huge did once live in the lake, it would have died by now. In the early 2000s, several rivers in the area were dammed to produce hydroelectricity, and two glacial rivers were diverted to run into the lake. This initially made the lake deeper than it used to be, but has also increased how silty the water is. As a result, not as much light can penetrate deep into the water, which means not as many plants can live in the water, which means not as many small animals can survive by eating the plants, which means larger animals like fish don’t have enough small animals to eat. Therefore the ecosystem in the lake is starting to collapse. Some conservationists warn that the lake will silt up entirely within a century at the rate sand and dirt is being carried into it by the diverted rivers. I think the takeaway from this and episode 179 is that diverting rivers to flow into established lakes is probably not a good idea.

At the moment, though, the lake does look beautiful on the surface, so if you get a chance to visit, definitely go and take lots of pictures. You probably won’t see the Lagarfljót worm, but you never know.

You can find Strange Animals Podcast online at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 179: Lost and Found Animals

This week let’s learn about some animals that were discovered by science, then not seen again and presumed extinct…until they turned up again, safe and sound!

Further reading:

A nose-horned dragon lizard lost to science for over 100 years has been found

Modigliani’s nose-horned lizard has a nose horn, that’s for sure:

Before the little guy above was rediscovered, we basically just had this painting and an old museum specimen:

The deepwater trout:

The dinosaur ant:

The dinosaur ant statue of Poochera:

The false killer whale bite bite bite bite bite:

Some false killer whales:

Show transcript:

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

This week let’s learn about some animals that were discovered by scientists but then lost and assumed extinct, until they were found again many years later. There’s a lot of them and they’re good to think about when we feel down about how many species really are extinct.

We’ll start with a brand new announcement about a reptile called Modigliani’s nose-horned lizard, named after an Italian explorer named Elio Modigliani. He donated a specimen of the lizard to a natural history museum when he got home from exploring Indonesia. That was in 1891, and in 1933 scientists finally described it formally as Harpesaurus modiglianii.

The lizard was especially interesting because it had a horn on its nose that pointed forward and slightly up, and it had spines along its back. It looked like a tiny dragon.

But no one saw another one, not in Indonesia, not anywhere. Researchers knew it had lived where Modigliani said it did because a group of people from Indonesia called the Bataks knew about the lizard. It was part of their mythology and they carved pictures of it. But they didn’t have any, live or dead. Researchers thought it must have gone extinct.

Until 2018. In June 2018, a wildlife biologist named Chairunas Adha Putra was surveying birds in Indonesia, specifically in North Sumatra, when he found a dead lizard. Putra isn’t a lizard expert but he thought it might interest a herpetologist colleague named Thasun Amarasinghe, so he called him. Amarasinghe said oh yeah, that does sound interesting, do you mind sending it to me so I can take a look?

And that’s history, because once he saw it, Amarasinghe knew exactly what the lizard was.

Amarasinghe immediately called Putra, who was still out surveying birds. Could Putra please go back to where he’d found the dead lizard and see if he could find another one, preferably alive? It was really important.

Putra returned obligingly and searched for another lizard. It took him five days, but finally he found one asleep on a branch. He caught it and took pictures, measured it, and observed it before releasing it a few hours later. Hurray for scientists who go that extra mile to help scientists in other fields!

Modigliani’s nose-horned lizard is bright green with a yellow-green belly and spines, plus some mottled orange markings. At least, that’s what it looks like most of the time. It can change colors just like a chameleon. If it’s feeling stressed, it turns a darker gray-green and its spines and belly turn orangey. But it can change its color to match its environment too.

It’s related to a group of lizards called dragon lizards, which includes the bearded dragon that’s often kept as a pet. There are a lot of dragon lizards, and 30 of them have never been seen since they were first described.

Unfortunately, deforestation and habitat loss throughout North Sumatra and other parts of Indonesia threaten many animals, but the Modigliani’s nose-horned lizard was found just outside of a protected area. Hopefully it will stay safely in the protected area while scientists and conservationists study it and work out the best way to keep it safe.

