Tag Archives: rodents

Episode 484: The Sewellel and the Superflea

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The sewellel is a little rodent:

The superflea is a big flea (left, compared to a regular flea, right):

Show transcript:

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

Let’s learn about a rodent you may never have heard of, unless you live where it does, and a parasite that makes that rodent its host. It’s not an ordinary parasite, but don’t worry, it’s not icky. You can continue to snack.

The rodent is called the sewellel, Aplodontia rufa. It’s also called the mountain beaver even though it doesn’t always live in the mountains and it isn’t a beaver. It doesn’t even look like a beaver. For one thing, it only has a little nub of a tail and it only grows around 20 inches long, or 50 cm. It has small eyes and ears, short legs, a chunky body, and long claws. This body shape should give you a hint about its lifestyle: the sewellel is a digger, although it can also swim just fine and can even climb small trees to eat young twigs and leaves.

The sewellel is an aplodont, a large group of rodents that have been common in Europe, Asia, and North America for 40 million years. But it’s the only one left. All the other aplodonts went extinct several million years ago at least. We’ve actually talked before about one of the sewellel’s extinct relations, the horned gopher (which was not a gopher), in the Patreon episode about animals with nose horns.

The sewellel itself hasn’t been around all that long, only appearing in the fossil record a few million years ago. It lives in a small area of northwestern North America, in parts of British Columbia, Washington state, Oregon, and a few parts of California. It lives in forests where it doesn’t get too cold in the winter, since it doesn’t hibernate and isn’t as good at keeping itself warm as other rodents are. It also needs to drink more water than other rodents and prefers to live in wet climates as a result.

In fact, the sewellel is sometimes referred to as a living fossil since it lacks many features that all other living rodents have. Its teeth resemble a simpler version of squirrel teeth, so some researchers think it may be most closely related to squirrels, but even if that’s the case, it isn’t very closely related. The sewellel’s ancestors were more adapted to live in trees and a study published in 2018 determined that it had a larger brain than the sewellel. Since the sewellel is nocturnal and spends most of its life underground, it doesn’t need to see very well, and the part of the brain that processes vision is much smaller than in its ancestors.

The sewellel mostly eats ferns, although it also eats other plants, and some of its favorite plants are toxic to other animals. It’s a solitary, mostly nocturnal animal that digs deep, complex burrows, and it stays as close as possible to the burrow entrance so it can hide easily if it needs to. Everything eats the sewellel, from owls to coyotes to bobcats to eagles.

And that brings us to the parasite associated with the sewellel. Many animals have parasites that are specific to that particular species. The Patreon episode about whale lice has some information about how specific this can get. The male sperm whale has a different species of louse than the species that lives on female sperm whales, for instance. Also, the whale louse isn’t a louse, it’s a type of crustacean.

The sewellel’s parasite is a type of flea. Big deal, you say, fleas are all about the same.

Are they, though? Because the sewellel’s flea is actually kind of a big deal. It is, in fact, the largest flea known, called the superflea. It can grow up to 8 mm long (and possibly longer, reports vary). I just measured, and that’s the length of my little fingernail, from the base to the quick. Most species of flea are 3 mm long at most.

The superflea is only found on the sewellel. It looks like an ordinary flea except for its size, meaning it’s laterally flattened with legs that allow it to jump long distances. So why is it so big compared to other fleas, especially considering that it lives on an animal that’s about the size of a chonky cat? No one knows. No one has even the slightest idea why this flea is so big.

There used to be even bigger fleas, some up to two cm long. That’s 20 mm, or just a little more than twice the length of the superflea. Of course, those 20 mm fleas lived 165 million years ago and probably lived on dinosaurs. Also, they couldn’t jump and instead of being flattened laterally, or side to side, like modern fleas, they were flattened dorsoventrally, or top to bottom. So they weren’t very much like modern fleas.

That’s all we know about the superflea, but let’s have one last sewellel fact before we go. With all this talk of the sewellel being a primitive rodent whose closest relations are all extinct, you might think there’s nothing really special about it beyond its giant fleas. You would be wrong, though, because the sewellel’s front paws have opposable thumbs. It’s not as mobile as our opposable thumbs, but it allows the sewellel to manipulate food more easily. It will sometimes sit up on its big round bottom to eat, just like a really weird squirrel.

Thanks for your support, and thanks for listening!

Episode 483: Animals with Nose Horns

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The horned gopher:

Show transcript:

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

This time we’re going to learn about some mammals with weird horns. Specifically, weird nose horns. Nose horns are properly called rostral horns, but that’s not as funny.

We’ll start with a family of extinct rodents called horned gophers, or more properly, mylagaulids. The horned gopher wasn’t a gopher, but it probably looked similar to ground squirrels like prairie dogs and marmots. It lived in what is now North America around twenty million years ago, and it had a pair of short, broad horns that pointed upwards between the nose and eyes, like a rhino’s horns but side by side and made of bone, not keratin. It was big for a rodent, about a foot long, or 30 cm, and ate plants.

So what did the horned gopher use its horns for? Both males and females had the horns and they’re too short and placed too far back for males to use them to fight each other. Horned gophers had poor eyesight so males probably weren’t trying to look and act flashy to attract females anyway.

At first researchers thought the horns helped in digging burrows. The horned gopher primarily used what’s called the head-lift method of digging, which means it pushed its nose into the dirt, then lifted its head with powerful neck muscles to remove a chunk of soil—basically using its nose as a shovel. But its horns pointed straight up and were set too far back on the nose to help with digging. Most researchers today think the horns were used for defense. If a predator tried to grab the animal by the neck, it could snap its head back and stab the predator right in the face.

The horned gopher had tiny eyes and front feet that resembled a mole’s, with long claws. Researchers think its ancestors probably spent most of the time underground, but that as it evolved to become larger, it also spent more time foraging above-ground. That led to more predators being able to attack it, so evolving horns as a defensive weapon helped it survive.

While the horned gopher was distantly related to modern squirrels, its family is completely extinct these days. But it’s still the smallest known horned mammal that ever lived.

The horned gopher is also the only horned mammal known that lived mostly underground in burrows. Almost. There was once a type of armadillo, naturally called the horned armadillo but more properly referred to as Peltephilus [pelta-FEElus], that had a pair of horns over its eyes but a little in front of them, close to where the horned gopher’s horns were. The horned armadillo’s horns developed from scutes on its head, and if you remember, scutes are bony plates embedded in the skin as armor. It might also have had a smaller pair of horns over its nostrils. It lived in what is now South America and went extinct around 11 million years ago.

The horned armadillo dug burrows liked the horned gopher did, but it was much bigger than the horned gopher, with some species as much as five feet long, or 1.5 meters. Despite its size, it probably resembled the pink fairy armadillo in overall shape rather than the more common nine-banded armadillo that lives in parts of North America. It had a short tail and its rump was squared off instead of rounded. It also had big sharp teeth. It may have eaten insects, possibly digging up ant nests, but more likely it mostly ate roots and other plant parts.

Arsinoitherium was another animal with nose horns, this one from Africa. It lived around 30 million years ago and was related to modern-day elephants, but it lived in swampy areas and tropical rainforests and ate plants. It probably looked a little like a rhinoceros and a little like a small elephant without a trunk. Different species were different sizes, but they were all pretty big, probably no smaller than about six feet tall at the shoulder, or 1.75 meters. And they had two pairs of horns, a little pair more like bumps over the eyes and two side-by-side forward-pointing giant nose horns that looked a lot like rhino horns but thicker. But they were real horns made of bone, not keratin, although they may have been covered in skin and hair like ossicones. You know, ossicones are those hornlike structures giraffes have.

