Monthly Archives: July 2022

Episode 286: Chimerism, Mosaicism, and Venus the Cat

Thanks to Vaughn for suggesting this week’s episode topic about Venus the cat and her unusual coat pattern!

Further reading:

Mystery Cats of the World Revisited by Dr. Karl P.N. Shuker

Further listening:

Half-siders and sea monkeys Patreon episode from December 2018 (unlocked episode)

Venus the cat:

“Half-sider” birds can be spectacular:

Half-side chimeras are not just restricted to birds:

Ranger the “black lion” (photo by Peter Adamson, from this site which you should also read). Note the black patch on his right front leg:

Show transcript:

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

This week I had planned to release our updates episode, but I didn’t have time to finish it. The 2022 updates episode will run in September instead, since we’re doing Invertebrate August again this year!

Way back at least a year ago and possibly more, Vaughn suggested we do an episode about “rare two-tone animals like Venus the cat.” I put the suggestion on my list and totally forgot about it until today, when I saw it and thought, “hmm, who’s Venus the cat?”

If you don’t already know, Venus is a beautiful cat whose coloration is mostly what’s called tortoiseshell, meaning she has a mixture of colors on her body, in her case black and orange. But Venus’s face is completely black on one side with a green eye, but orange tabby on the other side with a blue eye. She also has a white bib and white on her paws.

Venus became famous after the family who adopted her as a stray in 2009 posted pictures of her online. Her coloration is so unusual that everyone wondered what caused it. The answer is that we aren’t exactly sure, but veterinarians and experts in cat genetics do have some pretty good ideas.

There are probably several things going on genetically with Venus that resulted in her interesting coloration. Her different-colored eyes are one result. When an animal has different-colored eyes, called heterochromia iridis, there are a number of possible causes, from an injury to one eye to various genetic conditions. Sometimes it’s not complete, meaning one eye may be partly a different color. It even happens in people sometimes, although it’s rare.

In Venus’s case, researchers think her heterochromia may be due to a gene that produces what’s called piebaldism. A piebald animal has white markings when an ordinary animal of the same species doesn’t have any white markings. Some animals who naturally have a white pattern may have the word pie or pied or just bald hidden in their name, such as the magpie and the bald eagle, because it used to mean just an outfit with different contrasting colors. In the story of the pied piper, the piper had on a suit made of different colors.

The white patches of a piebald animal actually don’t have any pigment, and if a white patch is over an eye, the eye may also lack pigment and appear blue. That’s pretty common in piebald or pinto horses or in some dog breeds with white markings. The piebald gene may also affect one or both eyes even if a white patch doesn’t cover the eye, which some researchers think may be the case in Venus. Her left eye is blue even though the left side of her face is orange tabby.

Venus’s unusual facial fur coloration may be due to a condition called chimerism. Chimerism happens long before an animal is born—in fact, it happens within a few hours after an egg cell is fertilized. I’ll do my best to explain it. A lot of the next section comes from a Patreon episode from 2018, and if you want to listen to the original I’ve unlocked it for anyone to listen to and put a link in the show notes.

As soon as an egg cell is fertilized, it starts to divide into more cells, which divide into more cells, which divide into more cells, and on and on. After a while, the groups of cells start to differentiate into parts of the body. Some cells become a heart, others become toes, and so on. Eventually there’s a whole finished baby ready to be born or hatched.

If there are two fertilized egg cells, they develop into two separate babies, which are fraternal twins that don’t necessarily look alike. Occasionally, a fertilized egg cell will split and each of the two resulting cells will start to develop separately. In that case, you get identical twins.

But very rarely, you start with two egg cells that should develop into fraternal twins—but for some reason, in those very first hours when each egg cell has only divided a few times, the egg cells fuse together. The cells continue to divide and develop into not two babies, but one that contains the genetic markers for both twins.

Since the resulting single baby has genes for both twins, sometimes it will show physical traits of both twins. For instance, if one twin’s genetic makeup would have developed into a green budgie, and the other twin’s genetic makeup would have developed into a blue budgie, you get a budgie that’s green on one side and blue on the other. Occasionally one side has the markings and coloration of a male, and the other side has the markings and coloration of a female. An animal with this kind of genetic anomaly is properly called a tetragametic chimera, but it’s often called a half-sider.

