Category Archives: North America

Episode 333: Robins and Ravens

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Thanks to Liesbet, Simon, and Thea for their suggestions this week! Let’s learn about some birds!

Further reading:

Blue Tits and Milk Bottle Tops

Ravens parallel great apes in flexible planning for tool-use and bartering

Further watching:

A Raven Calling [this is a great video of a raven making all sorts of interesting sounds–I only used a tiny clip of it in the episode but it’s worth watching the whole thing]

The European robin:

The American robin and a worm that is having a very bad day:

A blue tit [photo By © Francis C. Franklin / CC-BY-SA-3.0, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=37675470]:

A blue tit about to get the cap off that milk bottle [photo from link above]:

The Eastern bluebird:

A raven:

An American crow:

Show transcript:

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

This week we have suggestions from Liesbet, Simon, and Thea, who suggested some relatively common birds that you may already think you know all about, but there’s lots to learn about them!

We’ll start with Liesbet’s suggestion, about the European robin and bluebird, and while we’re at it we’ll learn about the American robin and bluebird. The European and American birds are completely different species. The reason they have the same names is because when Europeans first started paying attention to the birds of North America, they needed names for the birds. The native peoples had names for them, of course, but the Europeans wanted names in a language they understood, so in a lot of cases they just borrowed names already in use at home.

Let’s start with the robin, which we also talked about way back in episode 81.

The European robin is a little bitty bird, only around 5 inches long, or 13 cm, with a brown back, streaked gray or buff belly, and orange face and breast. It has a short black bill and round black eyes. It eats insects, worms, berries, and seeds. The eggs are pale brown with reddish speckles.

It lives throughout much of Eurasia, but robins in Britain tend to be fairly tame, probably because they were traditionally considered beneficial in Britain and Ireland, so farmers and gardeners wouldn’t hurt them. In other parts of Europe they were hunted and are much more shy. European robins are also common on Christmas cards in Britain and Ireland, possibly because in the olden days, postmen used to wear red jackets. The postmen started to be called robins as a result, and since postmen bring Christmas cards, the bird robin became linked with card delivery and finally just ended up on the Christmas cards. Plus, their orange markings are cheerful in winter.

This is what the European robin sounds like:

[robin song]

The American robin is a type of thrush. It lives year-round in most of the United States and parts of Mexico, spends summers in much of Canada, and winters in parts of Mexico. It’s very different from the European robin. The European robin is tiny and round and adorable, while the American robin is big and always looks kind of angry. It grows around 10 inches long, or 25 cm. It’s dark gray on its back, with a rusty red breast, white undertail coverts, and a long yellow bill. It also has white markings around its eyes. Young birds are speckled. It mostly eats insects, worms, and berries.

If you see a bird on the ground, running quickly and then stopping, it’s probably a robin. Mostly the robin hunts bugs by sight, but it has good hearing and can actually hear worms moving around underground. You can sometimes see a robin with its head cocked, listening for a worm, before pouncing and pulling it out of the ground, just like in a cartoon.

American robin eggs are a light teal blue, so common and well-known that robin’s-egg-blue is a typical description of that particular color. In the spring after eggs hatch, the mother robin will carry the eggshells away from the nest to drop them, so predators won’t see the shells and know there’s a nest nearby. That’s why you’ll sometimes see half a robin eggshell on the sidewalk. It doesn’t mean something bad happened to the baby, just that the mother bird is doing her job. Both parents feed the chicks, and the parents also carry off the babies’ droppings to scatter them away from the nest.

This is what an American robin’s song sounds like.

[robin song]

Liesbet also wanted to learn about the European bluebird, more commonly called the Eurasian blue tit. We haven’t talked about it or the American bluebird before, even though they’re both beautiful birds.

The blue tit lives throughout Europe and parts of western Asia. It grows around 4 and a half inches long, or 12 cm, and has a bright blue crown on its head with blue on its wings, tail, and back. Its face is mostly white but it has a black streak that crosses its eye and a black ring around its neck. In fact, if you’re familiar with the blue jay of North America, the blue tit looks a lot like a miniature blue jay. It even has a little bit of a crest that it can raise and lower.

Because it eats a lot of insects and other small invertebrates, along with some seeds, the blue tit is an acrobatic bird. It will hang upside down from a twig to reach a caterpillar on the underside of a leaf, that sort of thing. It will also peel bits of bark away from a tree trunk to find tiny insects and spiders hiding underneath it. This habit leads it to sometimes peel bits off of people’s houses, like the putty that holds windowpanes in place. It also once led to the blue tit learning a surprising way to find food, and to learn about that, we have to learn a little bit about how people in the olden days got their milk if they didn’t own cows.

Back in the early 20th century, people used to get milk delivered every morning by a milkman. Refrigerators and ice boxes weren’t common like they are today, and most people didn’t have a way to keep milk cold. That meant it would go bad very quickly, so people would just order how much milk they needed in one day and when they got up in the morning, the milkman would have left the milk and other dairy products on the doorstep for the family.

The milk was always whole milk, also called full-fat, and as it sat in its bottles on the doorstep waiting for the family to wake up and bring the milk in, the cream would separate and rise to the top of the milk. Cream is just the fattiest, richest part of the milk. These days milk is processed differently so even if you buy whole milk, the cream won’t separate from it, and most milk sold today has already had most of the cream separated out. That’s why skim milk is called that, because the cream has been skimmed off the top. It’s sold separately as heavy whipping cream or mixed with milk as half-and-half. But back in the olden days, if you wanted to make whipped cream or clotted cream or some other recipe that calls for cream, you’d just skim the cream off yourself to use it.

The problem is, cream is so rich and full of protein that other animals learned to rob milk bottles, especially the blue tit. Birds can’t digest milk, naturally, since only mammals produce milk and are adapted to digest it, and even most adult mammals have trouble digesting milk. But cream contains a lot less lactose than the milk itself, and lactose is the type of sugar in milk that can cause stomach upset in adults. Blue tits learned that if they peeled the little foil cap off a milk bottle, they could get at the cream, and it became such a widespread behavior that each generation of blue tits became more adapted to digest cream.

