Strange Animals Podcast

Photos of a mangy fox that make it look like it has stripes:

Show transcript:

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

Buderim is a small city in Queensland, Australia, right on the coast but extending up the side of a small mountain. It looks like an especially beautiful place in a beautiful part of the world, but in the 1990s it was in the news due to sightings of a strange animal.

The animal was dubbed the Beast of Buderim by reporters. It all seems to have started in 1993 when a local artist was driving with her husband and saw a striped animal run across the road. She thought for certain it was a Tasmanian tiger, more properly called a thylacine. When she got home, she drew what she’d seen. It looks like a foxlike animal with black stripes, a long whiskery muzzle, and a long thick tail.

In March of 1995 a local dentist and his ten-year-old daughter saw the animal while driving along the edge of the local rainforest one evening. It was dark but his headlights lit it up and he was able to give a good description of it. He said it was medium-sized, presumably meaning about the size of an average dog, and had stripes that were sort of like a tabby cat’s markings but somewhat like a brindled dog’s markings. He described its coat as goldy in color. He also said it had a pronounced bump above its eyes, although I’m not sure if he meant it had a bumped-up forehead or if he was referring to a brow ridge of some kind. The animal was standing on the road, but when the car approached, it arched its back and then ran into the trees.

Another sighting occurred in August of 1995, but not near Buderim. A man in Bundaberg, a city over 130 miles away from Buderim, or 210 km, was driving at night and had to brake hard to avoid hitting a gray kangaroo as it bounded across the road. A moment later a large animal leaped onto the road after the kangaroo. In the glare of the headlights, the man reported that the animal was sandy in color with stripes that started about halfway down its back, and that its eyes glowed green-yellow. It was big too, four or five feet long, or 1.2 to 1.5 meters, not even counting its long, thick tail. It also had long jaws that the man said reminded him of a crocodile’s when it snarled at him. It made another huge leap and disappeared into the brush.

Plenty of other sightings have been reported from around Buderim and other parts of Queensland, with the most recent in 2014 turning out to be a mangy fox. This is the same area where a different striped animal, usually called the Queensland tiger, was first reported in 1871 and occasionally spotted afterwards. Sometimes people confuse the Beast of Buderim and the Queensland tiger. We talked about the Queensland tiger in an episode a long time ago—I don’t remember which one, but I do remember there not being much evidence that it was a real animal.

Some people think the Queensland tiger is a descendant of an extinct animal called Thylacoleo [thyla-CO-leo], while the Beast of Buderim is supposed to be a thylacine.

Thylacoleo is sometimes called the marsupial lion, although it looked much different than a lion. It had a strong kangaroo-like tail that it could use as a balance to help it stand on its hind legs. Its front legs were extremely strong and it actually had a semi-opposable thumb that helped it grab onto prey. Its front claws were retractable like a cat’s claws too, an excellent example of convergent evolution. All these traits also meant that Thylacoleo could climb extremely well. It might not have been a very fast runner, though, and some researchers think it was an ambush predator, possibly dropping down from trees onto its prey. The largest species, Thylacoleo carnifex, stood over two feet tall at the shoulder, or 71 cm, and was heavy for its size.

Not only that, Thylacoleo had massive jaws with huge weird teeth. Its cheek teeth were enormous, basically just one giant tooth on each side. Its other teeth were much smaller in comparison and not very strong, but those giant cheek teeth and its strong jaws meant that Thylacoleo could bite right through meat and bones with no problem.

We don’t know for sure what Thylacoleo looked like, but we do have two separate pieces of rock art that probably depict it. They show it with pointed ears instead of rounded ones and stripes on its back.

Thylacoleo was an apex predator in the food web of Australian megafauna during the Pleistocene, and like many of the megafauna predators in other parts of the world, Thylacoleo required giant prey. When its prey started to go extinct due to climate change toward the end of the ice age, along with the arrival of humans who hunted megafauna efficiently, eventually Thylacoleo didn’t have anything to eat. It was too well adapted for killing large prey to switch over to smaller prey, and more nimble small predators out-competed it. We’re not sure when it went extinct, but the best guess right now is about 30,000 years ago and possibly 40,000 years ago. It’s definitely not alive today, no matter how awesome that would be.