This doesn’t just happen in birds. Occasionally someone will come across a butterfly where the pair of wings on one side is colored like a male of that species and the pair of wings on the other side is colored like a female. Occasionally someone will adopt a kitten that’s one color on one side and a totally different color and pattern on the other side.

So I bet now you’re wondering if it happens in humans. Yes, it does! It happens occasionally in everything, including plants. Usually no one knows if a particular animal is a chimera because most of the time it doesn’t show. It’s only when it produces a spectacular coloration difference like in half-siders that anyone takes a second look.

Venus’s facial markings look a lot like those of a half-sider, but the markings on the rest of her body don’t, so she’s probably not a half-sider. That doesn’t mean she isn’t a chimera, since while all half-siders are chimeras, not all chimeras are half-siders. However, she might have a genetic mutation called mosaicism instead.

Mosaicism is similar to chimerism, but instead of being caused by two fertilized egg cells fusing together, it’s caused by a chromosomal mutation in one cell during the embryo’s very early development. The mutation is replicated as that cell divides, and then replicated in the divided cells, and so on, so that when the organism has finished developing into a baby, part of its body contains the mutation while the rest doesn’t. The part of the body with the mutation has a different genetic profile from the rest of the body.

Mosaicism can result in various physical conditions, but for the most part you can’t tell by looking if an organism exhibits mosaicism. But sometimes you can. In 1975 a lion cub was born in Glasgow Zoo in Scotland, and he had a big black patch on his chest and right front leg, with a less dark patch on his left hind leg. Since black lions are rumored to exist but have never been scientifically documented, or even photographed, this was a big deal. When Ranger the lion grew up he was introduced to several different females in hopes that he would sire cubs that also had black patches, or which were even black all over. Unfortunately Ranger seemed to be sterile and none of his mates got pregnant.

Ranger lived to be 22 years old but died before genetic testing became widespread and sophisticated. These days we know a lot more about big cat genetics and researchers are pretty sure Ranger’s black patches resulted from somatic mosaicism, which affected some of his skin cells. Since the right side of Venus’ face is solid black, some researchers think she might have a similar condition.

Whatever the cause or causes of Venus the cat’s coloration, though, one thing is for sure. She’s an absolutely beautiful cat!

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

Thanks for listening!

Episode 285: The Mysterious Hueque

This week we have a mystery animal from South America, the hueque!

Further reading:

Llamas are having a moment in the U.S., but they’ve been icons in South America for millennia

Whatever happened to the hueque? Seeking the lost llama of Chile

First complete mitochondrial genome data from ancient South American camelids – The mystery of the chilihueques from Isla Mocha (Chile)

A dressed up person and her dressed up llama (picture from llama article linked above):

The noble guanaco:

Cuddly alpacas!

The noble vicuña:

A 1646 picture of a hueque:

A 1776 engraving of four camelids of South America, including the hueque. The “guemul” in the upper left is actually a llama (the huemul is a type of deer found in a small part of southern Patagonia):

A 1716 engraving supposedly depicting a hueque (central figure) alongside a llama (on the left with the carry-bags over its back):

Show transcript:

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

We’ve done a lot of listener suggestions lately and I still have lots more, but this week let’s look at a mystery animal that I really want to learn more about. It’s a South American animal, specifically from central Chile, called the chilihueque or hueque.

Whether the heuque turns out to be an animal unknown to science or not, it’s definitely a camelid of some kind. Camelids include camels, llamas, and their relations, four of which are native to South America. Those four are the guanaco, the llama, the vicuña, and the alpaca, which are all closely related.

The vicuña lives in high elevations in the Andes Mountains while the guanaco lives in lower elevations. The vicuña is smaller and more delicate than the guanaco. It grows not quite three feet tall at the shoulder, or about 85 cm, with a long, slender neck and small head, and a short fuzzy tail. Its legs are long and slender too. It’s white and light brown with thick, incredibly soft fur that keeps it warm in its mountain home. It eats grass and other plants.

The vicuña lives in small groups, usually consisting of a male, several females, and their babies. When the babies are about a year old or a little older, males leave and initially form small bachelor groups while females leave and form small groups too, called sororities. Eventually both males and females of various bachelor groups and sororities will seek each other out during mating season.

