Monthly Archives: December 2019

Episode 152: The Freshwater Seahorse and Other Mystery Water Animals

This week let’s look at some (mostly) smaller mystery animals associated with water! Thanks to Richard J., Janice, and Simon for the suggestions!

Further reading:

What Was the Montauk Monster?

The black-striped pipefish. Also, that guy has REALLY BIG FINGERTIPS:

The Pondicherry shark, not looking very happy:

A ratfish. What BIG EYES you have!

The hoodwinker sunfish, weird and serene:

The Montauk monster, looking very sad and dead:

Show transcript:

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

Let’s finish off the year with an episode about a few mystery animals, specifically a few mystery animals associated with water. Thanks to Richard, Janice, and Simon for the suggestions!

We’ll start off with a mystery suggested by Richard J, but not the Richard J. who is my brother. A different Richard J. Apparently half the people who listen to my podcast are named Richard, and that’s just fine with me.

Richard wanted to know if there are there such things as freshwater seahorses. We’ve talked about seahorses before in episode 130, but seahorses are definitely marine animals. That means they only live in the ocean. But Richard said he’d heard about a population of seahorses native to Lake Titicaca in Bolivia, which is in South America. I put it on my suggestions list, but Richard was on the case. He sent me a link to an article looking into the mystery, which got me really intrigued, so I bumped it to the top of my list. Because I can do that. It’s my podcast.

Freshwater seahorses are supposedly known in the Mekong River and in Lake Titicaca, and sometimes you’ll see reference to the scientific name Hippocampus titicacanesis. But that’s actually not an official scientific name. There’s no type specimen and no published description. Hippocampus is the generic name for many seahorse species, but like I said, they’re all marine animals and there’s no evidence that any live in freshwater at all. Another scientific name supposedly used for the Mekong freshwater seahorse is Hippocampus aimei, but that’s a rejected name for a seahorse named Hippocampus spinosissimus, the hedgehog seahorse. It does live in parts of the Indo-Pacific Ocean, including around Australia, especially in coral reefs, and sometimes in the brackish water at the Mekong River’s mouth, but not in fresh water.

On the other hand, there’s no reason why a seahorse couldn’t adapt to freshwater living. A few of its close relatives have. There are a few species of freshwater pipefish, and in the world of aquarium enthusiasts they are actually sometimes called freshwater seahorses. The pipefish looks like a seahorse that’s been straightened out, and most of them are marine animals. But some have adapted to freshwater habitats.

This includes the black-striped pipefish, which is found off the coasts of much of Europe but which also lives in the mouths of rivers. At some point it got introduced into the Volga River and liked it so much it has started to expand into other freshwater lakes and rivers in Europe.

The pipefish is closely related to the seahorse, but while it does have bony plates like a seahorse, it’s a flexible fish. It swims more like a snake than a fish, and it can anchor itself to vegetation just like a seahorse by wrapping its tail around it. It mostly eats tiny crustaceans and newly hatched fish, since it swallows its food whole. It usually hides in vegetation until a tiny animal swims near, and then it uses its tube-shaped mouth like a straw to suck in water along with the animal. Just like the seahorse, the male pipefish has a brooding pouch and takes care of the eggs after the female deposits them in his pouch.

So where did the rumor that seahorses live in the Mekong come from? The Mekong is a river in southeast Asia that runs through at least six countries, including China, Thailand, Cambodia, and Vietnam. Parts of it are hard to navigate due to waterfalls and rapids, but it’s used as a shipping route and there are lots of people who live along the river. Like all rivers, it’s home to many interesting animals, including a type of giant softshell turtle that can grow up to six feet long, or 1.8 meters, a type of otter, a bunch of enormous fish, including three species of catfish that can grow up to almost ten feet long, or 3 meters, and a giant freshwater stingray that can grow up to 16 feet long, or 5 meters, and of course lots more animals that aren’t as big or as impressive, but which are still important to the river’s biodiversity. But there’s no evidence of seahorses anywhere throughout the Mekong’s 2700 mile length, or 4,350 km.

But there is a hint about where the rumor of a Mekong seahorse could have come from. One researcher named Heiko Bleher chased down the type specimens of the supposed Mekong seahorse in a Paris museum, which were collected in the early 20th century by a man named Roule. Roule got them in Laos from a fisherman who had nailed the dried seahorses to his fishing hut. The fisherman told Roule the seahorses were from the Mekong, but when they were further studied in 1999 Roule’s specimens were discovered to actually be specimens of Hippocampus spinosissimus and Hippocampus barbouri. Both are marine fish but do sometimes live in brackish water at the mouth of the Mekong. So the fisherman wasn’t lying, but Roule misunderstood what he meant.

As for the freshwater seahorse supposedly found in Lake Titicaca, that one’s less easy to explain. Titicaca is a freshwater lake in South America, specifically in the Andes Mountains on the border of Bolivia and Peru. It’s the largest lake in South America and is far, far above the ocean’s surface—12,507 feet above sea level, in fact, or 3,812 meters. It’s also extremely deep, 932 feet deep in some areas, or 284 meters. It’s home to many species of animal that live nowhere else in the world. Why couldn’t it be home to a freshwater seahorse too?

Titicaca was formed when a massive earthquake some 25 million years ago essentially shoved two mountains apart, leaving a gap—although technically it’s two gaps connected with a narrow strait. Over the centuries rainwater, snowmelt, and streams gradually filled the gaps, and these days five rivers and many streams from higher in the mountains feed water into the lake. Water leaves the lake by the River Desaguadero and flows into two other lakes, but those lakes aren’t connected to the sea. Sometimes they dry up completely. So Titicaca isn’t connected to the ocean and never was, and even if it was, seahorses are weak swimmers and would never be able to venture up a river 12,000 feet above sea level. Some 90% of all fish in the lake are found nowhere else in the world. There’s just simply no way a population of seahorses could have gotten into the lake in the first place, even if they could survive there.