But that’s all beside the point, because most people who have reported sightings of the Beast of Buderim say it looks like a thylacine. We talked about the thylacine in episode one and then I’ve hardly mentioned it, so let’s learn a bit about it now.

Unlike Thylacoleo, the thylacine went extinct less than a century ago, and we know exactly what it looked like, where it lived, and why it went extinct. We have photographs and even video of living thylacines kept in captivity. The last thylacine reported in the wild was shot and killed in 1930, while the last captive specimen died in 1936. People have reported sightings since, but no definitive proof of a living thylacine has been found despite lots of people searching for it. It was officially declared extinct in 1982.

The thylacine looked superficially like a canid and was about the size of a big dog, with a long body and long, somewhat cat-like tail although the tail was stiff, not flexible like a cat’s. The thylacine was tan or brown in color with darker stripes that started just behind the shoulders and continued down the hindquarters and down the tail. It had large, somewhat rounded ears, a long muzzle, and jaws that could open extremely wide.

The thylacine looks like it should be a scary animal, and European settlers certainly acted like it was a monster that killed sheep and other large livestock. In reality, though, it was a timid animal with weak jaws that mostly ate small animals like a flightless bird called the Tasmanian native hen. It would definitely kill domestic chickens but it certainly wasn’t killing sheep. It also couldn’t run very fast, although it could stand on its hind legs for short periods of time.

That didn’t stop the Tasmanian government from offering a bounty for dead thylacines. Bounties started as early as 1830 and a century later the thylacine was extinct. Hunting was only part of the problem, though. Habitat loss was an increasing issue as more and more wild land was converted to farmland, and introduced predators like foxes and dogs competed for food and sometimes killed the thylacine. The thylacine’s preferred prey was also declining in numbers for the same reasons. As if that wasn’t bad enough, a disease similar to distemper decimated wild and captive thylacines, possibly because the remaining population was weakened by a lack of genetic diversity.

One interesting thing about the thylacine is that both males and females had a pouch. Like other marsupials, the female’s pouch was where her babies finished developing after they were born. Her pouch was under her tail and opened toward the rear of the body, as in wombats, which is somewhat rare. It contained four teats. The male’s pouch was in the same place and is called a scrotal pouch. The male could withdraw his scrotum into the pouch to protect it when he was traveling through tall brush.

The thylacine only survived in Tasmania until its recent extinction. It had once been common in mainland Australia too but probably went extinct there at least 2,000 years ago and probably closer to 3,000 years ago. There’s no conclusive proof that it survived in Australia until modern times and no conclusive proof that it lives there now. But Queensland is in Australia and that’s where the beast of Buderim has been sighted. Could the beast be a relict population of thylacines?

The August 1995 sighting at first seems plausible, since it’s so detailed and the description matches the thylacine. But remember, the thylacine wasn’t a very fast animal, mostly ate quite small prey like birds the size of chickens, and didn’t seem to be very aggressive. It certainly wouldn’t be chasing a full-grown male gray kangaroo, as the witness reported. The eastern gray kangaroo is a large, muscular animal that can bound extremely quickly, up to 40 mph, or 64 km/hour, and has sharp claws on its hind feet. A male can stand 6 ½ feet tall, or almost 2 meters.

Aside from humans, the gray kangaroo’s only living predator is the dingo, a canid introduced to Australia by humans over 8,000 years ago. We talked about it in episode 232. The dingo is usually tan or reddish in color and it carries its tail low, not curved upward. It also has pointed ears.

It doesn’t have stripes, though, and the stripes are a common detail in all the beast of Buderim sightings. But there are a number of possible solutions that don’t involve thylacines. The dentist’s sighting from 1995 might easily have been a big domestic cat. The dentist even reported that it had tabby-cat markings and that it arched its back when it saw the car. Size can be hard to estimate in darkness, especially when you’ve seen something unexpected.

The artist’s sighting in 1993 is less detailed. We have her drawing of the animal but we don’t know whether she saw it in daytime or at night. She saw it run across the road, which means that even if it was broad daylight she probably didn’t get a great look at it. I suspect a lot of the details she included in her drawing were things she expected to see, not things she actually necessarily saw. That doesn’t mean she was lying, just that her brain was filling in details without her even being aware of it. I think she saw a fox.

As for the August 1995 sighting, where the animal was chasing a kangaroo, I think that witness saw a dingo.

