Strange Animals Podcast

You may know what fossils are (I hope), but have you heard of trace fossils? You have now!

A giant ground sloth footprint with a human footprint inside it, made some 11,000 years ago:

Climactichnites:

A “devil’s corkscrew”:

A Paleocastor fossil found at the bottom of its fossilized burrow:

Stromatolite:

Coprolites:

Gastroliths found with a Psittacosaurus:

Show transcript:

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

This week we’re going back in time to look at fossils, but these aren’t regular fossils. They’re called trace fossils, or ichnofossils. Instead of fossilized bones and other body parts, trace fossils are records of where organisms were and what they were doing.

Fossil footprints are one of the most common trace fossils. We have lots of dinosaur footprints, and from them we know that dinosaurs held their tails off the ground, that some dinosaurs traveled in herds with the young in the middle, and things like that. A fossil footprint is formed when an animal steps in soft mud or sand, usually near water, and the resulting footprints were covered with sediment which then dried, protecting the footprints. If the footprints continued to be protected from water and other processes that might wipe them out, over the years more and more sediment was deposited on top, eventually compacting it so that pressure and chemical reactions within the sediment turned it to stone. This is why we sometimes have two impressions of the same footprints: the actual footprints and a cast of the footprints made by the sediment that filled them initially.

The White Sands National Monument in New Mexico has so many footprints of so many animals around what was once a lake that it’s referred to as a megatrack. Seriously, we’re talking hundreds of thousands of footprints. In 2014 a team studying the tracks found a set of ancient human footprints, the first ones found in the park. But while the tracks were well preserved, the team couldn’t pinpoint how old they were. They invited other researchers to come examine the prints to help date them.

In 2016 a British paleontologist named Matthew Bennett came to examine the prints, but while he was there, he took a look at some giant ground sloth prints nearby. And when he did, he made an amazing discovery. There was a sloth footprint with a human footprint on top of it, actually within the sloth’s footprint. The sloth’s print was 20 inches long, or almost 51 cm. And after that, the next sloth footprint also had a human footprint in it. And after that another. And another. And another. Ten sloth footprints in a row had human footprints inside.

Since the tracks were made in sandy lake mud and both tracks were reasonably clear, the researchers determined that the tracks were probably left on the same day. In other words, the human was probably trailing the sloth.

But that’s not all. Bennett and the other scientists at the site followed the tracks of both sloth and human and found marks where the sloth turned around and reared on its hind legs to face the approaching human. And there are more human prints that approach at a different angle—not just human prints, but prints that suggest the human was actually tip-toeing.

The most likely explanation is that the humans were hunting the sloth, with one human getting its attention while a second crept up behind it. But we don’t know for sure. One odd thing is that the human trailing the sloth actually had to stretch to step inside each sloth print. Even small giant ground sloths were enormous, nine or ten feet long, or about three meters, with long curved claws. Ground sloths were plant-eaters that used their claws to strip leaves from branches and dig giant burrows, but the claws made formidable weapons too. It’s possible that the ancient human was just amusing himself by stepping exactly in the sloth’s prints.

Since this initial finding,

It's mystery ape time! Learn about de Loys' ape and two other mystery apes this week!

The only photograph we have of de Loys' ape:

A white-fronted spider monkey:

Oliver the so-called "ape man":

A better picture of Oliver late in his life:

A Bili ape:

A regular gorilla (top) and a regular chimp (bottom, hearing no evil) for comparison with the Bili ape and Oliver:

Show transcript:

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

I don’t know about you, but I’m in the mood for a mystery animal this week. So let’s really dig in to a topic I haven’t covered much before, mystery apes!

A lot of people get apes and monkeys confused, but it’s actually easy to tell them apart. For one thing, there aren’t very many apes. Gorillas, chimpanzees, orangutans, and bonobos are called great apes, and gibbons and siamangs are called the lesser apes, mostly because they’re smaller.