Brontotherium looked a lot like a rhinoceros too, but that’s because it was distantly related to the rhino, although it was more closely related to the horse. It lived in North America around 35 million years ago and was enormous, standing around 8 feet tall at the shoulder, or 2.5 meters. It was a selective browser, probably preferring tender leaves to tough grass. It carried its massive head low like modern rhinos and buffalo do, and had a humped shoulder like both those animals where its massive neck muscles attached. And it had a pair of nose horns.

Both males and females had the nose horns, but the males’ horns were much larger. The horns were blunt and shaped sort of like a V, and researchers are pretty sure males used them to fight each other. We have fossilized brontotherium rib bones that show an injury shaped just like the nose horns. The horns were probably also useful to fight predators. Even though brontotherium was related to the rhino, its horns were bone, not keratin.

Our last nose horn animal lived in North America up to about five million years ago. The various species of Protoceratidae [pro-TOSS-e-rated-die] were hoofed animals that looked sort of like deer, but were more closely related to a living ungulate called the chevrotain, or mouse deer. Protoceratid probably ate grass and other plants and may have lived in herds. Males had a pair of ordinary horns that looked a lot like cow horns, and in some species females had the horns too, although they were smaller. But males also had a horn on the nose. And it was weird.

Once again, the nose horn wasn’t like a rhino’s horn, which as we have established by now is made of keratin. And maybe I should have reminded you before now that keratin is the same protein that makes hair, fingernails, hooves, and things like that. Keratin also doesn’t fossilize. This nose horn was an actual horn made of bone, but researchers think it may have been covered with skin and fur like an ossicone.

Different Protoceratidae had different nose horns. Syndyoceras had a pair of nose horns that were fused at the base, then split apart to form a V shape. It may also have had large nasal passages that made its muzzle look much bigger than the skull would suggest at first glance. Synthetoceras had a long nose horn that grew up and slightly forward but split into a Y at the tip. Kyptoceras had a pair of nose horns that pointed forward. Researchers think the males used these nose horns to fight each other, much like deer fight with their antlers today.

One older Protoceratid that lived up to around 20 million years ago was called Protoceras, and males had three pairs of horns, although they probably resembled ossicones and were all covered in skin and hair. A small pair grew between the ears, another pair between the eyes and nose, and the largest pair grew on the nose. Females only had one smaller pair of horns between the ears, so the extra horns males had were probably for display.

Some Protoceratidae also had a pair of fanglike canine teeth that they may have used to root around in dead leaves for plant material. Male chevrotains have fangs like this too, but they use them to fight each other since they don’t have horns.

So basically, this is what we’ve learned from this episode: There used to be a lot more nose-horned animals than we have now, most of them lived in the Americas for some reason, and they were all awesome. Also, even though the first animal we think of when someone mentions nose horns is the rhino, the rhino’s keratin horns are actually unusual. Just be glad you’re not an intelligent birdlike creature from the far future trying to figure out what a rhinoceros actually looked like when it was alive.

Thanks for your support, and thanks for listening!

Episode 479: Metal Animals

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Further reading:

Beavers Have Metal Teeth

Show transcript:

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

Let’s find out about some animals that incorporate metal into their bodies in more than just trace amounts.

We’ll start with the scaly-foot gastropod, a deep-sea snail. It lives around hydrothermal vents in the Indian Ocean, about 1 and ¾ miles below the surface, or about 2800 meters. The water around these vents, referred to as black smokers, can be more than 350 degrees Celsius. That’s 660 degrees F, if you even need to know that that’s too hot to live.

The scaly-foot gastropod was discovered in 2001 but not formally described until 2015. The color of its shell varies from almost black to golden, depending on which population it’s from, and it grows to almost 2 inches long, or nearly 5 cm. It doesn’t have eyes, and while it does have a small mouth, it doesn’t use it for eating. Instead, the snail contains symbiotic bacteria in a gland in its esophagus. The bacteria convert toxic hydrogen sulfide from the water around the hydrothermal vents into energy the snail uses to live. It’s a process called chemosynthesis.

In return, the bacteria get a safe place to live.

The snail’s shell contains an outer layer made of iron sulfides. Not only that, the bottom of the snail’s foot is covered with sclerites, or spiky scales, that are also mineralized with iron sulfides. While the snail can’t pull itself entirely into its shell, if something attacks it, the bottom of its foot is heavily armored and its shell is similarly tough.

Researchers are studying the scaly-foot gastropod’s shell to possibly make a similar composite material for protective gear and other items. The inner layer of the shell is made of a type of calcium carbonate, common in mollusk shells and some corals. The middle layer of the shell is regular snail shell material, organic periostracum, which helps dissipate heat as well as pressure from squeezing attacks, like from crab claws. And the outer layer, of course, is iron sulfides like pyrite and greigite. Oh, and since greigite is magnetic, the snails stick to magnets.

The scaly-foot gastropod is the only animal known that incorporates iron sulfide into its skeleton, but other animals use metals in their teeth. Some spiders have tiny amounts of zinc in the tips of their fangs. Some mollusks have small amounts of iron in the teeth of their radulas—you know, the tongue-like structure used to scrape food off rocks. The teeth of the limpet, a type of mollusk, may be one of the strongest structures in the world. It contains goethite nanofibers, and goethite is a type of iron.

The teeth of beavers and some other rodents contain iron in the enamel coating. This makes the teeth much harder, although the amount of iron is quite small and unstructured. Most other mammals, including humans, have magnesium in tooth enamel instead of iron. The iron content makes the teeth look orange because of rust.

Bloodworms are disgusting horrible worms that my uncle used to fish with when we visited the beach when I was a kid. I was scared of the bloodworms, which irritated my uncle, because I was very vocal about hating the worms and he wasn’t catching any fish with them. Bloodworms live in the sand or silt of shallow water, usually in the ocean but since they can tolerate low salt levels, they may also live farther inland in canals and inlets. Some species can grow nearly 15 inches long, or 37 cm. They’re usually pink or reddish in color with bristles along the body and four little antennae on the head. But the reason I’m talking about them here is that their teeth are reinforced with copper that makes them nearly as hard as teeth coated with enamel. Its jaw also contains copper ions.

Copper is toxic to most animals, which may be the source of the bloodworm’s venom. That’s right: horrible worms are also venomous.

Another invertebrate that incorporates metal in its body is the parasitic fig wasp. Fig wasps are interesting and there are a lot of them. Figs are pollinated by fig wasps that are not parasitic. The fig flower has a bulb at its base containing a tiny hole. The pollinating fig wasp crawls into the hole, pollinating the flower at the same time, and lays her eggs inside the bulb. She then dies. As the fig developes, the wasp eggs hatch into larvae and then develop into adult wasps. Males mate with females, then chew a hole out of the fig, but only the female wasps have wings, so the males remain and die. As the fig ripens, it actually digests the dead wasps, and—and this is important to those of us who really like figs—leaves no bits of dead wasp inside the fig. So that’s how the pollinating fig wasps work. It’s a symbiotic relationship between the fig tree and the wasp.