A fish called the deepwater trout, also known as the black kokanee or kunimasu salmon, used to live in a Japanese lake called Lake Tazawa, and that was the only place in the world where it lived. It’s related to the sockeye salmon but it’s much smaller and less flashy. It grows to about a foot long, or 30 cm, and is black and gray in color as an adult, silvery with black markings as a young fish.

In the 1930s, plans to build a hydroelectric power plant on the lake alarmed scientists. The plan was to divert water from the River Tama to work the power station, after which the water would run into the lake. The problem is that the River Tama was acidic with agricultural runoff and water from acidic hot springs in the mountains. The scientists worried that if they didn’t do something to help the fish, soon it would be too late.

In 1935 they moved as many of the fish’s eggs as they could find to other lakes in hopes that the species wouldn’t go extinct. In 1940 the plant was completed, and as expected, the lake’s water became too acidic for the deepwater trout to survive. In fact, it became too acidic for anything to survive. Soon almost everything living in the lake was dead. Within a decade the lake was so acidic that local farmers couldn’t even use it for irrigation, because it just killed any plants it touched. Lake Tazawa is still a mostly dead lake despite several decades of work to lessen its acidity by adding lime to the water.

So, the deepwater trout went extinct in Lake Tazawa along with many other species, and to the scientists’ dismay, they found no sign that the eggs they’d moved to other lakes had survived. The deepwater trout was listed as extinct.

But in 2010, a team of scientists took a closer look at Lake Saiko. It’s one of the lakes where the deepwater trout’s eggs were transferred, and it’s a large, deep lake near Mount Fuji that’s popular with tourists.

The team found nine specimens of deepwater trout. Further study reveals that the population of fish is healthy and numerous enough to survive, as long as it’s left alone. Fortunately, Lake Saiko is inside a national park where the fish can be protected.

Next, let’s look at a species of ant called the dinosaur ant. It was collected by an amateur entomologist named Amy Crocker in 1931 in western Australia. Crocker wasn’t sure what kind of ant she had collected, so she gave the specimens to an entomologist named John Clark. Clark realized the ant was a new species, one that was so different from other ants that he placed it in its own genus.

The dinosaur ant is yellowish in color and workers have a retractable stinger that can inflict painful stings. It has large black eyes that help it navigate at night, since workers are nocturnal. It lives in old-growth woodlands in only a few places in Australia, as far as researchers can tell, and it prefers cool weather. Its colonies are very small, usually less than a hundred ants per nest. Queen ants have vestigial wings while males have fully developed wings, and instead of a nuptial flight that we talked about in episode 175 last month, young queens leave the nest where they’re hatched by just walking away from it instead of flying. Males fly away, and researchers think that once the queens have traveled a certain distance from their birth colony, they release pheromones that attract males. If a queen with an established colony dies, she may be replaced with one of her daughters or the colony may adopt a young queen from outside the colony. Sometimes a queen will go out foraging for her food, instead of being restricted to the nest and fed by workers, as in other ant species.

The dinosaur ant is called that because many of its features are extremely primitive compared to other ants. It most closely resembles the ant genus Prionomyrmex, which went extinct around 29 million years ago. Once researchers realized just how unusual the dinosaur ant was, and how important it might be to our understanding of how ants evolved, they went to collect more specimens to study. But…they couldn’t find any.

For 46 years, entomologists combed western Australia searching for the dinosaur ant, and everyone worried it had gone extinct. It wasn’t until 1977 that a team found it—and not where they expected it to be. Instead of western Australia, the team was searching in South Australia. They found the ant near a tiny town called Poochera, population 34 as of 2019, and the town is now famous among ant enthusiasts who travel there to study the dinosaur ant. There’s a statue of an ant in the town and everything.

The dinosaur ant is now considered to be the most well-studied ant in the world. It’s also still considered critically endangered due to habitat loss and climate change, but it’s easy to keep in captivity and many entomologists do.