Apes never have tails and are closely related to humans. Humans, in fact, are considered great apes, but it’s rude to say so. We like to think we’re special because we can make podcasts and bulldozers and delicious cakes. Monkeys usually have tails, although not always, and a monkey, unlike an ape, can’t stand fully upright and can’t straighten its elbow out so that its arm is flat.

Now that we have a pretty good idea of what an ape is, let’s look at three mystery apes.

We’ll start with a big mystery from 1920, an ape supposedly killed in South America and subsequently dubbed de Loys’ ape. It’s not just one mystery, it’s several mysteries wrapped up together. And while the ape’s body has been lost, we still have a photograph.

In 1917, geologist François de Loys led an expedition to Venezuela and Colombia to search for oil. It was a disaster of an expedition, since not only did they not find oil, almost everyone in the expedition died. According to de Loys, in 1920 what was left of the group was camped along the Tarra River on the border between Colombia and Venezuela when two large animals appeared. De Loys said he thought they were bears at first, then realized they were apes of some kind. They were large, had reddish hair and no tails, and walked upright. The apes became aggressive toward the humans and, fearing for their lives, the geologists shot at the apes. They killed one and wounded the other, which fled.

The dead ape looked like a spider monkey, which was fairly common in the area, but it was much larger and had no tail. There was no way for the expedition to keep the body, so they propped it up on a crate with a stick under its chin to keep it upright, then took pictures. Only one of those pictures survived, since de Loys said the others were lost when a boat capsized later in the expedition.

But after de Loys got home to Europe, he didn’t tell anyone about the ape. He said he forgot all about it until 1929 when the anthropologist George Montandon noticed the surviving photograph in de Loys’s papers. After that, De Loys wrote an article about the ape which was published in the Illustrated London News.

It was a sensational article, not meant to be scientific. Here’s an excerpt:

“The jungle swished open, and a huge, dark, hairy body appeared out of the undergrowth, standing up clumsily, shaking with rage, grunting and roaring and panting as he came out onto us at the edge of the clearing. The sight was terrifying…

“The beast jumped about in a frenzy, shrieking loudly and beating frantically his hairy chest with his own fists; then he wrenched off at one snap a limb of a tree and, wielding it as a man would a bludgeon, murderously made for me. I had to shoot.”

Montandon was enthusiastic about the ape. He wrote three articles for scientific journals and proposed the name Ameranthropoides loysi for it. But scientists were skeptical. Who was this de Loys guy and did he have any proof that the ape wasn’t just a spider monkey?

What better way to start out the new year than by learning about some animals that fly (or glide) without wings! Thanks to Llewelly for suggesting the colugo!

Colugo looking startled:

A colugo, flying, which startles everyone else:

Flying fish! ZOOM!

A flying gurnard, not flying:

Flying squid! ZOOM!

Flying squid close-up, mid-zoom:

Show transcript:

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

It’s the first week of a new year, so let’s start it off right and learn about some animals that fly without wings.

The first of our non-winged flying animals is a suggestion from Llewelly, who sent me some links about it and we both freaked out a little because it’s such an awesome animal. It’s called the colugo, and technically it doesn’t fly, it glides. It looks kind of like a big squirrel and kind of like a small lemur, and in fact it’s also sometimes called a flying lemur. But it’s not closely related to squirrels or lemurs. It’s actually not related closely to anything alive today.

Before we learn about the colugo specifically, let me explain a little bit about gliding animals. Gliding animals have a flap of skin called a gliding membrane or patagium. In the case of gliding mammals, like the flying squirrel or the colugo, the patagium connects each foreleg with the hindleg on that side. When the animal wants to glide, it stretches its legs out, which also stretches out the patagium. For a long time scientists assumed that the patagium was just skin and didn’t do anything except increase the animal’s surface area and act as a sort of parachute. But it turns out that the patagium contains tiny muscles like those recently discovered in the membranes of bat wings. And the skin between the fingers of the bat’s forelimbs, which creates the wings, are actually considered patagia. In fact, any gliding membrane, even if it’s part of a real wing, is considered a patagium, so birds actually have them too.