These days, of course, most people buy their milk at the grocery store. The blue tits have had to go back to eating bugs and seeds.

This is what a blue tit sounds like:

[blue tit song]

The bluebird is a North American bird that also eats insects and other small invertebrates, along with berries and seeds. It grows around 7 inches long, or 18 cm. There are three species, the eastern bluebird and western bluebird, which look similar with bright blue above and white underneath with rusty red breast, and the mountain bluebird, which is blue almost all over and lives in mountainous areas of western North America. The bluebird is a type of thrush, meaning that it’s actually related to the American robin and used to be called the blue robin.

The bluebird spends a lot of its time sitting on a branch and watching for insects in the grass below. When it spots a grasshopper or beetle or spider or even a snail, it will drop down from its branch to grab it. It prefers open grasslands with trees or brush it can perch in, so it’s common around farmland. The mountain bluebird hunts like this too, but it doesn’t always bother to perch and will just hover above the ground until it spots a bug.

This is what an eastern bluebird sounds like:

[bluebird song]

Next, Simon and Thea wanted to learn about crows and ravens. The raven is another bird we covered a long time ago, in episode 112. I had a really bad cold the week of that episode and not only did I sound awful, I didn’t do a very good job with my research. I’m glad to revisit the topic and correct a few mistakes.

Crows and ravens look similar and are closely related, with both belonging to the genus Corvus. There are lots of species and subspecies of both, but let’s talk specifically about the American crow since it’s closely related to the hooded crow and the carrion crow found throughout Europe and Asia. Likewise, we’ll talk about the common raven since it’s found throughout much of the northern hemisphere.

The American crow can grow up to about 20 inches long, or 50 cm, with a wingspan over 3 feet across, or about a meter. Meanwhile, the common raven has a wingspan of up to 5 feet across, or 1.5 meters, and can grow up to 26 inches long, or 67 cm. Both are glossy black all over with large, heavy bills and long legs.

Crows and ravens both mate for life. Crows in particular are devoted family birds, with the grown young of a pair often staying to help their parents raise the next nest.

Both crows and ravens are omnivores, which means they eat pretty much anything. They will eat roadkill and other carrion, fruit and grain, insects, small animals, other birds, and eggs. They’re also extremely smart, which means a crow or raven can figure out how to get into trash cans and other containers to find food that humans think is secure.

Both also sometimes make and use tools, especially sticks that they use to dig out insects in places where their beaks can’t reach. But ravens in particular show a lot of tool use. Ravens sometimes throw pinecones or rocks at people who approach too close to their nests, and will even use sticks to stab at attacking owls. A few ravens have been observed to hold big pieces of bark in their feet while flying in strong winds, and they use the bark as a sort of rudder to help them maneuver. Other cognitive studies of ravens show that they have sophisticated and flexible problem-solving abilities where they can plan at least one step ahead, similar to great apes. Other corvids show similar abilities.

The raven can imitate other animals and birds, even machinery, in addition to making all sorts of calls. It can even imitate human speech. If a raven finds a dead animal but isn’t strong enough to open the carcass to get at the meat, it may imitate a wolf or fox to attract the animal to the carcass. The wolf or fox will open the carcass, and even after it eats as much as it wants, there’s plenty left for the raven.

Ravens also communicate non-vocally with other ravens. A raven will use its beak to point with, the way humans will point with a finger. They’ll also hold something and wave it to get another raven’s attention, which hasn’t been observed in any other animal besides apes.

The raven is much larger and heavier than a crow, and you can also distinguish a crow from a raven by their calls. This is what an American crow sounds like:

[crow call]

And this is what a raven sounds like:

[raven call]

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!

Episode 332: Hunting Partners and Mutualism

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Thanks to Vaughn and Jan for their suggestions this week! We’re going to learn about mutualism of various types.

Further reading:

The odd couple: spider-frog mutualism in the Amazon rainforest

What Birds, Coyotes, and Badgers Know About Teamwork

Octopuses punch fishes during collaborative interspecific hunting events

An Emotional Support Dog Is the Only Thing That Chills Out a Cheetah

Buddies [picture from the first link above]:

The honeyguide bird:

Cheetahs and dogs can be friends:

Show transcript:

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

This week we’re going to learn about a topic that I’ve been wanting to cover for a long time, mutualism. It’s a broad topic so we won’t try to cover everything about it in this episode, just give an overview with some examples. Vaughn suggested symbiotic behavior ages ago, and Jan gave me a great example of this, also ages ago, so thanks to both of them!

Mutualism is similar to other terms, including symbiosis, often referred to as “a symbiotic relationship.” I’m using mutualism as a general term, but if you want to learn more you’ll quickly find that there are lots of terms referring to different interspecies relationships. Basically we’re talking about two unrelated organisms interacting in a way that’s beneficial to both. This is different from commensalism, where one organism benefits and the other doesn’t but also isn’t harmed, and parasitism, where one organism benefits and the other is harmed.

We’ll start with the suggestion from Jan, who alerted me to this awesome pair of animals. Many different species have developed this relationship, but we’ll take as our specific example the dotted humming frog that lives in parts of western South America.

The dotted humming frog is a tiny nocturnal frog that barely grows more than half an inch long from snout to vent, or about 2 cm. It lives in swamps and lowland forests and spends most of the day in a burrow underground. It comes out at night to hunt insects, especially ants. It really loves ants and is considered an ant specialist. That may be why the dotted humming frog has a commensal relationship with a spider, the Colombian lesserblack tarantula.

The tarantula is a lot bigger than the frog, with its body alone almost 3 inches long, or 7 cm. Its legspan can be as much as 8 and a half inches across, or 22 cm. It’s also nocturnal and spends the day in its burrow, coming out at night to hunt insects and other small animals, although not ants. It’s after bigger prey, including small frogs. But it doesn’t eat the dotted humming frog. One or even more of the frogs actually lives in the same burrow as the tarantula and they come out to hunt in the evenings at the same time as their spider roommate.

