Category Archives: fossils

Episode 228: Monkey Lizards and Weird Turtle…Things



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Thanks to Ethan for this week’s topic, two weird animals that developed after the Great Dying we talked about last week!

Further reading:

Monkey Lizards of the Triassic

Placodonts: The Bizarre ‘Walrus-Turtles’ of the Triassic

Drepanosaurus (without a head since we haven’t found a skull yet, but with that massive front claw):

Drepanosaurus’s tail claw:

Hypuronector had a leaf-like tail:

Placodus was a big round-bodied swimmer:

Some placodonts [art by Darren Naish, found at the second article linked above]:

Henodus was the oddball placodont that probably ate plant material:

Show transcript:

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

 

Last week we talked about the end-Permian mass extinction, also called the Great Dying. This week let’s follow up with a couple of weird and interesting animals that evolved once things got back to normal on Earth. Thanks to Ethan who suggested both animals.

 

The great dying marks the end of the Permian and the beginning of the Triassic period, which lasted from about 251 million years ago to 201 million years ago. In those 50 million years, life rebounded rapidly and many animals evolved that we’re familiar with today. But some animals from the Triassic are ones you’ve probably never heard of.

 

We’ll start with a reptile called the drepanosaur. Drepranosaurs are also sometimes called monkey lizards for reasons that will soon become clear. Paleontologists only discovered the first drepanosaur in 1980, Drepanosaurus, and within a few years they recognized a whole new family, Drepanosauridae, to fit that first discovery and subsequent closely related specimens. Drepanosaurs were weird little reptiles that probably looked like lizards in many ways, although they weren’t lizards.

 

How weird was Drepanosaurus? Very weird. Very, very weird.

 

It was obviously a climbing animal that probably spent all of its life in the treetops. It had lots of adaptations to life in trees, such as hind feet where all the toes pointed in the same direction and were somewhat curved, sort of like a spider monkey’s hand. That would help it get a good grip on branches. But those hind feet aren’t why it’s called the monkey lizard.

 

Drepanosaurus and its relatives are called monkey lizards because of their tails. Many monkeys have prehensile tails, which act as a fifth limb and help keep the monkey stable in a tree by curling around branches and hanging on. Drepanosaurus had something similar. Instead of being mobile from side to side like most reptile tails, Drepanosaurus’s tail could mostly only curve downward. Modern chameleons have an even more pronounced downward-curving tail that helps them climb. But the chameleon’s tail is still just a tail. The end of Drepanosaurus’s tail had several modified caudal bones that were probably exposed through the skin. Those modified bones acted as a claw to help the animal grab onto tree trunks and branches. So Drepanosaurus had claws on its front feet, claws on its hind feet, and a claw on its tail. It’s sort of like having five feet.

 

As if that wasn’t weird enough, let’s talk about those claws on the front feet. It had five toes on each foot, and four of them had ordinary claws. They were sharp but fairly small, about what you’d expect from an animal that grew about 19 inches long at most, or 50 cm. But the second toe on each foot, which corresponds to the pointer finger on a human hand, had a much bigger claw. MUCH BIGGER CLAW. It was as big as its whole hand! Most researchers think it used the claw to dig into rotting wood, insect nests, and bark to find insects and other small animals to eat.

 

But that’s not all. Drepanosaurus also had a structure called a supraneural bone at the base of its neck, made up of fused vertebrae, that would have made it look like it had a little hunch on its shoulders. While we don’t have a skull of Drepanosaurus, since we only have three specimens so far, this structure is also present in other drepanosaur species where we do have the neck and head, and they all have fairly long, slender necks and birdlike skulls with large eyes. It’s possible that the supraneural bone was the attachment site for special muscles that helped Drepanosaurus extend its neck very quickly to grab insects and other small animals.

 

Drepanosaurs in general shared many of the traits seen in Drepanosaurus, although with some differences. Many drepanosaurs had opposing toes on the feet that would help them grasp branches and twigs more securely. Most don’t have the giant claw on the front feet although most do have the tail claw. But one monkey lizard doesn’t live up to its name at all.

 

A little drepanosaur called Hypuronector limnaios, which only grew about five inches long, or 12 cm, had a much different tail from its relations. Its tail didn’t curve downward at all—in fact, it stuck up behind it and was probably not very flexible. Not only was the tail longer than the body and head together, it had long points growing down from the vertebrae, called haemal arches, which made the tail extremely large top to bottom but flattened from side to side.

 

In other words, its tail looked like a leaf. The drepanosaur could cling to a branch with its tail sticking up, and any nearby predators would probably think it was just another leaf growing from the branch, especially if the tail was covered in green skin. Some researchers speculate that it could have used its tail as a sail to glide from branch to branch too, or it might have acted as a parachute if it had to jump from a branch to escape a predator. Hypuronector’s front legs were longer than its hind legs, unlike other drepanosaurs, which suggests it might have had a flap of skin that helped it glide.

 

Drepanosaur fossils have been found in parts of the United States and western Europe, but were probably more widespread than that. We still don’t know a whole lot about them, so every new specimen that’s found can give paleontologists lots of new information. Most drepanosaurs resembled weird chameleons with birdlike heads, but they weren’t related to birds or chameleons. We don’t actually know what they were closely related to.

 

Ethan also suggested placodonts, another reptile that evolved in the Triassic. Don’t confuse them with placoderms, the armored fish that went extinct in the great dying. The “placo” part of both words means tablet or plate. Therefore, placoderms have skin—that’s the “derm” part—covered in plates, while placodonts have flattened teeth, because the “dont” part refers to teeth. That’s why you get braces on your teeth at the orthodontist but you go to the dermatologist for skin problems.

 

What did placodonts do with their flattened teeth? They used them to crush the shells of shellfish and crustaceans. From that you can infer that they were marine reptiles, and you would be right. The earlier species had big round bodies with heavy bones, which helped them dive to the ocean floor to find food. They lived in shallow coastal waters and had large flattened ribs that helped protect them from injury if currents pushed them into rocks. While the teeth in the back of the mouth were flattened to crush shells, the teeth in the very front of the mouth were sharp and pointed forward to grab prey.

 

One of the most common early placodonts was Placodus [PLAK-oh-dus], which grew nearly six and a half feet long, or 2 meters. Its long tail was flattened laterally to help it swim and it probably had webbed toes. Since its legs were small and relatively weak considering how heavy its body was, it probably couldn’t get around very well on land, so it would have stayed close to the water. It probably looked kind of like the modern marine iguana, which we talked about in episode 92, but with longer jaws. On the other hand, unlike the marine iguana, placodus had a third eye.

 

THIRD EYE ALERT! If you remember way back in episode 3, where we talked about the tuatara, we learned a little bit about the parietal eye, or third eye. Parietal eyes are found on the top of a few animals’ heads, including the tuatara, but they aren’t the same as ordinary eyes. They’re very small photoreceptive eyes that can only sense light and dark. In Placodus’s case, researchers think that ability helped it figure out which way was up more easily when it was underwater. If you’ve ever been knocked down by a wave you’ll understand how easy it is to get disoriented underwater.

 

Placodus and other early placodonts had a ridge of bony scutes on the back to help protect it from predators. In later placodonts those scutes were bigger and bigger until they were more like armor, which added weight to the body and meant that the bones didn’t have to be so dense. This meant that instead of having barrel-like bodies, later placodonts were a little more streamlined. Their bodies were more flattened than round, but still broad across with big plates protecting the back. Their legs were more like flippers.

 

Does this make you think of something? Something like a sea turtle?

 

Later placodonts looked a lot like turtles, a classic case of convergent evolution because they weren’t related to turtles at all. If you saw Placochelys, for instance, you’d probably just think it was a weird sea turtle, unless you got a really close look at it. It grew about three feet long, or 90 cm, with a triangular head, a knobby shell, and flippers with clawed toes at the ends. It had a beak like a turtle’s instead of Placodus’s forward-pointing teeth, but unlike a turtle it also had teeth in the back of the mouth. These were still big flat teeth used for crushing shellfish, but like other placodonts the upper teeth grew from the palate, or the roof of the mouth.

 

Other placodonts would have looked strange to us, like Psephoderma. It grew up to six feet long, or 180 cm, and instead of a single turtle shell, it had two shells. One covered its body from the back of the head down to the pelvis. The other covered its pelvis and was smaller. It had a long tail and a pointy nose.

 

At least one placodont didn’t live in the ocean and didn’t eat shellfish and crustaceans. Henodus grew about three feet long, or one meter, and lived in brackish water or possibly freshwater. Its shell was twice as broad as it was long. It also had a lower shell, or plastron, on its belly. Its nose was short and squared-off and it had a turtle-like beak, and instead of teeth it had denticles on the sides of its jaws. Some researchers think it was a filter feeder, filtering tiny animals from the water through the denticles, while other researchers think it may have eaten water plants. It might have done both.

 

There’s a lot we don’t know about placodonts. We don’t know if they laid eggs or gave birth to live young, and we don’t know what exactly they ate. Obviously their teeth were best suited to crushing shells, but we don’t actually know what kind of shellfish they preferred or if they only ate crustaceans or something else. Placodont remains have been found in Europe, the Middle East, and China, but they were probably more widespread than that. During the Triassic, as the supercontinent Pangaea broke up, it created lots of shallow oceans and island chains that would have been ideal for placodonts.

 

Unfortunately for the placodonts, as the landmasses moved farther apart over millions of years, the shallow seas became deeper. Populations would have become isolated from each other. Eventually placodonts went extinct, probably by a combination of habitat loss and competition from other animals as dinosaurs and their relatives spread throughout the world.

 

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way, and don’t forget to join our mailing list. There’s a link in the show notes.

 

Thanks for listening!


Episode 227: The Great Dying



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It’s another extinction event episode! This one’s about the end-Permian AKA the Permian-Triassic AKA the GREAT DYING.

Further Reading:

Ancient mini-sharks lived longer than thought

Lystrosaurus’s fossilized skeleton:

Lystrosaurus may have looked something like this but I hope not:

This artist’s rendition of lystrosaurus looks a little less horrific but it might not be any more accurate:

Show transcript:

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

It’s time for our next extinction event episode, and this week it’s the big one. Not the extinction event that killed the dinosaurs, but one you may not have heard of, one that almost destroyed all life on earth. I mean, obviously it didn’t and things are fine now, but it was touch and go there for a while. It’s the Permian-Triassic extinction event, or end-Permian, which took place just over 250 million years ago. It was so bad that scientists who aren’t given to hyperbole refer to it as the Great Dying.

Don’t worry, we won’t talk about extinction the whole time. We’ll also learn about some interesting animals that survived the extinction event and did just fine afterwards.

We have a better idea of what happened at the end of the Permian than we have about the earlier extinction events we talked about in episodes 205 and 214. Right about 252 million years ago, something caused a massive volcanic eruptive event in what is now Siberia. Some researchers speculate that the cause of the volcanic eruptions may have been a huge asteroid impact on the other side of the Earth, which was so powerful that it caused magma to move away from the impact like water sloshing in a jostled glass. The magma rose up toward the earth’s crust and eventually through it onto the surface.

The result was probably the largest volcanic event in the last half-billion years and it continued for an estimated two million years. Most of the eruptions were probably pretty low-key, just runny lava pouring out of vents in the ground, but there was just so much of it. Lava covered almost a million square miles of land, or 2.6 million square km. Ash and toxic gases from some eruptions also ended up high in the atmosphere, but one big problem was that the lava poured through sediments full of organic material in the process of turning into coal. Lava, of course, is molten rock and it’s incredibly hot. It’s certainly hot enough to burn a bunch of young coal beds, which added more ash and toxic gases to the air—so much ash that shallow water throughout the entire world became choked with ash.

The carbon dioxide released by all that burning coal caused severe ocean acidification and ocean anoxia—a lack of oxygen in the water. But it gets worse! A lot of lava erupted into the ocean right at the continental shelf, where the shallow coastal water becomes much deeper. This is exactly the place where you find methane deposits in the sediments on the ocean floor. When those deposits were suddenly disturbed by lava flowing into them, all the methane in the formerly tranquil depths was released and bubbled to the surface. Methane is a powerful greenhouse gas, meaning that if a whole lot of it ends up in the atmosphere in a short amount of time, it can cause rapid global warming—much faster than that caused by carbon dioxide. This global warming would have happened after a period of global cooling due to reduced sunlight reaching the earth through ash clouds, which lasted long enough and was severe enough that sea levels dropped as glaciers formed. Then everything heated way, way up. The ice caps melted, which may have led to a stagnation of ocean currents. This in turn would have contributed to the water’s anoxicity and toxicity. The average temperature of the ocean would have increased by almost 15 degrees Fahrenheit, or 8 degrees Celsius. Atmospheric warming may have been as much as 68 degrees Fahrenheit in places, or 20 degrees Celsius. That’s not the average temperature of the world, that’s the temperature increase.