That doesn’t mean there aren’t any freshwater seahorses out there ready to be discovered, of course. But I don’t think you’re going to find any in Lake Titicaca. And I have no idea how the rumor got started that any live there.

From a tiny seahorse let’s move on to a small shark, another topic suggested by Richard J. The Pondicherry shark grows to about 3.3 feet, or 1 meter, and once lived throughout the Indo-Pacific, especially in coastal waters. It’s considered critically endangered, but it’s so rare these days that we hardly know anything about it except that it’s harmless to humans, eats small fish and other small animals, and was once common. But until the mid-2010s, scientists were starting to worry it was already extinct. Then in 2016 two different Pondicherry sharks were photographed in two different places—and not where anyone had expected to find it. Some tourists took a photo of one in a river called the Menik and a freshwater fish survey camera caught a photo of one in the Kumbuk River. Both rivers are in Sri Lanka. Since then researchers have spotted a few more. The shark is protected, and hopefully the excitement around the shark’s rediscovery has helped people in the area learn about it so they know not to bother it. Some sharks tolerate fresh water and brackish water quite well, so it’s not surprising that the Pondicherry shark has moved into the rivers where it has less competition from commercial fishing boats.

Our next water mystery is actually not really a mystery, just a really strange-looking fish related to sharks. This one was suggested by my aunt Janice who doesn’t actually listen to the podcast but who likes to send me links to strange animal articles that she comes across on the internet. This one is called Chimaera Monstrosa, sometimes called the rat fish.

The rat fish mostly lives in the deep sea, although it’s sometimes seen in shallower water, and can grow up to 5 feet long, or 1.5 meters. It’s mostly brown but has white markings. Its body looks more or less like a regular plump shark-like fish, but it has great big round green eyes, relatively long pectoral fins, and a very long tail that tapers to a point. The tail gives it its common name, since it kind of resembles a rat’s tail. It eats whatever it can catch on the ocean floor, including crustaceans and echinoderms.

Ratfish, and other chimaeriformes, are most closely related to sharks, and like sharks they have skeletons that are made of cartilage instead of bone. Since they’re rarely seen and look really weird, every so often someone catches one and posts about it online, and then my aunt sends me a link. They are really interesting fish, though.

Simon also sent me an article about an interesting fish a while back, the hoodwinker sunfish. We talked about the sunfish, or mola mola, in episode 96. The hoodwinker sunfish, or mola tecta, was only discovered in 2017 despite its large size. So far it’s known to live in the South Pacific around New Zealand, Australia, South Africa, and Chile, but only off the southernmost parts of those countries. But in early 2019 one washed up in Southern California.

The mystery sunfish was measured at almost 7 feet long, or 2.1 meters. An intern at the University of California at Santa Barbara found it, but didn’t know what it was. But once photos of the fish were posted online, two experts from Australia recognized it immediately—but because it showed up so far out of its known range, they were cautious about IDing it from just a photo. That’s despite the fact that one of the experts, Marianne Nyegaard, was actually the person who named the species. She asked for samples and more photos, and when she got the results, it really was a hoodwinker sunfish. But what was it doing in the warm waters of the northern Pacific instead of the cold southern waters? No one knows except the sunfish.

Let’s finish with another mystery animal you may have heard of. On July 12 or 13, 2008, depending on which source you consult, three friends visited Ditch Plains Beach, two miles away from the little town of Montauk in New York state in eastern North America. It was a hot day and the beach was crowded, and when the three noticed people gathered around something, they went to look too. There they saw a weird dead animal that had obviously washed ashore. One of the three took a picture of it, which appeared in the local papers and then the local TV news along with an interview with the three. From there it went viral and was dubbed the Montauk monster.

The monster was about the size of a cat, but with shorter legs and a chunkier body, and a relatively short tail. It didn’t have much hair but it did have sharp teeth, and the front part of its skull was exposed so that it almost looked like it had a beak. Its front paws were elongated with long fingers, almost like little hands.

So what was the monster? People all over the world made guesses, everything from a sea turtle without a shell to a diseased dog or just a hoax. Some people thought it was a mutant animal that had been created in a lab on one of the nearby islands, escaped, and died trying to swim to the mainland.

But while no one knows what happened to the animal’s body, scientists have studied the photo and determined that it was probably a dead raccoon that had been washed into the ocean. The waves had tumbled the animal’s body around through the sand long enough to rub off most of its remaining fur and some of its facial features, and then it washed ashore during the next high tide. It was also somewhat bloated due to gases building up inside during decomposition. It’s the animal’s teeth and paws that made the identification possible, since both match a raccoon’s exactly. Remember that raccoons have clever front paws that help them open locking trash bins, as we learned in episode 138.

So the Montauk monster isn’t actually a mystery, except what happened to it, but don’t be discouraged. There are still lots of genuinely mysterious animals in the ocean, from misplaced sunfish to creatures no one has ever seen yet. Maybe you’ll be the one to discover them.

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

Thanks for listening!

Episode 151: Fossils with other fossils inside

Thanks to Pranav who suggested this week’s amazing topic, animals that fossilized with the remains of their last meal inside!

Indrasaurus with a lizard inside. Yum!


Rhamphorhynchus (left, with long wing bones) and its Fish of Doom (right):

The fish within a fish fossil is a reminder to chew your food instead of swallowing it alive where it can kill you:

The turducken of fossils! A snake with a lizard inside with a bug inside!

Show transcript:

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

This week we have a listener suggestion from Pranav, who has sent me so many amazing suggestions that he has his own page on the ideas spreadsheet. When he emailed me about this one, he just suggested cool fossils, but the links he provided had a really interesting theme that I never would have thought about on my own. This week we’re going to learn about some fossil animals that have fossils of their last meal inside them!