Vicuña wool is extremely soft and fine, and in the days of the Inca Empire, around 500 to 600 years ago, only royalty were allowed to wear clothes made of it. It’s actually not wool like sheep wool but a fiber similar to cashmere from goats or angora from bunnies. Because the vicuña is a wild animal, it has to be captured and its fur cut off, or shorn, but it’s hard to catch. Not only that, since the vicuña is small, it doesn’t give very much fiber so you need to shear a whole lot of the animals to get enough to make a single piece of clothing.

In the olden days, the Inca people constructed traps and worked together to herd vicuña into the traps. Then they would shear the animals and release them again, but only once every four years. These days the practice has been re-instituted by the Peruvian government, although the capture and shearing is done every three years. The fiber is only supposed to be sold outside of Peru after it has been certified by the government as being gathered lawfully and humanely, and most of the money remains with the villagers who gather it. It’s extremely expensive to buy, but unfortunately that means that poachers will sometimes kill the animals to shear and sell the fiber illegally, even though it’s a protected species.

I don’t remember if I’ve ever mentioned this on the podcast, but one of my hobbies is spinning. I can take raw wool from a sheep or fiber from some other animal and turn it into yarn or thread using my spinning wheel or hand spindle, and yes, I have bought legal vicuña fiber and spun it into thread. I bought a single gram of it ages ago, and spun it using a very small support spindle, because the fibers are so fine and short that they’re hard to spin any other way. My single gram produced enough thread to knit into a square about the size of a small handkerchief, which I made for a quilt the handspinning guild I was part of at the time was putting together to showcase all sorts of different animal fibers. It was a pretty amazing quilt, by the way. One woman cut her own hair short and spun her hair into thread which she then wove into a square with a small hand loom. Human hair is actually really coarse when you spin it, because the ends stick out and are prickly.

Anyway, the guanaco is very similar to the vicuña but it’s a larger, more robust animal that’s brown above and white underneath, with a gray face. It’s common in the lower elevations of the Andes and throughout much of Patagonia. It also produces soft fiber, but it’s not quite as fine or soft as the vicuña’s.

The alpaca is the domestic descendant of the vicuña while the llama is the domestic descendant of the guanaco. One interesting thing is that all four of these animals have quite thick skin on the neck. This helps protect their necks from the bites of predators.

All these animals are in the genus Lama, and they all look very similar, like small, delicate camels without humps. But until just a few hundred years ago, there might have been a fifth member of the genus Lama in parts of Chile, the hueque.

As reported by Spanish and Dutch explorers and colonizers, the hueque was a domesticated animal kept for its meat and its fine, soft, very long fur. Its fur was so long that it supposedly brushed the ground. It wasn’t supposed to be the same animal as the guanaco, which lived in the area and was also sometimes kept as a semi-domesticated animal. It was smaller than a llama or guanaco but larger than a vicuña, standing up to four feet tall at the shoulder, or about 1.2 meters.

As more Spanish colonized Chile and other parts of South America, bringing sheep and cattle with them, the hueque became less and less common. Not only did the introduced animals compete with the hueque and other South American camelids for resources, they brought diseases that camelids could catch. Eventually the local people switched to raising sheep for wool and meat and the hueque was supposed to have died out completely by the late 18th century.

Many people have suggested that the hueque was actually another word for the alpaca, which did decline in numbers during this time, although of course it didn’t go extinct. The hueque might have been a particular variety of alpaca or even a subspecies that looked somewhat different. Remember that the alpaca is a domesticated animal descended from the vicuña. Other people hypothesize that the hueque was a type of llama or guanaco, and remember that the llama is the domesticated descendant of the guanaco.

In December of 2016, the scientific journal Nature published a genetic study of camelid remains found on Isla Mocha, a volcanic island off the coast of Chile. The people living on the island in the early 17th century kept hueques, according to reports of Dutch and Spanish explorers. People have lived on the island for about 1,500 years but the hueque probably didn’t. Instead, it was transported to the island in small boats on special occasions, to be used as ritual sacrifices where the meat was then eaten. Then again, there is at least one report that the animal did live on the island and was used to pull plows or possibly wagons.

A 1615 report by a Dutch captain who saw the hueque is that it was like a “sheep of a very wonderful shape, having a very long neck and a hump like a camel, a hare lip and very long legs.” This is strange because while it is otherwise a good description of any South American camelid, no South American camelid has a hump like a camel. The hump the captain reported might actually have been thick fur that can look a little bit like a hump above the shoulders.