The colugo has a patagium between its legs like other gliding mammals, but it also has a patagium between its hind legs and its tail, and even its fingers and toes are connected with small patagia. It’s the most well-adapted mammal known for gliding, so well-adapted that it can glide incredible distances. One was measured as having glided almost 500 feet in one jump, or 150 meters. This is almost the length of two football fields.

The colugo lives in South Asia and is endangered mainly due to habitat loss. It grows to about 16 inches long, or 40 cm, with a small head, big eyes, and little round ears. It’s gray with some mottled white and black markings that help hide it against tree trunks, and its legs are long and slender. It eats plants. We don’t know a whole lot about the colugo, because it’s shy and lives in the treetops of tropical forests, but what we do know is really weird.

For instance, its babies. If you listened to episode 45 about monotremes, where we also discuss the differences between marsupial and placental mammals, you may remember that placental mammal babies are born mostly developed while marsupial mammal babies are born very early and finish developing outside of the mother, either in a pouch or just clinging to the mother’s fur. Well, the colugo is a placental mammal, but its babies are born extremely early, more like a marsupial. They finish developing outside of the mother, which takes six months or so, and the mother colugo keeps her tail curved up most of the time so that her patagium is wrapped around her babies like a pouch.

The colugo has weird teeth, too. The front teeth, or incisors, are shaped like tiny combs. This is similar to the incisors of lemurs, which look like tiny combs because the lemur uses them as tiny combs to groom its fur. But unlike any other mammal known, some of the colugo’s upper incisors have two roots instead of just one. Why? No one knows.

So what is the colugo related to? For a long time,

It’s our 100th episode! Thanks to my fellow animal podcasters who sent 100th episode congratulations! Thanks also to Simon and Julia, who suggested a couple of animals I used in this episode.

An Amazonian giant centipede eating a mouse oh dear god no:

The kouprey:

The Karthala scops owl:

A sea mouse. It sounds cuter than it is. Why are you touching it? Stop touching it:

A sea mouse in the water where it belongs:

Mother and baby mountain goats. Much cuter than a sea mouse:

A hairy octopus:

Further reading:

Silas Claiborne Turnbo's giant centipede account collection

Show transcript:

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

This is our 100th episode! I’ll be playing clips from some of my favorite animal podcasts throughout the show, and I highly recommend all of them if you don’t already listen!

For our big 100 show, I’ve decided to cover several animals, some mysterious, some not so mysterious, and all weird. But we’ll start with one that just seems to fit with the 100th episode, the centipede—because centipedes are supposed to have 100 legs.

So do they have 100 legs? They don’t, actually. Different species of centipede have different numbers of legs, from only 30 to something like 300. Centipedes have been around for some 430 million years and there are thousands of species alive today.

A centipede has a flattened head with a pair of long mandibles and antennae. The body is also flattened and made up of segments, a different number of segments depending on the centipede’s species, but at least 15. Each segment has a pair of legs except for the last two segments, which have no legs. The first segment’s legs project forward and end in sharp claws with venom glands. These legs are called forcipules, and they actually look like pincers. No other animal has forcipules, only centipedes. The centipede uses its forcipules to capture and hold prey. The last pair of legs points backwards and sometimes look like tail stingers, but they’re just modified legs that act as sensory antennae. Each pair of legs is a little longer than the pair in front of it, which helps keep the legs from bumping into each other when the centipede walks.

Like other arthropods, the centipede has to molt its exoskeleton to grow larger. When it does, some species grow more segments and legs. Others hatch with all the segments and legs they’ll ever have.