We’ll start with a recent discovery of a new microraptor species, Indrasaurus wangi, which lived about 120 million years ago. It was an interesting animal to start with, because it had arms that were very similar to bird wings, although with claws, but its hind legs also had long feathers that made it almost like a four-winged animal. It was found in 2003 in northeastern China, but when researchers were studying it in 2019 they found something amazing. Not only did it have an entire lizard skeleton where its stomach once was, showing us that it swallowed its prey whole, the lizard itself was a species new to science.

We know what else Indrasaurus ate because more Indrasaurus fossils have been found in the area, many of them so well preserved that its fossilized stomach contents have been preserved too. It ate mammals, birds, lizards, and fish—basically anything it could catch.

Another species that was similar to Indrasaurus, called Anchiornis, also called a four-winged bird-like dinosaur, was found with what appears to be a gastric pellet in its throat. The pellet contains the bones of more than one lizard and was probably ready to be horked up the way many carnivorous birds still regurgitate pellets made up of the indigestible parts of their prey, like bones, scales, and fur.

The fossilized remains of food inside a fossilized organism has a term, of course. It’s called a consumulite. It’s a type of bromalite, which is a broader term for any food or former food found in a fossilized organism’s digestive tract. The term bromalite also includes coprolites, which are fossilized poops.

Naturally, it requires a high degree of preservation for consumulites to form, and a high degree of skill to reveal the often tiny and delicate preserved details. And consumulites are important because they let us know exactly what the animal was eating.

Consumulites aren’t limited to prey animals, either. A small armored dinosaur, a type of ankylosaur, called Kunbarrasaurus, which lived around 115 million years ago in what is now Australia, was a herbivore. The type specimen of the species, which was described in 2015, was incredibly well preserved—almost the entire skeleton, most of its body armor, and the contents of its stomach. Paleontologists can determine not just what kinds of plants it had eaten—which include ferns and seeds—but how it was processing its food. Most herbivorous dinosaurs swallowed leaves and other plant parts whole, then crushed the food in a powerful gizzard or gizzard-like organ along with rocks or grit. The rocks helped break up the plant material, and we have lots of these rocks associated with fossilized dinosaurs. The rocks are called gastroliths and are usually worn smooth. But Kunbarrasaurus didn’t have any gastroliths, and the plant material was so well preserved that researchers could see the cut ends of the plants where Kunbarrasaurus had bitten them. And all the pieces were small. Kunbarrasaurus therefore probably chewed its food, which meant it also probably had lips and cheeks of some kind to help keep the food in its mouth while it was chewing.

Another example of an animal with a consumulite that helped solve a mystery about its diet is Baryonyx. Baryonyx is a type of spinosaurid, a theropod dinosaur that grew at least 33 feet long, or 10 meters. It was discovered in 1983 in Surrey, England, and was described in 1986. It lived around 125 million years ago. It walked on its hind legs and probably used its arms to tear its prey into bite-sized pieces, because its first finger had a huge claw 12 inches long, or 31 cm.

But its skull was the real puzzle. Most theropods are meat-eaters, although a few evolved to eat plants. But Baryonyx had a long, relatively slender snout with a lot of close-growing teeth, and a sort of bulb at the end of its snout called a rosette. It looks more like the skull of a crocodilian called a gharial than a theropod. But as far as anyone knew when Baryonyx was discovered, there were no fish-eating theropods.

Until 1997, that is, when paleontologists studying Baryonyx spotted some overlooked details. In addition to a gastrolith in its belly area, they found some fish scales and teeth that showed evidence of being damaged by digestive acids. It probably hunted by wading through shallow water like a heron, catching fish and other animals with its long toothy snout.

It’s not just dinosaurs that are found with consumulites. Animals of all kinds eat all the time, so as long as the conditions are right to fossilize the remains of an animal, there’s a chance that whatever food was in the digestive tract might fossilize too. For instance, the same part of China that has yielded amazingly well preserved feathered dinosaurs has also produced other animals—including a carnivorous mammal called Repenomamus that grew more than three feet long, or one meter. I think we’ve talked about Repenomamus before, because we have evidence that it actually ate dinosaurs—at least baby ones, or it might have scavenged already dead dinosaurs. Either way, it lived around 125 million years ago and was shaped sort of like a badger with a long tail, although it wasn’t related at all to badgers or any other modern mammal. It probably laid eggs like monotremes still do. The reason we know what Repenomamus ate is because one specimen was found with pieces of a young Psittacosaurus in its stomach.

In at least one case it’s hard to tell which animal should be considered the eater and which should be considered the eaten. A fossil slab found in Southern Germany and described in 2012 contains a Rhamphorhynchus associated with two different fish.

Rhamphorhynchus lived around 150 million years ago and was a type of pterosaur with a long tail. Its wingspan was about six feet across, or 1.8 meters. It mostly ate fish, which it probably caught not by flying down to grab fish out of the water, like eagles do, but by floating like a goose and diving for fish. It had large feet and short legs, which would have helped it take off from the water just like a goose.

A fish that lived at the same time as Rhamphorhynchus was called Aspidorhynchus, and it grew up to two feet long, or 60 cm. It had long jaws filled with teeth, with the upper jaw, or rostrum, extending into a pointy spike.

In the fossil found in Germany, a Rhamphorhynchus has a small fish in its throat that it had probably just caught. While it was still swallowing it, an Aspidorhynchus fish attacked! But things obviously went wrong for everyone involved. Researchers suggest that the fish’s rostrum cut right through the flying membrane of Rhamphorhynchus’s left wing. The fish bit down but its teeth became tangled in the tissue. It started thrashing to free itself and Rhamphorhynchus was thrashing around too trying to get away, which only got them more tangled up together. The fish dived, drowning Rhamphorhynchus, and the weight of its body dragged Aspidorhynchus into deep water where there wasn’t enough oxygen for it to survive. It died too, and its heavier body lay partially across Rhamphorhynchus, holding it down so it wouldn’t drift away. The fossil shows Rhamphorynchus, Aspidorhynchus, and the tiny fish that Rhamphorhynchus never did get to finish swallowing.