So, basically, everything was terrible and it happened very quickly in geologic terms. A 2018 study found that everything looked pretty much fine for the 30,000 years leading up to the great dying. Some researchers even think the initial extinction event might have taken place over just a few centuries.

Marine animals were affected the most, especially marine invertebrates. Trilobites and placoderms went extinct, eurypterids went extinct, and corals went extinct until about 14 million years later when modern corals developed. Some researchers estimate that 95% of all marine species went extinct.

Things were better on land, but not that much better. At the end of the Permian, life was good on land and it was especially good for insects because of the high percentage of oxygen in the air and the variety of plant life in huge swamps around the supercontinent Pangaea. The largest insects that ever lived were buzzing around in the Permian. This included an order of insects called Meganisoptera, or griffinflies. Griffinflies looked like dragonflies and may be related to them. Some species had a wingspan 28 inches across, or 71 cm. The arthropod Anthopleura, sometimes called the giant millipede, lived in the Permian too. Some species grew six feet long, or 2.5 meters, and were about 18 inches wide, or 45 cm. It looked like a millipede but had even more legs. It probably looked scary, but it only ate plants as far as we know.

Instead of actively breathing the way most vertebrates do, most invertebrates use a passive system to absorb oxygen from the air. This is great when there’s a lot of oxygen. When the level of oxygen drops, though, the largest species can’t absorb enough oxygen to function and die out rapidly. That’s one reason why you don’t have to worry about spiders the size of bears. So all the large invertebrates and a lot of the smaller ones went extinct as oxygen was replaced with carbon dioxide, methane, and other toxic gases in the atmosphere.

The acid rain caused by toxic gases and the reduced sunlight caused by ash in the atmosphere also killed off plants. Forests died, so that the fossil record during and after the extinction event contains massive amounts of fungal spores from fungi that decompose trees. Some researchers think all of the world’s trees died. Forests disappeared for some four million years. Since trees absorb carbon dioxide from the atmosphere and release oxygen, the lack of trees made oxygen levels drop even more.

Animals that depended on forests to survive also went extinct, including about two-thirds of all amphibians, reptiles, and therapsids. Therapsids were proto-mammals and it’s a good thing they didn’t all die out because they eventually gave rise to mammals.

Everything I’ve described sounds so incredibly bad, you may be wondering how anything survived. One stroke of luck was probably the size of Pangaea. That was the supercontinent made up of most of the world’s landmasses all smushed together. Before the extinction event, the middle of Pangaea was probably pretty dry with swampier climates around the edges. After the extinction event, the interior of the supercontinent was the safest place to be.

One of the most common land animals after the extinction event was a herbivore called Lystrosaurus. Lystrosaurus was a therapsid, and it was nothing exciting to look at unless you were also a lystrosaurus. Some species were the size of a cat while some were much larger, up to 8 feet long, or 2.5 m. It had a short snout, a short tail, and a semi-sprawling gait. A lizard walks with its legs stuck out to the sides, while a dog or cat or pig walks with its legs underneath its body. Lystrosaurus was somewhere between the two.

It probably lived in burrows that it dug with its strong front legs. While it had a pair of tusks that grew down from the upper jaw, those were its only teeth. Instead it probably had a turtle-like beak that helped it bite off pieces of vegetation.

Lystrosaurus lived in the central part of Pangaea, in what is now Asia, Antarctica, South Africa, and eastern Europe back when all those areas were all scrunched up close together. It survived the extinction event and expanded its range, and for millions of years it was almost the only big land animal in the world. It had almost no predators because they’d all gone extinct, and it had very few competitors for food because they’d all gone extinct. Lystrosaurus made up 90% of all land vertebrates for millions of years.

How did it survive when so many other animals died out? There are several theories, but the most important factor was probably its lack of specialization. It could survive on any kind of plant instead of needing to feed on specific species of plant. There’s also evidence that it could enter a torpor similar to hibernation where its metabolism slowed way down. This would have been a literal lifesaver during the time when the air and water were toxic and very little plant life survived. Lystrosaurus could hunker down in its burrow for long stretches of time, then come out and find enough food and water to keep it going for another stretch of torpor.

Just imagine the world back then, after the initial extinction event but before the world had recovered—say, a million years after the volcanic activity stopped. Picture a series of gentle rolling hills dotted with grazing animals. It’s peaceful and very open because there are no trees. Grass hasn’t evolved yet so the ground is covered in fern-like plants from the genus Dicroidium, which lives in dry conditions. As you look closer with your mind’s eye, you realize that every single one of those grazing animals—thousands of them visible in every direction—are the same kind of animal that looks sort of like a fuzzy pig with a stumpy lizard tail, clawed feet, and a turtle’s beak. Lystrosaurus, living the good life.

In the ocean, the situation was similar. The shallows were toxic waste dumps of ash where the water had so little oxygen that nothing could survive. But the deeper ocean was still livable for some animals.

For a long time, scientists thought a group of early sharks called cladodontomorphs had gone extinct during the great dying. Their distinctive teeth had been common in the fossil record, but after the extinction event they disappeared. Cladodontomorphs only grew about a foot long at most, or 30 cm, and may have had a weird-shaped dorsal fin that pointed forward. They lived in shallow coastal waters. You know, the worst possible place to be 252 million years ago.

Then palaeontologists found some of those teeth in rocks that were in much deeper water 135 million years ago. It turns out the little sharks had survived the extinction event by moving into the open ocean where conditions were better. And they didn’t just survive, they lasted for another 120 million years.

So let’s break it down. It was probably four million years before trees developed again from different plants. It was some 14 million years before coral reefs could rebuild as modern corals developed after their cousins went extinct. It took 30 million years for terrestrial vertebrates to recover from the great dying and 50 million years for all the ocean’s ecosystems to fully recover. That’s a colossally long time. But it did recover.

So what animals arose once the recovery was well underway? Icthyosaurs. Archosaurs, which eventually evolved into pterosaurs, crocodilians, dinosaurs, and birds. And therapsids that eventually gave rise to modern mammals.

I don’t usually tease the following week’s show, but next week we’re going to learn about some weird and interesting animals that developed in the early to mid Triassic, after the extinction event was over and life started evolving in new directions. As I’ve said in the previous extinction event episodes: no matter how bad things get, there’s always going to be some little animal stumping along out of the carnage to get on with the business of surviving and thriving.

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

Thanks for listening!


Episode 219: The Strange and Mysterious Tarsier



Thanks to Phoebe for suggesting the tarsier, this week’s strange and interesting primate!

Further Reading:

Decoding of tarsier genome reveals ties to humans

Long-lost ‘Furby-like’ Primate Discovered in Indonesia

Tarsiers look like weird alien babies:

A tarsier nomming on a lizard:

A tarsier nomming on an insect:

The pygmy tarsier and someone’s thumb:

There’s probably not much going on in that little brain:

Show Transcript:

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

This week we’re looking at a weird and amazing little primate, but it’s not a monkey or ape. It’s the tarsier, with thanks to Phoebe who suggested it. It’s pronounced tarsiAY or tarsiER and both are correct.

The tarsier is such a little mess that until relatively recently scientists weren’t even completely certain it was a primate. A 2016 genetic study determined for sure that it is indeed a primate even though it differs in many ways from all other primates alive. For instance, it’s a carnivore. Most primates are herbivores and some are omnivores, including humans and chimpanzees, but only the tarsier is an obligate carnivore. That means it has to eat meat and only meat, whether it’s invertebrates, birds, reptiles, or small mammals like rodents.

Scientists divide primates into two groups informally, into wet-noses and dry-noses. Wet-nose doesn’t refer to a nose that’s runny but to a nose that stays moist, like a dog’s nose. This splits along the same lines as simians and prosimians, another way to group primates. Humans and other apes, along with monkeys, are simians, and also dry-noses. If you’re not sure if that’s accurate, just touch the end of your nose. Make sure you’re not standing in the rain or just got out of the bathtub, though. All other primates are wet-noses, and also prosimians, except for the tarsier. The tarsier is sort of in between. It’s grouped with the wet-nose primates, but it turns out to be more closely related to the dry-nose primates than the wet-noses. Also, its nose is actually dry.

One interesting difference between prosimians and simians concerns vitamin C. Vitamin C is found in a lot of foods, but especially in fruit and vegetables. If you don’t have any vitamin C in your diet, you will eventually die of scurvy like an old pirate, so make sure to eat plenty of fruit and vegetables. But most animals don’t need to eat foods containing vitamin C because their bodies already produce the vitamin C they need. Humans, apes, and monkeys have to worry about scurvy but prosimians don’t. But the tarsier does need vitamin C even though it’s a prosimian. A lot of researchers think the tarsier should be grouped with the simians, not prosimians.

The tarsier currently lives only in southeast Asia, mostly on forested islands, although tarsier fossils have been found throughout Asia, Europe, and North America. Genetic studies also indicate it probably started evolving separately from other primates around 55 million years ago in what is now China.

As it happens, we have a fossil that appears to be an early ancestor of the tarsier. Archicebus achilles was discovered in 2003 and studied for an entire decade before it was described in 2013, and it lived about 55 million years ago in what is now central China. It looks a lot like a tiny tarsier, but with smaller eyes that suggest it was active during the day. Its feet were shaped like a monkey’s, though, not like a tarsier’s feet. It probably only weighed about an ounce, or 28 grams. That’s about the same weight as a pencil. It had sharp little teeth and probably ate insects. So far the 2003 specimen is the only one found, but it’s remarkably complete so researchers have been able to learn a lot about it. If I’d been one of the scientists studying it, there is no way I could have waited ten whole years to tell people about it. I’d have studied it for like six months and then thought, “Okay, good enough, HEY EVERYONE LET ME TELL YOU ABOUT THIS COOL ANIMAL.”

The tarsier is nocturnal and has enormous eyes to help it see better in the dark. Its eyes are so big and round, and frankly the tarsier is not the brainiest animal, that its eyes are actually bigger than its brain. The tarsier also has mouse-like ears, long fingers and toes with sucker-like discs at the end to help it grip branches, and an extremely long tail that’s scaly on the underside. It spends almost its whole life in trees, where it climbs and jumps from branch to branch. When it climbs up a tree, it presses its long tail against the trunk to help it balance.

It’s not a big animal, though. A typical tarsier measures about six inches long, or 15 cm, from the top of its little round head to the bottom of its bottom, not counting its tail. Its tail can be almost a foot long, or 25 cm, though, and its hind legs are also extremely long, about as long as the tail. Its body is rounded with short plush fur, usually brown, gray, or dark gold in color.

With its big eyes and chonky body, if you wrapped up a tarsier in a little robe so you can’t see how small its ears are and how long its legs and tail and fingers are, it would kind of look like a miniature baby Yoda guy from that Mandalorian TV show. Someone please do that. Also, it kind of looks like a cute and furry Gollum from the Lord of the Rings movies.

Unlike other primates, the tarsier can turn its head 180 degrees in both directions. Basically it can turn its head like an owl. This is helpful because its eyes are so big it can’t move them. It can only look straight ahead, so it needs to be able to move its head all around instead. This is actually the same for the owl, too.

The tarsier mostly eats insects, but it will eat anything it can catch, including venomous snakes. It doesn’t just eat the meat, though. It eats just about everything, including bones. It has a wide mouth and strong jaws and teeth, and it’s so agile that it’s been observed to jump up and catch a bird as it flies past. Current speculation is that the tarsier gets enough vitamin C from the insects it eats that it doesn’t need to eat fruit, but no one knows for sure yet. Some species of bat can’t synthesize vitamin C in the body and have to get it from their diet, which is made up of insects.

We talked about the tarsier a little in episode 43, about the Chinese ink monkey, and also way back in episode eight, the strange recordings episode, because the tarsier can communicate in ultrasound [not infrasound]—sounds too high for humans to hear. It has incredibly acute hearing and often hunts by sound alone. Researchers speculate that not only can the tarsier avoid predators by making sounds higher than they can hear, it can also hear many insects that also communicate in ultrasound. As an example of how incredibly high-pitched their voices are, the highest sounds humans can hear are measured at 20 kilohertz. The tarsier can make sounds around 70 kh and can hear sounds up to 91 kh.

The tarsier also makes sounds humans can hear. Here’s some audio of a spectral tarsier from Indonesia:

[tarsier sound]

Some species of tarsier are social, some are more solitary. All are shy, though, and they don’t do well in captivity. Unfortunately, because the tarsier is so small and cute and weird-looking, some people want to keep them as pets even though they almost always die quite soon. As a result, not only is the tarsier threatened by habitat loss, it’s also threatened by being captured for the illegal pet trade. Fortunately, conservation efforts are underway to protect the tarsier within large tracts of its natural habitat, which is also beneficial for other animals and plants.