But wait, you may be thinking, neither foxes nor dingos have stripes! We’ve established their lack of stripes already.

To solve the mystery of the stripes, we have to look at another reported sighting. This is the most recent one, from 2014. The animal in question turned out to be a mangy fox, but it also definitely looked like it had stripes. We know because the witness got photographs, and the photographs show a scruffy fox with a thin tail and what look like thin dark stripes along its sides. All the beast of Buderum witnesses described their animals as looking brindled, and the marking known as brindled in dogs and a few other animals consist of thin dark stripes that are fairly close together.

Many things can make an animal look like it has brindled stripes, including poor coat quality, a coat that’s damp from rain or fog, or a coat that’s so thick it’s almost quilted and is therefore likely to appear unusual in bright headlights. The August 1995 sighting happened in wintertime in Australia, when a dingo might be expected to have a thick undercoat.

Whatever the animals were that witnesses reported, I don’t think they saw thylacines. That doesn’t necessarily mean they didn’t see something mysterious, though. There might be some rare striped animal in Queensland that gets seen occasionally and mistaken for a thylacine. It’s just much more likely that foxes, dingoes, and other known animals are the actual Beast of Buderim. But I would love to be proven wrong!

Thanks for your support, and thanks for listening!

Further reading:

Scientists solve a shark murder mystery

Stone Age Animal Urine Could Solve a Mystery about Technological Development

South African rock art possibly inspired by long-extinct species

The porbeagle shark [photo by Andy Murch, taken from this site]:

Dicynodont fossils and their possible art interpretation by the San people:

Show transcript:

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

It’s finally monster month, and I’m looking forward to sharing lots of fun mystery animals and animal mysteries over the next four weeks.

Our first mystery is from an article titled “Scientists solve a shark murder mystery.” The word solve is doing a lot of heavy lifting in this case, but let’s find out what happened to the shark.

The shark in question was a porbeagle shark, a type of mackerel shark that can grow as much as 12 feet long, or over 3.5 meters, and is gray and white in color. It lives in cold water in the North Atlantic and around Antarctica, and it eats fish and cephalopods like squid. It hardly ever bothers people although people like to eat it, and in some regions it’s been so overfished that the species is listed as endangered.

The porbeagle is especially unusual because it’s able to thermoregulate to some degree, like the basking shark and some other sharks that we talked about in episode 353, about warm-blooded fish. The porbeagle is actually really good at keeping its brain, eyes, and internal organs warm, which is why it’s so successful in cold water. It can live to be at least 65 years old.

There’s still a lot we don’t know about the porbeagle, including where exactly it lives and how far it migrates throughout the year. A team of scientists has been tagging porbeagle sharks with little transmitters, like shark Air Tags, to find out where the sharks travel and other information, like how deeply they dive and what the water temperature is. The transmitter is attached to a shark’s fin and is designed to stay in place for a year, then detach and transmit all the information it’s gathered as soon as it floats to the water’s surface.

In October 2020, the scientists captured an 8-foot, or 2.5 meter, female porbeagle and fitted her with a transmitter before releasing her again. They were especially happy to see that she was pregnant, partly because the porbeagle is endangered and reproduces slowly, partly because they were interested to find out where a pregnant shark traveled.

About six months later, in April 2021, the tag began to transmit its information. It was too early for it to have detached on its own, but sometimes something happens to a tag and it ends up removed from the shark before it’s scheduled to.

The team’s lead scientist, Brooke Anderson, examined the transmitter’s information and knew something weird had happened to the shark. Everything seemed normal until about a week before the tag began to transmit, when the tag indicated a slight but steady increase in the temperature of its surroundings, even though it was still deep underwater. Anderson suspected that the shark had been killed and eaten at that point, and the tag ended up inside the body of another animal that was able to thermoregulate. When the transmitter was expelled from the predator’s body, it floated to the surface and did what it was designed to do, transmit its saved information.

But while the porbeagle isn’t a huge shark, it’s still big and dangerous. It’s also a fast swimmer. Something really big had to have attacked the shark.

The first thing Anderson suspected was an orca, but she and her team immediately rejected that theory. Orcas are mammals, which means an orca’s internal temperature is much higher than the tag had recorded. That narrowed the suspects down to another shark that’s able to thermoregulate, but it also had to be a really big shark. They decided in the end that the porbeagle was probably eaten by a great white.