So what’s going on? Obviously the frog gains protection from predators by buddying up with a tarantula, but why doesn’t the tarantula just eat the frog? Scientists aren’t sure, but the best guess is that the frog protects the spider’s eggs from ants. Ants like to eat invertebrate eggs, but the dotted humming frog likes to eat ants, and as it happens the female Colombian lesserblack tarantula is especially maternal. She lays about 100 eggs and carries them around in an egg sac. When the babies hatch, they live with their mother for up to a year, sharing food and burrow space.

This particular tarantula also gets along with another species of frog that also eats a lot of ants. Researchers think the spiders distinguish the frogs by smell. The ant-eating frogs apparently smell like friends, or at least useful roommates, while all other frogs smell like food. Or, of course, it’s possible that the ant-eating frogs smell and taste bad to the spider. Either way, both the frogs and the tarantulas benefit from the relationship–and this pairing of tiny frogs and big spiders is one that’s actually quite common throughout the world.

Mutualism is everywhere, from insects gathering nectar to eat while pollenating flowers at the same time, to cleaner fish eating parasites from bigger fish, to birds eating fruit and pooping out seeds that then germinate with a little extra fertilizer. Many mutualistic relationships aren’t obvious to us as humans until we’ve done a lot of careful observations, which is why it’s so important to protect not just a particular species of animal but its entire ecosystem. We don’t always know what other animals and plants that animal depends on to survive, and vice versa.

Sometimes an individual animal will work together with an individual of another species to find food. This may not happen all the time, just when circumstances are right. Sometimes, for example, a coyote will pair up with a badger to hunt. The coyote is closely related to wolves and can run really fast, while the American badger can dig really fast. Both are native to North America. They also both really like to eat prairie dogs, a type of rodent that can run really fast and lives in a burrow. Some prairie dog tunnels can extend more than 30 feet, or 10 meters, with multiple exits. The badger can dig into the burrow and if the prairie dog leaves through one of the exits, the coyote chases after it. When one of the predators catches the prairie dog, they don’t share the meal but they will often continue to hunt together until both are able to eat.

Other animals hunt together too. Moray eels will sometime pair up with a fish called the grouper in a similar way as the coyote and badger. The grouper is a fast swimmer while the eel can wriggle into crevices in rocks or coral. The grouper will swim up to the eel and shake its head rapidly to initiate a hunt, and if the grouper has seen a prey item disappear into a crevice, it will lead the eel to the crevice and shake its head at it again.

Groupers also sometimes pair up with octopuses to hunt together, as will some other species of fish. Like the eel, the octopus can enter crevices to chase an animal that’s trying to hide. But the octopus isn’t always a good hunting partner, because if the grouper catches a fish, sometimes the octopus will punch the grouper and steal its fish. Not cool, octopus.

Birds have mutualistic relationships too, including the honeyguide that lives in parts of Africa and Asia. It’s a little perching bird that’s mostly gray and white or brown and white, with the males of some species having yellow markings. It eats insects, spiders, and other invertebrates, and it especially likes bee larvae. But it’s just a little bird and can’t break open wild honeybee hives by itself.

Some species of honeyguide that live in Africa have figured out that humans can break open beehives. When the honeyguide bird finds a beehive, it will fly around until it hears the local people’s hunting calls. The bird will then respond with a distinct call of its own, alerting the people, and will guide them to the beehive. This has been going on for thousands of years. The humans gather the honey, the honeyguide feasts on the bee larvae and wax, and everyone has a good day except the bees.

The honeyguide is also supposed to guide the honey badger to beehives, but there’s no definitive evidence that this actually happens. Honey badgers do like to eat honey and bee larvae, though, and when a honey badger breaks open a beehive, honeyguides and other birds will wait until it’s eaten what it wants and will then pick through the wreckage for any food the badger missed. But the honeyguide might lead the honey badger to the hive, we just don’t know for sure.

Humans sometimes even help other animals into a commensal relationship. Vaughn gave me an example of a cheetah in a zoo who became best friends with a dog. This hasn’t just happened once, it’s happened lots of times because zookeepers have found that it helps cheetahs kept in captivity. Cheetahs are social animals but sometimes a zoo doesn’t have a good companion for a cheetah cub. The cub could be in danger from older, unrelated cheetahs, but a cheetah all on its own is prone to anxiety. It’s so important for a cheetah to have a sibling that if a mother cheetah only has one cub, or if all but one cub dies, a lot of times she’ll abandon the single cub. If this happens in the wild, it’s sad, but if it happens in captivity the zoo needs to help the cub.

To do this, the zoo will pair the cub with a puppy of a sociable, large breed of dog, such as a Labrador or golden retriever. The cub and the puppy grow up together. The cheetah has a mellow friend who helps alleviate its anxiety, and the dog has a friend who’s really good at playing chase.

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 just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!

Episode 328: Giant Ants

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Thanks to Richard from NC for suggesting Titanomyrma!

Further reading:

‘Giant’ ant fossil raises questions about ancient Arctic migrations

A fossilized queen Titanomyrma ant with a rufous hummingbird (stuffed) for scale:

Show transcript:

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

This week we have a suggestion from Richard from North Carolina, who sent me an article about an extinct giant ant called Titanomyrma. This episode is short, but I think you’ll find it interesting.

We’ve talked about ants in previous episodes, most recently episode 185. Most ant colonies consist of a single queen ant who lays all the eggs for her colony, seasonally hatched males with wings who fly off as soon as they’re grown, and worker ants. The worker ants are all female but don’t lay eggs. Army ants have another caste, the soldier ant, which are much larger than the worker ants and have big heads and strong, sharp mandibles. In many species of ant, the worker ants are further divided into castes that are specialized for specific tasks.

The biggest species of ant alive today is probably the giant Amazonian ant. The workers can grow over 1.2 inches long, or more than 3 cm, which is huge for an ant. It lives in South America in small colonies, usually containing less than 100 workers, and unlike most ants it doesn’t have a queen. Instead, one of the workers mates with a male and lays eggs for the colony. The giant Amazonian ant can sting and its sting contains venom that causes intense pain for up to two days. Fortunately, you will probably never encounter these giant ants, and even if you do they’re not very aggressive.