Let’s finish with a mammal, and the situation here is a little different. In 1846 a British paleontologist published a book about British fossils, and one of the entries was a description of a dolphin. The description was based on a partially fossilized skull discovered three years before and dated to 126,000 years ago. It was referred to as the false killer whale because its skull resembled that of a modern orca. Scientists thought it was the ancestor of the orca and that it was extinct.

Uh, well, maybe not, because in 1861, a dead but very recently alive one washed up on the coast of Denmark.

The false killer whale is dark gray and grows up to 20 feet long, or 6 meters. It navigates and finds prey using echolocation and mostly eats squid and fish, including sharks. It’s not that closely related to the orca and actually looks more like a pilot whale. It lives in warm and tropical oceans and some research suggests it may migrate to different feeding spots throughout the year. It often travels in large groups of a hundred individuals. That’s as many dolphins as there are ants in dinosaur ant colonies. Part of the year it spends in shallow water, the rest of the year in deeper water, only coming closer to shore to feed.

Researchers are only just starting to learn more than the basics about the false killer whale, and what they’re learning is surprising. It will share food with its family and friends, and will sometimes offer fish to people who are in the water. It sometimes forms mixed-species groups with other species of dolphin, sometimes hybridizes with other closely-related species of dolphin, and will protect other species of dolphin from predators. It’s especially friendly with the bottlenose dolphin. So basically, this is a pretty nice animal to have around if you’re a dolphin, or if you’re a swimming human who would like a free fish. So it’s a good thing that it didn’t go extinct 126,000 years ago.

This is what the false killer whale sounds like:

[false killer whale sounds]

You can find Strange Animals Podcast online at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave a rating and review on Apple Podcasts or wherever you listen to podcasts. We also have a Patreon at if you’d like to support us that way.

Thanks for listening!

Episode 168: The Longest Lived

This week let’s take a look at some animals (and other living organisms) that live the longest!

This isn’t Methuselah itself (scientists aren’t saying which tree it is, to keep it safe), but it’s a bristlecone pine:

The Jaya Sri Maha Bodhi, a sacred fig tree in Sri Lanka, planted in 288 BCE by a king:

Some trees of the quaking aspen colony called Pando:

Glass sponges (this one’s called the Venus Flower Basket):

Further reading:

Glass sponge as a living climate archive

Show transcript:

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

This week we’re going to look at the world’s longest lived animals and other organisms. We’re straying into plant territory a little bit here, but I think you’ll agree that this is some fascinating information.

The oldest human whose age we can verify was a French woman who lived to be 122 years old, plus 164 days. Her name was Jeanne Calment and she came from a long-lived family. Her brother lived to the age of 97. Jeanne was born in 1875 and didn’t die until 1997. But the sad thing is, she outlived her entire family. She had a daughter who died of a lung disease called pleurisy at only 36 years old—in fact, on her 36th birthday—and her only grandson died in a car wreck in his late 30s. Jeanne remained healthy physically and mentally until nearly the end of her life, although she had always had poor eyesight.

It’s not all that rare for humans to live past the age of 100, but it is rare for anyone to live to age 110 or beyond. But other animals have average lifespans that are much, much longer than that of humans.

In episode 163 we talked about the Greenland shark, which can live for hundreds of years. The oldest Greenland shark examined was possibly as old as 512 years old, and the sharks may live much longer than that. It’s actually the longest-lived vertebrate known.

No one’s sure which terrestrial vertebrate lives the longest, but it’s probably a tortoise. Giant tortoises are famous for their longevity, routinely living beyond age 100 and sometimes more than 200 years old. The difficulty of verifying a tortoise’s age is that to humans, tortoises all look pretty much alike and we don’t always know exactly when a particular tortoise was hatched. Plus, of course, we know even less about tortoises in the wild than we do ones kept in captivity. But probably the oldest known is an Aldabra giant tortoise that may have been 255 years old when it died in 2006. We talked about giant tortoises in episode 95.