Next, we need to learn a little about the rock hyrax, because a deposit of ancient rock hyrax urine is helping scientists learn more about our own prehistoric ancestors.

The rock hyrax looks like a weird rodent but it’s actually more closely related to dugongs, manatees, and elephants. I’m literally not even kidding. Hyraxes are native to Africa although the rock hyrax also lives in parts of the Middle East. It’s also called the dassie. It’s a chonky animal with a short tail and thick fur, small rounded ears, and nails instead of claws. Even a big male rock hyrax grows less than two feet long, or 50 cm, about the size of a small marmot or groundhog, which it resembles superficially. It eats plants.

The rock hyrax lives in family groups of one male and several females, along with their young offspring. It doesn’t dig a burrow but lives in holes and shelters it finds already dug, including caves, and that brings us to the sort-of mystery.

Like many animals, the rock hyrax tends to pee in the same place every time it needs to go, and a group of hyraxes living in the same shelter tend to all pee in the same place. A good shelter, like a cave, will get used by generation after generation of hyraxes. The rock hyrax is well adapted to dry areas and its kidneys are efficient. It doesn’t need a lot of water. As a result, its urine tends to be fairly thick and it also hardens quickly when exposed to the air.

In other words: rock hyraxes have been peeing in one part of Boomplaas Cave in South Africa for at least 50,000 years, and that urine is preserved in thin layers that contain pollen and other clues about the climate over the last 50 millennia. The urine can be carbon dated, too. That means scientists can cut samples from that huge deposit of ancient urine, determine how old each layer is, and examine the pollen trapped inside to learn what kind of plants were growing in the area at the time. That helps them determine what the climate was like, which in turn helps them learn more about the ancient humans who lived in the area too.

Until the samples were tested in 2022, the changes in South Africa’s climate over the last 50,000 years wasn’t well known. Now we have an unbroken record of the climate. The main problem is that the urine smells really, really bad. Like, really really bad. But it’s worth it, for science.

Let’s finish with another mystery from South Africa. Around 200 years ago, between 1821 and 1835, some artists among the San people painted an interesting animal on a rock wall. It’s not the only part of the painting, which contains art of other animals and various cultural elements, but it’s the only animal that can’t be identified as something real.

Of course, you can’t study art the same way you’d study a fossil. If you draw a dragon from your imagination, that’s art. If a scientist comes along 200 years later and tries to claim that dragon was based on a real animal that had four legs and two wings and could breathe fire, they’re misunderstanding what art is. But if that same scientist looked at your drawing along with the journal you kept at the same time telling about how you visited the zoo, they might suggest that your drawing was inspired by the crocodiles and monitor lizards you saw.

That’s what Julien Benoit thinks about the painting of an animal referred to as the horned serpent. The San have lived in that particular part of South Africa for longer than hyraxes have been peeing in Boomplaas Cave, and their culture is rich and in many ways unchanged from that of their ancient ancestors. They know everything about their land, including all the animals that live there now and a lot that used to live there.

The horned serpent painting is a long-bodied animal that doesn’t actually look like a serpent or an animal with horns. It very clearly has legs even though they’re short, and its body is thick but with a long thin tail and a small head with downward pointing tusks. If the animal was painted near somewhere that you’d expect to find walruses, everyone would assume it’s a walrus. But it’s not a walrus, or probably not, and the painting doesn’t resemble anything that actually lives in South Africa.

However, Benoit suggests that it does resemble an animal that used to live in what is now South Africa, the dicynodont. It had downward-pointing tusks, a thick body, and fairly short, strong legs. It ate plants and was very common in the area when it was alive—but it went extinct over 200 million years ago.

Clearly, as ancient as the San culture is, they weren’t around in the Triassic, so how could they possibly have known about dicynodonts? The answer is pretty simple. Dicynodonts were so common that their fossils are regularly found in the Karoo Basin of South Africa, including well-preserved skulls eroding out of the ground.

The San would have undoubtedly come across these fossils. They even have myths about huge animals that once roamed the area but that died out long ago, and archaeologists have found collections of fossils made by the San centuries ago. Benoit thinks the so-called horned serpent is an artistic depiction of a dicynodont, with elements taken from the fossils and from myth.

In other words, basically, the San people understood paleontology and extinction long before Europeans figured it out.