The centipede lives throughout the world, even in the Arctic and in deserts, which is odd because the centipede’s exoskeleton doesn’t have the wax-like coating that other insects and arachnids have. As a result, it needs a moist environment so it won’t lose too much moisture from its body and die. It likes rotten wood, leaf litter, soil, especially soil under stones, and basements. Some centipedes have no eyes at all, many have eyes that can only sense light and dark, and some have relatively sophisticated compound eyes. Most centipedes are nocturnal.

Many centipedes are venomous and their bites can cause allergic reactions in people who also react to bee stings. Usually, though, a centipede bite is painful but not dangerous. Small centipedes can’t bite hard enough to break the skin. I’m using bite in a metaphorical way, of course, since scorpions “bite” using their forcipules, which as you’ll remember are actually modified legs.

The largest centipedes alive today belong to the genus Scolopendra. This genus includes the Amazonian giant centipede, which can grow over a foot long, or 30 cm. It’s reddish or black with yellow bands on the legs, and lives in parts of South America and the Caribbean. It eats insects, spiders, including tarantulas, frogs and other amphibians, small snakes, birds, mice and other small mammals, and lizards. It’s even been known to catch bats in midair by hanging down from cave ceilings and grabbing the bat as it flies by. Because it’s so big, its venom can be dangerous to children.

Those of us in the northern hemisphere are thinking a lot about island life right about now, where it’s warm and sunny. But there are islands everywhere, not just the tropics, and the animals on islands often evolve to look strange and different from their mainland cousins. Thanks to Richard E. and Lucy for their suggestions this week!

A fossa:

A tamaraw, miniature water buffalo:

A Socotra starling, my new favorite bird:

Adorable little Galapagos penguin:

A dragonblood tree, good grief!

A blue baboon. It's not a baboon but it is blue:

A ground dragon:

Further listening:

The unlocked Patreon bonus episode about vampire finches on the Galapagos Islands

Show transcript:

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

In a lot of episodes, we talk about animals from islands like the Galapagos and the Canaries. There’s a reason why islands give rise to strange animals. This week we’ll focus on island life—how island habitats lead to unique animals and how introduced animals can destroy an entire island ecosystem in a matter of a few years. Massive thanks to listener Richard E., who suggested the topics of introduced animals and island life!

Islands, of course, are surrounded by water and isolated from larger landmasses as a result. Some are close to the mainland so it’s easy for animals to swim or float across to the island. In cold areas, animals can sometimes walk across ice to islands. But other islands are more remote, or used to be close to the mainland but were pushed farther away by tectonic forces.

Once a piece of land is cut off from the mainland, the animals and plants on that piece of land start to evolve independently of the larger population of animals and plants on the mainland. If the island is isolated enough that potential predators can’t get to it, the animals already living on the island start to adapt to life with no or few predators. As a result, they may appear tame when humans arrive.

And that is where the problems start. Humans don’t just arrive alone. We bring other animals with us, either on purpose, like dogs, cats, and livestock, or by accident, like rats and mice. And these animals, along with humans, can destroy an entire island habitat really easily.

I’ll use one of Richard’s examples, since it’s a good one and not one you’d think of when thinking of islands. The red squirrel is native to Europe and parts of Asia, but it also lives in the UK and Ireland. It’s usually red-brown in color, although some populations can be brown, gray, or even black. The belly is white. It has long ear tufts and a poofy tail. It lives in trees and eats seeds, nuts, berries, fungi, and occasionally eggs or baby birds.

But remember, Ireland and the UK are islands. And in the 1870s, someone thought it would be really great to import eastern gray squirrels from North America and release them in parks in the UK. In Ireland, in 1911 someone gave a bunch of gray squirrels as a wedding gift, which is not a great gift, honestly, and they got loose because of course they did. They’re squirrels.

Grey squirrels are larger than red squirrels and don’t have ear tufts. They eat the same foods red squirrels do. They also carry a disease called squirrel parapoxvirus that doesn’t bother them but which kills red squirrels. The population of red squirrels has dropped substantially as introduced gray squirrel populations climb in the UK and Ireland. The red squirrel is now protected, with conservation efforts in place that are making a difference. But that just goes to show how easy it is to lose even a well-established species on large islands when an outside species is introduced.