Another contender for the biggest species of ant alive today is the Dorylus genus of army ants, also called driver ants, which we talked about in episode 185. It lives in Africa in colonies that have millions of members, and the queen is the largest ant known. A queen army ant can measure 2.4 inches long, or 63 millimeters, but worker ants are much smaller.

Around 50 million years ago, giant ants related to modern driver ants lived in both Europe and North America. The genus is Titanomyrma and three species are known so far, found in Germany, England, Canada, and the American states of Tennessee and Wyoming.

The Wyoming ant fossil was discovered years ago and donated to the Denver Museum of Nature and Science, where it was stored in a drawer and forgotten about. In 2011 a curator found it and showed it to a paleoentomologist named Bruce Archibald. Dr. Archibald recognized it immediately as a fossilized queen ant even though it was the size of a hummingbird. He also realized it was very similar to a type of giant ant that once lived in Germany.

The German discovery was the first Titanomyrma species discovered, and it’s also the biggest known so far. The queen Titanomyrma gigantea grew up to 2.8 inches long, or 7 centimeters. Males grew up to 1.2 inches long, or 3 cm. The fossilized queen ants found have wings, with a wingspan of over 6 inches, or 16 cm. The other two known species are generally smaller, although still pretty darn big for ants.While they’re not that much bigger than the living Dorylus queens, most of the size of a queen Dorylus ant comes from her enlarged abdomen. Titanomyrma ants were just plain big all over.

Titanomyrma didn’t have a stinger, so it’s possible it used its mandibles to inflict bites, the way modern army ants do. It might also have sprayed formic acid at potential predators, as some ants do today.

The biggest ants alive today all live in tropical areas, so researchers thought Titanomyrma probably did too. During the Eocene, the world was overall quite warm and parts of Europe were tropical. The northern hemisphere supercontinent Laurasia was in the process of breaking up, but Europe and North America were still connected by the Arctic. Even though the Arctic was a lot warmer 50 million years ago than it is now, it was still too cold for a tropical ant. If Titanomyrma couldn’t survive in cold weather, how did it spread from one continent to another when it had to go through the Arctic?

There were warming periods during the Eocene that lasted a few hundred thousand years at a time, so researchers thought the ants probably migrated through the Arctic while it was warmer than usual. Then, in early 2023, a fossilized Titanomyrma queen ant was discovered in Canada. Because the rock it was preserved in has been distorted over the years, we can’t be certain how big the ant actually was. What we do know, though, is that the ant lived in a mountainous area that could get quite chilly, very different from the tropical climate scientists thought the giant ants needed.

As a result of the new finding, researchers are reconsidering whether the giant ants that lived 50 million years ago were really all that similar to modern giant ants. Just because the biggest ants alive today require tropical climates doesn’t mean that ancient giant ants did.

Hopefully more giant ant fossils will turn up soon, so we can learn more about where they lived, how they lived, and precisely how big they could get.

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!

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!

Episode 322: The Javelina and Other Peccaries

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Thanks to Oceana and Leo for suggesting this week’s episode about the javelina! We’ll even learn about a mystery peccary too.

Further reading:

New Species of Peccary–Pig-Like Animal–Discovered in Amazon Region

A javelina, also called the collared peccary [By Wing-Chi Poon – Own work by uploader; at Cottonwood Campground, Big Bend National Park, Texas, USA, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4394434]:

Show transcript:

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

This week we have a suggestion by Oceana and Leo, the javelina! It’s an animal native to the Americas, also called the collared peccary. We’re going to learn about it and its close relations, including a mystery animal.

The javelina is in the family Tayassuidae, called the New World pigs. The rest of the world’s pigs, including the warthog and the babirusa and the domestic pig, belong to the family Suidae. While the two families are related, the ancestors of the New World pigs, or peccaries, split off from the ancestors of other pigs around 40 million years ago and they’ve been evolving separately for all that time.

Peccaries live throughout almost all of Central and South America up to southwestern North America and some of the Caribbean islands. All peccaries look like little hairy pigs, including a flat-ended pig snout that it uses to root in the ground, small eyes, short tusks, slender legs with cloven hooves, and a thin little tail. It’s relatively small compared to domestic pigs, about the size of a big dog at most, and is covered with a thick coat of bristly hair. When it’s angry or frightened, it can raise the bristles along its back to make it look larger. It also has scent glands that give off a pungent smell, which is how members of the same herd recognize each other, since peccaries have poor eyesight.

Peccaries mostly eat plant material, but they’re omnivores and will eat meat when they find it, from insects and grubs to frogs and even carrion. Because they root around in the ground and leaf litter, they stir up nutrients in a way that benefits other animals and the environment in general. In the case of the javelina, also called the collared peccary, musk hog, or skunk pig, it’s sometimes considered a pest since it will root up people’s flowerbeds and gardens. But the javelina doesn’t know the difference between a garden and a not-garden. It just wants to find some tasty grubs and roots.

Peccaries are social animals that usually live in small herds. The white-lipped peccary is widespread in the forests of Central and South America, and sometimes lives in herds of 300 animals or more, even as many as 2,000 according to some reports. It requires an enormous range as a result, and travels a lot of the day to find new areas to forage. It’s threatened by habitat loss, mostly deforestation. Like other peccaries, it smells sort of skunky and can be aggressive if threatened. It eats a lot of fruit in addition to other plant material, and because it has stronger jaws than the javelina, it can eat seeds and nuts that the javelina can’t, so the two species can coexist in the same environment without competing for the same food sources.

Until 1972, the Chacoan peccary was only known from some fossils found in 1930. Not only did scientists think it was extinct, they thought it had been extinct for a long time. But in the early 1970s, rumors about a new peccary species started to circulate. A team of biologists followed up with locals and discovered the peccary living in a small area of South America called Chaco. Surprise! New peccary just dropped.