Thanks for your support, and thanks for listening!

Further reading:

Wolves on rise in France as bears wreak mountain havoc

Can Brown Bears Survive in the Pyrenees?

Show transcript:

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

On the evening of August 4, 2019, two hikers set up camp in the Pyrenees Mountains. Laurent and Frédéric were familiar with the area and had plenty of experience hiking and camping. Once their camp was ready for the night, they took off their boots and socks and sat down to eat dinner and relax at a small campfire. If you’ve ever camped after a long hike, you’ll know that this is the best time of the day, when you can rest and air out your boots.

After only a few minutes, though, the two heard grunts and growls in the darkness not far from their camp. They were concerned, but they had a fire and most animals won’t approach a fire. But the sounds got closer and closer.

Then the animal roared—and it sounded like it was much closer than before. Laurent and Frédéric remembered that bears have become more common in the Pyrenees in the last few decades, and rather than take their chances with a hungry bear, they decided it was time to go. They shoved their bare feet into their boots, left everything behind, and raced back down the trail.

It was late when they made it to the village of Germ so the hikers took refuge in a church where they spent the night. In the morning they hiked back up to their campsite to retrieve their belongings, expecting it to be trashed by a bear hunting for food. But everything was where they’d left it.

Some people assumed the hikers had panicked over nothing, but the men were adamant that they’d heard something roaring as it came closer. In a news interview they said the final roar, the one that made them grab their boots and run, lasted several seconds and was so loud they could actually feel it in their chests.

Brown bears were once fairly common in the Pyrenees but by 1991 they had all been killed, mostly by hunters. Habitat loss was also a factor as people built more roads and houses in the mountains. In 1995 a conservation program brought three bears from Slovenia to start a reintroduction program, and the way people acted, you’d think someone had released a thousand rabid weasels into their homes.

Sheep and cattle farmers, and people who think the wilderness belongs to humans and humans only, protested the reintroduction of the bears, and one of the bears was shot and killed. This is despite the fact that farmers whose livestock are killed by bears get paid a lot of money by the French government. Approximately 1,000 sheep a year are killed in the Pyrenees—not by bears, but by pet dogs running loose.

Conservation efforts continued despite protests and finally, by 2020, there were 64 bears living in the Pyrenees Mountains. The number may be a little larger—some estimates are as high as 100—but conservationists have difficulty counting the bears properly because protesters threaten them and in one case actually set a conservationist’s car on fire.

The Pyrenees mountain range more or less divides France from Spain. It’s older than the Alps and especially known for its spectacular waterfalls. Many plants and animals that live in the Pyrenees are found nowhere else in the world, but unfortunately hunting and habitat loss have driven many of them to extinction. The Pyrenean ibex, a type of wild goat, went extinct in the year 2000.

Conservationists have introduced a related animal, the western Spanish ibex, to help keep the mountain ecosystems healthy. The bears now living in the mountains are similarly important to the ecosystems. Conservationists are frustrated by protesters who don’t want bears in the mountains at all, especially considering that the Great Pyrenees dog was developed in the area to protect livestock from bears and other predators. Some shepherds in British Columbia, Canada, where both black bears and grizzlies live, successfully use Great Pyrenees dogs to guard their flocks from bears. Grizzlies are a subspecies of brown bear.

But let’s go back to Laurent and Frédéric’s scary camping trip. Did they really encounter a bear or could it be something else?

Bears are generally quite shy animals who avoid people when they can. Unlike black bears, which don’t growl, brown bears do make growling and grunting sounds occasionally. Males will growl or even roar at other males during mating season in spring and early summer, signaling aggression and the willingness to fight. A brown bear will sometimes growl or roar at a person to warn them away too. So it’s possible the hikers heard a bear who wasn’t interested in their food but just wanted them out of its territory.

There’s another possibility, though, and it’s an animal that’s much more common in the Pyrenees Mountains than bears are. The wild boar lives throughout the Pyrenees, especially in forested areas and meadows. It’s mostly nocturnal and is usually shy of humans, and its numbers have increased considerably since its main predator, the wolf, was driven to extinction in the mountains and elsewhere in the 1930s.

An estimated two million wild boars live in France, including the Pyrenees. The most common time for people to encounter wild boars is at dusk, which is exactly when the hikers heard the growling. But wild boars are just pigs, right? Pigs oink, right?