The smallest species is the pygmy tarsier, which is only found in central Sulawesi in Indonesia, in high elevations. It’s four inches long, or 10.5 cm, from head to butt. You measure tarsiers like you measure frogs. It’s basically the size of a mouse but with a really long tail and long legs and big huge round eyes and teeny ears and a taste for the flesh of mortals. Or, rather, insects, since that’s mostly what it eats.

For almost a century people thought the pygmy tarsier was extinct. No one had seen one since 1921. Then in 2000, scientists trapping rats in Indonesia caught a pygmy tarsier. Imagine their surprise! Also, they accidentally killed it so I bet they felt horrible but also elated. It wasn’t until 2008 that some live pygmy tarsiers were spotted by a team of scientists who went looking specifically for them. This wasn’t easy since tarsiers are nocturnal, so they had to hunt for them at night, and because the wet, foggy mountains where the pygmy tarsier lives are really hard for humans to navigate safely. It took the team two months, but they managed to capture three of the tarsiers long enough to put little radio collars on them to track their movements.

One of the things Phoebe wanted to know about tarsiers is if there are any cryptids or mysteries associated with them. You’d think there would be, if only because the tarsier is kind of a creepy-cute animal, but I only managed to find one kinda-sorta tarsier-related cryptid.

According to a 1932 book called Myths and Legends of the Australian Aboriginals, a little red goblin creature lives in trees in some parts of Australia, especially the wild fig tree. It’s called the yara-ma-yha-who and it looks sort of like a frog but sort of like a monitor lizard. It’s bright red and stands around four feet tall, or 1.2 meters, with skinny arms and legs. The ends of its fingers and toes are cup-shaped suckers. Its head is large with a wide frog mouth and no teeth.

When a person comes along, the yara-ma-yha-who drops down from its tree and grabs them by the arm. It uses the suckers on its fingers and toes to drain blood from their arm, then swallows the person whole. Then later it horks them back up, but they’re smaller than before and their skin is starting to turn red. Eventually the person turns into a yara-ma-yha-who, unless they manage to escape in time.

Some cryptozoologists speculate that the yara-ma-yha-who may be based on the tarsier. The tarsier has never lived in Australia, but it does live in relatively nearby islands. Most tarsier species do have toe pads that help them cling to branches, but frogs also have toe pads and frogs are found in Australia. Likewise, by no stretch of the imagination is the tarsier bright red, four feet tall, toothless, or active in the daytime. It’s more likely the legend of the yara-ma-yha-who is inspired by frogs, snakes, monitor lizards, and other Australian animals, not the tarsier. But just to be on the safe side, if you live in Australia you might want to walk around wild fig trees instead of under them.

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

Thanks for listening!


Episode 218: More Unusual Hoofed Animals



So many interesting hoofed animals in this episode, so many awesome suggestions! Thanks to Page, Elaine, Pranav, Richard E., Richard from NC, and Llewelly!

Further Reading:

Meet the Takin: The Largest Mammal You’ve Never Heard Of

New hope for the elusive okapi, the Congo’s mini giraffe

The Resurrection of the Arabian Oryx

Eucladoceros was not messing around with those antlers:

Megaloceros and Thranduil’s elk in the Hobbit movies. COINCIDENCE?

The stag-moose. What can I say? This thing is AWESOME:

Hoplitomeryx. Can you have too many horns? No, no you cannot:

The gerenuk, still beautiful but freaky-looking:

The golden takin looking beautiful [pic from the article linked above]:

The elusive okapi:

Okapi bums [pic from the article linked above]:

The giraffe being really tall and a baby giraffe being somewhat less tall:

A giraffe exhibiting dwarfism but honestly, he is still plenty tall:

The Arabian oryx is just extra:

The weird, weird tusks of the babirusa. Look closely:

Show Transcript:

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

Back in episode 116, we talked about some amazing hoofed animals. This week we’re going to look at some more amazing hoofed animals that you may have never heard about. Some are extinct but some are running around out there looking awesome even as we speak! Thanks to Page, Elaine, Pranav, Richard E., Richard from NC, and Llewelly for their suggestions! If you’re a Patreon subscriber you may recognize part of the end of the episode as largely from a Patreon episode, by the way.

Let’s start with an extinct deer with amazing antlers. Llewelly suggested it, or more accurately replied to a Twitter conversation mentioning it. That counts as a suggestion. It’s been a while but I think the conversation was about the Hobbit movies.

Eucladoceros was a deer the size of a moose but with much weirder antlers. We’re not talking about the Megaloceros, often called the Irish elk, although it was distantly related. Eucladoceros’s antlers were much different. They branched up and out but were spiky like an ordinary deer’s antlers instead of palmate like a moose’s or Megaloceros’s antlers. But they were seriously big, with up to twelve points each and over five and a half feet across, or 1.7 meters. The deer itself stood just under 6 feet tall at the shoulder, or 1.8 meters. It’s often called the bush-antlered deer because the antler’s many points look like the branches of a bush.

Eucladoceros lived in Eurasia but we’re not completely sure when it went extinct or why. We don’t really know that much about it at all, in fact, which is surprising because it was such a big animal. It was one of the earliest deer with branching antlers and it probably went extinct before humans encountered it, but we don’t know that for sure either.

Another deer relation is a gigantic animal called the stag moose that lived at the very end of the Pleistocene, or ice age, until around 13,000 years ago. It probably looked a lot like a huge, muscular deer more than a moose, but had moose-like antlers that grew up to 6 1/2 feet across, or 2 meters. The animal itself stood almost six feet tall at the shoulder, or 1.8 m, which is about the size of the modern moose. It lived in northern North America until melting glaciers allowed other animals to migrate into the area, and the modern moose outcompeted its cousin.

Early deer and deer relations looked a lot different from the deer we’re familiar with today. For instance, Hoplitomeryx. It was a ruminant and therefore related to modern deer, but while it probably looked a lot like a deer, it didn’t have antlers. It had horns. Antlers grow every year from the skull and the animal sheds them later, usually after breeding season. Horns are permanent, usually made of a bony core with a keratin sheath over it.

Hoplitomeryx lived around 11 to 5 million years ago in one small area of Europe. Specifically, it lived on a large island near what is now Italy, although the island is now part of a little peninsula. It probably also lived on other, smaller islands nearby. While some specimens found are quite small, probably due to island dwarfism, some grew as big as the bush-antlered deer, over 5 ½ feet tall, or 1.7 meters.

It had a pair of horns that were shaped like a modern goat’s, that grew from the top of its head and curved backwards. And it had a smaller pair of horns underneath those horns that grew outward. And it had a single horn that was about the same size or bigger and shaped the same as the goat-like horns, but which grew in the middle of the forehead like a really weird unicorn. Also, it had fangs. I am not making this up. It’s sometimes called the five-horned deer for obvious reasons.

We also don’t know much about Hoplitomeryx except that it was really awesome, so let’s move on to our next strange hoofed animal. This one is a suggestion by Page, who wanted to know more about the gerenuk. We talked about it in episode 167 but it’s such an interesting animal that there’s more to learn about it.

The gerenuk is an antelope that lives in East Africa. It’s considered a type of gazelle, although it’s not very closely related to other gazelles. It’s slender with long legs and a long neck, and stands about three feet tall at the shoulder, or 105 cm. The male has a pair of S-shaped, ridged black horns that can grow up to 18 inches long, or 45 cm, while the female doesn’t have horns at all. It’s reddish-brown with a pale belly and a pale stripe down its sides, a short tail, and a white patch around each eye. But as we talked about in episode 167, its legs are extremely thin—so thin that they look like sticks, especially the front legs.

The gerenuk is the only type of antelope that can stand on its hind legs, which it does all the time. It will even use its front legs to pull branches down closer to its mouth while standing on its hind legs. As a result, even though it’s not very big, it can reach leaves that other antelopes can’t. Not only does this mean it can find food where other antelopes can’t, it also means it doesn’t need very much water because it can reach tender leaves with a higher moisture content.

Like many gazelles, the gerenuk marks its territory with scent glands. It has scent glands on its knees, covered with tufts of hair, and scent glands in front of its eyes. So if you see a gerenuk rubbing its knees or face on a branch, that’s why.

Our next hoofed animal is the golden takin, which looks kind of like a musk ox except that it has pale golden fur. But it isn’t a musk ox although it is in the family Bovidae. It’s actually most closely related to sheep but is sometimes referred to as a goat-antelope. It does resemble the mountain goat in some respects, which makes sense because it lives in the Himalayan Mountains in China. As a result, it has a lot of adaptations to intense cold.

It has a thick coat that grows even thicker in winter, with a soft, dense undercoat to trap heat next to the body. It also has large sinus cavities that warm the air it breathes before it reaches the lungs, which means it has a big snoot. Its skin is oily, which acts as a water repellent during rain and snowstorms. In spring it migrates to high elevations, but when winter starts it migrates back down to lower elevations where it’s not quite as cold.

Like the gerenuk, the golden takin will stand on its hind legs to reach leaves, but it has to balance its front legs against something to stay upright. It will eat just about any plant material it can reach, including tree bark, tough evergreen leaves, and bamboo. Yes, bamboo. It sometimes shares the same bamboo forests where pandas live. The golden takin is a strong animal that will sometimes push over small trees so it can eat the leaves. It visits salt licks regularly, and some researchers think it needs the minerals available at salt licks to help neutralize the toxins found in many plants it eats.

Both male and female golden takins have horns, which grow sideways and back from the forehead in a crescent and can be almost three feet long, or 90 cm. It has a compact, muscular build and can stand over four feet tall at its humped shoulder, or around 1.4 m. Baby golden takins are born with dark gold-brown fur that helps camouflage it, but as it ages, it fur grows more and more pale gold. A full-grown golden takin is big enough and strong enough that it doesn’t have many predators. If a bear or wolf threatens it, it can run fast if it needs to or hide in dense underbrush.

Next, let’s learn about an animal requested by both Elaine and Pranav. In the 19th century and earlier, Europeans exploring central Africa kept hearing about an elusive animal that lived deep in the remote forests. It was supposed to be a kind of donkey or zebra, but it was so little-known that some Europeans started calling it the African unicorn because they didn’t even think it existed.

In 1899, a British man named Harry Johnston decided to get to the bottom of the African unicorn mystery. When he asked the Pygmy people about it, they knew exactly what he was talking about and showed him some hoof prints. Like most Europeans at the time, Johnston thought the African unicorn was a zebra, so he was surprised to learn that it had cloven hooves.

The Pygmy people also gave Johnston some strips of skin from the animal, and later he bought two skulls and a complete skin. He sent these to England where the animal was identified as a giraffe relation. It was named Okapia johnstoni, and is known by the name okapi.

The okapi’s discovery by science was as astounding in its way as the coelacanth’s discovery a few decades later. Until it was described in 1901, scientists thought all the giraffe relations had died out long ago. Paleontologists had found fossils that showed how the giraffe evolved from a more antelope-like animal, and suddenly there was a living animal with those same features. It was mind-blowing!

The okapi is the giraffe’s closest living relation, but it doesn’t look much like a giraffe. For one thing, it’s not quite five feet tall at the shoulder, or 1.5 meters, and while it does have a long neck, it’s nothing like as long as a giraffe’s. It looks more like an antelope than a giraffe, at least at first glance. It’s dark reddish-brown with pale gray markings on its face, and its lower legs are white and its rump and upper legs are striped black and white. It also has a tail with a tuft at the end like a giraffe’s. Females are usually larger than males.

The male okapi has a pair of ossicones on his head, but they’re not very long compared to giraffe ossicones. As you may remember, an ossicone is a bony projection from the skull that’s covered with skin and hair. The female has little forehead bumps instead of actual ossicones.

The okapi lives in rainforests in central Africa and is a solitary animal. It has a long tongue like a giraffe which it uses to grab leaves. Its tongue is almost as long as the giraffe’s, up to 18 inches long, or 46 cm, whereas the giraffe’s tongue is 20 inches long, or 56 cm. A female okapi has one calf every two years or so, and in the first month of life, the calf doesn’t defecate at all. Not a single baby okapi poop. Some babies may hold it until they’re ten weeks old. Scientists aren’t sure if this same behavior is found in the wild, since okapis are hard to observe in the wild and most behavioral observations come from captive animals, but the hypothesis is that by not defecating, the baby is less likely to attract the attention of leopards who would smell the poops.

For a long time scientists thought the okapi didn’t make any sounds at all, just some whistles and chuffing sounds. It turns out, though, that a mother okapi communicates with her baby with infrasound, which is below the range of human hearing.