The Chacoan peccary, also known as the tagua, looks a lot like a javelina although it doesn’t have a dew claw on its hind feet. It has a tough snout and brown and gray bristles, with white on its shoulders and around its mouth. It lives in small bands of around a dozen individuals that roam across a large range, eating tough vegetation that other animals wouldn’t even consider food—cacti, for instance. A peccary will roll a cactus around on the ground with its snout and hooves, rubbing the spines off so it can eat it. If that doesn’t work, it will pull the spines out with its teeth. Cacti contain acids that other animals can’t digest, but the Chacoan peccary has specialized kidneys that are adapted to break down those acids.

The Chacoan peccary is endangered due to hunting, habitat loss, and disease. The area where it lives is being rapidly deforested to make way for huge cattle ranches. This is bad enough, but when ranchers move in, they want roads to get to their land more easily, and once the roads are in place, not only can more hunters get to the area, but more peccaries are killed by traffic. It’s estimated that only about 3,000 Chacoan peccaries are alive today. The government of Paraguay is trying to reduce the impact of habitat loss by protecting key areas of forest, and breeding populations are kept in a number of zoos across the world.

There are only three living species of peccary known: the javelina, the white-lipped peccary, and the Chacoan peccary. But there may be a fourth, the giant peccary.

In 2000, a Dutch biologist named Marc van Roosmalen was researching animals in Brazil, and as part of his studies he talked to some local hunters. They showed him the hides of three big peccaries, but they looked different from the ordinary javelinas that lived in the area. Van Roosmalen had already spotted some javelinas that he’d thought seemed too big to be ordinary javelinas, so when he saw the hides he started wondering if there were two peccary species in that part of the Amazon region.

He returned in 2003 with a German filmmaker, who got video footage of a group of these mystery peccaries. They even found a skull. Van Roosmalen described the giant peccary as a new species in 2007, but not everyone agreed it was a new species.

The giant peccary is larger than the javelina but otherwise looks and acts very much like it. Since the javelina is common pretty much everywhere that peccaries are found, and can show a lot of variation in size and appearance, many scientists think the giant peccary is just a population of unusually large javelinas.

The giant peccary reportedly lives in pairs or small family groups instead of herds. The local people have a different name for it to differentiate it from the javelina, a name which means “the big javelina that lives in pairs.” But while a genetic study of the skull found in 2003 determined that the giant peccary diverged from all other peccary species around a million years ago, later analysis is less conclusive.

As of 2011, the giant peccary is in a sort of scientific limbo, waiting for more evidence and further studies to determine whether it’s actually a new species or just a bunch of big javelinas. Let’s hope we learn more about it soon and can clear up the mystery.

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!

Episode 320: More Elephants

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Thanks to Connor and Pranav who suggested this week’s episode about elephants! It’s been too long since we had an elephant episode and there’s lots more to learn.

Further reading:

Asian elephants could be the maths kings of the jungle

Many wild animals ‘count’

A big difference between Asian and African elephants is diet

Study reveals ancient link between mammoth dung and pumpkin pie

The Asian elephant (left) and the African elephant (right):

The African bush elephant (left) and the African forest elephant (right) [photo taken from this page]:

The osage orange is not an orange and nothing wants to eat it these days:

Show transcript:

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

We haven’t talked about elephants since episode 200! It’s definitely time for some elephant updates, so thanks to Conner and Pranav for their suggestions!

Conner suggested we learn more about the Asian elephant, which was one we talked about way back in episode 200. The biggest Asian elephant ever reliably measured was a male who stood 11.3 feet tall, or 3.43 meters, although on average a male Asian elephant, also called a bull, stands about 9 feet tall, or 2.75 meters. Females, called cows, are smaller. For comparison, the official height of a basketball hoop is 10 feet, or 3 meters. An elephant could dunk the ball every single time, no problem.

The Asian elephant used to live throughout southern Asia but these days it’s endangered and its range is reduced to fragmented populations in southeast Asia. There are four living subspecies recognized today although there used to be more in ancient times.

Elephants are popular in zoos, but the sad fact is that zoo elephants often don’t live as long as wild elephants, even with the best care. The elephant is adapted to roam enormous areas in a family group, which isn’t possible in captivity. In the wild, though, the elephant is increasingly endangered due to habitat loss and poaching. Even though the Asian elephant is a protected species, people kill elephants because their tusks are valuable as ivory. Tusks are a modified form of really big tooth, and it’s valuable to some people because it can be carved into intricate pieces of art that can sell for a lot of money. That’s it. That’s the main reason why we may not have any elephants left in another hundred years at this rate, because rich people want carvings made in a dead animal’s tooth. People are weird, and not always the good kind of weird.

In happier Asian elephant news, though, a 2018 study conducted in Japan using zoo elephants replicated the results of previous studies that show Asian elephants have numeric competence that’s surprisingly similar to that in humans. That means they understand numbers at least up to ten, and can determine which group of items has more or less items than another group. That sounds simple because humans are really good at this, but most animals can only understand numbers up to three. It goes one, two, three, lots.

Many animals do have a good idea of numbers in a general way even if they can’t specifically count. Gray wolves, for instance, know how many wolves need to join the hunt to successfully bring down different prey animals. Even the humble frog will choose the larger group of food items when two groups are available. But the Asian elephant seems to have an actual grasp of numbers. I specify the Asian elephant because studies with African elephants haven’t found the same numeric ability.

Elephants make a lot of sounds, such as the iconic trumpeting that they make using the trunk. Way back in episode 8 we talked about the infrasonic sounds elephants also make with their vocal folds, sounds that are too low for humans to hear. But the Asian elephant also sometimes makes a high-pitched squeaking sound and until recently, no one was sure how it was produced. It turns out that the elephant makes this sound by buzzing its lips the same way a human does when playing a brass instrument. It’s the first time this particular method of sound production has been found outside of humans.

This is what a squeaking Asian elephant sounds like:

[elephant squeak]

Pranav suggested we learn more about the African forest and bush elephants. Those are the two species of African elephants that are still alive, and they’re also endangered due to habitat loss and poaching. The forest elephant is critically endangered. The forest elephant lives in forests, as you probably guessed, especially rainforests, while the bush elephant lives in grasslands and open forests. It’s sometimes called the savanna elephant since it’s well adapted to life on the savanna.