But for the really long-lived creatures, we have to look at the plant world. The oldest individual tree whose age we know for certain is a Great Basin bristlecone pine called Methuselah. Methuselah lives in the Inyo National Forest in the White Mountains in California, which of course is on the west coast of North America. In 1957 a core sample was taken from it and other bristlecone pines that grow in what’s called the ancient bristlecone pine forest. Many trees show growth rings in the trunk that make a pattern that’s easy to count, so the tree’s age is easy to determine as long as you have someone who is patient enough to count all the rings. Well, Methuselah was 4,789 years old in 1957. It probably germinated in 2833 BCE. Other trees in the forest were nearly as old, with at least one possibly older, but the sample from that older tree is lost and no one’s sure where the tree the sample came from is.

Another bristlecone pine, called the Prometheus Tree, germinated even earlier than Methuselah, probably in 2880 BCE, but it’s now dead. A grad student cut it down in 1964, possibly by accident—stories vary and no one actually knows why he cut the tree down. The bristlecone pine is now a protected species.

There are other trees estimated to be as old as Methuselah. This includes a yew in North Wales that may be 5,000 years old and is probably at least 4,000 years old, and a cypress in Iran that’s at least 2,000 years old and possibly 5,000 years old. Sequoyahs from western North America, baobabs from Africa, and kauri trees from New Zealand are all documented to live over a thousand years and possibly many thousands of years.

In at least one case, a sacred fig tree in Sri Lanka, we know exactly when the tree was planted. A Buddhist nun brought a branch of the original sacred fig tree, the one that the Buddha was sitting under when he achieved enlightenment, to Sri Lanka and presented it to King Devanampiya Tissa. He planted the branch in the royal park in 288 BCE, where it grew into a tree which remains in the park to this day, more than 2,000 years later. It’s cared for by Buddhists monks and people come from all over Sri Lanka to visit the tree. If this sounds a little too good to be true, the easiest way to grow a sacred fig is to use a cutting from another tree. The cutting will root and grow into a new tree.

Not all trees are individuals. You may not know this and I didn’t either until recently. Some trees grow as colonies. The most well known tree colony is called Pando, made up of quaking aspens that live in Utah in North America. While the individual trees are only around 130 years old on average, Pando itself has been alive for an estimated 80,000 years. Each tree is a male clone and all the trees are connected by a root system that covers 106 acres, or 43 hectares. Because its root system is so huge and deep, Pando is able to survive forest fires that kill all other trees. Pando’s trees die, but afterwards the roots just send up shoots that grow into new trees. Researchers estimate that it’s been 10,000 years since Pando’s trees actually flowered. Unfortunately, Pando is currently threatened by humans stopping the forest fires that otherwise would kill off rival trees, and threatened by grazing livestock that kill off young trees before they can become established.

Pando isn’t the only quaking aspen colony known, though. There are a number of smaller colonies in western North America. Researchers think it’s an adaptation to frequent forest fires and a semi-arid climate that makes it harder for seedlings to grow. Quaking aspens that live in northeastern North America, where the climate is much wetter, grow from seeds instead of forming colonies.

Other species of tree form colonies too, including a spruce tree in Sweden whose root system dates to nearly 10,000 years ago and a pine colony in Tasmania that is about the same age but with individual trees that are themselves 3,000 years old. Not all long-lived plant colonies are trees, though. A colony of sea grass in the Mediterranean may be as much as 200,000 years old although it may be only 12,000 years old, researchers aren’t sure.

I could go on and on about long-lived plants, but let’s get back to the animals. If the Greenland shark is the longest lived vertebrate known, what’s the longest lived invertebrate? Here’s your reminder that a vertebrate is an animal with some form of spine, while an invertebrate has no spine.