But the parasitic fig wasp is different. The female has a long ovipositor, which it uses to drill into developing figs and into the pollinating fig wasp larvae. When its eggs hatch, they eat the larva alive. This is yet another reminder that nature is disgusting! But the really interesting thing is that at least one parasitic fig wasp species, Apocrypta westwoodi, has an ovipositor that resembles a drill bit, and it’s hardened with zinc. The ovipositor is basically a syringe with a drill bit, but since it’s so strong while being much thinner than a human hair, researchers are studying its structure to help develop minimally invasive medical syringes.

One interesting note. You’d think that iron and other metals would be more common in animal bodies as armor. Animals use some metals for various purposes as it is, like the iron containing hemoglobin in our blood. But incorporating iron and other metals into the body has a high metabolic cost and frequently biological materials are stronger than metal in the ways that count. Plus, they don’t rust.

Thanks for your support, and thanks for listening!

The Books Have Been Claimed! and a bonus mouse

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I just wanted everyone to know that a listener has claimed the books and magazines I offered for giveaway in episode 443. You can also learn about 60 seconds’ worth of information about the African pygmy mouse.

The tiniest mouse [photo by Alouise Lynch – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=59068329]:

Episode 437: Updates 8 and the Nutria

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Thanks to Nicholas, Måns, Warblrwatchr, Llewelly, and Emerson this week, in our yearly updates episode!

Further reading:

An Early Cretaceous Tribosphenic Mammal and Metatherian Evolution

Guam’s invasive tree snakes loop themselves into lassos to reach their feathered prey

Rhythmically trained sea lion returns for an encore — and performs as well as humans

Scientists Solve Mystery of Brown Giant Pandas

Elephant turns a hose into a sophisticated showering tool

New name for one of the world’s rarest rhinoceroses

Antarctica’s only native insect’s unique survival mechanism

Komodo dragons have iron-coated teeth to rip apart their prey

The nutria has really orange teeth:

Show transcript:

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

This week is our annual updates episode, and we’ll also learn about an animal suggested by Emerson. But first, we have some corrections!

Nicholas shared a paper with me that indicates that marsupials actually evolved in what is now Asia, with marsupial ancestors discovered in China. They spread into North America later. So I’ve been getting that wrong over many episodes, over several years.

Måns shared a correction from an older episode where I mentioned that humans can’t get pregnant while breastfeeding a baby. I’ve heard this all my life but it turns out it’s not true. It is true that a woman’s fertility cycle is suppressed after giving birth, but it’s not related to breastfeeding. Some women can become pregnant again only a few months after giving birth, while others can’t get pregnant again for a few years. It depends on the individual. That’s important, since the myth is so widespread that many women get pregnant by accident thinking they can’t since they’re still feeding a baby.

Warblrwatchr commented on the ultraviolet episode and mentioned that cats can see ultraviolet, which is useful to them because mouse urine glows in UV light.

Finally, Llewelly pointed out that in episode 416, I didn’t mention that fire ant venom isn’t delivered when the ant bites someone. The ant bites with its mandibles to hold on, then uses the stinger on its back end to sting repeatedly.

Now, let’s dive into some updates about animals we’ve talked about in past episodes. As usual, I don’t try to give an update on every single animal, because we’d be here all week if I did. I just chose interesting studies that caught my eye.

In episode 402, we talked about snakes that travel in unusual ways, like sidewinders. Even though I had a note to myself to talk about the brown tree snake in that episode, I completely forgot. The brown tree snake is native to parts of coastal Australia and many islands around Indonesia and Papua New Guinea. It’s not native to Guam, which is an island in the western Pacific, way far away from the brown tree snake’s home. But in the late 1940s, some brown tree snakes made their way to Guam in cargo ships and have become invasive since then.

The brown tree snake can grow up to six and a half feet long, or 2 meters, and is nocturnal, aggressive, and venomous. It’s not typically a danger to adults, but its venom can be dangerous to children and pets. The government employs trained dogs to find the snakes so they can be removed, and this has worked so well that brown tree snake population is declining rapidly on the island. But that hasn’t stopped the snake from driving many native animals to extinction in the last 75 years, especially birds.

One of the things scientists did in Guam to try and protect the native birds was to place smooth poles around the island so birds could nest on top but snakes couldn’t climb up to eat the eggs and chicks. But before long, the snakes had figured out a way to climb the poles, a method never before documented in any snake.

To climb a pole, the snake wraps its body around it, with the head overlapping the tail. Then it sort of scoots itself up the pole with tiny motions of its spine, a slow, difficult process that takes a lot of energy. Tests of captured brown tree snakes afterwards showed that not all snakes are willing or able to climb poles this way. Scientists think the brown tree snake evolved this method of movement to climb smooth-trunked trees in its native habitat. They also suspect some other species of snake can do the same.

Way back in episode 23 we talked about musical animals, including how some species can recognize and react to a rhythmic beat while most can’t. Sea lions are really good at it, especially a sea lion named Ronan.

Ronan was rescued in 2009 when she was a young sea lion suffering from malnutrition, wandering down a highway in California. She was determined to be non-releasable after she recovered, so she’s been a member of the Pinniped Lab in the University of California – Santa Cruz ever since, where she participates in activities that help scientists study sea lions. The rhythm studies are only one of the things she does, and only occasionally. The scientists put on a metronome and she bobs her head to the beat while they film her in ultra-slow motion.

The latest study was published in May of 2025. Ronan is 16 years old now and in her prime, so it’s not surprising that she performed even better than her last tests when she was still quite young. The study determined that not only does Ronan hit the beat right on time, she’s actually better at it than a human a lot of the time. She hits the beat within 15 milliseconds. When you blink your eye, it takes 150 milliseconds. If only she had hands, she’d be the best drummer ever!

The greatest thing about this process is that Ronan enjoys it. She’s rewarded with fish after a training session, and if she doesn’t feel like doing an activity, she doesn’t have to.

Back in episode 220, we talked about the giant panda, especially the mysterious Qinling panda that’s brown and tan instead of black and white. A study published in March of 2024 looked into the genetics of this unusual coat color and determined that it was a natural genetic mutation that doesn’t make the animals unhealthy, meaning it probably isn’t a result of inbreeding.

We talk occasionally about tool use in animals, especially in birds like crows and parrots, and in primates like chimpanzees. But a study published in November of 2024 detailed an elephant in the Berlin Zoo that uses a water hose to shower.

You may not think that’s a big deal, but the elephant in question, named Mary, uses the hose the way a human would to shower off. She holds the hose with her trunk just behind the nozzle, then moves it around and shifts her body to make sure she gets water everywhere she wants. She has to sling the hose backwards to clean her back, and when researchers gave her a heavier hose that she couldn’t move around as easily, she didn’t bother with it but just used her own trunk to spray water on herself.

Even more interesting, another elephant, named Anchali, who doesn’t get along with Mary, will interfere with the hose while Mary is using it. She lifts part of the hose to kink it and stop the water from flowing. Sometimes she even steps on the hose to stop the water, something the elephants have been trained not to do since zookeepers use hoses to clean out the enclosures. Anchali only steps on a hose if Mary is using it.

This is the first time researchers have studied a water hose as tool use, but it makes sense for elephants to understand how to use a hose, since they have a built-in hose on their faces.