The forest elephant is only a little larger on average than the Asian elephant, while the bush elephant is much bigger on average. A big bull bush elephant can stand as much as 13 feet tall, or 4 meters, which means it might not dunk the basketball every time because the basketball hoop is awkwardly low.

The bush elephant lives in areas where it’s often extremely hot and dry. Since large animals retain heat, the bush elephant has many adaptations to stay cool. Its ears are really big, for instance, and have lots of blood vessels. This means the blood is close to the surface of the skin where it can shed heat into the air. In hot weather the elephant can flap its ears to help cool its blood faster. But one big adaptation has to do with its skin. The bush elephant’s skin is covered with what look like wrinkles but are actually crevices in the skin only a few micrometers wide. The crevices retain tiny amounts of water that help keep the elephant cool. Since elephants don’t have sweat glands the way people do, they have to bathe in water and mud to get moisture in the crevices in the first place.

Elephants are megaherbivores, meaning they eat mega amounts of plants. This has an impact on forest dynamics, but until recently the only studies on elephant diets and ecological effects were on African elephants. A 2017 study on Asian elephants in Malaysia found that instead of mostly eating sapling trees, the elephants preferred to eat bamboo, grasses, and especially palms.

In comparison, the African bush elephant eats plant parts that other animals can’t chew or digest, including tough stems, bark, and roots. It also eats grass, leaves, and fruit. The African forest elephant eats a lot more fruit and softer plant parts than the bush elephant, and in fact the forest elephant is incredibly important as a seed disperser. Seeds that pass through the forest elephant’s digestive system sprout a lot faster than seeds that don’t, and they also have the added benefit of sprouting in a pile of elephant dung. Instant fertilizer! At least 14 species of tree need the elephant to eat their fruit in order for the seeds to sprout at all. If the forest elephant goes extinct, the trees will too.

Around 11,000 years ago, when the North American mammoths went extinct, something similar happened. Mammoths and other megafauna co-evolved with many plants and trees to disperse their seeds, and in return the animals got to eat some yummy fruit. But when the mammoths went extinct, many plants seeds couldn’t germinate since there were no mammoths to eat the fruit and poop out the seeds. Some of these plants survive but have declined severely, like the osage orange. It produces giant yellowish-green fruits that look like round greenish brains, and although it’s related to the mulberry, you wouldn’t be able to guess that from the fruit. Nothing much eats the fruit these days, but mammoths and other megafauna loved it. The osage orange mostly survives today because the plant can clone itself by sending up fresh sprouts from old roots.

Another plant that nearly went extinct after the mammoth did is a surprising one. Wild ancestors of modern North American squash plants relied on mammoths to disperse their seeds and create the type of habitat where the plants thrived. Mammoths probably behaved a lot like modern elephants, pulling down tree limbs to eat and sometimes pushing entire trees over. This disturbed land is what wild squash plants loved, and if you’ve ever prepared a pumpkin or squash you’ll know that it’s full of seeds. The wild ancestors of these modern cultivated plants didn’t have delicious fruits, though, at least not to human taste buds. The fruit contained toxins that made them bitter, which kept small animals from eating them, because the small animals would chew up the seeds instead of swallowing them whole. But the mammoths weren’t bothered by the toxins and in fact probably couldn’t even taste the bitterness. They thought these wild squash were delicious and they ate a lot of them.

After the mammoth went extinct, the wild squash lost its main seed disperser. As forests grew thicker after mammoths weren’t around to keep the trees open, the squash also lost a lot of its preferred habitat. The main reason why we have pumpkins and summer squash is because of our ancient ancestors. They bred for squash that weren’t bitter, and they planted them and cared for the plants. So even though the main cause of the mammoth’s extinction was probably overhunting by ancient humans, at least we got pumpkin pies out of the whole situation. I mean, I personally would prefer to have both pumpkin pie AND mammoths, but no one asked me.

World Elephant Day is on August 12, and this episode is going live in late March. That means you have a little over four months to get your elephant celebration plans ready!

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!

Episode 317: Wild Ponies

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Thanks to Leo for suggesting this week’s topic, the ponies of Assateague Island!

Further reading:

Assateague Wild Ponies

Some ponies running free on Assateague Island [photo taken from the site linked above]:

Show transcript:

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

This week we’re going to learn about the feral horses of Assateague! Thanks to Leo for the suggestion! That’s the grown-up Leo; we also have a young Leo who’s sent some great suggestions, including one we’re hopefully going to get to pretty soon.

Before we talk about Assateague ponies, though, we need to start somewhere else. The kelpie is a Scottish water spirit that’s supposed to appear as a pony wandering by itself, but if someone tries to catch the pony or get on its back to ride it, suddenly it drags the person into the water and either drowns them or eats them. It’s said that the only way to tell that the pony isn’t really a pony is to examine its feet. A real pony has hooves, but a kelpie has claws.

The story comes from the olden days when it was common to see ponies wandering around loose in Scotland and other parts of the UK. Some of the ponies in these areas were semi-feral, meaning they lived a lot of the time like wild animals. Some ponies were kept in stables and farmyards as working animals, but others were allowed to roam around and feed themselves as they liked. Every so often the wild ponies would be rounded up and any young ones branded by their mother’s owner. Sometimes the owner would need another pony to pull a cart or something, and they’d catch one of their ponies and bring it home to train. Sometimes the owner needed money so would catch some of their ponies to sell. The ponies that lived this way had to be tough and hardy to survive almost without human care, but luckily ponies are famously tough.

Ponies are a type of small horse, but they’re still horses. They’re generally sturdy, with a thicker coat than a full-sized horse, and usually stand around 14 hands high at the withers at most. The withers is the little bump of shoulder at the base of a horse’s neck, and the horse’s back starts behind the withers. A hand is an old horse measurement that has been standardized to four inches, or just over 10 cm, roughly the width of an adult person’s hand. 14 hands is equivalent to about 4 and a half feet tall, or 1.4 meters.