Many invertebrates that live in the ocean have long lifespans. Corals of various kinds can live for thousands of years, for instance. The ocean quahog, a type of clam that lives in the North Atlantic Ocean, grows very slowly compared to other clams. It isn’t fully mature until it’s nearly six years old, and populations that live in cold water can live a long time. Sort of like tree rings, the age of a clam can be determined by counting the growth rings on its shell, and a particular clam dredged up from the coast of Iceland in 2006 was discovered to be 507 years old. Its age was double-checked by carbon-14 dating of the shell, which verified that it was indeed just over 500 years old when it was caught and died. Researchers aren’t sure how long the quahog can live, but it’s a safe bet that there are some alive today that are older than 507 years, possibly a lot older.

But the invertebrate that probably lives the longest is the glass sponge. It’s found throughout the world’s oceans, but is especially common in cold waters of the Northern Pacific and Antarctic. It usually grows up to about a foot tall, or 30 cm, although some species grow larger, and is roughly shaped like a vase. Most species are white or pale in color. In some places the sponges fuse together to form reefs, with the largest found so far 65 feet tall, or 20 meters, and nearly four and a half miles long, or 7 km.

The glass sponge is a simple creature with a lattice-like skeleton made of silica covered with porous tissue. It anchors itself to a rock or the ocean floor, frequently in deep water, and as water flows through the openings in its body, it filters microscopic food out. So it basically lives a very slow, very plant-like existence.

One glass sponge, Monorhaphis chuni, anchors itself to the sea floor with a long basal spicule that looks like a stem. This stem can be over nine feet long, or 3 m. It needs to be long because it lives in deep water where there’s a lot of soft sediment at the bottom. In 1986 the skeleton of a dead Monorhaphis was collected from the East China Sea so it could be studied. Since a glass sponge adds layers of skeleton to its basal spicule every year as it grows, you guessed it, the layers can be counted just like tree rings—although it requires an electron microscope to count since the layers are very small. The sponge was determined to be about 11,000 years old when it died. Researchers are able to determine local ocean temperature changes from year to year by studying the rings, just as tree rings give us information about local climate.

Let’s finish with something called an endolith. An endolith isn’t a particular animal or even a group of related animals. An endolith is an organism that lives inside a rock or other rock-like substance, such as coral. Some are fungi, some lichens, some amoebas, some bacteria, and various other organisms, many of them single-celled and all of them very small if not microscopic. Some live in tiny cracks in a rock, some live in porous rocks that have space between grains of mineral, some bore into the rock. Many are considered extremophiles, living in rocks inside Antarctic permafrost, at the tops of the highest mountains, in the abyssal depths of the oceans, and at least two miles, or 3 km, below the earth’s surface.

Various endoliths live on different minerals, including potassium, sulfur, and iron. Some endoliths even eat other endoliths. We don’t know a whole lot about them, but studies of endoliths found in soil deep beneath the ocean’s floor suggest that they grow extremely slowly. Like, from one generation to the next could be as long as 10,000 years, with the oldest endoliths potentially being millions of years old—even as old as the sediment itself, which dates to 100 million years old.

That is way older than Jeanne Calment and all those trees.

You can find Strange Animals Podcast online at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave a rating and review on Apple Podcasts or wherever you listen to podcasts. We also have a Patreon at if you’d like to support us that way.

Thanks for listening!

Episode 165: Furry Fish

I hope you’re all well and not too bored if you’re one of the millions who are having to stay inside right now! This week let’s learn about a fishy mystery, fish with fur!

Further reading:

Mirapinna esau – a Furry Fish from the Azores

The so-called fur-bearing trout:

A hairy frogfish:

The hairyfish (I couldn’t find any actual photos of one):

This man is serious about moldy fish. He wants the mold to think about what it’s done while it’s in time out:

Show transcript:

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

This week let’s learn about a fishy mystery, if not an actual mystery fish. Are there any fish with hair?

Sometimes you’ll see a mounted fish that has fur, usually decorating a restaurant. It may be the same type of restaurant that also has a stuffed jackalope, which we talked about in episode 113. Fur-bearing trout are jokes by taxidermists, who usually attach rabbit fur to a stuffed fish.