Speaking of giraffes, in March of 2021 a study of the giraffe genome was published, focusing on the giraffe’s adaptations for growing so extremely tall. One interesting discovery is that the giraffe has very little sense of smell although it has excellent eyesight. This makes sense considering that the giraffe’s head is so far above the ground. Most scents left by predators will be on or close to the ground, not high up in the air. The giraffe also doesn’t sleep very much and it shows a lot of genetic adaptations for extremely high blood pressure. It needs that high blood pressure to push blood up its long neck to its brain. Researchers are especially interested in the genetics of blood pressure, since high blood pressure in humans is a serious problem that can lead to all sorts of medical issues.

We’ve talked about giraffes before, especially in episode 50, about the tallest animals. Giraffes have extremely long necks and legs and a big male can stand 19.3 feet high, or 5.88 m, measured at the top of his head. Even a short giraffe is over 14 feet tall, or 4.3 meters. To put that into perspective, the average height of a ceiling in an average home is 8 or 9 feet high, or just over 2.5 meters. This means a giraffe could look into an upstairs window to see if you have any giraffe treats, and not only would it not need to stretch to see in, it would probably need to lower its head.

But in 2015, a team of biologists surveying the animals in the Murchison Falls National Park in Uganda, which is in eastern Africa, noticed a male giraffe that had much shorter legs than usual. They nicknamed him Gimli after one of the dwarf characters from Lord of the Rings, and estimated his height as just over nine feet tall, or about 2.8 meters. Gimli would not be able to peek into an upstairs window, but he was still a fully grown giraffe.

Since dwarfism affects the length of an animal’s limbs, it was obvious that Gimli was actually a dwarf giraffe, the first ever documented.

Then, in 2018, a different team of scientists found a different giraffe in a different place, Namibia in southwest Africa, who was fully grown but also had short legs. He was also a male, nicknamed Nigel, and was hanging around with some other giraffes on a private farm. The farmer had seen Nigel plenty of times over several years. Nigel’s height was estimated at 8 ½ feet tall, or 2.6 meters.

In animals, dwarfism can result from inbreeding, which is sometimes done on purpose by humans trying to breed cute pets. It also just sometimes happens, a random mutation that affects growth hormones. In the wild, an animal with unusually short legs usually doesn’t live very long. Either it can’t run fast enough to escape a predator or it can’t run fast enough to catch prey. Both Gimli and Nigel appear healthy, though, and even a short giraffe is still a large animal that can kick and run pretty fast.

Next, Richard from North Carolina suggested the Arabian oryx, and it is a beautiful and amazing hoofed animal. It’s a large antelope and used to live throughout the Middle East, but by the 1930s, habitat loss and hunting had restricted it to the desert in northwestern Saudi Arabia. Then oil company employees and Arabian princes both discovered the fun that is to be had when you have a car and a machine gun and can just drive around shooting everything you see. Such fun, driving animals to extinction, I’m being sarcastic of course. The last few Arabian oryx survived to 1972, but they were effectively extinct decades before then.

But. Zoos to the rescue. The Arabian oryx is a beautiful animal that does well in captivity, so lots of zoos had them on display. In 1960 conservationists realized they had to act fast if the oryx wasn’t going to go extinct completely, and they started a captive-breeding project called Operation Oryx at the Phoenix Zoo in Arizona, which is in the southwestern United States. They managed to capture three of the remaining wild animals and added to the herd with captive-bred oryxes donated by other zoos.

Operation Oryx was such a success that in only twenty years they were able to reintroduce oryx into the wild. Currently there are an estimated 1,200 oryxes in the wild with another 7,000 or so in zoos and conservation centers around the world. It’s still vulnerable, but it’s not extinct.

The oryx is white with dark brown or black markings, including dark legs and a pair of long, straight, slender black horns. Both males and females have these horns, which can grow up to two and a half feet long, or 75 cm. Since the oryx itself only stands a little over three feet high at the shoulder, or 1 meter, the horns are sometimes longer than the animal is tall. The oryx lives in small herds of mixed males and females, which travel widely in their desert habitat to find food and water. During the hot part of the day, the oryx digs a shallow nest under a tree or bush to lie in. It also has a short tufted tail. I just noticed the tail in a picture I’m looking at. It’s so cute.

In the last weird hoofed animals episode, we ended with a pig relation, so we’re going to end this episode with a pig relation too. Richard E. suggested the babirusa, and you definitely need to know about this weird piggy.

The babirusa is native to four islands in Indonesia. It’s related to pigs, but researchers think it split off from other pigs early on because of how different it is. Females have only one pair of teats, for instance, and usually only one piglet is born at a time, sometimes two. Females make a nest of branches to give birth in.

The babirusa also lacks the little bone in the snout that helps most pig species root. The babirusa only roots in very soft mud, but sometimes it digs for roots with its hooves. It eats plants of all kinds, including cracking nuts with its strong jaws, and will eat insect larvae, fruit, mushrooms, and even occasionally fish and small animals when it can catch them. Unlike most pigs, the babirusa is good at standing on its hind legs to reach branches, much like deer, which is why it’s sometimes called the deer-pig. Its stomach is more like a sheep’s than a pig’s, with two sacs that help it digest fibrous plant material, and it has relatively long, slender legs compared to most pigs.

Most pigs have tusks of some kind, but the babirusa’s are really weird. At first glance they’re just surprisingly long tusks that curve up and back, but when you look closer, you see that the upper pair actually grows up through the top of the snout.

The babirusa boar has two pairs of tusks, which are overgrown canine teeth. The lower pair jut out from the mouth the way most pig tusks do. The upper pair are the weird ones. Before a male babirusa is born, the tooth sockets for its upper canines are normal, but gradually they twist around and the teeth grow upward instead of down. They grow right up through the snout, piercing the skin, and then continue to grow up to 17 inches long, or 43 cm, curving backwards toward the head. In at least one case, a tusk has grown so long it’s actually pierced the boar’s skull.

For a long time researchers assumed males used their tusks to fight, but males fight by rearing on their hind legs and kicking each other with their forehooves. Then researchers decided the tusks were actually for defense during fights, to keep a boar from getting its face kicked. But the tusks aren’t actually very strong and don’t appear to be used for much of anything. Most likely, it’s just a display for females.

The babirusa does well in captivity, even becoming quite tame. Many zoos keep them, which is a good thing because they’re becoming more and more endangered as their island habitats are taken over by farming and development.

So that’s it for the second episode about strange hoofed animals. I guarantee you that we’re going to have a third because there are so many.

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

Thanks for listening!


Episode 216: Gentle Giant Sharks



Let’s learn about some of the biggest sharks in the sea–but not sharks that want to eat you!

Further reading:

‘Winged’ eagle shark soared through oceans 93 million years ago

Manta-like planktivorous sharks in Late Cretaceous oceans

Before giant plankton-eating sharks, there were giant plankton-eating sharks

An artist’s impression of the eagle shark (Aquilolamna milarcae):

Manta rays:

A manta ray with its mouth closed and cephalic fins rolled up:

Pseudomegachasma’s tooth sitting on someone’s thumbnail (left, photo by E.V. Popov) and a Megachasma (megamouth) tooth on someone’s fingers (right):

The megamouth shark. I wonder where its name came from?

The basking shark, also with a mega mouth:

The whale shark:

Leedsichthys problematicus (not a shark):

Show transcript:

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

This week we’re going to look at some huge, weird sharks, but they’re not what you may expect when you hear the word shark. Welcome to the strange world of giant filter feeders!

This episode is inspired by an article in the brand new issue of Science, which you may have heard about online. A new species of shark is described in that issue, called the eagle shark because of the shape of its pectoral fins. They’re long and slender like wings.

The fossil was discovered in 2012 in northeastern Mexico, but not by paleontologists. It came to light in a limestone quarry, where apparently a quarry worker found it. What happened to it at that point isn’t clear, but it was put up for sale. The problem is that Mexico naturally wants fossils found in Mexico to stay in Mexico, and the authors of the study are not Mexican. One of the authors has a history of shady dealings with fossil smugglers too. On the other hand, the fossil has made its way back to Mexico at last and will soon be on display at a new museum in Nuevo León.

Fossils from this quarry are often extremely well preserved, and the eagle shark is no exception. Sharks don’t fossilize well since a shark’s skeleton is made of cartilage except for its teeth, but not only is the eagle shark’s skeleton well preserved, we even have an impression of its soft tissue.

The eagle shark was just slightly shorter than 5 ½ feet long, or 1.65 meters. Its tail looks like an ordinary shark tail but that’s the only ordinary thing about it. The head is short and wide, without the long snout that most sharks have, it doesn’t appear to have dorsal or pelvic fins, and its pectoral fins, as I mentioned a minute ago, are really long. How long? From the tip of one pectoral fin to the other measures 6.2 feet, or 1.9 meters. That’s longer than the whole body.

Researchers think the eagle shark was a filter feeder. Its mouth would have been wide to engulf more water, which it then filtered through gill rakers or some other structure that separated tiny animals from the water. It expelled the water through its gills and swallowed the food.

The eagle shark would have been a relatively slow swimmer. It glided through the water, possibly flapping its long fins slowly in a method called suspension feeding, sometimes called underwater flight. If this makes you think of manta rays, you are exactly correct. The eagle shark occupied the same ecological niche that manta rays do today, and the similarities in body form are due to convergent evolution. Rays and sharks are closely related, but the eagle shark and the manta ray evolved suspension feeding separately. In fact, the eagle shark lived 93 million years ago, 30 million years before the first manta remains appear in the fossil record.

The eagle shark lived in the Western Interior Seaway, a shallow sea that stretched from what is now the Gulf of Mexico straight up through the middle of North America. Because it’s the only specimen found so far, we don’t know when it went extinct, but researchers suspect it died out 65 million years ago at the same time as the non-avian dinosaurs. We also don’t have any preserved teeth, which makes it hard to determine what sharks it was most closely related to. Hopefully more specimens will turn up soon.

Now that we’ve mentioned the manta ray, let’s talk about it briefly even though it’s not a shark. It is big, though, and it’s a filter feeder. If you’ve never seen one before, they’re hard to describe. If it had gone extinct before humans started looking at fossils scientifically, we’d be as astounded by it as we are about the eagle shark—maybe even moreso because it’s so much bigger. Its body is sort of diamond-shaped, with a blunt head and short tail, but elongated fins that are broad at the base but end in drawn-out points.

Manta rays are measured in width, sometimes called a wingspan since their long fins resemble wings that allow it to fly underwater. There are two species of manta ray, and even the smaller one has a wingspan of 18 feet, or 5.5 meters. The larger species can grow 23 feet across, or 7 meters. Some other rays are filter feeders too, all of them closely related to the manta.

The manta ray lives in warm oceans, where it eats zooplankton. Its mouth is wide and when it’s feeding it moves forward with its mouth open, letting water flow into the mouth and through the gills. Gill rakers collect tiny food, which the manta ray swallows. It has a pair of fins on either side of the mouth that are sometimes called horns, but which are properly called cephalic fins. Cephalic just means “on the head.” These fins help direct water into the mouth. When a manta ray isn’t feeding, it closes its mouth just like any other shark, folding its shallow jaw shut. For years I thought it closed its mouth by folding the cephalic fins over it, but that’s not the case, although it does roll the fins up into little points. The manta ray is mostly black with a white belly, but some individuals have white markings on the back and black speckles and splotches underneath. We talked about some mysteries associated with its coloring in episode 96.

The eagle shark isn’t the only filter feeding shark. The earliest known is Pseudomegachasma, the false megamouth, which lived around 100 million years ago. It was only described in 2015 after some tiny shark teeth were found in Russia. The teeth looked like those of the modern megamouth shark, although they’re probably not related. The teeth are only a few millimeters long but that’s the same size as teeth from the megamouth shark, and the megamouth grows 18 feet long, or 5.5 m.

Despite its size, the megamouth shark wasn’t discovered until 1976, and it was only found by complete chance. On November 15 of that year, a U.S. Navy research ship off the coast of Hawaii pulled up its sea anchors. Sea anchors aren’t like the anchors you may be thinking of, the big metal ones that drop to the ocean’s bottom to keep a ship stationary. A sea anchor is more like an underwater parachute for ships. It’s attached to the ship with a long rope on one end, and opens up just like a parachute underwater. The tip of the parachute has another rope attached with a float on top. When the navy ship brought up its sea anchors, an unlucky shark was tangled up in one of them. The shark was over 14 ½ feet long, or 4 ½ m, and didn’t look like any shark anyone had ever seen.

The shark was hauled on board and the navy consulted marine biologists around the country. No one knew what the shark was. It wasn’t just new to science, it was radically different from all other sharks known. Since then, only about 100 megamouth sharks have ever been sighted, so very little is known about it even now.