The 2016 report looked at DNA samples extracted from the subfossil remains of 14 camelids found on the island, including the complete genomes of three individual animals. Then the samples were compared to those of other South American camelids. They most closely matched the DNA profile of the guanaco.

The study suggests that “chilihueque” was the local term for the guanaco, especially a guanaco kept as a domesticated or semi-domesticated animal.

That’s just one study of one specific island, of course. Hopefully genetic analysis of other camelid remains will be made soon and we can learn more about what exactly the hueque might have been.

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

Thanks for listening!

Episode 284: Billy Possum and Teddy Bear

Thanks to Pranav and Zachary for their suggestions this week, where we learn the story behind two cuddly toys and the animals that inspired them!

The cartoon that inspired the toy:

My own teddy bear:

An American black bear (not William Taft although yes, there is a resemblance, including a willingness to eat entire possums in one sitting):

William Taft:

A Virginia opossum:

A possum with babies!

Stop trying to make Billy Possum a thing:

Admittedly it was pretty cute:

Show transcript:

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

This week we’re going to learn about two cuddly animals, one of which you’ve definitely heard of, the other you might not have. Oh wait, you’ve heard of both animals for sure—but you might not have heard about the toys based on the animals. Thanks to Pranav and Zachary for their suggestions.

The president of the United States at the beginning of the 20th century was Theodore Roosevelt, who served from 1901 to 1909. He was sometimes called Teddy instead of Theodore, although he didn’t actually like the nickname. Roosevelt is widely considered to have been a very good president, as well as an interesting and sometimes eccentric man, but his main contribution to history as far as most people are concerned is the teddy bear.

Roosevelt was an active man who spent a lot of time horseback riding, playing tennis, hiking, swimming, boxing, and lots of other things. He also liked to read, spoke several languages, and wrote poetry—and he was an avid hunter and would travel the world to kill things. That’s what he was doing in November 1902, when the governor of Mississippi invited him on a bear hunting trip.

The hunting party killed several bears that day, but Roosevelt hadn’t shot anything. Some of the president’s attendants decided to help things along, and they chased a bear down with hounds until it was exhausted, beat it until it was almost dead, and tied it to a tree. I know, this is awful. I’m sorry. Then they said, “Hey, Mr. President, we found you a bear to shoot.”

Not only did Roosevelt refuse to kill the bear, he was angry at the people who had treated it so badly. He requested that the poor animal be shot to put it out of its misery, since by that point it was already dying from its treatment.

Because Roosevelt was the president, everything he did made its way into the newspapers, including this event. A political cartoonist used the bear hunt in a cartoon, only instead of an adult bear he made the bear a cute little cub. This inspired an inventor named Morris Michtom and his wife Rose to make a little bear cub doll to sell at their candy shop in Brooklyn, New York. They labeled it “Teddy’s bear” and the rest is history.

Most teddy bears don’t look much like an actual American black bear. The black bear lives in forested areas throughout much of North America and used to be even more widespread, but was hunted to extinction in many areas. It’s more closely related to the Asian black bear than it is to other bears found in North America, including the grizzly and polar bears. Its fur is usually black although some black bears are gray, various shades of brown, or sometimes even a rare cream color. The biggest American black bear ever measured was just barely under 8 feet long, or 2.41 meters, and probably weighed 1,100 pounds, or 500 kg. Most black bears are a lot smaller than that, though.

Black bears mate in summer but the fertilized egg cells don’t start developing until November. This gives the female plenty of time to gain lots of healthy weight before she finds a safe place to spend the winter. Black bears hibernate in cold weather, although scientists are still debating whether its metabolic changes constitute true hibernation. A bear will use a hollow tree or small cave as a den, or will dig a den. It gets comfortable in its den and soon its heart rate starts to drop until it only beats about 8 times a minute. Its body temperature stays about the same as usual and unlike many other animals that hibernate, it’s not sound asleep the whole time. It spends a lot of time awake and may even get up and move around, maybe even go out on nice days and look for food. Mostly, though, a hibernating bear doesn’t eat or drink, and it doesn’t need to defecate or urinate. Once the weather starts warming up, it emerges from its den and spends a few weeks just roaming around, eating whatever it can find while its body returns to non-hibernation status.