On islands, especially smaller islands, small animals tend to grow larger overall and big animals tend to grow smaller overall. This is called Foster’s rule. It comes about partly because there are fewer predators but limited resources.

This week let's learn about some unusual cetaceans, river dolphins!

An Amazon river dolphin and the nose of another Amazon river dolphin:

Another Amazon river dolphin. Note the teeny eye and disk-like teeth:

A South Asian river dolphin. Note the almost nonexistent eye:

A Chinese river dolphin in better days:

Show transcript:

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

This week we’re going to learn about an animal I’ve wanted to cover for a long time but never got around to, the river dolphin.

All whales and almost all dolphins live in the ocean. They can survive for a short while in fresh water but need saltwater to thrive. But as the name suggests, the river dolphin lives in rivers, usually in fresh water and sometimes in the brackish water where rivers empty into oceans. Brackish just means a mixture of fresh and salt water, so it’s saltier than fresh water but not as salty as ocean water. When I was a kid I thought it meant ocean water with a lot of seeweed and dead leaves in it, because I thought the word brackish had something to do with bracken, which is a type of fern.

There are only a few species of river dolphin alive today. They live in warm water and have very little blubber as a result. They primarily use echolocation to navigate since river water tends to be muddy and hard to see through. Their flippers are broad and most have long snouts and flexible necks, or at least flexible compared to other cetaceans. All river dolphins are endangered due to pollution, habitat loss, and accidental drowning in fish nets, with the Chinese river dolphin only having been declared extinct in 2006.

River dolphins evolved from dolphins that once lived in the ocean, but most aren’t closely related to the marine dolphins alive today. Researchers think that when modern dolphins and other toothed whales evolved, they outcompeted their more primitive cousins, who moved into freshwater habitats as a result.

A few years ago, fossils of an extinct river dolphin that grew more than nine feet long, or almost three meters, were found in Panama. It lived around 6 million years ago in the Amazon River, but researchers don’t think modern river dolphins are closely related to it. In other words, freshwater dolphins have evolved repeatedly in different parts of the world to fit an available ecological niche.

In the case of the newly discovered fossil river dolphin, Isthminia panamensis, it probably lived in the warm, shallow Caribbean Sea between North and South America before the Isthmus of Panama formed. It took millions of years for the isthmus to form, with undersea volcanos first emerging from the ocean around 15 million years ago to form islands, then the land itself being pushed upward as the Pacific Plate slid underneath the Caribbean Plate. Researchers think the isthmus became fully formed around 3 million years ago, separating the Atlantic Ocean from the Pacific and connecting North and South America. Because we have Isthminia panamensis’s fossil from the Amazon River, we can hypothesize that by around 6 million years ago, there wasn’t enough of the original Caribbean Sea habitat to support the dolphins and they had already moved into the Amazon River and adapted to life in freshwater.

The river dolphin isn’t the only cetacean that lives in freshwater. There’s a species of porpoise called the finless porpoise that lives around Asia in shallow coastal waters, but often spends at least part of the time in mangrove swamps and in rivers not too far from the sea. Porpoises and dolphins look very similar but belong to different families, which means they aren’t actually very closely related at all. Like, seriously not related at all. Like, the difference between horses and cows. The finless porpoise can grow almost seven and a half feet long, or over two meters, and is called finless because it doesn’t have a dorsal fin. Instead,

Thanks to listeners Finn and Leo, who suggested this week's topics of strange lizards, and the thorny devil and mata mata turtle, respectively! Join us this week to learn about those reptiles and a bunch more!

Thorny devil. Definitely do not eat.

The mata mata turtle. Big leafhead boi

A frilled lizard BWAAAAAMP

A Pinocchio lizard. Wonder where that name comes from.