This is what an aggressive wild boar sounds like:

[boar growl]

A boar will growl to warn other boars that there’s danger nearby and to signal aggression. That would explain why the hikers heard grunts and growls, which finished in a loud, angry roar. It would also explain why the campsite was undisturbed. Wild boars mostly eat plants, including roots, nuts, and fruit, although they’ll also eat carrion and the occasional small animal if they can catch it. Unlike a bear, which almost always wants to eat people food when it can, a wild boar is a lot less interested in people food. If the hikers did hear a boar instead of a bear, once they ran away the boar was probably satisfied and just went around finding its natural food in the area as usual.

Wild boars have been introduced to parts of North and South America, Australia, and other places where they’ve become an invasive species. The wild boar is native to Europe and Asia, though, so the ones in the Pyrenees are right where they belong. The only real issue is the lack of natural predators to keep the boar population at a healthy level.

The good news is that wild boars aren’t usually as aggressive as they can sound, as long as they’re not cornered. The two hikers were probably not in any danger after all. Still, it’s better to be safe than sorry when you get roared at by a large creature in the dark.

Thanks for your support and thanks for listening!

Further reading:

A possible home for a bizarre Carboniferous animal: is Typhloesus a pelagic gastropod?

Typhloesus

An artist’s rendition of what Typhloesus might have looked like [pic taken from the Nix Illustration link above]:

Show transcript:

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

I recently discovered the excellent Nix Illustration blog, which is about scientific illustration and palaeontology. I’m finding so many fun topics that I keep going back to it, so I hope you don’t mind another invertebrate mystery I learned about from the site. There are links in the show notes if you want to read the original blog posts.

This month’s mystery is Typhloesus wellsi, sometimes referred to as the “alien goldfish” because of its shape and its peculiar anatomy. It definitely wasn’t a fish. It lived around 324 million years ago and was first discovered in the early 1970s in Montana, in the middle of North America. It grew up to four inches long, or 10 cm, and was shaped not like a real goldfish but kind of like a goldfish cracker. Its body was roughly cylinder-shaped, and it had a vertical tail fin and a pair of fin-like lobes on its sides that are referred to as keels. But it didn’t have eyes or, as far as scientists can determine, an anus. It did have a mouth and gut cavity–but it also had something truly unexpected and mysterious in its body, a pair of disc-shaped organs that contained a lot of iron but whose function is completely unknown and unlike anything scientists have ever seen.

Those initial specimens also contained lots of conodont teeth, which led scientists to hope they’d finally discovered the conodont animal. We’ve talked about conodont teeth before, but it’s been quite a while ago. Conodont animals were incredibly common for around 300 million years, and their teeth are found throughout the world. Technically they’re not teeth but tooth-like structures called conodont elements, some of them microscopic, some of them almost an inch long, or 2 cm. Each animal had three types of conodont elements, and they interacted in a way that we don’t fully understand since they were completely different from modern animal mouthparts.

Until the 1980s, no one knew what the conodont animal looked like. The only fossils we had were the tiny teeth. Then some body impressions of the conodont animal were discovered. Now we know it was shaped like an eel and grew up to 20 inches long, or 50 cm. We also know it had large eyes, a notochord (or primitive spine), and fins on the tail end. It was probably related to hagfish and lampreys and may have looked similar, although not everyone agrees with this classification.

Whatever the conodont animal was related to, Typhloesus definitely wasn’t one. It turns out that the conodont teeth associated with Typhloesus fossils were actually in its gut, after the alien goldfish ate a conodont animal.

So scientists were back to square one. What was Typhloesus?

In 2022, a study of several specimens revealed a clue. Typhloesus had a radula. That’s a mouthpart that resembles a tooth-studded tongue. Snails, for instance, use tiny radulas to scrape algae and other food off of rocks. True radulas are a trait of mollusks, which means Typhloesus was most likely an early mollusk, maybe even a gastropod like snails and slugs.

That’s a start to classifying Typhloesus, but it doesn’t explain the pair of weird disc-shaped organs. It’s called a ferrodiscus and we still don’t know what it was for. Because of its placement just under the midgut and its high concentration of iron, which would have made it quite hard in comparison to most of the rest of its body, the ferrodiscus might have had something to do with digestion. Then again, it might have had something to do with chemoreception, which is probably how Typhloesus found its food. Some modern mollusks have a chemoreceptor organ under the radula, but it’s mainly a bundle of nerve cells and not any kind of weird iron discs. We just don’t know what the ferrodiscus was.