The megamouth is dark brown in color with a white belly, a wide head and body, and a large, wide mouth. The inside of its lower lip is a pale silvery color that reflects light, although researchers aren’t sure if it acts as a lure for the tiny plankton it eats, or if it’s a way for megamouths to identify each other. It’s sluggish and spends most of its time in deep water, although it comes closer to the surface at night.

The basking shark is even bigger than the megamouth. It can grow up to 36 feet long, or 11 meters. It’s so big it’s sometimes mistaken for the great white shark, but it has a humongous wide mouth and unusually long gill slits, and, of course, its teeth are teensy. It’s usually dark brown or black, white underneath, and while it spends a lot of its time feeding at the surface of the ocean, in cold weather it spends most of its time in deep water. In summer, basking sharks gather in small groups to breed, and sometimes will engage in slow, ponderous courtship dances that involve swimming in circles nose to tail.

But the biggest filter feeder shark alive today, and possibly alive ever, is the whale shark. It gets its name because it is literally as large as some whales. It can grow up to 62 feet long, or 18.8 meters, and potentially longer.

The whale shark is remarkably pretty. It’s dark gray with a white belly, and its body is covered with little white or pale gray spots that look like stars on a night sky. Its mouth is extremely large and wide, and its small eyes are low on the head and point downward. Not only can it retract its eyeballs into their sockets, the eyeballs actually have little armored denticles to protect them from damage. The body also has denticles, plus the whale shark’s skin is six inches thick, or 15 cm.

The whale shark lives in warm water and migrates long distances. It mostly feeds near the surface although it sometimes dives deeply to find plankton. It filters water differently from the megamouth and basking sharks, which use gill rakers. The whale shark has sieve-like filter pads instead. The whale shark doesn’t need to move to feed, either. It can gulp water into its mouth by opening and closing its jaws, unlike the other living filter feeders we’ve talked about so far.

We talked about the whale shark a lot in episode 87, if you want to know more about it.

All these sharks are completely harmless to humans, but unfortunately humans are dangerous to the sharks. Even though they’re all protected, they’re vulnerable to getting tangled in nets, killed by ships running over them, and killed by poachers.

One interesting thing about these three massive filter feeding sharks is their teeth. They all have tiny teeth, but the mystery is why they have teeth at all. Their teeth aren’t just tiny, they have a LOT of teeth, more than ordinary sharks do. It’s the same for the filter feeding rays. They have hundreds of teensy teeth that the animals don’t use for anything, as far as researchers can tell. One theory is that the babies may use their teeth before they’re born. All of the living filter feeders we’ve talked about, including manta rays, give birth to live pups instead of laying eggs. The eggs are retained in the mother’s body while they grow, and she can have numerous babies growing at different stages of development at the same time. The babies have to eat something while they’re developing, once the yolk in the egg is depleted, and unlike mammals, fish don’t nourish their babies through umbilical cords. Some researchers think the growing sharks eat the mother’s unfertilized eggs, and to do that they need teeth to grab hold of slippery eggs. That still doesn’t explain why adults retain the teeth and even replace them throughout their lives just like other sharks. Since all of the filter feeders have teeth although they’re not related, the teeth must confer some benefit.

So, why are these filter feeders so enormous? Many baleen whales are enormous too, and baleen whales are also filter feeders. Naturally, filter feeders need large mouths so they can take in more water and filter more food out of it. As a species evolves a larger mouth, it also evolves a larger body, and this has some useful side effects. A large animal retains heat even if it’s not actually warm-blooded. A giant fish can live comfortably in cold water as a result. Filter feeding also requires much less effort than chasing other animals, so a giant filter feeder has plenty of energy for a relatively low intake of food. And, of course, the larger an animal is, the fewer predators it has because there aren’t all that many giant predators. At a certain point, an adult giant animal literally has no predators. Nothing attacks an adult blue whale, not even the biggest shark living today. Even a really big great white shark isn’t going to bite a blue whale. The blue whale would just bump the shark out of the way and probably go, “HEY, STOP IT, THAT TICKLES.” The exception, of course, is humans, who used to kill blue whales, but you know what I mean.

Let’s finish with a filter feeder that isn’t a shark. It’s not even closely related to sharks. It’s a ray-finned fish that lived around 165 million years ago, Leedsichthys problematicus. Despite not being related to sharks and being a member of what are called bony fish, its skeleton is partially made of cartilage, so fossilized specimens are incomplete, which is why it was named problematicus. Because the fragmented fossils are a problem. I’m genuinely not making this up to crack a dad joke, that’s exactly why it got its name. One specimen is made up of 1,133 pieces, disarticulated. That means the pieces are all jumbled up. Worst puzzle ever. Remains of Leedsichthys have been found in Europe and South America.

As a result, we’re not completely sure how big Leedsichthys was. The most widely accepted length is 50 feet long, or 16 meters. If that’s anywhere near correct, it would make it the largest ray-finned fish that ever lived, as far as we know. It might have been much larger than that, though, possibly as long as 65 feet, or 20 meters.

Leedsichthys had a big head with a mouth that could open extremely wide, which shouldn’t surprise you. Its gills had gill rakers that it used to filter plankton from the water. And we’re coming back around to where we started, because like the eagle shark, Leedsichthys had long, narrow pectoral fins. Some palaeontologists think it had a pair of smaller pelvic fins right behind the pectoral fins instead of near the tail, but other palaeontologists think it had no pelvic fins at all. Because we don’t have a complete specimen, there’s still a lot we don’t know about Leedsichthys.

The first Leedsichthys specimen was found in 1886 in a loam pit in England, by a man whose last name was Leeds, if you’re wondering where that part of the name came from. A geologist examined the remains and concluded that they were part of (wait for it) a type of stegosaur called Omosaurus. Two years later the famous early palaeontologist Othniel Marsh examined the fossils, probably rolled his eyes, and identified them as parts of a really big fish skull.

In 1899, more fossils turned up in the same loam pits and were bought by the University of Cambridge. IA palaeontologist examined them and determined that they were (wait for it) the tail spikes of Omosaurus. Leeds pointed out that nope, they were dorsal fin rays of a giant fish, which by that time had been named Leedsichthys problematicus.

In 1982, some amateur palaeontologists excavated some fossils in Germany, but they were also initially identified as a type of stegosaur—not Omosaurus this time, though. Lexovisaurus. I guess this particular giant fish really has been a giant problem.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. 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 patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!


Episode 214: Armored Fish and the Late Devonian Mass Extinctions



It’s the next in our short series of episodes about mass extinctions! Don’t worry, it won’t be boring, because we’re going to learn about a lot of weird ancient fish too.

Further reading:

Titanichthys: Devonian-Period Armored Fish was Suspension Feeder

Behind the Scenes: How Fungi Make Nutrients Available to the World

Dunkleosteus was a beeg feesh with sharp jaw plates that acted as teeth:

Titanichthys was also a beeg feesh, but it wouldn’t have eaten you (picture from the Sci-News article linked above):

Pteraspis: NOSE HORN FISH:

Cephalaspis had no jaws so it couldn’t chomp you:

Bothriolepis kind of looked like a fish in a mech suit:

Show transcript:

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

Here’s the second in our small series of episodes about extinction events, this one the Late Devonian extinction. We’ll also learn about some weird and amazing fish that lived during this time, and a surprising fact about ancient trees.

The Devonian period is often called the Age of Fish because of the diversity of fish lineages that arose during that time. It lasted from roughly 420 million years ago to 359 million years ago. During the Devonian, much of the earth’s landmasses were smushed together into the supercontinent Gondwana, which was mostly in the southern hemisphere, and the smaller continents of Siberia and Laurussia in the northern hemisphere. The world was tropically warm, ocean levels were high, and almost all animal life lived in the oceans. Some animals had adapted to living on land at least part of the time, though, and plants had spread across the continents. The first insects had just evolved too.

Shallow areas of the ocean were home to animals that had survived the late Ordovician extinctions. There were lots of brachiopods, bivalves, crinoids, trilobites, and corals. Eurypterids were still thriving and ammonites lived in deeper water. But while all these animals are interesting, we’re mainly here for the fish.

The fish of the Devonian were very different from modern fish. Most had armor. Way back in episode 33 we talked about the enormous and terrifying dunkleosteus, which lived in the late Devonian. It might have grown up to 33 feet long, or 10 meters. Since we still don’t have any complete specimens, just head plates and jaws, that’s an estimate of its full size. However long it grew, it was definitely big and could have chomped a human in half without any trouble at all. It’s probably a good thing mammals hadn’t evolved yet. Instead of teeth, dunkleosteus had jaw plates with sharp edges and fanglike projections that acted as teeth.

Another huge fish from the Devonian is called titanichthys, which might have grown as long as dunkleosteus or even bigger, but which was probably not an apex predator. Its jaw plates were small and blunt instead of sharp, which suggests it wasn’t biting big things. It might not have been biting anything. Some researchers think titanichthys might have been the earliest known filter feeder, filtering small animals from the water by some mechanism we don’t know about yet. Filter feeders use all sorts of adaptations to separate tiny food from water, from gill rakers to baleen plates to teeth that fit together closely, and many others. A study published in 2020 compared the jaw mechanisms of modern giant filter feeders (baleen whales, manta rays, whale sharks, and basking sharks) to the jaw plates of titanichthys, as well as the jaw plates of other placoderms that were probably predators. Titanichthys’s jaws are much more similar to those of modern filter feeders, which it isn’t related to at all, than to fish that lived at the same time as it did and which it was related to.

Titanichthys and dunkleosteus were both placoderms, a class of armored fish. That wasn’t unusual, actually. In the Devonian, most fish ended up evolving armored plates or thick scales. What was unusual in placoderms were their jaws. Specifically, the fact that they had jaws at all. Placoderms were probably the first fish to evolve jaws.

Pteraspis, for instance, was an armored fish that wasn’t a placoderm. It had no fins at all but it was a good swimmer, streamlined and possibly a predator, although it might have been a plankton feeder at the surface of the ocean. It grew about 8 inches long, or 20 cm. It used its tail to propel itself through the water, and instead of fins it had spines growing from its armor that helped keep it stable. A spine on its back, near the rear of the body armor, acted as a dorsal fin, while spines on the sides of its armor, just over its gills, acted like pectoral fins. It also had some smaller spines along its back and a big spike on its nose. Probably not a good fish to swallow whole.

Cephalaspis lived in the early Devonian, around 400 million years ago in fresh water. It wasn’t very big, maybe a foot long, or 30 cm. Basically, it would have fit nicely on a dinner plate, but it wouldn’t have looked much like a trout other than its size. It wasn’t a placoderm either although it did have armor. It was probably a bottom feeder and was flattened in shape with a broad, roughly triangular head covered in armor plates. Its eyes were at the top of its head and its mouth was underneath. The rest of its body was thinner and tapered to a thin tail. It probably used its head to dig around in the mud and sand to find small invertebrates, which it slurped up and swallowed whole because it had no jaws to bite with.

In comparison, the placoderm bothriolepis was about the same size as cephalaspis and was also a bottom feeder in fresh water, but that’s where the resemblance ends. It lived later, around 375 million years ago, and probably ate decomposing plant material. Like other placoderms, it had armored plates on its head and the front part of its body. The armor at the front of its head had a little opening for its eyes, which were really close together. Its tail wasn’t armored and was probably only covered in skin without scales. Bothriolepis also had long armored pectoral fins that look sort of like spikes. Its head armor was so heavy that it probably used these spike-like fins to help push itself off the bottom. The pectoral fins of some bothriolepis species had an elbow-like joint as well as a joint at the top of the fin, making them more arm-like than fin-like. Basically, bothriolepis looks like a fish wearing a mech suit that doesn’t cover its tail. It looks like an armored box with a fish tail and spikes for arms. It looks weird.

Bothriolepis was really common throughout the world with lots of species known. The largest was B. rex, which grew up to 5 1/2 feet long, or 1.7 meters, and which had thicker armor than other placoderms. Researchers think its heavy armor would have kept it from being swept to the surface by currents. Most bothriolepis species were much smaller, though.

Because it was so common, we know quite a bit about bothriolepis. In addition to the fossilized armor plates, we have some body impressions and even fossilized internal organs. This is really rare, and the reason it’s happened more than once in bothriolepis is that the internal organs were protected by the armor plates long enough for fine sediment to fill the body before the organs decomposed or were eaten by other animals. We know that the digestive system was simple compared to modern fish but the gut was spiral shaped, which allowed more time for the plant material it ate to stay in the body so more nutrients could be extracted from it. The gills were likewise primitive, and it may have also had a pair of primitive lungs. Yes, lungs! Not all palaeontologists agree that the sacs were actually lungs, but those who do think the fish would have gulped air at the surface like a lungfish. Since most, if not all, bothriolepis species seem to have lived in freshwater, it’s possible it needed lungs to breathe air if the water where it lived was low in oxygen. Some researchers think it might even have been able to use its pectoral fins to move around on land, at least enough to move to a new water source if its home dried up. Because bothriolepis remains are sometimes found in marine environments, some researchers also speculate that it may have migrated from or to the ocean to spawn, and that it used its possible land-walking ability to navigate around obstacles while migrating along rivers.