Babies are born during the winter, and they’re extremely small and underdeveloped at birth, only about 8 inches long on average, or 20 cm. A mother bear usually has two or three cubs, sometimes just one and occasionally four. The mother bear nurses her babies and keeps them warm through the rest of the winter, and once the weather warms up they’re big enough to come outside with her for the first time.

The American black bear is an omnivore, but it eats a lot more plant materials than it does meat. It especially likes berries and other fruit. It also eats a lot of insects, including ants, bees, and an especially nasty type of wasp called a yellow jacket. The bear has thick fur to help protect it from stings, but it also eats up the insects really fast. You can’t sting a bear if a bear just crunched you up with its big teeth. The black bear will catch fish whenever it can, will eat fawns and other baby animals when it can find them, will eat small animals like rodents when it gets the chance, will eat eggs when it comes across a nest, and will eat carrion, especially when it first emerges from hibernation.

Although black bears are dangerous, they’re also shy and avoid people when they can. The exception is when they get used to people food, either because they were given food by people, or because they found food that people left. That’s why it’s so incredibly important to never feed wild animals, especially dangerous ones like bears, and why you should learn how to properly hang your backpack from a tree when you’re camping so a bear can’t get it. If a bear learns to associate humans with food, it will become aggressive. When that happens, forest rangers have to make the hard decision to kill the bear before it hurts or kills a person.

While other species of bear growl, the American black bear doesn’t. The closest it comes to a growl is a deep call it makes in its throat, and it also makes huffing sounds, moans and grunts, squeals, clicks and pops that it makes with its mouth, including tongue clicking, and when it’s comfortable a bear may make a rumbling sound something like a hum or a purr.

This is what a black bear sounds like:

[bear sounds]

So, back to teddy bears. Plush toy bears were incredibly popular while Teddy Roosevelt was in office, but toy manufacturers were pretty sure the fad would drop in popularity once Roosevelt was no longer president. William H. Taft became president after Roosevelt, and in January 1909 he attended a banquet in Atlanta, Georgia where the main course served was possum and sweet potatoes.

These days most people don’t eat the Virginia opossum, more commonly called the possum in the United States, but it used to be considered a delicacy. Taft wolfed down an entire roast possum by himself, so fast that a doctor sitting at the table with him said he needed to slow down. Taft liked his food and he especially liked possum, and when his supporters presented him with a plush toy possum after the meal, he found it amusing.

But the people who’d given him the toy possum weren’t playing around. Ha ha, get it? Playing? Toy? They were certain their possum was going to be the next big thing. They formed a company called the Georgia Billy Possum Company and advertised the toys with the slogan, “Good-bye, Teddy Bear. Hello, Billy Possum.” They also released postcards, pins, songs and sheet music, and all sorts of other stuff branded with Billy Possum in hopes of hyping up their toy and becoming millionaires.

The problem, of course, is that while everyone cared about the poor bear that Roosevelt refused to kill, no one cared that Taft could eat a whole roast possum in one sitting. Besides, Taft was boring. Billy Possum never took off and people kept their teddy bears.

In many articles about Billy Possum, the whole idea of a possum being cute enough to make a cuddly toy from is laughed at. But possums are adorable! The Virginia opossum is a nocturnal marsupial that lives throughout much of the eastern United States, especially the southeast, and just about all of Mexico. It’s gray and white with a bare pink nose and bare pink toes, and it also has a long prehensile tail that’s mostly bare of fur that it uses to help it climb around in trees. Most possums are about the size of a cat but with much shorter legs. It’s the only marsupial that lives in North America.

The possum is omnivorous and eats fruit, carrion, eggs, nuts, vegetables, insects, and other small animals like mice and frogs. It’s resistant to the venom of snakes, bees, and scorpions, and will happily eat all three of these types of animals. It’s even less picky than the bear about what it eats and will genuinely eat pretty much anything, from birdseed and cat food it finds in people’s yards, to crayfish and baby rabbits, to ticks and persimmons, to slugs and snails.

The possum doesn’t live very long, and pretty much anything that can catch it will eat it, but it reproduces efficiently. Like other marsupials, the female has two vaginas and wombs and the male has a double penis. The female can have more than 20 babies at a time, although 8 or 9 is more common, and like other marsupials they’re born extremely early. The newborn babies are the size of a bean or a honeybee, but they’re strong enough to crawl into their mother’s pouch to find a teat. Since the possum has 13 teats, and each baby needs a teat to stay latched onto while it finishes developing, even if the mother has more than 13 babies, only 13 babies will survive.