We talked about the rhinoceros in episode 346, and more recently in the narwhals and unicorns episode. A study published in March of 2025 suggested that the Javan rhino should be classified as a new species of rhino in its own genus. The Javan rhino is incredibly rare, with only about 60 individuals alive in the world, all of them living in the wild in one part of Java. The Javan rhino is also called the Sundaic rhinoceros, and it’s been considered a close relation of the Indian rhinoceros. It’s smaller than the Indian rhino and most Javan rhino females either don’t have a horn at all or only have a big bump on the nose instead of a real horn.

The Javan rhino is so rare that we don’t really know much about it. The new study determined that there are big enough differences between the Javan rhino and the Indian rhino, in their skeletons, skin, diet, behavior, and fossil remains, that they should be placed in separate genera. The proposed new name for the Javan rhino is Eurhinoceros sondaicus instead of Rhinoceros sondaicus.

The only insect native to Antarctica is the Antarctic midge, which we mentioned in episode 221 but haven’t really talked about. It’s a flightless insect that can grow up to 6 mm long, and it’s the only insect that lives year-round in Antarctica. It’s only been found on the peninsula on the northwestern side of the continent.

Every animal that lives in Antarctica is considered an extremophile, and this little midge has some remarkable adaptations to its harsh environment. Its body contains compounds that minimize the amount of ice that forms in its body when the temperature plunges. It’s so well adapted to cold weather that it actually can’t survive if the temperature gets much above freezing. It eats decaying vegetation, algae, microorganisms, and other tiny food in its larval stages, but doesn’t eat at all as an adult.

The midge spends most of its life as a larva, only metamorphosing into its adult form after two winters. During its first winter it enters a dormant phase called quiescence, but as soon as the weather warms, it can resume development. It enters another dormant phase called obligate diapause for its second winter, where it pupates as soon as the weather gets cold. When summer arrives, all the midges emerge as adults at the same time, which allows them to find mates and lay eggs before dying a few days later.

The female midge lays her eggs and deposits a jelly-like protein on top of them. The jelly acts as antifreeze and keeps the eggs from drying out, and when the eggs hatch, the babies can eat the jelly.

In episode 384, we talked about the Komodo dragon, and only a month or so after that, and right after the 2024 updates episode, a new study was released about Komodo dragon teeth. It turns out that the Komodo dragon has teeth that are tipped with iron, which helps keep them incredibly sharp but also strong. As if Komodo dragons weren’t already scary enough, now we know they have metal teeth!

Many animals incorporate iron in their teeth, especially rodents, which causes some animals to have orange or partially orange teeth. In the Komodo dragon, the iron is incorporated into the tooth’s enamel coating, but only on the tips of the teeth. Since Komodo dragons have serrated teeth, that’s a lot of very sharp points.

There’s no way currently to test fossilized teeth to see if they once contained iron, especially since the iron would most likely be deposited in the tooth coating, the way it is for animals living today, not in the tooth itself. But because the Komodo dragon has teeth that are very similar in many ways to the teeth of meat-eating dinosaurs, scientists think some dinosaurs may have had iron in their teeth too.

And that brings us to the nutria, an animal suggested by Emerson. Emerson likes the nutria because of its orange teeth, and hopefully you can guess why its teeth are orange.

The nutria is also called the coypu, and it’s a rodent native to South America. In Spanish the word nutria means otter, so in South America it’s almost exclusively called the coypu, and the name coypu is becoming more popular in other languages too. It’s been introduced to other parts of the world as a fur animal, and it has become invasive in parts of Europe, Japan, New Zealand, and the United States.

The nutria is a semi-aquatic rodent that looks like a muskrat but is much bigger, up to two feet long, or 64 cm, not counting its tail. It also kind of looks like a beaver but is smaller. If you’re not sure which of these three animals you’re looking at, since they’re so similar, the easiest way to tell them apart is to look at their tails. The beaver has a famously flattened paddle-like tail, the muskrat’s tail is flattened side to side to act as a rudder, and the nutria’s tail is just plain old round. The nutria also has a white muzzle and chin, and magnificent white whiskers.

The nutria mostly eats water plants and is mostly active in the twilight. While it usually lives around slow-moving streams and shallow lakes, it will also tolerate saltwater wetlands. Wild nutrias are generally dark brown, but ones bred for their fur are often blond or even white.

The nutria digs large dens with the entrance usually underwater, but the nesting chamber inside is dry. It also digs for roots. This can cause a lot of damage to levees and riverbanks, which is why the nutria is so destructive as an invasive animal. It will also eat people’s gardens and commercial crops like rice and alfalfa.

One interesting thing about the nutria is that the female has teats that are high up on her sides, which allows her babies to nurse even when they’re all in the water.

The nutria’s big incisor teeth are bright orange, as we mentioned before. This is indeed because of the iron in the enamel that strengthens the teeth. Like other rodents, the nutria’s incisors grow throughout its life and are continually worn down as it chews tough plants. A nutria eats about 25% of its weight in plants every single day. That’s almost as much as me and pizza.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 432: The Fossa and Other Animals of Madagascar

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This week we learn about the fossa and a few other animals of Madagascar, a suggestion by Pranav!

Further reading:

The stories people tell, and how they can contribute to our understanding of megafaunal decline and extinction in Madagascar

The fossa!

The votsotsa is a rodent, not a rabbit! [photo by Andrey Giljov – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=113271739]:

The golden mantella frog is sometimes golden, but sometimes red:

The nano-chameleon may be the smallest reptile in the world:

Show transcript:

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

This week we have a very old Pranav suggestion, animals of Madagascar!

The island country of Madagascar is off the southeastern coast of Africa. About 88 million years ago, it broke off from every other landmass in the world, specifically the supercontinent Gondwana. The continent we now call Africa separated from Gondwana even earlier, around 165 million years ago. Madagascar is the fourth largest island in the world and even though it’s relatively close to Africa these days, many of its animals and plants are much different from those in Africa and other parts of the world because they’ve been evolving separately for 88 million years.

But at various times in the past, some animals from Africa were able to reach Madagascar. We’re still not completely sure how this happened. Madagascar is 250 miles away from Africa, or 400 kilometers, and these days the prevailing ocean currents push floating debris away from the island. In the past, though, the currents might have been different and some animals could have arrived on floating debris washed out to sea during storms. During times when the ocean levels were overall lower, islands that are underwater now might have been above the surface and allowed animals to travel from island to island until they reached Madagascar.

We’re not sure when the first humans visited Madagascar, but it was at least 2,500 years ago and possibly as much as 9,500 years ago or even earlier. It’s likely that hunting parties would travel to Madagascar and stay there for a while, then return home with lots of food, but eventually people decided it would be a nice place to live. By 1,500 years ago people were definitely living on the island.

Let’s start with the fossa, an animal we’ve only talked about on the podcast once before, and then only in passing. It resembles a type of cat about the size of a cougar, although its legs are short in comparison to a similarly-sized cat. Its tail is almost as long as its body, and if you include its tail, it can grow around five feet long, or 1.5 meters. It’s reddish-brown with a paler belly. Its head is small with a short muzzle, rounded ears, and big eyes.