One of the best-known pony breeds is the Shetland pony, which also happens to be one of the smallest. It only stands 42 inches tall at most, or 107 cm. That’s about 3 and a half feet tall. It’s mostly used as a child’s mount but originally the Shetland was used to pull carts and plows and carry heavy loads, since despite its small size the Shetland pony is incredibly strong.

The Shetland comes from the Shetland Isles off the northeastern coast of Scotland, where it’s lived for at least two thousand years and probably more like 3,000. The islands get very cold in winter and there isn’t a lot of food, so over time the ponies evolved to be small and tough to survive.

On the other side of the Atlantic Ocean, there are feral horses living on an island called Assateague. Assateague Island is off the eastern coast of the United States, closest to the states of Virginia and Maryland. They’re actually not technically ponies except that they’re small, since ponies actually share certain traits that differentiate them from horses, even though these differences aren’t enough to call ponies a subspecies of horse. But because the Assateague horses rarely grow taller than 4 and a half feet tall, or 140 cm, people call them ponies.

I’m going to stop here and tell you a personal story, because I’ve actually seen the Assateague ponies myself. I lived in Pennsylvania for a little while after I finished grad school, and at the time I had an awesome dog named Jasper, a Newfoundland I got through Newf rescue. Newfies are bred to be water dogs in the harsh coastal regions of Newfoundland, Canada, but Jasper had never seen the ocean. I knew he didn’t know or care, but it mattered to me that he got to experience the ocean at least once in his life. I had also wanted to see the Assateague ponies since I was a little girl and read Misty of Chincoteague and its sequels approximately 10,000 times, books by Marguerite Henry.

So I planned a trip to Assateague Island, which is a wildlife refuge these days. I decided to go over a weekend in October, when it wouldn’t be crowded. At the time I was working in a sales office while I tried to find a job I actually liked, and I mentioned my trip to my boss. He said he’d been to the island, and of course I asked if he’d seen the ponies. He said yes, and said, “We brought a picnic and put all the food on a picnic table while we looked around, and when we came back to our table the ponies had eaten all our food. I cried. As a grown man, I cried.”

That’s literally what he said, and he wasn’t kidding. He was genuinely mad at those ponies for eating his picnic, which I find hilarious even though at the same time, yes, getting your picnic eaten by wild ponies is no fun. I’m sorry I laughed. Still, it’s really funny. Also, you’re not supposed to leave food out where the ponies can find it so it was his fault.

Anyway, I took Jasper to Assateague Island not knowing what to expect, except that if I left any food out, ponies would eat it. This was the first time I’d visited the ocean so far north and so late in the year, so I was surprised that the water was actually chilly. It was beautiful, though, and I enjoyed walking along the beach with Jasper. I thought he might have fun chasing waves, but he was quite an old dog at this point and was happy just to walk with me, although what he really wanted to do was go home to his regular routine. So we didn’t stay long, but we did see ponies! (Unfortunately I have lost all the pictures I took of the ponies and of Jasper, since this was before I got my first smartphone and all I had was a terrible little camera.)

About 75 ponies live in the northern part of Assateague, which is controlled by the state of Maryland, with about 150 more living in the southern part of the island, which is controlled by the state of Virginia. It gets confusing here because the Virginia part of Assateague is the Chincoteague National Wildlife Refuge, but Chincoteague is actually a neighboring island that’s smaller than Assoteague but has a town, also named Chincoteague.

These islands are really very small. They’re barrier islands not far from the mainland coast, and while they change shape over time since they’re mostly just formed of sand, Assateague is only about 37 miles long, or 60 km, and only about 7 miles wide, or 11 km. Chincoteague is separated from Assateague by a small bay. The ponies in the Chincoteague National Wildlife Refuge are taken care of by the Chincoteague Volunteer Fire Department, and if you’ve read Misty of Chincoteague you probably already know what I’m about to tell you.

There are too many ponies on the island to thrive, no matter how small they are, because the island is so small. There’s just not enough food. The ponies eat whatever plants they can find in the salt marshes that make up large parts of the island, and they eat brush and seaweed and sometimes people’s picnics. Its small stature is mainly from its poor diet, since the foals don’t get enough nutrition when they’re growing.

In the early 19th century, the people of Chincoteague periodically rounded up some of the ponies and captured them, bringing them home to train and use as farm and riding animals. Hey, free horses! In 1924, the Chincoteague Volunteer Fire Department took over the task of pony penning, making it into an annual event in July that attracts thousands of tourists.

The ponies are rounded up and made to swim across the bay, which sounds horrible but it’s a short swim, only five or maybe ten minutes long. Mounted riders swim alongside to help any foals who have trouble. When the horses arrive on Chincoteague, they’re given a good feed and a veterinarian checks them over and treats them if needed. Then the older foals are separated from the herd to auction off. The proceeds of the auction fund the fire department, the ponies are saved from starving to death by keeping their numbers down, and the ponies that aren’t sold are allowed to return home. To solve the same issue in the northern part of the island, members of the Maryland herd are given contraceptives that stop them from having very many babies.

More recently, starting in 1990, veterinarians have started treating the Virginia ponies twice a year to vaccinate them and treat any injuries or illnesses. This helps keep the herd healthy since so many of the foals born will eventually go on to live on the mainland around other horses, so it’s important that the ponies don’t carry diseases.

Another reason to keep the number of ponies low is because ponies aren’t the only animals that live on Assateague Island. Whitetail deer live on the island along with a whole lot of birds, some of which are endangered. Sika deer also live in marshy areas of the island, although it’s not native to North America. It was introduced to the island from Asia in 1923, although I have no idea why. The sika is mostly dark brown but it retains its white fawn spots into adulthood, and it’s a large, attractive animal.