Typhloesus probably swam around until it encountered a small animal like a conodont, and then it would stick its radula out like a spiky tongue and use it to grab the animal. Typhloesus had no anus, so after it digested its meal it just spat out the indigestible parts. It might also have been a scavenger that used its radula to pull pieces off of a dead animal to eat.

Not every scientist agrees that Typhloesus was a mollusk. Only mollusks have true radulas, although not all mollusks have them, but other animals have evolved similar structures. Typhloesus is so different from known mollusks, living and extinct, that scientists can’t definitively determine what it was related to. It had no gills and no notochord, so we know it had to be an invertebrate. Some cnidarians, which include jellyfish and sea anemones, have no anus, but Typhloesus has even less in common with that phylum of animals than it has with mollusks. Some flatworms have no anus, but again, Typhloesus doesn’t seem to have a lot of other traits in common with flatworms.

Until we learn more about it from studying well-preserved fossils, we can only speculate about where Typhloesus fits in the tree of life and what the ferrodiscus actually was. Mysteries like this are part of the challenge of science, and part of the fun too.

Thanks for your support, and thanks for listening!

Show transcript:

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

Life arose in the oceans and only much later spread to the land. But some land animals returned to the ocean and eventually became fully marine animals. That’s our topic this month, animals that returned to the sea.

Vertebrates that evolved on land are called tetrapods, meaning four-footed. It applies even to animals like birds that have two legs and two wings, and snakes that have no legs, because all the ancestors of tetrapods had four legs.

Returning to marine life as a tetrapod eventually results in an animal developing certain characteristics. Even animals like sea turtles become more streamlined, which helps the animal swim more easily, and arms and legs develop into flippers for the same reason. Sometimes limbs are lost completely, like the rear legs of cetaceans and sirenians, because they’re not needed. One interesting note is that as far as we know, all marine tetrapods still have to breathe air, which requires them to come to the surface of the water periodically.

The ancestors of marine tetrapods probably all started out as partially aquatic and gradually became more and more at home in the water. That’s true even for animals as well adapted to marine life as whales.

Some of the earliest whale ancestors were the ambulocetids, which probably looked sort of like a cross between a hippopotamus and a crocodile. Ambulocetid means “walking whale,” but there’s some evidence that it might have already evolved to be fully aquatic 49 million years ago. It had short legs that might not have been strong enough to support it out of water. It might have been covered with short fur like a seal but it might have had little to no fur, more like a hippopotamus. Either way, it had long toothy jaws, strong legs with webbed toes that it used to propel itself through the water, and a tail that probably resembled that of an otter. It grew about ten feet long, or 3 meters.

Ambulocetids lived in shallow coastal areas where the land was swampy, and it may have spent part of its time in fresh water. It wouldn’t have looked or acted much like a whale to us, but it was already developing features now found only in whales.

By around 41 million years ago, the basilosaurids and their close relations had evolved, and were definitely fully aquatic. Their nostrils had moved almost to the location of modern whales’ blowholes. Their forelegs were basically flippers with little fingers, their hind legs had almost disappeared, and they had tail flukes. They were also much bigger than their ancestors. Basilosaurus could grow up to 60 feet long, or 18 meters, and probably looked more like a gigantic eel than a modern whale. It was long and relatively thin, and may have mostly lived at the ocean’s surface instead of diving for food.

Dakosaurus wasn’t a dinosaur despite its name, although it lived at the same time as the dinosaurs, about 145 million years ago. It was a crocodylomorph that grew up to about 16 feet long, or 5 meters, and looked kind of like a shark with legs—but also a lot like a crocodile wearing a shark costume. Its tail had a fin near the end that made it resemble a shark’s tail, and its legs were flipper-like but still obviously legs. It had a whole lot of big serrated teeth in a deep skull with strong jaws. Because its jaws and teeth were so strong, in fact, scientists think Dakosaurus probably ate other marine reptiles instead of just fish.

While Dakosaurus was streamlined and well adapted to life in the ocean, we don’t know if it left the water to lay its eggs on land the way sea turtles still do or if it gave birth in the water. We don’t have any nest sites or young specimens one way or another.