But the fossa isn’t a felid. It resembles a really big mustelid in many ways, especially a mongoose, and some studies suggest it’s most closely related to the mongoose. Really, though, it’s not closely related to anything living today. It spends a lot of time in trees, where it uses its long tail to help it balance. It even has semi-retractable claws. It eats lemurs and other mammals, birds, insects, crabs, lizards, and even fruit.

There used to be an even bigger fossa called the giant fossa, although we don’t know much about it. We only know about it from some subfossil remains found in caves. We’re not sure how big it was compared to the fossa living today, but it was definitely bigger and stronger and might have grown 7 feet long including its tail, or a little over 2 meters. There used to be much bigger lemurs living on Madagascar that have also gone extinct, so the giant fossa probably evolved to prey on them.

Most scientists estimate that the giant fossa went extinct at least 700 years ago, but some think it might have survived in remote areas of Madagascar until much more recently. There are even modern sightings of unusually large fossas, sometimes reported as twice the size of a regular fossa.

One interesting thing about the fossa is that its anus is hidden most of the time by a little fold of skin called an anal pouch, sort of like built-in underwear.

One animal most people outside of Madagascar have never heard of is the votsotsa, also called the Malagascar giant rat or the giant jumping rat since it’s a rodent that is especially known for its ability to jump. It actually looks a lot like a rabbit in size and shape, including its long ears, but it has a long tail. It’s gray or brown in color and grows about a foot long, or 30 cm, with a tail that can be up to 10 inches long, or 25 cm.

The votsotsa mates for life and both parents raise the single baby the mother gives birth to once or twice a year. It’s a nocturnal animal that spends the day in its burrow, which can be as much as 16 feet long, or 5 meters, with multiple exits. It eats nuts and seeds, fruit, leaves, and other plant material, along with insects and other small animals.

Lots of bats live on Madagascar, including the Madagascar flying fox. It’s a fruit-eating bat that’s brown or golden-brown in color with gray or black wings, and it’s the biggest bat native to the island. It has a wingspan of more than four feet across, or 125 cm. Like other species of flying fox, it lives in colonies of up to a thousand individuals that roost together in trees during the day. It mostly forages in the evenings, searching for fruit like figs. It eats flowers and sometimes leaves as well as fruit, and it may even be a pollinator for the kapok tree’s flowers.

Naturally, Madagascar also has a lot of reptiles, amphibians, and other non-mammalian animals. For instance, the golden mantella frog. It’s a little frog that’s only found in a few small areas, and measures around 20 millimeters long snout to vent. Some individuals are golden yellow while others are bright orange or red. As you may remember from our many previous episodes about frogs, such bright colors act as a warning to potential predators, to let them know that the frog is toxic. It absorbs toxins from some of the insects it eats. It’s active during the day in summertime, and in winter it spends most of the time hiding and doing nothing, which is the best way to spend the winter.

There are also lots of chameleons on Madagascar, including one called the nano-chameleon. It gets its name from its size, which is extremely small. It’s the smallest chameleon in the world, only 29 mm long at the very most, which is barely more than an inch long. Males are smaller than females, usually around 22 mm. It was described in 2021 and is brownish-grey with pale yellow or yellow-brown markings. Chameleons are famous for changing color, but the nano-chameleon doesn’t. It also mostly lives on the ground, where it hunts tiny insects and other invertebrates. Some scientists think it may be the smallest reptile in the world.

The female Darwin’s bark spider is about the same size as the female nano-chameleon, if you don’t count the spider’s legs. Males are much smaller. Darwin’s bark spider is a type of orb-weaver, which is the kind of spider that spins large webs that look like Halloween decorations. It was described in 2010 after first being discovered by scientists in 2009, which is surprising because it builds the largest orb webs known. Some webs can be over 30 square feet in size, or 2.8 square meters.

The silk is the strongest biological material ever studied, twice as strong as any other spider silk studied. The spider builds its web over water, because it eats a lot of mayflies and other insects that are attracted to water. It also eats a lot of dragonflies, and dragonflies are quite large and strong insects that don’t usually get caught in spiderwebs.

The people of Madagascar are considered very poor compared to other countries, after almost a century of French colonization and the resulting instability after it regained independence in 1960. A lot of animals that were once considered to be forbidden to bother, for religious and cultural reasons, now end up killed so people can eat them instead of starving. Mining and slash-and-burn agriculture has also contributed to pollution, habitat loss, and other factors that aren’t good for the animals of Madagascar or its people. Luckily, eco-tourism, where people visit the island to experience its beauty and see animals and plants found nowhere else on earth, is becoming more common. Hopefully that will help improve conditions for the people who live there and for the animals too.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 423: Pack Rats and Busy Mice

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Further reading:

Mouse filmed moving items in man’s shed in Bristol

The pack rat:

Show transcript:

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

This week I’m sharing a Patreon episode from last year because I have surgery scheduled. Don’t worry, it’s minor thyroid surgery and I’ll be fine, but my doctor said that a side effect might be hoarseness while I recover. Rather than risk sounding like an old frog, and to allow myself lots of time to rest afterwards, I’ve scheduled Patreon episodes for this week and next week.

At the beginning of this year, in early January 2024, you may have heard about a man in Wales who had an interesting visitor to his work shed. Rodney Holbrook is 75 years old and a retired postal worker, and at the end of 2023 he started noticing something weird. Things in his work shed kept being moved, and not in a way that suggested another person was getting in.

Initially Rodney noticed that some bird food had been moved into an old pair of shoes. This wasn’t just a one-time thing that would suggest an accident, like maybe Rodney had absent-mindedly decided to store the bird food in his shoes, or maybe it just fell there. The bird food kept ending up in the shoes.

Other things kept getting moved too. Small items that Rodney had left out while making and repairing things at his work bench kept getting put into a box, like tools and nuts and bolts. It happened almost every night.

Fortunately, Rodney is also a wildlife photographer, and he just happened to have a night vision camera. He set it up in the shed to find out what on earth was going on.

A mouse was going on, that’s what was going on. This actually wasn’t a huge surprise to Rodney, because years before, in 2019, a friend of his had had the same thing happen.

His friend was Steve Mckears who lived near Bristol, England. Steve kept crushed peanuts in a tub to use as bird food, but he started to notice other things mixed in with the peanuts. First it was just one screw, then it was lots more things that he’d left around his shed. He couldn’t figure out a solution, because he always locked his shed at night.

As Steve said at the time, “I was worried. I’m 72 and you hear of things going wrong with 72-year-old gentlemen in the mind.” Fortunately, Steve’s friend Rodney set up a camera and proved that there was nothing wrong with Steve’s mind or with the shed’s lock. It was just a mouse who was tidying up.

The question is why are these mice tidying up someone else’s shed? Don’t the mice have sheds of their own to clean up? It’s probable that the mice are actually living in the sheds and are wondering why some humans keep barging in every day and making a mess.

Rodents of all kinds do tend to tidy up as part of the foraging and nesting process. Sometimes that means moving debris so the animal can find important items more easily, sometimes it means bringing items back to its nest. House mice and rats will steal small items from humans to make nests, like socks and facecloths. Some rodents are attracted to shiny things and will stash them away or even bury them.