Poke poke poke does this bother you? poke poke

om nom nom

A shingleback, or as I like to call it, an ambulatory poop:

Show transcript:

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

We have more listener suggestions this week! Ages ago, listener Finn suggested strange lizards, and more recently, listener Leo suggested a particular type of strange lizard and a strange turtle.

We’ll start with Leo’s suggestion, the thorny devil. He describes it as “a cool animal with spikes all around it,” which is definitely a good way to put it. The thorny devil is a lizard from Australia, and it does indeed have spikes all over its head, back, and tail, and smaller spikes on its legs. The spikes are modified scales and are sharp.

The thorny devil grows to around 8 inches long, or 20 cm, with females being larger than males on average. In warm weather its blotchy brown and yellow coloring is paler than in colder weather, when it turns darker. It can also turn orangey, reddish, or gray to blend in to the background soil. Its color changes slowly over the course of the day as the temperature changes. It also tends to turn darker if something threatens it.

It has a thick spiny tail that it usually holds curved upward, which makes it look kind of like a stick. It moves slowly and jerkily, rocking back and forth on its legs, then surging forward a couple of steps. Researchers think this may confuse predators. It certainly looks confusing.

As if that wasn’t enough, the thorny devil has a false head on the back of its neck. It’s basically a big bump with two spikes sticking out of the sides. When something threatens the lizard, it ducks its head between its forelegs, which makes the bump on its neck look like a little head. But all its spines make it a painful mouthful for a predator. If something does try to swallow it, the thorny devil can puff itself up to make itself even harder to swallow, like many toads do. It does this by inflating its chest with air.

The thorny devil eats ants and only ants, specifically various species of tiny black ants found only in Australia. It has a sticky tongue to lick them up. Because it has such a specific diet, it’s hard to keep in captivity. Only a few zoos in Australia have thorny devils on display. If you listened to episode 93, where we talked about invasive ant species having an effect on entire ecosystems, the thorny devil is an example of this. Fortunately the ants it eats are doing just fine, but if an invasive ant species were introduced to the areas where it lives, the thorny devil would probably be in trouble. So no moving ants around, everyone, I mean it.

The thorny devil lives in desert and scrubland regions, and in hot weather it digs a burrow to shelter in. Females lay their eggs in burrows. To get enough water in its desert environment, the thorny devil has microscopic grooves between its scales that suck up water by capillary action. At night dew condenses on the lizard’s body, and it also collects dew by brushing against dewy vegetation or just by standing or lying on damp sand. If it does happen across water in a puddle, it will put a leg in the water and the tiny grooves in its skin suck up water and funnel it to the mouth. It’s like a living straw.

While I was researching this, I found some information on how rattlesnakes drink. When it starts to rain, a rattlesnake will coil up tightly so that rainwater collects in its coils. Then it drinks the water. This sounds like something someone just made up, but it’s real.

BREAKING NEWS, EVERYONE! A new giant salamander has been discovered, right here in the southern United States! It was only formally described YESTERDAY if you’re listening to this the night it goes live, assuming I manage to get it finished and uploaded before Friday morning. I should have put this together yesterday but didn’t think about it until today. Today being Thursday.

We’re talking about the reticulated siren, also called the leopard eel although it’s not an eel. It’s also not a leopard. There are three species of siren alive today, including the reticulated. Reticulated means spotted or mottled, if you were wondering. Sirens look a lot like eels except that instead of fins they have tiny vestigial forelegs and external gills. They have no hind limbs at all.

The greater siren lives in wetlands near the Atlantic coast of North America, specifically in the southern coastal states like Alabama and Florida. It grows over three feet long, or 97 cm, and is usually dark greenish or gray with tiny green or yellow dots along its sides. It eats water insects, mollusks, and occasionally plants. The lesser siren is very similar to the greater siren but doesn’t grow as big, and lives throughout much of the eastern United States and northeastern Mexico.

The reticulated siren is almost the size of the greater siren, and is gray-green and covered with a maze of spots. Its head is relatively small and its gill branches are large. It’s only been found in southern Alabama and the Florida panhandle.