At least some bothriolepis individuals also had a pair of weird frills at the base of the tail. They might have acted as fins but they might have had something to do with mating, like a male shark’s claspers. It’s not clear if all individuals had them or only some.

Placoderms were the first fish to develop jaws, teeth, and pelvic fins. Pelvic fins were important not just because it made the fish more stable in the water, but because they correspond to hind legs in tetrapods. Here’s something to think about: if pelvic fins hadn’t evolved in fish, would land animals have eventually evolved four legs or would all land animals have just two legs and a tail? Would humans look like mermaids and mermen, or weird seals? Would birds have evolved wings even if it meant they had no feet?

Okay, so, back to the Devonian. There were lots more fish than just the placoderms, of course. Coelacanths, lungfish, and early sharks evolved at this time and are still around, as are ray-finned fish that are the most common fish today.

But maybe with all this talk of weird fish, you’ve forgotten this is an episode about an extinction event. Ocean life in the Devonian was chugging along just fine–but then something happened, something that resulted in the same loss of oxygen in the oceans that caused so many extinctions in the late Ordovician. But no one’s sure what that was.

The extinction event actually took place in several waves millions of years apart. Researchers generally think that the same events that caused the late Ordovician extinction events may have caused the late Devonian extinction events. Toward the end of the Devonian the Earth did appear to go through several rapid temperature changes, and some researchers think the cause of these temperature changes might have been trees.

At the beginning of the Devonian, there were lots of plants on land, but they were all small. You could walk from one side of a continent to another and never encounter a plant taller than knee-high. But plants were evolving rapidly, and before long the first trees appeared. They were related to ferns, club moss, and a type of plant called horsetails, which wouldn’t have looked much like trees to us. The progymnosperms also evolved during this time, and they were ancestors of modern gymnosperms, a group which includes conifers, gingkos, and cycads. Some of these early trees didn’t even have leaves, while some had what looked like fern fronds. Some grew almost 100 feet tall, or 30 meters.

Tall trees need strong roots, and roots loosened the soil and underlying rocks to great depths. This made it more likely that heavy rains would wash soil into the water, potentially causing microbial blooms. All these trees also absorbed enormous quantities of carbon dioxide and released oxygen into the atmosphere. This sounds great, because animals need oxygen to breathe! But as trees spread across the land, growing bigger and taller, they absorbed as much as 90% of the available carbon dioxide, so much that it actually caused the earth to cool enough to cause glaciers to form.

One interesting thing about trees. Trees and other plants contain complex polymers called lignin that harden the cells. Lignin is why trees have bark and wood. Lignin is also really resistant to decay, which is why it takes so long for a fallen tree to rot down into nothing. There are specialized bacteria and fungi that can break down lignin, but most bacteria and fungi can’t affect it at all.

Plants first evolved lignin around 400 million years ago, and early trees contained a lot of it, way more than modern trees have. It took bacteria and fungi a long time to evolve ways to break that lignin down to extract nutrients from it—around 100 million years, in fact. So for 100 million years, whenever a storm knocked over a tree and it died, its trunk just…stayed there forever–or at least for a really long time, becoming more and more buried over the centuries. Lignin isn’t water soluble either, so even trees that fell into a lake didn’t rot, or at least the lignin in the trunks didn’t rot. All those tree trunks were eventually compressed by the weight of the soil above them into coal beds.

Anyway, the peak of this cycle of trees absorbing carbon dioxide and releasing oxygen actually happened in the Carboniferous period, which occurred just after the final wave of the Devonian extinctions. That’s why insects could grow so incredibly large during the Carboniferous, because the atmosphere contained so much oxygen.

But in the build-up to the late Devonian extinction events, there were periods of colder and warmer climate worldwide, possibly caused by trees, possibly by other factors, most likely by a combination of many factors. Glaciers would form and melt rapidly, possibly leading to the same issues that caused the late Ordovician extinction events.

I’ll quote a bit from episode 205 to remind you what scientists think happened in the Ordovician when a whole lot of glaciers suddenly melted:

As the glaciers melted, cold fresh water flowed into the ocean and may have caused deep ocean water to rise to the surface. The deep ocean water brought nutrients with it that then spread across the ocean’s surface, and this would have set off a massive microbial bloom.

Microbial blooms happen when algae or bacteria that feed on certain nutrients suddenly have a whole lot of food, and they reproduce as fast as possible to take advantage of it. The microbes use up oxygen, so much of it that the water can become depleted.

Rivers were also a major source of nutrients flowing into the ocean, as tree roots continued to break up rock and soil, which made its way into the water.

Whatever the cause or causes, the result was that the ocean lost most or all of its oxygen, especially in the deep sea. Oxygen, of course, is what animals breathe. Fish push water over their gills and absorb oxygen from it by a chemical process the same way we absorb oxygen from the air with our lungs. The air contains a lot of other gases in addition to oxygen, but it’s the oxygen we need.

The first wave of extinctions in the Devonian is called the Taghanic Event. A lot of brachiopods and corals went extinct then, among many other animals. About the time life started to rebound from that wave, the Kellwasser Event killed off more brachiopods and corals, a lot of trilobites, and jawless fish. Finally, the biggest and worst wave of all was the Hangenberg Event.

The Hangenberg Event was really bad. Really, really bad. In the late Ordovician extinction event, some researchers think it took three million years for the oceans to recover from their lack of oxygen. In the late Devonian extinction event, it may have taken 15 million years for the oceans to fully recover. Some researchers think that in addition to everything else going on in the world, a nearby star may have gone supernova and damaged the ozone layer that protects the earth, which would have damaged plants and animals that lived on land.

The end result of the late Devonian extinction event was that 97% of all vertebrate species went extinct, especially those that lived in shallow water, and 75% of all animal species. All placoderms went extinct and almost all corals went extinct.

Most people think that oil—you know, the stuff we use to make gasoline and plastic—came from dead dinosaurs, but that’s not the case. A lot of oil actually formed from the animals that died in the Devonian extinction events. Fish and other animals suffocated as the water lost oxygen, and the lack of oxygen at the bottom of the ocean meant that all those bodies that sank into the depths didn’t rot. They were buried by sediment and as the years and then centuries and millennia passed, more and more sediment piled up, causing pressure and heat that transformed the organic remains into a substance called kerogen. Kerogen is still an organic material and if it’s exposed to oxygen it will oxidize and decay, but if it remains deep underground for millions of years the heat and pressure will eventually transform it chemically into hydrocarbons that make up oil. Don’t ask me to explain this in any more detail than that. My mind is still blown about tree trunks not decomposing for 100 million years; there’s really no room left in my brain to wonder about how oil forms.

Anyway, luckily for us, by the time of the late Devonian extinction events, the first land vertebrates had already evolved and they survived. They spread throughout the world and thrived for 110 million years until the next major extinction event, which was so profound it’s called “the great dying” by palaeontologists. We’ll learn about that one in a few months. Next week I promise we’ll have a light, happy episode where nothing goes extinct!

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. 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 patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!


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 strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. 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 patreon.com/strangeanimalspodcast 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 208: The Happiest Animals in Australia



Thanks to Phoebe for suggesting the quokka and the wombat, two of the cutest, happiest-looking animals in Australia!

Further Reading:

Viral stories of wombats sheltering other animals from the bushfires aren’t entirely true

Satellites reveal the underground lifestyle of wombats

Giant Wombat-Like Marsupials Roamed Australia 25 Million Years Ago

Further Listening:

Animals and Ultraviolet Light (unlocked Patreon episode)

The adorable quokka with a nummy leaf and a joey in her pouch:

Quokka (left) and my chonky cat Dracula (right)

Some quokka selfies showing quokka smiles. That second picture really shows how small the quokka actually is:

Wombats!

A wombat and its burrow entrance:

A wombat mom with her joey peeking out of the rear-facing pouch:

Golden wombats. All they need is some Doublemint Gum:

Two (dead, stuffed) wombats glowing under ultraviolet light:

Show Transcript:

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

This week we’re going to look at two super-cute animals from Australia, both of them suggestions by Phoebe. Thank you, Phoebe!

Let’s start with the quokka. It’s a marsupial, which as you may recall means that it’s a mammal that gives birth to babies that aren’t fully formed yet, and the babies then finish developing in the mother’s pouch. It’s related to kangaroos and wallabies but is quite small, around the size of an ordinary domestic cat. It’s kind of a chonk, though, which means it’s probably closer in size to my big chonk cat Dracula. It’s shaped roughly like a little wallaby or kangaroo but with a smaller tail and with rounded ears, and it’s grey-brown in color.

You may have seen pictures of the quokka online, because the reason it’s considered so incredibly cute is because it looks like it’s smiling all the time. If you take a picture of a quokka’s face, it looks like it has a happy smile and that, of course, makes the people who look at it happy too. Those are real pictures, by the way. Because of the way its muzzle and mouth are shaped, the quokka really does look like it’s smiling.

This has caused some problems, unfortunately. People who want to take selfies with a quokka sometimes forget that they’re wild animals. While quokkas aren’t very aggressive and are curious animals who aren’t usually afraid of people, they can and will bite when frightened. The Nature Conservancy of Australia recommends that people who want to take a selfie with a quokka arrive early in the morning or late in the evening, since quokkas are mostly nocturnal, and that they let the quokkas approach them instead of following one around. Touching a quokka or giving it food or drink is strictly prohibited, since it’s a protected animal.

The quokka lives on a few small islands off the coast of western Australia and a few small forested areas on the mainland. The largest population lives on Rottnest Island, and in fact the island was named by a Dutch explorer who thought the quokkas were rats. It means rat’s nest. The island’s actual name was Wadjemup and it was a ceremonial area for the local Whadjuk Noongar people.

Only an estimated 14,000 quokkas live in the wild today, with most of those on Rottnest Island. It used to be much more widespread, but once white settlers arrived and introduced predators like dogs, cats, and foxes, its numbers started to decline. It’s also threatened by habitat loss. It reproduces slowly, since a female only raises one baby a year.

A baby quokka is born after only a month, but like other marsupial babies, called joeys, it’s just a little pink squidge when it’s born. It climbs into its mother’s pouch where it stays for the next six months. Once it’s old enough to leave her pouch, it still depends on her milk for a few more months. While she’s raising one baby, though, the mother has other babies still in her womb ready to be born but held in suspended animation. This means that if something happens to her joey and it dies, the mother can give birth to another baby very quickly.

The quokka is most active at night. It sleeps during most of the day, usually hidden in a type of prickly plant that helps keep predators from bothering it. It gets most of its water needs from the plants it eats, and while it mostly hops around like a teensy kangaroo, it can also climb trees.

The wombat is another adorable Australian marsupial. For some reason, I’ve talked about the wombat several times in Patreon episodes but have barely mentioned it in the main feed–but that’s about to change. Mostly because I am going to recycle a lot of the information from the Patreon episodes, but I’ve also added a lot of interesting new details.

The wombat mainly lives in southern and eastern Australia, including Tasmania. It looks a little like a cartoon bear, a little like a cartoon badger, and a little like a cartoon giant hamster. Perhaps you notice a theme here. It has short legs, no tail to speak of, and is about the size of a medium-sized dog but stockier, with a broad face and rounded ears. The female has a rear-facing pouch to keep dirt and debris from getting on her baby while digging. There are three species alive today.

The wombat is mostly nocturnal and sleeps in a burrow during the day, although it will come out during the day when it’s overcast. It eats grass and other plants. It can dig really well and some people in Australia consider it a pest because it digs under fences.

The wombat has a big round rump with tough skin reinforced with cartilage. If a dingo or other animal chases a wombat, it dives into a hole and blocks the hole with its rump. The predator can’t get a purchase on the tough hide and there’s no tail to grab. The wombat isn’t helpless, though. It can kick hard, bite hard, and if the dingo gets its head over the wombat’s back to grab for its neck, the wombat will push upward and crush the dingo’s head against the roof of the tunnel. The wombat takes no prisoners and presents its butt to danger. Also, its poop is square, as you may remember if you listened to the animal poop episode.

The wombat has a very slow metabolism and takes a week or even two weeks to fully digest a meal. It can run fast when it needs to, although it can’t keep up a fast pace for long. Wombats have even been known to knock people down by charging them, which I personally find hilarious. It can also bite ferociously if it feels threatened, and while it mostly uses its long claws for digging, they also make fearsome weapons. So it’s best to leave the wombat alone.