One animal, the pack rat, is so famous for storing items that we call a person who likes to collect things a pack rat. The pack rat lives throughout much of North and Central America and is related to mice and rats. It’s bigger than a mouse but smaller than most rats, and some species have furry tails like ground squirrels. It builds a den out of whatever materials are available where it lives, and its den is complex and usually well hidden. Desert species like to build under a cactus, while others live in cliffs or among rocks, in abandoned buildings or sometimes non-abandoned buildings, under bushes, in the tops of trees, or even in the entrances to caves. The den can be quite large and contains numerous rooms used for food storage, sleeping, and storing all the interesting things the pack rat finds while foraging.

A pack rat constructs a debris pile to hide its den, referred to as a midden. “Midden” is an old-fashioned word used to describe a place where household waste used to be thrown. Archaeologists love middens because you can learn a lot about people by the things they throw away, and other scientists love pack rat middens for the same reason. Some pack rat middens have been discovered preserved for 50,000 years, which has allowed scientists to learn a lot about what plants were growing in the area at the time. Since the middens also contain the pack rat’s fecal pellets, the scientists can also learn a lot about what the rat was eating, how big it was, and so forth.

Pack rats especially like shiny objects and will steal from people. In 2017 when historians were restoring an old home in Charleston, South Carolina dating back to 1808, they discovered several old pack rat middens in the walls of the kitchen. The middens contained buttons, marbles, sewing pins, and even some scraps of paper, including bits of newspaper with a readable date from November 1833. But some of the other bits of paper were torn from a writing primer, a book for people learning how to read or write. That’s not much of a surprise until you remember that this was the early 19th century, that the house was owned by a slave trader, and that the kitchen in particular would have been staffed by enslaved people, who were not supposed to learn how to read. Thanks to the pack rats, we know that at least one person was secretly learning how to read and write. I just hope the rats didn’t do too much damage to their book.

The pack rat is also sometimes called a trader rat, because it can only carry one thing at a time. If it’s carrying an acorn home and it chances upon a shiny gold ring, it will drop the acorn and carry the ring home. But you wanted an acorn, didn’t you, instead of that ring?

As for mice tidying up, we don’t really know why they do it, but it’s probably actually quite common. It just happens at night when people aren’t around, and in the morning they don’t know why all the nails have been moved into the box of nails, but hey, isn’t that handy? It reminds me of the stories of little house spirits called brownies, which were supposed to work at night cleaning and tidying. When the family woke up the next morning, the house or workshop was, ahem, squeaky clean, and all the family had to do was leave out a little cake or cream every night for the brownie.

Thanks for your support, and thanks for listening!

Episode 418: Animals Discovered in 2024

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This week we take a look at some of the many animals that were discovered last year!

Further reading:

‘Blob-Headed’ Catfish among New Species Discovered in Peru

New Species of Dwarf Deer Discovered in Peru

Hylomys macarong, the vampire hedgehog

Hairy giant tarantula: The monster among mini tarantulas with ‘feather duster’ legs

Woods Hole Oceanographic Institution and partners discover new ocean predator in the Atacama Trench

Never-before-seen vampire squid species discovered in twilight zone of South China

The blob headed catfish [photo by Robinson Olivera/Conservation International]:

A new mini tarantula [photo by David Ortiz]:

Show transcript:

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

This week is the 8th year anniversary of this podcast, so thanks for listening! It’s also our annual discoveries episode, where we’ll learn about a few animals that were discovered last year–in this case, in 2024.

Let’s start in Peru, a country in western South America. A 2022 survey of organisms living in the Alto Mayo region was published at the very end of 2024, revealing at least 27 new species and potentially more that are still being studied. One of those new species is a fish called the blob headed catfish.

The new fish has been placed in the bristlemouth armored catfish genus, but as you can probably guess from its name, it has a big blobby head and face. Scientists have no idea why it has a blob head. It lives in mountain streams and that’s about all we know about it right now.

Another animal found in the same survey is a new mouse. It lives in swampy forests and is semi-aquatic, including having webbed toes. It’s dark gray in color and is probably closely related to the Peruvian fish-eating rat, which is mostly brown in color and was only described in 2020.

Another new species from Peru is a type of small deer, called a pudu, that has been named Pudella carlae. It’s one of those “hidden in plain sight” discoveries, because until 2024 it was thought to be the same as the northern pudu that also lives in Ecuador and Colombia. The new deer is only 15 inches tall, or 38 cm, and is dark brownish-orange in color with black legs and face. It only lives in Peru, mostly in high elevations. It’s also the first deer species discovered in the 21st century, although hopefully not the last.

While we’re talking about mammal discoveries, we have to talk about the vampire hedgehog just because of its name. It was actually described at the very end of 2023, but it’s such an interesting animal that we’ll say it’s a 2024 discovery.

The vampire hedgehog was actually discovered a whole lot earlier than 2023, but no one noticed it was new to science for a long time. A small team of researchers studying soft-furred hedgehogs decided to collect DNA samples from all the museum specimens they could find. One of the specimens was in the archives of the Smithsonian National Museum of Natural History, collected in 1961 but never studied. When the scientists compared its DNA to the other specimens they’d found, it didn’t match up. Not only that, a closer look showed that it had fangs. Naturally, they named it the vampire hedgehog and went searching for living ones.

The vampire hedgehog lives in parts of Vietnam and is a member of the soft-furred hedgehogs, also called gymnures, hairy hedgehogs, or moonrats. Instead of spines, moonrats have bristly fur and long noses that make them look like shrews, but hairless tails that make them look like rats. They’re not rodents but are closely related to other hedgehogs. They eat pretty much anything but especially like to eat meat. This includes mice and frogs, along with various invertebrates.

As for the vampire hedgehog’s fangs, both males and females have them, but males have bigger fangs. Scientists don’t know yet what the hedgehogs use their fangs for. It could be they help the animals keep a better hold on wiggly prey, but it could be the hedgehogs just think big fangs look good on other hedgehogs so they’re one way the animals decide on a mate.

Just a few weeks ago we talked about the biggest tarantula in the world, the goliath birdeater, but did you know that there are tiny tarantulas too? The genus Trichopelma contains miniature tarantulas with body lengths measured in millimeters, and a new one was described in 2024 from western Cuba. But the great thing is, this tiny tarantula is the largest of the two dozen species known. Of the four specimens found so far, the largest body length is 11.2 millimeters—a veritable giant among miniature tarantulas!

The new species has been named Trichopelma grande, and the males, at least, have been discovered in trap-door burrows in the ground. No female specimens have been observed yet. Ground-dwelling tarantulas usually have a lot less hair on their legs, while tarantulas that live in trees are the ones with especially hairy legs, but T. grande is ground-dwelling but has very hairy legs. Or at least the males do. We don’t know about females yet.

Now let’s talk about some ocean animals, and we have to go back to Peru for our first one. The Atacama Trench is also called the Peru-Chile Trench because it’s about 100 miles, or 160 km, off the coast of both countries. At this spot a continental plate in the ocean is pushing underneath the South American plate, and it’s incredibly deep as a result. It’s been measured as 26,460 feet below the ocean’s surface, or 8,065 meters. That’s five miles deep!

Not a lot of animals live near the bottom, where the water pressure is intense and there’s not much to eat, but little crustaceans called amphipods are fairly common in the trench. Amphipods are common animals throughout the world’s oceans and freshwater, with almost 10,000 species discovered so far. There’s even a terrestrial amphipod called the sandhopper. Amphipods look a little bit like tiny shrimp, although there are some giant species. Giant in this case means 13 inches long, or 34 cm, but most are like the miniature tarantulas and are measured in millimeters.