The first reticulated sirens known to science were actually caught in the 1970s in Alabama, but although those three specimens were preserved and held in a museum for study, it wasn’t formally described. Another reticulated siren wasn’t found until 2009, when a herpetologist, David Steen, caught one while trapping water snakes and turtles in Florida.

Steen and biologist Sean Graham worked together to find more. It took them five years to trap three more specimens in a pond in Florida. After lots of study, including DNA analysis, they determined they had found a new species.

Now that we know the reticulated siren is a species of its own, researchers like Steen and Graham are working to find out more about it. They suspect it’s rare since it’s been so hard to find, and that means it needs to be protected. The wetlands where it lives are constantly in danger of being drained and filled in to make way for houses, Walmarts, parking lots, and other things we should put somewhere else and leave the wetlands alone.

Sirens are fully aquatic, specifically living in swamps, ponds, and boggy areas with a lot of vegetation they can hide in. If a siren’s pond dries up, it can burrow into the mud and aestivate in a cocoon of slime and sloughed-off skin, sometimes for a year or two until water returns to the area. But we don’t yet know if the reticulated siren can do this too.

That’s it for our breaking news update. We’ll be back on Monday morning as usual with an episode about strange reptiles.

Thanks for listening!

Because there are so many weird fish out there, I’ve narrowed this week’s episode down to weird BIG fish! We’ll cover the smaller ones another time. Thanks to Damian and Sam for suggestions this week!

A manta ray being interviewed by a diver:

A manta ray with white markings:

A mola mola, pancake of the sea, with a diver:

The flathead catfish head. So many teeth:

A Wels catfish with Jeremy Wade:

A couple of red cornetfish:

Howick Falls in South Africa. Put that on my endless list of places I want to visit:

Further reading:

Karl Shuker's blog post about the black and white manta rays

Show transcript:

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

It’s another listener suggestion week! Recently, Damian sent a list of excellent topic suggestions, one of which was weirdest fish, and I am ALL OVER that! But because there are so many weird fish, I’m going to only look at weird humongous fish this time, including a mystery fish.

We’ll start with a fish that doesn’t actually look very fishlike. Rays are closely related to sharks but if you didn’t know what they were and saw one, you’d probably start to freak out and think you were seeing some kind of water alien or a sea monster. The ray has a broad, flattened body that extends on both sides into wings that it uses to fly through the water, so to speak. The wings are actually fins, although they don’t look like most fish fins. Like sharks, rays have no bones, only cartilage. Rays are so weird that I’m probably going to give them their own episode one day, but for now let’s just look at one, the manta ray.

There are two species of manta ray alive today. The reef manta can grow 18 feet from wingtip to wingtip, or 5.5 meters. Manta birostris is even bigger, up to 29 feet across, or 8.8 meters, which is why it’s called the giant manta ray. This is just colossally huge. I didn’t realize how big manta rays were until just now. Both species live in warm oceans throughout the world and both eat plankton, krill, and tiny fish. Sometimes the manta ray is called the devil fish because of its horns, which aren’t horns at all, of course. The two protuberances that stick forward at the manta ray’s front are actually fins that grow on either side of the rectangular mouth. These fins help direct plankton into the mouth. When the manta ray isn’t feeding, it can roll up these fins into points and close its mouth. Its eyes are on the sides of its head.

Manta rays are white underneath and black or dark brown on top. But there is a mystery associated with the giant manta ray, with reports of black and white striped rays dating back to at least 1923. In April of that year, naturalist William Beebe spotted a manta ray near the Galapagos Islands that had white wingtips and a pair of broad white stripes extending from the sides of the head halfway down the back. Beebe thought it might be a new species of manta ray. There are other reports of manta rays with white or grayish V-shaped markings on the back.