The wombat’s fur can be gray, tan, brown, black, or any variation on those colors, but there are rare reports of wombats with golden fur. In a 1965 letter to The Times, an anonymous writer reported spotting a golden wombat but couldn’t get anyone to believe him. “Of course you were mistaken, my family said. They said it with an irritating sureness… The golden wombat became the subject of family jokes.” And then two years later, the letter-writer saw the golden wombat again. I thought that would be a fine cryptozoological mystery to share, but when I did a search for golden wombat sightings, actual golden wombats in zoos turned up. Golden wombats are a real thing, just extremely rare. The sunshine golden fur is due to a mutation in coat color.

The Cleland Wildlife Park in Adelaide has a pair of golden hairy-nosed wombats that were discovered in 2011 and sent to the park in 2013. Golden wombats don’t survive long in the wild since their coloring makes them stand out to predators. Wombats in general are having trouble in the wild anyway due to habitat loss, introduced predators like domestic dogs, introduced rabbits and other animals that compete with it for food, the mange mite, also introduced to Australia and spread by domestic dogs, and drought.

Last year, during the awful summer bushfires in Australia, there were reports of wombats saving other animals by herding them into their deep burrows when fires approached. It’s a great story, but like many other stories that seem too good to be true, it’s not completely accurate. The wombats didn’t herd other animals into their burrows like little furry firefighters, but lots of animals did take shelter in wombat burrows to escape the fires. A wombat’s burrow isn’t just a little tunnel with a bedroom at the end. It’s way more elaborate than that, with lots of entrances and adjoining tunnels. One wombat’s burrow complex had 28 entrances and almost 295 feet of tunnels, or 90 meters. A wombat usually only sleeps in one particular burrow for a day or two before moving to a different one, and other animals routinely use the other burrows for themselves. As long as the other animal isn’t a threat, the wombat doesn’t seem to mind. So it’s not surprising that lots of animals hide in wombat burrows to escape fire.

In October of 2020 a team of scientists published a paper about ultraviolet fluorescence in the platypus, which glows greenish in ultraviolet light. The discovery was made by accident but prompted scientists throughout the world, and especially Australia, to borrow black lights from other departments to shine on their mammal collections. It turns out that a lot of nocturnal or crepuscular animals have fur that glows various colors under ultraviolet light. This includes the wombat.

There’s more ultraviolet light at dawn and dusk than during full daylight or at night, so some researchers think the glow may be a way for the animals to blend in with the increased ultraviolet light at those times. If this is the case, it’s a new type of camouflage, or rather a very old type since it’s found in animals like the platypus that have been around for a really, really long time.

Ultraviolet light is the wavelength of light beyond purple, which humans can’t see. Most humans, anyway. In April 2019 I released a Patreon episode about animals and ultraviolet light, and I’ve decided to unlock that episode for anyone to listen to. I’ll put a link in the show notes so you can click through and listen. Be aware that I did make a mistake in that episode, where I mentioned that a black light allows humans to see into the ultraviolet spectrum, but actually what people see when they shine a black light around is fluorescence and ordinary violet light.

A relative of the wombat, Diprotodon, is the largest marsupial ever known. It went extinct around 45,000 years ago, not long after the first humans populated Australia, and is also an ancestor of the koala. It and some other of the Australian megafauna may have influenced Aboriginal myths of dreamtime monsters. It stood around 6 ½ feet tall at the shoulder, or two meters, and like the wombat it had a rear-facing pouch and ate plants. Recent analysis of the front teeth, which were large and flat and grew continuously throughout the animal’s life, indicated it might have been migratory. Researchers also think it lived in social groups something like elephants do today. Its feet were flat and toed inward like modern wombat feet, and although it had claws it probably only used them to dig plants up.

A partial fossil found in 1973 in South Australia was finally described in mid-2020 as a wombat relation, although it may not be a direct ancestor to modern wombats. It lived about 25 million years ago and was the size of a bear, and had powerful front legs with claws used for digging up roots. It’s named Mukupirna nambensis and is different enough from other wombat relations that it’s been assigned to a new family of its own.

There have been reports for centuries of giant wombats or wombat-like animals in Australia and even from nearby Papua New Guinea. Some cryptozoologists think the sightings are of a smaller relative of the wombat, Hulitherium tomasetti. Hulitherium lived in the rainforests of New Guinea, and probably went extinct about the same time as Diprotodon, possibly due to hunting from newly arrived humans. It was about three feet high, or one meter, and may have eaten bamboo as a primary part of its diet. Like the panda, it seems to have a number of adaptations to feeding on a bamboo diet, including very mobile front legs, more like an ape’s than a wombat’s. It may have been able to stand on its hind legs like a bear too.

An October 26, 1932 story in The Straits Times, a Singapore newspaper, is interesting in light of the hulitherium’s size and possible appearance. I’ll quote the story, which appears in the 2016 Fortean Zoology Yearbook:

“One of our strangest visits was reserved for this morning, when Mr. Paul Pedrini, wild animal hunter and trainer, arrived leading a curious beast, brown, furry, about two feet high and four feet long and looking like no animal one could call to mind. It was very fat and adorning its neck was a large pink bow. This latter fact was the chief cause of the uneasiness shown by the oldest sub-editor. Mr. Pedrini explained that he found his little pet in Australia eighteen months ago.

“He calls it the ‘What Is It?’ because nobody can give it a name. Described as being something like a wombat, it is certainly not a wombat neither does it belong to any other known family. The ‘What Is It?’ is very tame and friendly and has kind eyes. Its chief diet is bananas and toast. We said good bye to Mr. Pedrini, patted the strange animal and returned, slightly shaken, to the normal round.”

The story isn’t sensational enough to feel like a hoax, but it doesn’t really give enough of a description of the animal to be sure it wasn’t just a larger than usual wombat. After all, the wombat does have kind eyes.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. 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 patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!


Episode 205: Sea Scorpions and the Late Ordovician Mass Extinction Event



Happy new year! This week we’ll learn about the oldest mass extinction event, some 450 million years ago, and also sea scorpions.

Further reading:

Coming up for air: Extinct sea scorpions could breathe out of water, fossil detective unveils

Sea scorpions could get really, really big:

A fossil Eurypterus:

Show transcript:

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

Hello, 2021, please be better than 2020 was. I’ve got lots of fun, interesting episodes planned for this year, but let’s start the year off right with an episode about, uh, a major extinction event. Specifically it’s the Late Ordovician mass extinction, which occurred around 450 million years ago. This is the first of a series of episodes about extinction events I have planned for this year, which I hope you’ll find interesting. We’ll also learn about an animal called the sea scorpion.

If you’ve listened to episode 69, about the Cambrian explosion, you may remember that the fossil record shows that around 540 million years ago life on earth evolved from simple organisms into much more complicated ones. This happened relatively quickly in geologic terms, about 15 to 25 million years for life to go from microbial mats, simple worms, and single-celled animals to fantastical creatures with shells and spikes and novel ways of feeding as animals adapted to fit new ecological niches.

But what happened after that? A series of extinction events, that’s what.

The first extinction event researchers can identify from the fossil record is called the End-Botomian extinction event, which happened around 510 million years ago in two phases. We’re not sure what caused the extinctions, but the main theory is that a series of massive volcanic eruptions caused climate changes that led to acidification of the oceans and a resulting loss of oxygen from the water. This was followed by another extinction event around 500 million years ago. All told, during these ten million years or so, about 40% of all species of animal went extinct.

But remember, all we have to work with is the fossil record. Researchers know how old particular rock strata are, strata being the term for layers, so when they find a fossil embedded in a rock they know roughly how long ago it lived. Only a small percentage of animals that ever live end up fossilized, and only a small percentage of fossils are ever found by humans, and only a small percentage of fossils found by humans get studied by experts. So while scientists do their best, they’re working with a limited amount of data to determine what happened half a billion years ago. It’s like trying to determine the rise and fall of empires from a series of random photographs.

But when older rocks show a whole lot of fossils of various kinds, and then slightly younger rocks show way fewer or no fossils, researchers can be pretty sure that something catastrophic happened to kill off a lot of animal life in a relatively short amount of time. If they find the same changes in rocks of the same age in different parts of the world, the catastrophe was probably worldwide and serious enough to impact life on Earth for thousands or even millions of years. That’s what happened in the late Ordovician.

Around 460 million years ago, about the time that life was getting back to normal after the last extinction event, glaciers started to form across the land. Most of the continents at this time were smushed together into a supercontinent called Gondwana, which was mostly in the southern hemisphere. Much of the rest of the Earth was one big ocean, and it was hot and tropical just about everywhere. But that changed when temperatures dropped drastically. Glaciers formed, sea levels fell, and some 60% of all life on Earth went extinct, all possibly within about one million years.

We don’t know why, but we do have some clues and some theories. We know there was a major meteor event around 467 million years ago, which can be pinpointed because of the craters and specific minerals and bits of meteorites found that can only come from meteors hitting the earth. The impacts kicked dust into the atmosphere that then reflected sunlight back into space, causing less light to reach the earth.

Another cause might have just been a cyclical movement of the Earth in space. As you hopefully know, Earth rotates on its axis in a 24 hour period, giving us day and night, and at the same time it’s moving in an elliptical orbit around the sun in a 12-month period, which of course is a year. The sun and the other planets and everything else in our solar system are also moving in space in a larger orbit, and there are other even larger orbits that our solar system is part of within our galaxy, which is moving too. With all this movement all the time, it’s not surprising that Earth’s climate is affected in very long cycles, together with the effects of the moon’s gravitational pull making the Earth’s orbit just slightly wobbly. A combination of events, including where the Earth was in its orbit, might have caused the Earth to cool just enough that it set off an ice age. If this happened at about the same time that the meteor event also caused the Earth to cool a little, that would explain why the onset of glaciation happened so quickly in geological terms.

Whatever the cause or causes, it had serious repercussions. The cooling climate and drop in ocean levels as ice formed caused rapid extinctions of animals that lived in shallow water and were adapted to tropical climates.

But the extinction event was a one-two punch. The cold didn’t kill off every animal, of course, and those that remained evolved to take advantage of ecological niches that were suddenly empty. This is always how life manages after an extinction event. But these new species were adapted to the cold. And then, almost as suddenly as they formed, the glaciers melted.

Sea levels rose dramatically. The Earth warmed again, although not to its former levels. As the glaciers melted, cold fresh water flowed into the ocean and may have caused deep ocean water to rise to the surface, a process called upwelling. The deep ocean water brought nutrients with it that then spread across the ocean’s surface, and this would have set off a massive microbial bloom.

Microbial blooms sometimes happen today in small areas of the ocean or in lakes, especially in places where fertilizers make it into the water. Algae or bacteria that feed on certain nutrients suddenly have a whole lot of food, and they reproduce as fast as possible to take advantage of it. But the microbes use up oxygen, so much of it that the water can become depleted. This leads to massive die-offs of fish and other animals. But these modern microbial blooms are relatively small. The ones 450-odd million years ago might have been worldwide. As the glaciers melted they exposed more land, which meant more nutrients flowing into the ocean, feeding the microbial blooms that continued to deplete oxygen from the ocean.

The result was a severe lack of oxygen in the water that would have driven more species to extinction. Some researchers think it took three million years for the oceans to recover.

There are many other possible causes for the Late Ordovician mass extinction, although right now the cooling and then warming of the earth seems to be the most widely accepted among scientists. But whatever the causes, the results were dramatic. Entire families of animal went extinct, probably around 100 of them, and many others were affected. Some 70% of trilobite species went extinct, for instance.

The Late Ordovician mass extinction marks the end of the Ordovician era and the beginning of the Silurian around 443 million years ago. Remember that these names for eras are just the way that geologists and other scientists can indicate the age of an event or rock or fossil. It’s not like trilobites and brachiopods had little calendars and on one particular day that calendar said “Extinction” and everyone died. It was a gradual process, no matter how fast it occurred in geologic terms. If you had a time machine and could travel back to 450 million years ago, whatever day you arrived, the world would just look normal. You’d have to observe for at least hundreds of years to understand that the Earth was in the process of an extinction event.

You’ll be glad to know that the Silurian lasted almost 25 million years and was nice and quiet geologically. Life rebounded after the extinctions, as it always does, and more animals and plants adapted to live on land. Fish evolved rapidly during this time, developing bony skeletons and jaws. The Earth was comfortably warm but stormy, since the warm water and massive oceans would have spawned hurricanes that make the ones today look puny. But for the most part life was good in the Silurian.

The ocean was populated with lots of animals, including early fish, trilobites, crinoids, corals, leeches, and shelled animals called brachiopods as well as the more familiar mollusks. Sea levels were high and the land was mostly flat. There weren’t many mountains. So around Gondwana were lots of islands that were barely higher than the water level.