The babies stay in their mother’s pouch for 2 1/2 months, at which point they start riding on her back instead. She carries them around for the next couple of months, teaching them how to be possums.

The possum has one real defense against predators, which it only resorts to when running away or hissing with its fur puffed up doesn’t help. It will flop onto its side with its tongue hanging out but its eyes open, and its heart rate drops and its breathing becomes shallow and slow. It also expels a stinky fluid from its anal glands. In short, it looks, acts, and smells like it’s already dead. It’s called “playing possum,” and it actually works pretty well…until the possum plays dead when threatened by a car. That’s why possums are so often killed by cars.

Many people think the possum is dirty or carries diseases, but this isn’t actually true. The possum grooms its fur and keeps it clean, and it’s actually less likely to have a disease than many other mammals. It’s even resistant to rabies, possibly because its body temperature is lower than that of most mammals and this helps keep the rabies virus from reproducing.

The Virginia opossum also has a secret that scientists only recently discovered. Its fur glows bright pink under ultraviolet light. No one is sure why.

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

Thanks for listening!

Episode 283: Crocodylomorphs and Friends

Thanks to Max and Pranav for their suggestions this week! We’re going to learn about some crocodylomorphs and a few other ancient non-dinosaur reptiles.

Further reading:

Mammal-like crocodile fossil found in East Africa, scientists report

Ancient crocodiles walked on two legs like dinosaurs

Fossil Footprints Help Uncover the Mysteries of Bipedal Crocodiles

Fossil mystery solved: super-long-necked reptiles lived in the ocean, not on land

Kaprosuchus had TEETH:

Anatosuchus earned its name “duck crocodile”:

Ancient bipedal croc footprints (picture taken from link above):

Tanystropheus had a super long neck:

Show transcript:

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

This week we’re going back in time to learn about some prehistoric reptiles that aren’t dinosaurs. Most are crocodylomorphs, which Pranav suggested a while back, but not all. Thanks to Pranav and Max for their suggestions this week! Max even made some clay models of two of these animals and sent me pictures, which was amazing! I have some really talented listeners.

Pranav and Max both wanted to know about kaprosuchus, also called the boar crocodile. The boar croc lived around 95 million years ago and probably grew nearly 20 feet long, or 6 meters, although all we know about it right now comes from a single nearly complete fossilized skull. The skull was found in Niger, a country in West Africa, and only described in 2009.

The boar croc gets its name from its teeth. It had lots of teeth, because it was a crocodyliform, although not actually an ancestral crocodile. It was related to modern crocs, though. Three sets of its teeth were especially long and large and projected out of its mouth much farther than ever found in any croc or croc relative, with one pair of teeth so big the upper jaw had little grooves for them to fit into so it could actually close its mouth. The teeth look like boar tusks, especially warthog tusks.

The boar croc also had some other differences from other croc relatives. The tip of its snout is unusually heavy, and some researchers think it might have had a keratin sheath over it. It might have used its heavy snout as a battering ram, possibly to stun prey before grabbing it with its huge teeth. It most likely hunted on land instead of in the water, since its eyes were lower on its head than crocs that hunt in water. Modern crocodiles and their relations mostly have eyes at the top of the head, which allows them to stay submerged except for their eyes. Whether it hunted in water or on land, though, the boar croc definitely killed and ate small dinosaurs, or maybe not so small dinosaurs.

The boar croc also had some horn-like projections on the back of its head. I don’t want to alarm you, because this animal went extinct millions and millions of years ago, but this thing was basically a dragon.

Anatosuchus was another crocodylomorph whose fossils have been found in Niger, but it’s much smaller and weirder than you’d expect. It was a tiny little thing, estimated to grow only a little more than 2 feet long, or 70 cm, and it was lightly built with relatively long legs for a croc relation, although it was still smaller than a cat. Its small teeth curve backwards but its snout has a little pointy projection at the front, although its head is broad and flat so that from above, its snout looks kind of like a duck’s bill. That’s why it’s sometimes called the duck crocodile. It lived around 145 million to 100 million years ago. Researchers think it may have waded in shallow water to catch small animals like fish and frogs, something like a heron.