In 2023 a new amphipod was discovered near the bottom of the Atacama Trench, and it was described in 2024 as a new species in its own genus. It grows just over an inch and a half long, or almost 4 cm, and appears white because of its lack of pigment. And most interesting of all, it’s a predator that catches and eats other species of amphipod.

Our last 2024 discovery is one that I find extremely exciting. We talked about the vampire squid way way way back in episode 11, before some of my listeners were even born, and while it has the word squid in its name, it’s not exactly a squid. It’s also not exactly an octopus. It’s the last surviving member of its own order, Vampyromorphida, which shares similarities with both squids and octopuses. And as of 2024, the vampire squid is not the only member of its own order, because they’ve found a second vampire squid!

The vampire squid is a deep-sea animal that grows about a foot long, or 30 cm, and eats whatever organic material floats down from far above. That could mean part of a dead amphipod or it could mean fish poop, the vampire squid is not picky. The new species of vampire squid was found around 3,000 feet below the surface, or a little over 900 meters, in the South China Sea. A genetic study determined that it does seem to be a new species, and the scientific name Vampyroteuthis pseudoinfernalis has been proposed. The official description hasn’t yet been published, but that just means we’ll probably get to talk more about it in a future episode.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 409: Guinea Pigs and Capybaras

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Thanks to Mary, Mila, and Riley for their suggestions this week!

Further reading:

Comfortable and dermatological effects of hot spring bathing provide demonstrative insight into improvement in the rough skin of Capybaras

Comfort of capybaras determined by SCIENCE:

An especially attractive guinea pig:

Guinea pigs come in lots of colors, patterns, and fur types [picture taken from this excellent site]:

Show transcript:

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

This week we’re going to learn about two rodents, one small and one big. Thanks to Mary and Mila who both suggested the guinea pig, and thanks to Riley who suggested the capybara.

This episode is a bit unusual because part of it comes from a Patreon episode from 2023. Like, literally a big chunk of this episode is the original audio from that one, and you’ll be able to tell the difference in audio and know just how lazy I was this week. The episode actually came together in an unusual way too. Riley’s parent emailed me last week with some new suggestions, including capybaras, but wasn’t sure if we had already covered the topic. I thought we had, but of course there’s always more to learn about an animal. Well, since this is the beginning of a new month I was on the Patreon page to upload the December episode, and while I was there I did a quick search for capybaras and discovered the episode I was thinking of. I decided to add some more information about guinea pigs to it since I already mention guinea pigs a lot in that episode, and here is the result!

The capybara is a rodent, and a very big one. It is, in fact, the biggest rodent alive today. To figure out just how big the capybara is, picture a guinea pig. The guinea pig is also a rodent, native to the Andes Mountains in South America. No one’s sure why the guinea pig is called that in English, since it doesn’t come from Guinea and doesn’t have anything to do with anything else called guinea, but as someone who had two pet guinea pigs when I was a kid, I know exactly why they’re called guinea pigs. This is what an actual pig sounds like:

[pig squealing]

And this is what a guinea pig sounds like:

[guinea pig squealing]

Also, it’s sort of shaped like a pig. The guinea pig is a chonky little animal with short legs, only a little stub of a tail, and little round ears. Its face is sort of blocky in shape and it has a big rounded rump, similar to that of a capybara. The guinea pig is actually closely related to the capybara, and is a pretty good-sized rodent in its own right. It grows about 10 inches long, or 25 cm, on average, and roughly half that size tall.

The guinea pig has been domesticated for at least 7000 years, but it wasn’t domesticated for people to keep it as a pet. In South America and many other places now, it’s a very small farm animal raised for its meat. Guinea pig has been an important source of protein for all that time, so important that it was considered sacred in many cultures.

In the early 16th century when Europeans started arriving in South America, sailors took guinea pigs with them on ships so they’d have fresh meat on the voyage. But when the cute little animals arrived in Europe, people started buying them as pets.

Guinea pigs eat plants, mostly grass, and are social animals. If you want a pet guinea pig, make sure to get at least two. Like rabbits and some other animals, including the capybara, the guinea pig excretes special pellets that aren’t poop, but are semi-digested pellets of food. The guinea pig eats the pellets so they can pass through the digestive system again and the body can extract as many nutrients as possible from it. What’s left is then excreted as a regular poop pellet.

Even in places where the guinea pig is routinely kept as livestock and eaten, people breed guinea pigs as pets too. The pet variety is smaller than the meat variety and has different markings and different colors. Guinea pigs naturally have short, smooth hair and are usually reddish-brown in color, but different colors, fur length and texture, and white markings have been bred into different varieties. There are even mostly hairless varieties.

Most people these days are familiar with what a guinea pig looks like, but most people are not familiar with what a capybara looks like.

So, picture a guinea pig. Now, imagine it growing and growing and growing until it’s the size of a large dog. Instead of orange and white, or black and white, or any of the other colors and patterns of a pet guinea pig, imagine its fur as being a solid rusty-brown color. The capybara can grow almost 4.5 feet long, or 134 cm, and can stand up to two feet tall, or 62 cm. That is a big rodent!

The capybara lives throughout most of South America, although it doesn’t live in the Andes or in Patagonia. It’s semi-aquatic and spends a lot of time in the water, sometimes even sleeping in the water with just its nose poking up so it can breathe. It can hold its breath for up to five minutes, and of course it swims extremely well. It even has webbed toes. It eats a lot of water plants and also eats grass, fruit, and other plants and plant parts.

The capybara has some features that are typical of rodents, like its teeth. Rodent teeth grow continuously since they’re easily worn down by chewing, especially chewing tough plants like grass. It also has some features that are uncommon in rodents. For instance, it can’t synthesize vitamin C, a trait it shares with the guinea pig and with humans. If a capybara kept in captivity isn’t given fruit and other foods that contain vitamin C, eventually it will develop scurvy.

But the capybara doesn’t otherwise have any resemblance to a pirate. It’s a sociable animal and famously chill. In the wild it lives in groups that can number up to 100 individuals, although up to 20 is more common.

The capybara has a scent gland on its nose called a morillo. The female has a morillo but the male’s is bigger since he scent marks more often by rubbing the gland on plants, trees, rocks, other capybaras, and so on. During mating season, the female capybara attracts a male by whistling through her nose, because who doesn’t like a lady who can whistle through her nose? The capybara will only mate in water, so if a female decides she doesn’t like a male, she just gets out of the water and walks away from him.

The female usually gives birth to four or five babies in one litter. Females with babies, called pups, help care for the babies of their friends. Most often, the pups who are too young to wander around without someone to watch them carefully, stay in a group. One or two females remain close to the pups to watch them while the other mothers find food, and the babysitters trade out every so often. When a capybara pup gets hungry, if its mother isn’t nearby, another lactating female will allow the pup to drink some of her milk. This is rare in most animals, since producing milk takes a lot of energy and a mother animal naturally wants to expend her energy on her own babies. But it’s beneficial for the whole group for capybara pups to be cared for by all the mothers.

Capybaras are big enough that adults have a certain amount of protection from predators, but they do have to worry about animals like jaguars, caimans, and anacondas. Smaller predators like eagles will eat capybara pups if they can catch them. Fortunately the capybara can swim fast and run fast, and with everyone in its group watching out for danger, it’s a lot safer than it is by itself.