Other marine reptiles definitely gave birth in the water, including ichthyosaurs. Ichthyosaurs and their close relations were incredibly successful, first appearing in the fossil record around 250 million years ago and last appearing around 90 million years ago. Most ichthyosaurs grew around 6 and a half to 11 feet long, or 2 to 3.3 meters, depending on species, so while they were pretty big animals, they weren’t enormous. They would have been fast, though, and looked a lot like fish or dolphins, with four flippers, a dorsal fin, a long tail with fins, and a long thin rostrum with lots of little teeth. We know they gave birth to live young because we have fossils of female ichthyosaurs who died in the process of giving birth, with the baby’s tail outside of its mother but the rest of it still in the birth canal. We have other fossils of ichthyosaurs with partially developed young in what would have been the mother’s uterus.

We also have lots of ichthyosaur coprolites that show us what it ate, since the coprolites fossilized with pieces of undigested food in them. This includes fish scales and squid beaks.

Of course, if you want to talk about big marine reptiles, you have to talk about mosasaurs. They lived in the late Cretaceous and went extinct at the same time as the non-avian dinosaurs. The earlier species of mosasaur are pretty small, but after ichthyosaurs went extinct, mosasaurs got really really big. Some estimates for the largest species range up to almost 50 feet long, or 15 meters, and maybe even longer. Mosasaurs looked kind of like streamlined iguanas, with four flippers, a shark-like tail, but a very lizard-like head. They probably ate other marine reptiles, including smaller species of mosasaur, along with sharks and other fish, dinosaurs that made the mistake of getting in the water, and sea turtles. Honestly, mosasaurs could eat whatever they could catch, and they could probably catch just about anything. Their jaws were double-hinged, which allowed them to swallow prey whole like snakes do.

We even have some skin impressions of mosasaurs that show smooth scales similar to those of snakes, and one study suggests that mosasaurs might have had forked tongues too. Mosasaurs were distantly related to snakes, but they were more closely related to monitor lizards that also have forked tongues.

Speaking of snakes, we’ll finish with an animal that people don’t usually remember when they think of animals that have returned to the ocean: sea snakes.

Not all sea snakes are fully marine. One genus spends part of its time on land and still lays eggs, but fully marine sea snakes give birth to live young. Researchers aren’t sure if the sea snakes that are fully marine were able to completely stop returning to the land because they already gave birth to live young or if that developed after the snakes started spending part of the time in the water.

The sea snake has a single lung, like most snakes, but unlike snakes that live on land this lung extends almost the length of the whole body (but not the tail). The snake’s nostrils are at the top of its snout so it can breathe without sticking too much of its head above water, and its extra-long lung can store lots of air so the snake doesn’t have to breathe too often. Some sea snakes can stay underwater for up to about two hours, partly because of the air stored in the lung, but also because they can absorb some oxygen from the water through their skin. Studies have shown that a sea snake can absorb almost 25% of the oxygen it needs through its skin.

Sea snakes are pretty big, with the largest growing up to 10 feet long, or 3 meters. Most are about half that length. They live in warm tropical oceans, usually in shallow water, and eat fish and other small animals. The sea snake’s body is slightly flattened side to side and its tail is much more flattened like a paddle, which is how it swims. In most cases, if a sea snake is washed ashore, it’s unable to crawl and is pretty much helpless. Terrestrial snakes have enlarged ventral scales that the snake can move up and down, allowing the edges of the scales to grab dirt or leaves or whatever the snake is moving over. This gives it a purchase, and as the scales move they push the body forward. Most sea snakes don’t have these specialized ventral scales and have regular smooth scales instead.

But while most sea snakes can’t move on land, if you see one stranded, don’t try to pick it up to help it. All sea snakes are extremely venomous. (Use a long paddle to push the sea snake back into the water, or better yet, call an expert who can safely return the snake to the water.) Most sea snakes are brightly colored as a result, to warn potential predators away. Many have stripes and are absolutely gorgeous.

Generally, if you encounter a sea snake while you’re swimming, the snake isn’t going to bite you. You’re too big for it to swallow and it doesn’t want to waste its venom on you. Don’t bother it and it won’t bother you unless it feels threatened. Just swim calmly away and be glad it’s not a mosasaur.

Thanks for your support, and thanks for listening!