But some cultures have stories about fish with hair. This includes the Japanese story of big river fish with hair on their heads like people, although since these fish are supposed to come out of the water at night to fight and play, they’re probably not actual fish. There’s also an Icelandic legend about an inedible trout with fur that shows up in rivers where people are not being nice enough.

Could these stories be based on a real animal? Are there any fish that grow fur or hair?

Mammals are the only living animals that grow actual hair from specialized cells, but lots of animals have hair-like coverings. Baby birds have downy fuzzy feathers that look like hair and many insects have hairlike structures called setae [see-tee], made of chitin, that make them look furry.

Some fish grow hairlike filaments that help camouflage them among water plants and coral. We’ve talked about the frogfish and its relatives, the anglerfish, many times before, because they’re such weird-looking fish, many of them deep-sea species that are seldom seen. The hairy frogfish isn’t a deep-sea species, though. It lives in warm, shallow waters, especially around coral reefs, and grows to about 8 inches long, or 20 cm. The hairlike filaments that cover its body help it blend in among seaweed and anemones. It’s usually brownish-orange or yellowish, but it can actually change its color and pattern to help it blend in with its surroundings. This color change doesn’t happen fast, though. It takes a few weeks.

Like other frogfish, it has a modified dorsal spine called an illicium with what’s called an esca at the end. In deep-sea species of anglerfish, the esca contains bioluminescent bacteria, but in the hairy frogfish it just looks like a worm. The fish sits immobile except for the illicium, which it twitches around. When a fish or other animal comes to catch what looks like a worm swimming around in the water, the frogfish goes YOMP and gulps the animal down. Like other frogfish species, the hairy frogfish has large, strong pectoral and pelvic fins that it uses to walk across the sea floor instead of swimming.

Another fish that looks like it has hair is called the hairyfish. The hairyfish barely grows more than two inches long, or 5.5 cm. It eats copepods and other tiny crustaceans that live near the ocean’s surface and it’s covered with small hairlike filaments. Its close relations are equally small fish called tapetails because its tail fin has a narrow extension at least as long as the rest of its body called a streamer. The tapetail was described in 1956 but scientists were confused because no one had ever found an adult tapetail, just young ones. It wasn’t until 2003 that a team of Japanese scientists discovered that the DNA of tapetails matched the DNA of a deep-sea fish called the flabby whalefish. There are lots of whalefish species, but the largest only grows to about 16 inches long, or 40 cm. It looks very different from its larval form, with loose skin without scales or hair-like filaments or the tail streamer. But even after researchers figured out that the tapetail and hairyfish are larvae of whalefish, there was still another mystery. All the whalefish ever found were females. Where were the males? Finally they identified yet another deep-sea fish called a bignose fish as the male of the species. The bignose fish has a huge liver but its mouth doesn’t go anywhere—it doesn’t have a throat or stomach. It gets its name from a bulge on its snout that gives it a keen sense of smell.

It turns out that after a larval whalefish develops into an adult, the male doesn’t need to eat. It lives off the fat and nutrients stored in its huge liver and uses its sense of smell to find a female in the depths of the ocean. The female remains a carnivore, eating any small animals it can catch, and it often migrates at night from the deep sea to nearer the surface, then returns to the depths during the day. So far we don’t know which species the hairyfish develops into as an adult.

But the hairy frogfish and the hairyfish are both rarely seen marine fish. Are there hairy-looking freshwater fish that might have inspired the legends of furry fish?

There is a disease called cotton mold that infects fish and makes them look like they have white or grayish spots of fur. Saprolegnia is the name of the mold, which lives in water and can infect fish in the wild and in aquariums. It mostly prefers cold fresh water and usually infects fish that are already injured. It spreads across the fish’s skin and makes it look fuzzy, and eventually it kills the fish. Salmon and trout are common targets of this mold, which may be the source of the Icelandic story.