The capybara does well in captivity and is a popular animal in zoos, and in some zoos you might even be able to pet one. You’ve probably seen pictures of capybaras relaxing in what looks like a big outdoor tub with tangerines floating in it, or if you’re from Japan or just familiar with Japanese customs, relaxing in a yuzu bath. Hot springs baths, called onsen, are popular in Japan, and in winter when the days are short and chilly, adding a citrus fruit called yuzu to the bath is supposed to help prevent colds and help moisturize the skin. Some zoos in Japan now extend this custom to capybaras, because it’s adorable.

As an added bonus, it turns out that the yuzu bath is really good for the capybara. The capybara is a warm-weather animal, and winters in Japan can be very cold and dry. As a result, the capybara’s skin becomes dry too. Soaking in natural hot springs, with or without yuzu, restores the capybara’s skin to its normal condition, which is a lot more comfortable for the capybara and helps it stay healthy. We know this is the case because of a study published in December 2021 in the journal Nature.

Before we go, here’s one last interesting fact about the guinea pig, to bring us back to the beginning of this episode. The guinea pig is a fully domesticated animal and its wild ancestor appears to have gone extinct. There are related species that resemble a guinea pig, but there are no wild guinea pigs in the world today.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!

Episode 327: The Humble Marmot

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Thanks to Dean for suggesting this week’s topic, the marmot!

Thanks also to Al-Ka-Lines Studio for the beautiful bat pin! You should definitely visit their online shop, because all their jewelry is hand-made by the two of them.

Further reading:

The secret to longevity? Ask a yellow-bellied marmot

The yellow-bellied marmot doing a sit [By Inklein, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2675916]:

A groundhog keeping an eye out for danger:

Show transcript:

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

This week we’re going to have a short little episode about a short little animal suggested by Dean, although I don’t know if Dean is short and/or little. Probably not. The name Dean makes me think of a tall person, probably someone who plays sports and can run really fast, so basically completely unlike a marmot. Dean suggested the marmot, specifically the yellow-bellied marmot.

Before we get started, two quick notes. First, thanks so much to Kathi and Alex of Al-Ka-Lines Studio for the gorgeous bat pin! They make hand-crafted leather jewelry and while they usually sell wholesale to shops, I checked with Kathi to see if it was okay to link to their shop and they said that yes, they sometimes sell to individuals too. I’ve put a link in the show notes in case you’re interested in seeing what they have for sale. They recently started listening to the podcast in order from the first episode and so far they’re not sick of my voice yet.

Second, I’ll be at Furry Weekend Atlanta this coming weekend, assuming you’re listening to this episode when it comes out on May 8, 2023. If you’re going to be there too, let me know and we can meet up. I went to way too many conventions last year so this one and Dragon Con at the end of August are the only ones I have planned this year, and I’m not on any programming on either. I just plan to look at people’s amazing costumes and attend interesting panels and have fun dancing in the evenings. Also, I’ll probably eat a lot of pizza.

Now, on to the marmots!

If you live in North America, you may have seen a marmot without realizing it. I didn’t realize that the groundhogs that are pretty common where I live in the eastern United States are a type of marmot. Similarly, if you live in the western part of North America, especially in mountainous areas, you may have seen the yellow-bellied marmot. Other species of marmot live in Asia, Europe, and other parts of North America. One interesting thing is that the groundhog of eastern North America is actually more closely related to the marmots of Europe and Asia than it is to the other North American marmot species.

Marmots are big rodents related to squirrels, and in fact they’re considered a type of ground squirrel along with the closely related chipmunks and prairie dogs. They dig burrows and mostly eat plant material, and can grow quite large. The largest species is probably the Olympic marmot that only lives in the state of Washington in the Pacific Northwest of North America, which can weigh up to 18 lbs, or 8 kg. That’s its summer weight, though, when it’s had time to eat lots of food. All marmots hibernate and during that time they survive on the fat reserves they build up in warm weather. Basically all marmots are about the size of a cat, but they’re big chonks with short legs, short tails, little round ears, and a blunt muzzle. Its thick fur makes it look even larger than it really is.

The yellow-bellied marmot mostly lives in higher elevations and, like all marmots, it’s well adapted to cold weather. It’s a social animal that lives in small colonies and spends most of its time underground when it’s not out finding food. It’s mostly brown with yellowish markings underneath and a spot of white between its eyes. It usually digs its burrow among rocks and can have multiple burrows in its territory, so if it spots a predator it doesn’t have far to run to get safely underground. It digs an especially deep burrow to hibernate in, sometimes as much as 23 feet deep, or 7 meters. Since it spends as much as eight months hibernating every year, it needs to stay comfortable. It lines its sleeping chamber with dried leaves and even digs a little side burrow that acts as a latrine.

In a study released in March of 2022, a team of scientists studying yellow-bellied marmots discovered that when it hibernates, an adult marmot’s body basically stops aging. The marmot exhibits true hibernation where its body temperature drops almost to the air temperature and its breathing and heart rate slow dramatically. It will hibernate for a week or two, wake up slightly for about a day so it can stretch and rearrange itself more comfortably, and then will go back into hibernation for another few weeks. This goes on for almost three-quarters of the year and during that time, the yellow-bellied marmot doesn’t eat or drink anything. It just lives off its fat reserves, and because its metabolic rate is so low it hardly uses any energy on any given day, only burning about a gram of fat. A small paperclip weighs about a gram, to give you a comparison. As a side effect, the marmot basically only ages during the summer when it’s active. The scientists think this may be the case for all animals that hibernate.

Like other marmots, the yellow-bellied marmot starts its mating season as soon as it emerges from hibernation around May. Males may have several mates and they all live together with him. Females give birth to around four babies during the summer, which like kittens and puppies are born without fur and with their eyes still sealed shut. They stay in the mother’s nesting burrow for the next six weeks, at which point they can see and have grown fur, so they can go outside with their mother. The babies stay with their mother for up to two years.

Most marmot species are social like the yellow-bellied marmot, but the groundhog is different. It’s mostly solitary, although it’s still part of a complex social network of all the groundhogs in a particular area, and sometimes it will share a burrow with other groundhogs. It also prefers lower elevations while most marmots prefer high elevations. It lives throughout most of the eastern United States and throughout much of Canada.

Because the marmot is a relatively big, common animal, it’s an important food source for many animals. Bears will sniff out marmot burrows and dig them open, and badgers, foxes, coyotes, and mountain lions eat lots of marmots in North America. In Europe and Asia, marmots are frequently eaten by foxes, wolves, snow leopards, and hawks. People will eat them too. In parts of Mongolia where marmots are common, it’s been a food source for thousands of years, traditionally prepared on special occasions by putting hot stones into the dead animal’s body cavity and letting the heat cook the meat slowly. But the marmot can carry diseases that humans can catch, including the plague, so these days a dead goat is often used instead of a marmot.

After I learned this, I naturally got distracted and started reading about other traditional Mongolian foods, and now I suddenly remember that I haven’t eaten anything today but trail mix and toast. So I’ll leave you with a final marmot fact. When a marmot sees a predator, it will whistle to warn other marmots, and the whistle sounds like this:

[marmot whistle]

Now I’m going to go make myself dinner. But it won’t be marmot.

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

Thanks for listening!