Another fish, Cimolichthys, lived around 75 or 80 million years ago and grew a little over six feet long, or two meters. Its body was heavily armored by large scutes and it had several rows of teeth. It may have been related to modern salmon. It lived in what is now North America and Europe, and ate fish and squid. We know it ate fish and squid because, of course, we have the remains of various last meals found with preserved fossil Cimolichthys. For instance, one specimen was found with the internal shell of a cephalopod lodged in its throat. Researchers suspect the fish had tried to swallow a Tusoteuthis that was too big to fit down its throat. The Tusoteuthis got stuck and blocked the flow of water over the fish’s gills, basically drowning it. Tusoteuthis, by the way, could possibly grow up to 36 feet long, or 11 meters, although that depends on whether it had long feeding tentacles like modern squid or not. If it didn’t have long feeding tentacles, it was probably only about 19 feet long, or 6 meters, which is pretty darn big anyway. I wouldn’t want to have to swallow that thing whole. Not even if it was deep-fried first.

Another fish called Xiphactinus, which grew up to 20 feet long, or 6 meters, lived in the late Cretaceous period. It died out at the same time as the non-avian dinosaurs. It had massive fangs and was a terrifying predator, but sometimes that backfires. The fossil of a 13 foot, or 4 meter, Xiphactinus was found with a 6 foot long, or 1.8 meter, fish called Gillicus inside it. Paleontologists think Xiphactinus swallowed its prey whole, which thrashed around so much inside it that it ruptured an organ and killed the predator fish. Both fish sank to the bottom of the shallow Western Interior Seaway in North America until it was discovered in 1952.

Let’s finish with two even more incredible fossils. In 2008 paleontologists found a fossilized freshwater shark they dated to 250 million years ago. Right before it died, it had eaten two animals called temnospondyls. Temnospondyls were common animals, with many species found throughout the world, and researchers still aren’t sure if they were the ancestors of modern amphibians or a similar type of animal that died out without any descendants. One of the temnospondyls that the shark ate had the well digested remains of a spiny fish in its stomach.

But a few years later researchers in Germany found something even better. It’s a fossilized snake called a Palaeopython, related to boas. It was about three feet long, or one meter, and was still young. If it had lived to grow up, it would have doubled in size. It lived in trees but also hunted along the edges of rivers and lakes. About 48 million years ago, this particular snake caught a lizard that’s related to modern basilisk lizards. It swallowed the lizard headfirst. But then the snake died, possibly asphyxiated by a cloud of carbon dioxide from the volcanic lake nearby. We have a lot of incredibly detailed fossils from that lake, known as the Messel Pit.

Researchers aren’t sure how the snake made it into the lake. Maybe it was already in the shallow water when it died, or on the bank, and a wave washed it into the water. Maybe the wave was actually what killed the snake, washing it into the lake where it drowned. However it died, it sank into deep water and was covered in sediment that preserved it. Then, 48 million years later, paleontologists found it.

When the fossil was cleaned and prepared for study, researchers found that the lizard was preserved inside it. But there was another surprise inside the lizard! Right before it had been eaten by the snake, the lizard had eaten an insect. And the insect was so well preserved that researchers could tell it had an iridescent exoskeleton.

If I was fossilized right now, paleontologists from the far future would find a lot of chocolate in my stomach. Happy holidays to everyone, whatever your reason for celebrating at this time of year!

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

Thanks for listening!

Episode 150: Hamsters, Gerbils, and Ferrets

This week we venture into the land of CUTE to learn about hamsters, ferrets, and some other small domesticated animals. Thanks to Kim and the Angel City Ferret Club for the suggestions!

Hamsters are SO CUTE:

Hamsters have giant cheek pouches to carry food in:

Gerbils are also SO CUTE:

Ferrets are SO CUTE in a totally different way:

The black-footed ferret does not want anything to do with the domestic ferret, thank you:

An extremely complicated but neat way to use your pet’s exercise wheel to generate power:

Hamster-Powered Night Light

Show transcript:

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

Back in episode 106 we learned about domestication, especially the domestication of dogs and other canids. But recently, Kim suggested an episode about the domestication of other animals, like hamsters and ferrets. Then the Angel City Ferret Club suggested I talk about ferrets too. So this week, let’s learn about hamsters, gerbils, and ferrets.

Hamsters are rodents, and there are lots of different species. The most common domesticated hamster is the golden hamster, also called the Syrian hamster, which is indeed from Syria. A DNA study of domesticated golden hamsters indicate that they’re all descended from a single female captured in Syria in 1930 and kept as a laboratory animal. It wasn’t long before some of her babies became pets, because hamsters are incredibly cute.

The golden hamster is about five inches long, or 13 cm, and is a chunky little rodent with a little nub of a tail, short legs, and rounded ears. And a little pink nose and shiny black eyes. I had a pet hamster named Wembley when I was little. It’s a golden tan in color with lighter fur underneath, and some breeds of domesticated golden hamsters may have white spots on the body or long fur.

Some other hamster species, most of which aren’t kept as pets, can grow much larger than the typical golden hamster. The European hamster, which lives in parts of eastern Europe, can grow up to 14 inches long, or 35 cm. It’s mostly brown with white patches. One of the smallest hamster species is Campbell’s dwarf hamster, which is sometimes kept as a pet but is originally from Mongolia. It grows about three inches long, or 8 cm. It’s brown-gray in color with a darker stripe down the middle of its back and pale gray fur underneath.