As for the Japanese story about the hairy fish creatures that come out of the river at night, zoologist Karl Shuker suggests the legend may be based on sightings of the northern fur seal. While seals are mammals, not fish, they do look superficially like fish, and while seals also usually live in the ocean, they occasionally stray into rivers.

So that seems to cover the hairy fish mystery. But next time you go on a fishing trip or just hang out in a boat, keep an eye out for fish with fur just in case.

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

Thanks for listening!

Episode 163: Three Weird Fish

Thanks to Nathan for his suggestions! This week we’re going to learn about three strange and interesting fish!

A northern snakehead:

A giant snakehead:

A Greenland shark, fish of mystery:

The upside-down catfish is indeed upside down a lot of the time (this is actually a picture of Synodontis nigriventris, closely related to the upside-down catfish we talk about in the episode):

An ancient Egyptian upside-down catfish pendant that ladies wore in their hair:

Show transcript:

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

We haven’t done a fish episode in a while, so this week let’s learn about three weird fish. Thanks to Nathan for suggesting the first two fish, the snakehead and the Greenland shark.

The snakehead is a freshwater fish that gets its name because while it’s an ordinary-looking fish for the most part, it has a flattened head that looks a little bit like a snake’s. Different species of snakehead look different in other ways, of course, so let’s examine a couple of typical species.

The northern snakehead is native to Asia, but it’s been introduced into other parts of the world by accident or as a food fish. It’s one of the largest species, with reports of some specimens growing up to five feet long, or 1.5 meters. It’s usually no more than three feet long, though, or 1 meter. It’s brown with darker blotches and has sharp teeth that it uses to catch fish, frogs, and other small animals.

Like other snakeheads, the northern snakehead can breathe air and survive out of water for several days as long as it stays damp. Young snakeheads can even wriggle considerable distances on land to find water. It likes stagnant or slow-moving water.

Because it’s a fierce predator that can find its way to new waterways, introduced snakeheads are invasive species that can cause havoc to populations of native fish. The northern snakehead has been introduced into many waterways in the United States in the last twenty years, as a result of people releasing unwanted aquarium fish and accidental release of snakeheads in fish-farming operations. Since snakeheads reach mature age quickly and females can lay thousands of eggs at a time, snakeheads are illegal to own in many places now and release snakeheads into the wild is even more against the law.

The giant snakehead also grows up to five feet long, or 1.5 m, and is from parts of southeast Asia. Young giant snakeheads are red, but when they grow up they’re black and white with a thick black stripe down each side. It’s also been introduced into a lot of places as a food fish and a game fish, but since it’s a tropical species it can’t survive colder weather and isn’t as invasive as a result, at least not outside of tropical and subtropical areas.

The giant snakehead can be aggressive, though, especially when it’s guarding its nest. Both parents act as guards of the eggs and the newly hatched babies, which follow their mother around wherever she goes. That’s actually really cute.

Next let’s talk about the Greenland shark. We covered it briefly in episode 74, about colossal squid and the things that eat them, but mostly we talked about its close relative the sleeper shark. The Greenland shark is similar in some ways but it’s much bigger than the sleeper shark. It lives in the North Atlantic and Arctic Oceans where the water is barely warmer than the freezing point and it grows up to 24 feet long, or 7.3 meters, with females being larger than males.

But despite how enormous it is, it’s not a shark you need to worry about. First of all, what are you doing swimming in water that cold? Second, the Greenland shark is a slow swimmer, no more than about 1 ½ miles per hour, or 2.6 km/h. You can walk faster than that without even trying. You can probably dog-paddle faster than that.

And yet, the Greenland shark manages to eat seals and fish and other animals that move quickly. Since no one’s actually observed a Greenland shark hunting, no one knows how they catch prey. Some researchers speculate that it sneaks up on sleeping seals and grabs them. It also eats a lot of carrion, including dead moose and reindeer and polar bears that fall into the water and drown. One shark was found with an entire reindeer in its stomach.