In the shallow oceans around what is now North America, an arthropod called the eurypterid was incredibly common, with some 250 species known. Many of them persisted until about 250 million years ago and they lived throughout the world. Eurypterids are often called sea scorpions, but they didn’t look much like modern scorpions. The typical Eurypterid looked a lot like the modern horseshoe crab, but with a longer segmented body and tail. But even though it looked sort of like a horseshoe crab, it may have been more closely related to modern scorpions.

The earliest sea scorpion known was Pentecopterus, which has been found in the fossil record in rocks dated to about 467 million years ago. It grew up to five feet 7 inches long, or 1.7 meters. One interesting thing to note is that it lived in a particular round basin some three miles across, or a bit over 5 km, in what is now Iowa in the United States. Researchers think it was actually a crater from a meteor impact near the ocean’s shore, and that the water in it was probably brackish. Remember how there was a major meteor event 467 million years ago? Pentecopterus was probably living in a crater made by one of those pieces of meteorite. It would have been the apex predator in that small environment, eating anything it could catch with its crablike legs. Later sea scorpions developed a pair of crab-like pincers at the front, along with a flattened tail that sometimes had a pointed barb at the end.

Eurypterids lived in the water. While some grew less than an inch long, or a few cm, some grew quite large. One species of Jaekelopterus could grow 8 ½ feet long, or 2.6 meters. That doesn’t even include the claws at the front that could extend at least another 18 inches, or 45 cm. It was probably a freshwater animal, and despite its size it was streamlined and lightweight, so it would have been an active predator. We even have fossilized fish bones that show puncture wounds that might have been made by its claws. Some eurypterids weren’t very good swimmers, though, and probably spent more time walking along the bottom of the shallow ocean.

So between Jaekelopterus in fresh water and the earliest known sea scorpion, Pentecopterus, in possibly brackish water, it’s obvious that from the very beginning the sea scorpion could adapt to various environments that other animals couldn’t. This adaptability is probably why the sea scorpion survived the extinction event that killed off so many other animals, and it continued to thrive for hundreds of millions of years afterwards.

Not only that, one fossil takes its adaptability a step farther. A geology professor named James Lamsdell heard about a strange eurypterid found in France that had been in a Scottish museum for 30 years. He arranged to have the fossil imaged with a CT scanner, which revealed its gills. And to Lamsdell’s surprise, the gills contained structures found in modern scorpions and spiders, which keep the gill plates from collapsing when it’s out of water. These structures have been retained in modern arachnids from their marine ancestors, and finding them in a eurypterid was shocking. It means that particular eurypterid could spend time on land. Lamsdell and his team think it came out of the water to lay its eggs, either in sheltered pools or in wet sand.

Eurypterids died out eventually, but their cousins, modern scorpions, are doing just fine after surviving many other extinction events. So try to be more like a scorpion, because obviously they’re doing something right.

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

Thanks for listening!


Episode 202: Terror Birds and Pseudotooth Birds



Let’s find out about some gigantic birds this week! Thanks to Pranav and Richard for the suggestions!

Further reading:

Exceptionally preserved fossil gives voice to ancient terror bird

Antarctica yields oldest fossils of giant birds with 21-foot wingspans

Look at that beak! Llallawavis scagliai:

Big birdie!

A red-legged seriema and an unfortunate snake:

Another big birdie!

Toothy birdie!

Show transcript:

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

This week we’re going to learn about some gigantic extinct birds! Pranav wants to hear about Phorusrhacidae, also known as the terror bird. Something called a terror bird is definitely going to be interesting. My brother Richard also tweeted me about some huge extinct birds called pelagornithids, so we’ll talk about them too. Both birds were huge and successful, but extremely different from each other.

Phorusrhacidae is the name for a family of flightless birds that lived from about 62 million years ago to a little under 2 million years ago. Flightless birds may make you think of ostriches and penguins and dodos, but remember that Phorusrhacids were called terror birds. They were carnivores and many of them were enormous.

Most terror birds lived in South America, with one species known from southern North America. A few newly discovered bird fossils from Africa and Europe may have been close relations of terror birds, but palaeontologists are still studying them.

Various species of terror bird ranged in size from about 3 feet tall to 10 feet tall, or 1 to 3 meters, and had long, strong legs that made them fast runners. The terror bird also had a long, strong neck, a sharp hooked beak, and sharp talons on its toes. The beak was strong but the jaw muscles were relatively weak. Researchers think that it ambushed prey and chased it down, then either kicked it to death with its sharp talons or held it down with its feet and stabbed it to death with its beak. Smaller species may have grabbed its prey and thrown it back down with enough force to injure, stun, or outright kill the animal. It may have swallowed small prey whole and regurgitated pellets made up of compressed fur and bones, the way many modern carnivorous birds do today.

Although the beak was strong, it was also hollow. This would have made it weigh less, which meant that the bird could move its head more quickly. Some researchers think that it might also have acted as a resonant chamber, and that the bird could clap its beak closed to make a loud noise to communicate with other terror birds. It had excellent hearing and vision, but a poor sense of smell.

Many details of what we know about terror birds come from a single specimen discovered in 2010 in Argentina. The bird lived around 3 million years ago and stood four feet tall, or 1.2 meters. It was described in 2015 and is named Scaglia’s magnificent bird. I am not going to attempt to pronounce its scientific name [Llallawavis scagliai], but I’ll put it in the show notes along with a picture. Almost the entire skeleton is preserved in stunning detail, including details that hardly ever preserve, like the tiny bones that help the eye focus. Studies of the tiny ear bones and other details of the ear indicate that its hearing was most acute at low frequencies, which meant it would have been good at hearing footsteps. It also probably had a deep voice.

The terror bird had wings, but they were small and probably only used for display. The wings did have claws, though, and may have been used to fight other terror birds over mates or territory. Young terror birds of some species might have been able to fly, although adults certainly couldn’t.

The earliest known terror bird, Paleopsilopterus, lived about 60 million years ago in what is now Brazil. It was relatively small, only about three feet high, or 1 meter. It evolved only a few million years after the non-avian dinosaurs went extinct, and its descendants became larger and more fearsome until they were apex predators throughout South America.

Kelenken, for instance, grew up to ten feet tall, or three meters, and had an enormous beak, 18 inches long or almost 46 cm. It lived in what is now Argentina around 15 mya. It’s the tallest terror bird known but it was more slenderly built than others so was probably a faster runner. It was only discovered in 1999.

Brontornis, however, was the one that puts the terror into terror bird. It grew over 9 feet tall, or 2.8 meters, but it was massively built. It probably wasn’t a very fast runner and would have definitely been an ambush predator. Most likely it hid among trees or other tall vegetation, and when an animal came too close, BOOM! THERE’S A TERROR BIRD! RUN! TOO LATE, ARGH!

Titanis lived in parts of North America, with fossils found in Texas and Florida. It probably stood a little over eight feet tall, or 2.5 meters, although we don’t have any complete skeletons so can only estimate its actual size compared to other species of terror bird. You may find information online that says Titanis lived as recently as 10,000 years ago in Florida, and that it used the claws on its wings like hands to help catch prey. Both these things are wrong, unfortunately. The fossil bones found in the Santa Fe River in Florida had washed out of their original location and were mixed in with much more recent bones, and there’s no evidence that any terror bird used its wings like hands. Terror birds were descended from birds that could fly, not descended directly from dinosaurs, so its wings were still highly modified for flight.

Titanis lived in North America about five million years ago. But how did it get to North America from South America before the Isthmus of Panama formed around three million years ago? Before then, a big stretch of ocean separated the two continents. Researchers think it island-hopped, as the tops of mountains and hills in what is now Central America first emerged from the ocean as sea levels dropped, forming islands. Volcanoes also formed islands in the area. Titanis may have traveled to these islands by swimming or rafting during storms.

Terror birds went extinct after the Isthmus of Panama opened up when sea levels lowered. This connected North and South America, which allowed animals from North America to cross into South America and vice versa. The Andes Mountains also formed about this time and changed the climate of much of South America. Forests became open savanna where terror birds wouldn’t have been able to hide to ambush prey. Climate change combined with increased competition from saber-toothed cats and other North American predators probably led to the terror birds’ extinction.

There are no descendants of terror birds living today, but its closest living relations are probably the seriema birds, the red-legged and the black-legged seriema. Both live in South America and both are carnivorous birds that eat small animals like rodents, lizards, snakes, and even other birds. When it catches an animal, it beats it against the ground until it dies. It will also sometimes eat fruit and eggs.

The red-legged seriema stands a little over three feet tall, or a meter, with long legs, long neck, and long tail. It’s mostly brown and gray and it has a fan-shaped crest low down on its forehead, just above the bill. The gray-legged seriema looks very similar but is mostly gray. The seriema also has a sickle claw on each foot that it uses to cut pieces off its dead prey so it can swallow them more easily.

The seriema can fly, but it prefers to walk or run. It can run up to 15 mph, or 25 km/h. It builds its nest in low bushes so it can just hop up onto the nest instead of having to fly. It’s also aggressive and will attack animals much larger than it is, driving them away from its nest or chicks. Farmers sometimes catch young seriemas and tame them, then allow them to patrol the farmyard to catch rats and snakes and drive away larger predators.

Next, let’s learn about a different giant extinct bird, Richard’s suggestion. Unlike the terror bird, pelagornithids could fly. They’re sometimes called pseudotooth birds because they had teeth, but they weren’t real teeth. They were pointy projections of the jaw bones that grew along the edges of its beak and were covered with keratin. Pelagornithids evolved around the same time as the terror bird, around 62 million years ago, and didn’t die out until about the same time as the terror bird, around 2.5 million years ago.

And like the terror bird, pelagornithids were huge, but in a different way than terror birds. They were sea birds that may have superficially resembled modern albatrosses, but they were much larger. The largest living albatross has a wingspan of about 11 1/2 feet, or 3.5 meters, but the largest known pelagornithid had a wingspan estimated at up to 21 feet, or almost 6.5 meters. Its wings were narrow and pointed like albatross wings are.

Researchers think that the pelagornithid probably mostly ate soft-bodied animals like squid and other cephalopods, because its teeth were not very strong. It probably scooped its prey up from the water while flying, like many modern seabirds do, although it could probably also sit on the water and dip its long, strong beak down to catch anything that swam too close. Its bones were too delicate for diving. It may have had a throat sac like a pelican too. It was probably white or gray in color and its wings and tail were probably black, which is the most common coloration for sea birds of any kind.

It had short legs but enormously long wings, so long that it probably couldn’t flap them. Its strongest muscles were the ones that held the wings out straight. It was definitely a bird, of course, but it was proportioned more like a flying reptile, Pteranodon, even though they weren’t related. You know what that means, of course. Convergent evolution! Researchers think the pelagornithid spent almost all its time soaring on ocean breezes, scooping up cephalopods and fish to swallow whole, and that Pteranodon probably did the same. These days, modern albatrosses fill that particular ecological niche, and the albatross has many similarities to the pelagornithid too.

Pelagornithids of various species were found throughout the world, from the Arctic and Antarctic to the tropics. It was extremely successful and unlike the terror bird, which was restricted to land, it could travel as far as it liked as long as it had a breeze to keep it aloft. It evolved soon after the non-avian dinosaurs went extinct and didn’t die out until the beginning of the Pleistocene. What happened then? Why aren’t these enormous birds still flying around?

The Pleistocene, of course, was the ice age, or more properly the ice ages. Its onset resulted from a lot of factors, including the movement of continents that changed ocean currents radically. Once the changes started, they accelerated quickly. As more water froze and became massive glaciers that weighted down entire continents, sea levels dropped and more land was exposed, including the Isthmus of Panama that connected North and South America. This would have radically changed the air currents that pelagornithids used to travel around the world, from nesting sites to feeding sites and back. It also drove many sea animals to extinction as their environments became too cold or too warm for them to adapt to, or the water where they lived just dried up completely.

The one place where pelagornithids couldn’t go was across continents. They needed constant sea breezes and lots of water where they could catch prey, and steep cliffs near water to nest on. As the ecological changes of the Pleistocene became more pronounced, pelagornithids had more and more trouble surviving, and finally they went extinct. Modern albatrosses, gulls, and cormorants expanded at the same time to fill the ecological niche left open by the pelagornithid.

While there are no living descendants of pelagornithids, researchers tentatively think they’re most closely related to living ducks, geese, and swans. Since most pelagornithid fossils are badly damaged and fragmented, so that we only have one or two bones preserved from any given animal, it’s hard for scientists to make conclusions as to what they were most closely related to. Hopefully more and better fossils will be found soon so we can learn more about these gigantic birds!

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