All hamsters have cheek pouches that extend down to their shoulders. In the wild, a hamster tucks food into its cheek pouches to carry back to its burrow, where it pushes the food out by pressing its forefeet against its sides and pushing them forward. Campbell’s dwarf hamster has cheek pouches that are big even compared to other hamsters. They extend all the way down the sides of its body.

Hamsters in the wild like warm areas without a lot of rain, like deserts and dry grasslands. They dig well and spend most of their time underground when they’re not out searching for food. They’re most active at dawn and dusk, although they’re nocturnal to some degree also. In cold weather some species hibernate for short periods of time, generally only a few days. A hamster’s burrow can be pretty elaborate, with several entrances, a cozy sleeping burrow, a pantry where the hamster stores food, and even a bathroom where the hamster urinates. Hamsters are hindgut fermenters, and like some other rodents and rabbits, some of the poops they produce aren’t waste material, they’re partially digested food that the hamster eats again to gain as much nutrients from it as possible.

Hamsters are omnivores, eating seeds and other plant material as well as insects and other small animals. Occasionally wild hamsters hunt together to catch insects, although in general the hamster is a solitary animal. In addition to its ordinary diet of hamster food, a pet hamster likes seeds and nuts, green vegetables, root vegetables like carrots, a little bit of fruit, and other plant foods, but shouldn’t be given people food since it can contain too much salt, sugar, or other additives that can harm it. Give your hamster deep bedding that it can burrow into to sleep and dig around in, but cedar shavings can be bad for their lungs. Paper bedding made for small pets is safest. And, of course, your hamster needs to chew to keep its teeth from growing too long, since like other rodents its teeth continue to grow throughout its life. It also needs an exercise wheel and toys designed for hamsters so it can get exercise and have fun. You can find good books about how to care for a hamster in the library. I mean you can find a book on hamster care in the library, not how to turn your hamster into a tiny furry librarian.

Hamsters don’t see very well but have a good sense of smell and hearing, and in fact they communicate mostly in the ultrasonic range—too high-pitched for humans to hear most of their calls. Generally hamsters only call to each other during courtship, when a male and female are trying to decide if they’ve found a good mate.

I tried to find audio of hamster calls, pitched down so humans could hear it, but had no luck. I guess the sound of their calls is a secret only hamsters know.

Gerbils are also closely related to mice and therefore to hamsters, and have a lot in common with the hamster. Both are about the same size but the gerbil is smaller, less chunky, and has a much longer tail. The tail has fur on it and helps the gerbil retain its balance while climbing.

There are a lot of gerbil species, all of them native to dry areas like deserts and grasslands in parts of Asia and Africa. The Mongolian gerbil was domesticated in the late 19th century but wasn’t well known until the 1950s when it became a popular pet. In the wild the Mongolian gerbil is a gray-brown color but pets have been selectively bred to produce colors from white to black with various patterns. Unlike the hamster, the gerbil is a social animal and is healthier when it lives with at least one other gerbil. It also likes to burrow in its bedding and needs to chew to keep its teeth from growing too long. It’s important to get an exercise wheel that’s solid instead of having rungs, since otherwise the gerbil could catch its tail between the rungs and get injured.

In the wild, gerbils live in groups with extensive burrows, sometimes connected with the burrows of other groups. It has a good sense of smell and if a gerbil whose smell it doesn’t recognize approaches, the two will probably fight. The Mongolian gerbil grows about 2 ½ inches long, or 6 cm, not counting its tail, which is about the same length as its body. But the biggest species of gerbil is the great gerbil from central Asia. It grows up to 8 inches long, or 20 cm, not counting its tail. That’s the size of a squirrel.

If a gerbil feels threatened or nervous, it may thump its hind legs on the ground to warn other gerbils. Other gerbils that hear the thumping may also start thumping. Sometimes pet gerbils will start thumping in response to rhythmic sounds in a house, like a washing machine on a spin cycle. This is hilarious, but of course if your pet gerbil is thumping you should look around to see if there’s something near its cage that it finds frightening, like a pet dog or a light that’s too bright. This is what a gerbil sounds like when stamping its tiny feet.

[gerbil thumping sound]

Next, let’s look at the ferret. The ferret isn’t a rodent. It’s a type of weasel called the European polecat, which has been domesticated. Unlike the hamster and gerbil, which are small and somewhat delicate animals, the ferret is much larger and more robust. It grows nearly two feet long, or almost 60 cm, with a long, slender, flexible body, long neck, and short legs.

The ferret is generally a crepuscular animal, meaning it’s most active at dawn and dusk. It’s solitary in the wild, but domesticated ferrets are much more social. It likes to burrow, and in the wild it sleeps in a burrow during the day.

No one is sure when the ferret was domesticated, but it may be descended from animals kept to hunt for rats and rabbits. Like other members of the weasel family, ferrets are carnivores and evolved to be slender and short-legged to fit into burrows of smaller animals. There’s even a term for hunting with a ferret, called ferreting. It was also used to keep mice and rats out of grain stores. Ferret breeders selected for white or albino ferrets because they were easier for their handlers to see, so many pet ferrets are albinos.

The ferret makes a good pet although it’s an intelligent, active animal and will get into all sorts of mischief if it doesn’t have enough to do. It likes to climb, explore, and solve puzzles, and needs lots of exercise and a safe place to play. The ferret can be litter trained like a cat and trained to wear a harness and walk on a leash like a dog. It’s sociable so it’s always better to have more than one ferret if you can.