Better than that, in the last few decades divers and boaters started to get photographs and even video of these manta rays with white markings. These days, manta rays with white markings are known to be common, although for decades scientists thought all manta rays were unmarked dorsally, or on the back. Since the markings are unique to individuals, it makes it easy for researchers to track individuals they recognize. The manta ray also sometimes has black speckles or blotches on its belly.

But wait, there’s more! According to zoologist Karl Shuker, in 2014, researchers in Florida published a paper discussing the ability of manta rays to actually CHANGE COLOR in minutes when they want to. The color in question that it changes? Its white markings. The markings can be barely visible against its background color, and then will brighten considerably when other manta rays are around or when it’s feeding.

This week let’s learn about giant tortoises! What’s the difference between a turtle and a tortoise? The most basic difference is that the turtle lives in water and the tortoise lives on land. And there are some really, really big tortoises in the world!

A Galapagos tortoise:

Show transcript:

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

This episode was supposed to be about strange reptiles, with more awesome suggestions from listeners. I was going to include some information about a couple of giant tortoises…but the more I researched, the longer that part of the episode became, until it just took over. So here’s an episode about giant tortoises, and we’ll have the strange reptiles episode in a couple of weeks instead. I’m going to give a shout-out to listeners Leo and Finn, who have been waiting patiently to hear their suggestions. Sorry you’ll have to wait a little bit longer.

The biggest tortoise in the world is the Galapagos Tortoise, which as you probably know, or can guess from the name, lives in the Galapagos Islands off the coast of Ecuador. In fact, the islands were named after the tortoises. Galapago means tortoise in Old Spanish. There are eleven species of Galapagos tortoise alive today, but there used to be 15. The others were mostly eaten to extinction by sailors who would stop by the Galapagos Islands, capture tortoises, and sail away with them to eat later.

The biggest individual Galapagos tortoise ever measured was a male named Goliath. When he died in 2002, Goliath was 4.5 feet long, or 1.36 meters, 2 feet three inches high, or 68.5 cm, and weighed 919 pounds, or 417 kg. He was only 42 years old when he died, but Galapagos tortoises frequently live for more than 150 years. Adult tortoises have no predators except humans. They’re just too big, too heavy, too strong, and have too tough a shell for other predators to bother with.

The Galapagos tortoise eats plants, including grass, leaves, fruit, and even cacti. Its neck is long, which allows it to reach plants that are farther away, since it can’t exactly climb trees. It can survive up to six months without water, getting most of its moisture from the plants it eats, but some tortoises on more arid islands will lick dew from rocks to get moisture. Some of the boulders have been licked by tortoises so much over the centuries that they have deep grooves worn in the surface from turtle tongues.

As I’ve mentioned before in other episodes, sometimes herbivores will eat meat when they can get it. The Galapagos tortoise does this too on occasion. There’s a type of finch on the Galapagos that cleans parasites off the tortoises, and to help the finch reach as much of its skin as possible, the tortoise will stand up straight with its legs extended. The finches hop underneath and clean ticks and other parasites from the tortoise’s legs, neck, and the skin between the carapace, or upper shell, and the plastron, the lower shell. But occasionally a tortoise will suddenly pull its legs into its shell and drop, smashing the finches flat. Then it stands up and eats the squashed birds. This is not cool, tortoise. Those birds are trying to help you.

Galapagos tortoises lay round, hard-shelled eggs. The female digs a hole in the dirt that’s about a foot deep, or 30 cm, and lays about a dozen eggs in it. She covers the eggs with dirt, tamps it down with her plastron, and leaves. When the babies hatch, they have to dig their way out of the hole. This can take weeks, but fortunately the babies still have yolk sacs attached that keep them from starving.

One of the Galapagos tortoise species that went extinct recently was the Pinta Island tortoise. The last known individual was called Lonesome George. He was found in 1971 on Pinta Island and taken to the Charles Darwin Research Station on Santa Cruz Island. Although researchers tried to find more Pinta Island tortoises, even offering $10,000 if someone found a female,