The Greenland shark spends winter in shallow water where it’s warmer, but in summer it spends more time in deep water. At least one submersible observed a Greenland shark 7,200 feet below the surface of the ocean, or 2,200 meters. Occasionally a Greenland shark travels more widely, usually in deep water where the water is cold. In 2013 one was caught by researchers in the Gulf of Mexico, which is way far away from the Arctic. It was swimming at over 5,700 feet deep, or 1,750 meters.

The Greenland shark is adapted to the cold and pressure of the deep sea in many ways. Its blood contains three types of hemoglobin, which help it absorb as much oxygen as possible from water that’s poorly oxygenated to start with. Its muscles and other tissues contain high levels of urea and other compounds that increase its buoyancy, so that it doesn’t need to work as hard to stay in one place. But the presence of urea in its muscles means that the Greenland shark not only tastes horrible, it’s toxic. In Iceland Greenland sharks are considered a delicacy, but only after the toxins have been removed from the meat by long treatment. This includes burying it in the ground for weeks, partially fermenting it, and drying it for several months afterwards. Most people don’t bother and any commercial fishing boats that catch Greenland sharks just toss them back overboard.

The Greenland shark has a very slow metabolism and grows extremely slowly too. That’s okay, though, because it lives a very long time. A VERY long time. The biggest Greenland sharks may be as much as 600 years old. Researchers examine the crystals in dead Greenland shark eyeballs to determine when they were hatched.

And speaking of Greenland shark eyeballs…some of you know where this is going. I hope you’re not eating grapes or anything right now. There’s a type of copepod, a crustacean, that acts as a parasite of the Greenland shark and the Pacific sleeper shark, its close relative. The copepod grows to about an inch long, or 28 mm, and attaches itself to the shark’s cornea, which is part of the eyeball. This impairs the shark’s vision but it doesn’t seem to care and it doesn’t seem to have any trouble finding food.

Okay let’s stop talking about that. Our third and final weird fish for this episode is a type of catfish that’s sometimes kept in aquariums. It’s called the upside-down catfish.

There are actually a number of closely-related catfish known as upside-down catfish, but the one we’ll talk about today is Synodontis batensoda. It lives in parts of Africa in marshy areas and slow-moving water. It grows to a little over a foot and a half long, or 50 cm, and eats plankton, algae, mollusks, insects and larvae, and crustaceans.

But the upside-down catfish gets its name from its habit of swimming upside down. Because it’s kept as an aquarium fish so often, many people assume that the upside-down swimming is something it developed because it’s kept in an enclosed aquarium habitat. But that’s actually not the case.

The catfish used to be well-known in Egypt, and there’s even an Egyptian tomb carving depicting a catfish swimming upside down, dating to the Middle Kingdom around 4,000 years ago. The upside-down catfish was often depicted in jewelry, too, including hair ornaments so beautifully made that the species of catfish can be determined. Young women in Egypt traditionally wore fish ornaments to decorate their braids. There’s a story about one young woman who was helping row a king across a lake when her fish pendant fell into the water. She stopped rowing, naturally, which messed up the other rowers. The king wanted to know why the boat had stopped, and when the woman explained, he offered to give her a new fish pendant. But no, she said, she wanted that one, the one that was now at the bottom of the lake. But the king had a magician who said no problem, and caused the water to fold back like a blanket, exposing the lake’s bottom so the pendant could be retrieved. I didn’t make that story up, either. It’s from the Westcar Papyrus that dates to around the 17th century BCE.

So why does the upside-down catfish swim upside down? Like other catfish, its mouth is angled downward so it can find food in the mud at the bottom of the water. So when it wants to grab an insect on the water’s surface, or eat algae off the bottom of a submerged leaf, it can only do so by turning upside down.

So that’s it for this week’s episode. I don’t know what else to say because I’m just sitting here trying to imagine how I’d manage if someone told me I had to swim upside down. But then, I can barely swim right side up. Good job, upside-down catfish!

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

Thanks for listening!