The ferret needs to eat frequently, so it’s a good idea to keep a feeder full of ferret kibble where your pet can eat whenever it’s hungry even if you’re not home. Since ferrets are carnivores like cats are, your pet’s diet should be high in animal-based protein and fat. If you can’t find ferret food in your area, you can feed high-quality cat kibble, but food formulated just for ferrets is best. For treats, ferrets like cooked eggs, freeze-dried liver treats that you can get for dog training, and small pieces of cooked meat. You shouldn’t feed fruit to your ferret, since it can lead to digestive issues.

Ferrets are illegal to own in some areas because escaped and released ferrets can breed in the wild and cause a lot of problems as an invasive species. This is particularly true in small, fragile ecosystems like islands, so it makes sense that Hawaii doesn’t allow ferrets or many other animals as pets, including gerbils and hamsters.

Ferrets occupy the same ecological niche as the black-footed ferret, and the black-footed ferret is the most endangered mammal in North America. It was even declared extinct in 1979, but a small population was re-discovered in 1981 in Wyoming. Some of these animals were captured for a captive breeding program, so even though the black-footed ferret was declared extinct in the wild in 1996, the breeding program was able to reintroduce ferrets in parts of its original range in the western part of North America. It’s now considered an endangered species, which is still pretty bad but not as bad as extinct.

The black-footed ferret primarily eats prairie dogs, and prairie dogs are also on the decline due to habitat loss, poisoning and killing of them by ranchers and farmers, and disease. So saving the black-footed ferret also means saving the prairie dog. However, pet prairie dogs are legal to own in most states even though they’re not really domesticated animals and they can spread diseases fatal to humans, like bubonic plague. And since prairie dogs don’t breed well in captivity many animals sold as pets were captured in the wild, and many of them die soon after being captured.

But while feral domesticated ferrets are a problem in some areas, there don’t seem to be any feral populations of ferrets in the United States. It looks like ferret owners in North America take good care of their pets and make sure they don’t get out and cause problems for wildlife.

California has a lot of restrictions about what animals can be kept as pets. Ferrets are not allowed. Neither are gerbils, prairie dogs, or hedgehogs. But you can keep hamsters and chinchillas as pets in California, rabbits, camels, wolf-dog hybrids, and most birds including ostriches. The only reason I even mention California’s restrictions on pets is because the Angel City Ferret Club is working to get the ferret ban changed, and they told me all about it.

I don’t live in California so I don’t want to get involved in the debate. But wherever you live and whatever pet you have, always make sure that you know how to take care of it properly and that you only buy your pet from an ethical and reputable breeder. And, of course, never release a pet into the wild if you can’t take care of it anymore. Most of the time your pet will die of cold, starvation, injury, or predation from a wild animal. If you can’t find someone who can take your pet, contact your veterinarian who can give you information about rescue services in your area.

That is a super depressing way to end an episode, so let’s finish up with something cute and interesting. If you’ve ever watched a hamster or other small pet run on an exercise wheel, you may have wondered how much energy the little fuzzball was generating and if it could charge your phone or power a light. Well, other people have wondered the same thing. I found a how-to article at detailing how they made a working power generator from a hamster wheel. Their pet hamster Skippy was easily able to power a nightlight while running on his wheel. I’ve put a link to the article in the show notes. It looks really complicated but if you’re an engineer type of person you might look at it and think, “Oh, that’s simple and fun! Let’s try it!”

There’s even a new company based in Taiwan that’s marketing exercise equipment that generates energy as people use it. People are a lot bigger and stronger than hamsters, so we can generate a lot more energy by running on a treadmill or working out on a stationary bike, enough to power the lights in the room where the equipment is. Gyms that have installed the equipment report that users feel more motivated to exercise longer and harder when they know they’re generating power. That’s good for the person and helps reduce energy use for the gym. And that’s good for everyone, including our small pets.

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

Thanks for listening!

Episode 149: A Zebra with SPOTS

SOMEONE forgot their flash drive at work, so here’s a short but hopefully interesting episode about a mystery animal, a zebra with spots instead of stripes!

Ordinary zebras:



Show transcript:

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

This episode was going to be another listener suggestion, but I left my flash drive at work that has all my research and the half-written script on it. So that episode will be next week, and instead this week we’re going to learn about the mysterious spotted zebra.

Spotted zebras are occasionally, uh, spotted in the wild. They’re very rare but it’s well documented. A spotted zebra was photographed in a herd of ordinary plains zebras in Zambia in 1968, and much more recently, in September of 2019, a spotted zebra foal was photographed in Kenya.

A tour guide named Antony Tira in the Masai Mara National Reserve saw an unusual-looking zebra foal in the herd. Instead of the familiar black and white stripes of other zebras, with white belly, the foal was black all over except for small white spots. The foal has been nicknamed Tira after its discoverer.

Zebras, of course, are famous for their black and white stripes. But if a genetic mutation causes the ordinary striped pattern to be broken up, it can look like spots, or in some individuals narrow streaks. The only problem is, the spots on the zebra are white on a black background. You’d think that it would be the black stripes that would end up as black spots on a white background.

But, it turns out, we’re looking at zebras wrong. Zebras aren’t white with black stripes, they’re black with white stripes. So when a rare zebra is born with spots instead of stripes, the spots are white on a black background.

When a zebra embryo is developing inside its mother, its coat is entirely black. It develops its stripes late in its development, when skin cells form the pigments that will give the hair its color. The white fur grows from cells that contain less pigment than cells that grow black hair. Not only that, underneath the zebra’s hair, its skin is black.

Zebras live in parts of southern Africa on grasslands and savannas in both tropical and temperate areas. The common plains zebra is one of three species alive today, with a number of subspecies. It typically grows a little over four feet tall at the shoulder, or 1.3 meters, or about 12 hands high if you are measuring it the way you measure its close relation, the horse. It eats grass and other tough plants and lives in small herds. Each zebra’s stripe pattern is as unique as a fingerprint.