Around 105 million years ago, another small croc relation lived in what is now Tanzania in East Africa. It was first discovered in 2008 and has been named Pakasuchus, which means cat crocodile. It was even smaller than the duck crocodile, only 20 inches long, or 50 cm, with long legs and a delicate build. The really weird thing, though, is its teeth. Unlike other crocodile relations and in fact unlike reptiles in general, it had teeth that were specialized for different functions. Its teeth looked like they belonged to a mammal. It had sharp teeth at the front of its short jaws and broader teeth in the back of its mouth that it used to chew its food. It was a terrestrial animal that would have been active and fast-moving. It probably ate insects and other small animals, but some researchers think it may have eaten plants.

There were definitely some croc relatives that were herbivorous, like the aetosaurs. Aetosaurs lived a little over 200 million years ago and were a successful group, with fossils found in Europe, India, Africa, and North and South America. They had osteoderms that are really common in the fossil record, so common that they’re used as index fossils to date fossil sites. If you’re not sure how old a layer of rock is, and you find some aetosaur osteoderms, you can be pretty certain you’re looking at the late Triassic. The osteoderms are flattened like big scales, and in fact when they were first discovered, people thought they were actually fish scales. Aetosaurs were probably terrestrial animals and most were either herbivorous or omnivorous, although at least one known species had the kind of teeth that indicate it hunted small animals.

A typical aetosaur had a small head and a bulky body with relatively small front legs but stronger hind legs. Its tail was long and tapering like a modern crocodile’s tail. It had lots of armor in the form of interlocking osteoderms, including armor on its belly and the underside of its tail. It might have looked like it had a carapace something like a weird reptilian armadillo. Depending on its species, our typical aetosaur may have also had spikes or spines on its back sort of like modern crocodiles have.

One species of aetosaur, Desmatosuchus spurensis, had massive shoulder spikes. Desmatosuchus grew almost 15 feet long, or 4.5 meters, and was heavily armored, with a spike on each shoulder blade. The spikes curved up and out kind of like a bull’s horns, but instead of pointing forward, they pointed backwards. It also had smaller spikes down its sides, some of which pointed out, some up. The big shoulder spikes could be almost a foot long, or 28 cm.

If you look at Desmatosuchus’s skeleton, it looked like it must have been a dangerous animal, and this would have been true when it comes to worms and plants. Its head was small and ended in a shovel-like snout, probably covered in a keratin sheath like a turtle’s beak. Scientists think it probably used its snout to dig plants up from soft mud along waterways, and it would probably also eat any small animals it found in the mud too. It lived in groups and despite its size and all its spikes, it got eaten a lot by an even bigger reptile, Postosuchus.

Postosuchus wasn’t a dinosaur, and was in fact a crocodylomorph just like the other reptiles we’ve talked about so far, but it sure looked like a dinosaur in a lot of ways. Its front legs were about half the length of and not very strong compared to its hind legs, so it probably walked on its hind legs only. It also had an oversized claw on one of its toes that it probably used to slash at prey, while its big head had a mouth full of big, sharp teeth. In other words, it looked a lot like a theropod dinosaur and lived at about the same time as the first theropods.

Despite not being a dinosaur, Postosuchus was one of the biggest land animals around, growing up to about 23 feet long, or 7 meters, although it probably only stood about 4 feet high, or 1.2 meters. Its remains have only been found in North America.

Other bipedal croc relations have been found in Asia, though, specifically in South Korea where almost 100 beautifully preserved footprints have been found. The tracks are of hind feet only, and from their size, depth, and the length of stride, the animals were probably almost 10 feet long, or 3 meters, and had hind legs the length of an average adult human’s legs. The footprints are almost 9 ½ inches long, or 24 cm.

At first researchers thought the tracks belonged to giant pterosaurs, which were flying reptiles, and that the pterosaurs were walking on their hind legs so their wings would stay out of the mud. But the footprints are so well preserved that it was obvious they belonged to a crocodylomorph once paleontologists examined them closely. In fact, all footprints supposed to belong to pterosaurs walking on their hind legs have turned out to belong to bipedal croc relations. Pterosaurs had to use their wings as front legs when walking on the ground, like bats do but not like birds, and some crocs, which ordinarily walk on four legs, were walking on two. It’s topsy-turvy land!