A zebra’s stripes serve several purposes. It helps camouflage the animal, which sounds absurd at first since there’s nothing quite as eye-catching as a zebra. But a bunch of striped animals milling about together can make it hard to figure out where one zebra ends and the next one begins. The pattern disrupts the body’s outline, too, which means a predator may have trouble figuring out where exactly the zebra is, especially when it’s partially hidden by tall grass and brush.

Not only that, the white hair helps reflect some of the sun’s heat away from the zebra. Dark colors absorb heat, and the zebra spends a lot of time in the hot sun. But having dark hair and skin helps keep the zebra from getting sunburned. That’s right, animals can get sunburned just like humans, although their fur generally helps block much of the sun’s infrared rays, which are the part of the light spectrum that causes sunburn. The dark pigment in the skin, called melanin, also helps block some of the infrared, stopping it from penetrating deeper into the skin.

Results of a study published in early 2019 shows that the cooling effects of the zebra’s coat are more complicated than just color, though. The zebra can raise the black hairs of its coat while the white hairs remain flat. The researchers propose that this helps transfer heat from the skin to the surface of the hairs by causing tiny air currents to form, which helps the zebra’s sweat evaporate more quickly and cool the body.

But another, more surprising reason for the stripes is to deter biting flies, especially the tsetse fly and the horsefly. Both carry diseases that can be fatal to zebras and other animals. Researchers had long noticed that zebras seem to be bitten less by flies than other animals are, and studies show that this is actually the case. In a study published at the beginning of 2019, some horses were given zebra-striped coats and monitored to see how flies reacted. It turns out that while the flies still approached the horses, they didn’t land on them nearly as often as they should have. Sometimes they’d even bump into the horse before flying away again without landing.

Researchers are still working out why. One hypothesis is that the tiny air currents caused by the raised black hairs make the air around the zebra just unstable enough that flies have trouble landing on the animal. Another is that the flies are attracted to linearly polarized light, which is disrupted by the stripes and make it hard for a fly to land on the zebra. In effect, they can’t actually see where the surface of the body actually is because their little fly eyes are dazzled by the pattern.

All this means that spotted zebras are at a disadvantage compared to ordinary striped zebras. The genetic mutation that causes the spots is called pseudomelanism, which basically causes more skin cells to produce more pigment than they should. The opposite of pseudomelanism is partial albinism, where the skin cells produce less pigment than they should. This results in a zebra that looks like it has cream-colored or pale gold stripes on a white background. Occasionally true albino zebras are born, where none of the cells produce pigment and the zebra is pure white without stripes at all.

Hopefully, little Tira will be fine despite having spots instead of stripes. The spotted zebra foal is definitely getting a lot of attention from photographers, tourists, and scientists.

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

Thanks for listening!

Episode 148: Gastric Brooding and Other Frogs

Thanks for Merike for suggesting the gastric brooding frog and to Hally for suggesting newly-discovered frogs!!

The Gastric brooding frog:

Darwin’s frog, round boi:

The Surinam toad carries her eggs and tadpoles in the skin of her back:

Kermit the frog and a newly discovered glass frog:

Show transcript:

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

This week we have another fantastic listener suggestion, about frogs! Merike is a herpetologist from Estonia, who suggested the gastric brooding frog, and another listener, Hally, also wanted to learn about some of the new frog species discovered recently.

The gastric brooding frog is native to eastern Australia, specifically Queensland. There are two species, and both of them live in creeks in separate rainforests. The habitat is specific and small, and unfortunately both species went extinct less than forty years ago. Researchers aren’t sure why they went extinct, but it was probably due to pollution and habitat loss.

The gastric brooding frog was a slender frog, with the northern gastric brooding frog being about three inches long, or about 8 cm, while the southern gastric brooding frog was about half that size. Females were larger than males. It was grey or brown-gray in color with some darker and lighter patches on the back with a lighter belly. During the day it spent most of its time at the water’s edge, hidden in leaf litter or among rocks, although it generally only fully came out of the water when it was raining. It ate insects and may have hibernated in winter.

As you may have guessed from its name, the gastric brooding frog had a unique way of taking care of its eggs. After the eggs were fertilized, the female would actually swallow the eggs and keep them in her stomach while they developed. Even after the eggs hatched into tadpoles, they stayed in the mother’s stomach. As they grew larger, the stomach also grew larger, until it pretty much filled up the mother’s insides, to the point where she couldn’t even use her lungs to breathe. Fortunately many frogs, including the gastric brooding frog, can absorb a certain amount of oxygen through the skin. Finally the tadpoles metamorphosed into little frogs, at which point the mother regurgitated one or a few of them at a time, or sometimes all of them at once if she felt threatened.

So how did the mother keep from digesting her own eggs or tadpoles? How did she eat when her stomach was full of babies? How did the babies eat?

The jelly around the gastric brooding frog’s eggs contained prostaglandin E2, also called PGE2, which causes the stomach to stop producing hydrochloric acid. That’s a digestive acid, so once the eggs were inside the stomach, the stomach basically stopped stomaching. There is some speculation that the first eggs the mother frog swallowed actually got digested, but then the acid production stopped and the rest of the eggs remained. Once the eggs hatched, the tadpoles also produced PGE2 in the mucus in their gills.

The tadpoles continued to live off the yolk sac from their eggs as they developed, and in fact their mouths weren’t even connected to their gut yet. As for the mother, she just didn’t eat until the babies were developed and released into the water on their own, which took about six weeks.

The gastric brooding frog is the only frog known to raise its babies this way, but other frog species have interesting variations of the usual way frogs reproduce. Most female frogs lay their eggs, and then the male fertilizes them. But about a dozen species of frog have developed internal fertilization, where the female retains the eggs in her body until the male fertilizes them. The tailed frog from California in the United States, in North America, gets its name from a structure that looks like a tail, but is actually an extension of the cloaca. That’s the opening used for both excretion and reproduction. Only males have the tail, and it works like a penis to fertilize the female’s eggs without her needing to lay the eggs first. Once they’re fertilized, she can choose just the right spot to lay the eggs.