The tracks in South Korea are dated to a little over 113 million years ago, which is something like 100 million years more recent than Postosuchus. Postosuchus went extinct around 201 million years ago, at the end of the Triassic. By the time the Korean croc relation was walking around, it was the middle of the Cretaceous and dinosaurs ruled the earth. Gondwana was breaking up, the climate was warm worldwide and sea levels were high, mammals were tiny and unimportant, and little birds were flying around along with gigantic pterosaurs like Quetzalcoatlus. Crocodile relations lived in the mid-Cretaceous, sure, but not bipedal ones…or so paleontologists thought.

All we have of these croc relations are their tracks. We don’t have any fossils so we don’t know what they looked like. Hopefully one day some fossils will come to light and paleontologists will be able to match them up with their footprints.

Max specifically asked about Titanoboa, a gigantic extinct snake that lived around 58 million years ago in what is now northern South America. We talked about Titanoboa in episode 197 but I was certain I could find some new information for this episode. Unfortunately, there haven’t been any new studies about Titanoboa published recently, so Max, I’m going to keep it on the suggestions list until I find some interesting new information to share.

Titanoboa is estimated to have grown as much as 42 feet long, or 13 meters, and it probably spent most of its time in the water, eating giant lungfish and other animals. But, to wrap things back around to crocodylomorphs, it probably also ate a croc relation called Cerrejonisuchus. Cerrejonisuchus had a short, narrow snout and probably ate lots of frogs, fish, and other small animals. It grew a little over 7 feet long, or 2.2 meters, which is small but respectable for a crocodile but nowhere near big enough to make Titanoboa think twice about eating it. It wasn’t even the biggest croc relation living in its river habitat. Acherontisuchus grew to an estimated 21 feet long, or almost 6.5 meters. It had a long snout and lots and lots of big teeth, and probably ate the same fish that Titanoboa also liked.

Let’s finish with a non-crocodylomorph ancient reptile, Tanystropheus, and two mysteries associated with it that science solved in 2020. Tanystropheus lived during the mid to late Triassic, around 240 million years ago, and its fossils have been found in parts of Europe, the Middle East, and in China. It grew up to 20 feet long, or 6 meters, but literally half its length was its incredibly long neck.

When the first Tanystropheus fossils were discovered in the 19th century, paleontologists didn’t know what it was. There were some long, thin bones associated with the skeleton and they thought those might be elongated finger bones. Tanystropheus was classified as a type of pterosaur. But as more and better fossils were discovered, it was obvious that this animal wasn’t flying anywhere. The finger bones were actually cervical ribs, rod-like structures that helped stabilize the long neck and keep it from bending very far.

Tanystropheus was reclassified as a long-necked reptile, but no one was sure if it lived in water or just around water. Even more confusing, fossils of smaller long-necked reptiles, only about 4 feet long, or 1.2 meters, started being found too. No one was sure if this was a different species or juvenile Tanystropheus specimens.

To solve the first mystery, a research team took CT scans of some complete but crushed Tanystropheus skulls and generated a 3D image, which allowed them to put the pieces together and examine an image of a complete, un-crushed skull.

The skull had nostrils at the top of its snout, indicating that it probably spent a lot of time in the water. Some researchers suggest it was an ambush predator in shallow water, resting on the bottom of the ocean with its long neck raised so its nostrils were just above the surface. When a fish or other animal swam by, it could grab it without needing to move more than its head. Since its body was chonky with short legs, it probably wasn’t a very fast mover.

Next, the team took cross sections of bones from the smaller long-necked reptile and examined them for growth rings. They found a lot of them, indicating that the animals weren’t juvenile Tanystropheus hydroides, they were adults of another species, which has been named Tanystropheus longobardicus. The two species also had differently shaped teeth, which suggests that they were eating different types of food.

Even though Tanystropheus’s neck was really long, it was also much lighter than the rear half of its body, which had strongly muscled hind legs. Some researchers think it swam by kicking its hind legs sort of like a gigantic frog’s. We have some fossilized trackways from a shallow marine environment that show paired prints from hind legs, but no front leg prints, which may be from a small species of Tanystropheus.

There’s still a lot we don’t know about Tanystropheus, just as there’s a lot we don’t know about a lot of long-extinct animals. All we know for sure is that they were awesome.

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