Another weird way frogs take care of their eggs is something that Darwin’s frog does. Darwin’s frog lives in Chile and Argentina in South America, and grows to a little over an inch long, or 3 cm. It has a pointy snout that gives its head a wedge  shape something like a leaf, which helps keep it camouflaged on the forest floor. The female lays her eggs in damp leaf litter, and after the male fertilizes them he guards them for several weeks. When they start to move as they develop, the male swallows them—but instead of his stomach, he stores them in his vocal sac. That’s the expandable sac in the frog’s throat that males use to make their croaking sounds by filling the sac with air.

The eggs hatch into tadpoles, which the male carries around as they grow. They live off their egg yolks, but they also eat secretions from the lining of the vocal sac. Once the tadpoles metamorphose into little frogs, they hop out of the male’s mouth and are on their own. Until then, the male doesn’t eat.

The Surinam toad is a species of frog. Remember that all toads are frogs but not all frogs are toads. It lives in wetlands and forests in northern South America, and has a radically different way of keeping its eggs safe. The Surinam toad is a flattened, broad toad that can grow up to 8 inches long, or 20 cm, and looks a lot like a dead leaf. It lives in slow-moving water. Unlike other frogs it doesn’t have a tongue, so instead of catching insects with its sticky tongue, it grabs them with its hands. It’s sometimes called the star-fingered toad because its long, thin fingers have tiny star-shaped appendages that help it catch prey. Instead of croaking, male Surinam toads make a clicking noise by moving a small bone in the throat back and forth.

When the female is ready to lay her eggs, a male clasps her around the middle like most frogs do while mating. But instead of just releasing her eggs and letting the male release sperm to fertilize them, the female makes a sort of flipping movement in the water as she releases a few eggs at a time. The male fertilizes them, then presses them onto her back. The skin of the female’s back grows up over the eggs, embedding them in the skin in little pockets. When the tadpoles hatch they stay in these little pockets as they develop. They only leave when they’ve metamorphosed into tiny toads, at which point they emerge and live on their own. The mother then sheds the layer of skin on her back where her babies lived.

A frog described in 2014 that lives in parts of South Asia gives birth to tadpoles instead of laying eggs. It’s a species of fanged frog, which are frogs that do actually have teeth unlike most frogs. Limnonectes larvaepartus grows about 1 ½ inches long, or just under 4 cm. The eggs are fertilized internally, but instead of laying them the female keeps them in her oviducts until they hatch. They remain inside her until they no longer have any yolk left to nourish them, at which point the mother releases them into a slow-moving stream.

Lots of other interesting frogs have been discovered recently. A new frog discovered in southern India in 2018 was recently determined to be a member of its own genus. It’s called the narrow-mouthed frog and had gone unnoticed even though it lives in an area that’s been extensively explored by scientists. It only comes out into the open for less than one week out of the year during the short breeding season, and the rest of the time it hides. Obviously, we don’t know much about it yet.

In 2016 in the same area as the narrow-mouthed frog, researchers discovered a new species of frog with a tadpole that burrows through sand. It’s a member of the Indian dancing frog family, and not only do the tadpoles burrow through wet sand at the bottom of streams, they have ribs that help them move around more easily. Tadpoles are usually just squidges without bones. Dancing frogs get that name because the males wave their feet to attract females during mating season.

There are so many recently discovered frog species that it’s hard to know which ones to highlight. You know, like the new glass frog from Costa Rica described in 2015 that honestly looks just like Kermit the Frog, if Kermit had a translucent belly that showed his organs. Scientists don’t know why glass frogs have no pigmentation at all on their bellies. Or the three tiny frog species discovered in Madagascar and described earlier in 2019, all of them smaller than your thumbnail, that belong to a new genus, Mini. Their scientific names are therefore Mini mum, Mini scule, and Mini ature. The three are related to one of Madagascar’s biggest frogs, which grows over four inches long, or 10.5 cm, as opposed to the Mini frogs which top out at about 15 mm long. Hally sent me an article about eleven new species of frog discovered recently in the Andes, including the multicolored rain frog. It’s sometimes yellow, sometimes brown, sometimes green, speckled, splotched, spotted–so variable that at first scientists thought they were different related species. All eleven of the Andes frogs lay their eggs on land, and instead of hatching into tadpoles the eggs hatch into tiny froglets.

Frogs and other amphibians are sensitive to environmental change, which means a lot of species have either recently gone extinct or are critically endangered. Habitat loss and an amphibian fungal disease that has spread around the world are also making things hard for frogs and their relations. Scientists have been working hard lately to find species that are rare, suspected to be extinct, or are unknown to science, to learn about them while we can and do our best to preserve the species, either in the wild or in captivity. There are even multiple genetic resource banks, or biobanks, to preserve genetic material of frogs and other animals so that future scientists might be able to clone them.

There’s always the possibility that the gastric brooding frog isn’t actually extinct. The southern gastric brooding frog hasn’t been seen since at least 1981 despite extensive searches, though, with the last captive individual dying in 1983. The northern gastric brooding frog was only discovered in 1984 but hasn’t been seen since 1985.

But even if there aren’t any left in the wild, all hope isn’t lost. The gastric brooding frog is a good candidate for de-extinction, and cloning has actually been successful to a limited degree already. In 2013 a living embryo was produced from preserved genetic material, although it didn’t survive. Researchers are still working to clone the frogs and keep them alive. With luck the attempt will be successful, and not only can a population of the frogs be kept in captivity, they can be reintroduced to their former habitat one day.

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

Thanks for listening!