The ponies have been on Assateague for several hundred years, and by the 1920s they were in genetically poor shape overall. To reduce the effects of inbreeding, Shetland and Welsh ponies were added to the herd, and later twenty mustangs were released on the island too. Arabian stallions were also allowed to mate with some of the Assateague mares who were captured and later returned to the island when they were in foal. This helped the Assateague pony survive with improved genetic health, but it also made it harder to determine where the ponies came from in the first place.

The big mystery about the Assateague ponies is how they got to the island. No one knows. Some historians think white colonists set their horses loose on the island in the 17th century so they wouldn’t have to pay livestock taxes, and this is very likely. Many colonists were from parts of the UK where letting your ponies roam free until you needed them was a normal practice. Other animals were allowed to roam free on the island at the time too, including cattle and sheep, but there’s another possibility.

A local legend claims that the ponies originated from horses brought by Spanish Conquistadors traveling to Peru. When one of the Spanish ships wrecked nearby, the horses swam to Assateague Island and survived there. There are plenty of shipwrecks along that part of the coast, including Spanish galleons. Maybe one of those ships had tough little horses aboard, and now we have tough little horses on Assateague Island. Just be glad they’re not kelpies, and hide your picnics.

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!

Episode 314: Animals Discovered in 2022

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Let’s learn about some of the animals discovered in 2022! There are lots, so let’s go!

Further Reading:

In Japanese waters, a newly described anemone lives on the back of a hermit crab

Rare ‘fossil’ clam discovered alive

Marine Biologists Discover New Giant Isopod

Mysterious ‘blue goo’ at the bottom of the sea stumps scientists

New Species of Mossy Frog Discovered in Vietnam

A Wildlife YouTuber Discovered This New Species of Tarantula in Thailand

Meet Nepenthes pudica, Carnivorous Plant that Produces Underground Traps

Scientists discover shark graveyard at the bottom of the ocean

Further Watching:

JoCho Sippawat’s YouTube channel

A newly discovered sea anemone (photo by Akihiro Yoshikawa):

A mysterious blue blob seen by a deep-sea rover:

A newly discovered frog:

A newly discovered tarantula (photo by JoCho Sippawat):

Show transcript:

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

It’s the 2022 discoveries episode, where we learn about some of the animals discovered in 2022! Most of the time these animals were actually discovered by scientists before 2022, but the description was published in that year so that’s when we first learned about them. And, of course, a lot of these animals were already known to the local people but had never been studied by scientists before. There are lots of animals in the world but not that many scientists.

The great thing is, so many animals get discovered in any given year that I have to pick and choose the ones I think listeners will find most interesting, which in a stunning coincidence turns out to be the ones that I personally find most interesting. Funny how that works out.

We’ll start in the ocean, which is full of weird animals that no human has ever seen before. It’s about a hermit crab who carries a friend around. The hermit crab was already known to science, but until a team of scientists observed it in its natural habitat, the deep sea off the Pacific coast of Japan, no one realized it had an anemone friend.

The sea anemone is related to jellyfish and is a common animal throughout the world’s oceans. Some species float around, some anchor themselves to a hard surface. Many species have developed a symbiotic relationship with other animals, such as the clownfish, which is sometimes called the anemonefish because it relies on the anemone to survive. Anemones sting the way jellyfish do, but it doesn’t sting the clownfish. Researchers aren’t sure why not, but it may have something to do with the clownfish’s mucus coating. Specifically, the mucus may have a particular taste that the anemone recognizes as belonging to a friend. If the anemone does accidentally sting the clownfish, it’s still okay because the fish is generally immune to the anemone’s toxins.

The clownfish lives among the anemone’s tentacles, which protects it from predators, and in return its movements bring more oxygen to the anemone by circulating water through its tentacles, its droppings provide minerals to the anemone, and because the clownfish is small and brightly colored, it might even attract predators that the anemone can catch and eat.

Anemones also develop mutualistic relationships with other organisms, including a single-celled algae that lives in its body and photosynthesizes light into energy. The algae has a safe place to live while the anemone receives some of the energy from the algae’s photosynthesis. But some species of anemone have a relationship with crabs, including this newly discovered anemone.

The anemone anchors itself to the shell that the hermit crab lives in. The crab gains protection from predators, who would have to go through the stinging tentacles and the shell to get to the crab, while the anemone gets carried to new places where it can find more food. It also gathers up pieces of food that the crab scatters while eating, because crabs are messy eaters.

The problem is that hermit crabs have to move into bigger shells as they grow. Anemones can move, but incredibly slowly. Like, snails look like racecar drivers compared to anemones. The anemone moves so slowly that the human eye can’t detect the movement.

What the team of scientists witnessed was a hermit crab spending several days carefully pushing and pinching the anemone to make it move onto its new shell. If it wasn’t important, the crab wouldn’t bother. The sea anemone hasn’t yet been officially described since it’s still being studied, but it appears to be closely related to four other species of anemone that also attach themselves to the shells of other hermit crab species.

In other marine invertebrate news, a researcher named Jeff Goddard was turning rocks over at low tide at Naples Point, California a few years ago. He was looking for sea slugs, but he noticed some tiny clams. They were only about 10 mm long, but they extended a white-striped foot longer than their shells. Goddard had never seen anything quite like these clams even though he was familiar with the beach and everything that lived there, so he took pictures and sent them to a clam expert. The expert hadn’t seen these clams before either and came to look for the clams in person. But they couldn’t find the clams again. It took ten trips to the beach and an entire year before they found another of the clams.

They thought the clam might be a new species, but part of describing a new species is examining the literature to make sure the organism wasn’t already described a long time ago. Eventually the clam research team did find a paper with illustrations of a clam that matched, published in 1937, but that paper was about a fossilized clam.

They examined the 1937 fossil shell and compared it to their modern clam shell. It was a match! But why hadn’t someone else noticed these clams before? Even Goddard hadn’t seen them, and he’s a researcher that spends a lot of time along the coast looking specifically for things like little rare clams. Goddard thinks the clam has only recently started extending its range northward, especially during some marine heatwaves in 2014 through 2016. He suspects the clam’s typical range is farther south in Baja California, so hopefully a future expedition to that part of the Pacific can find lots more of the clams and we can learn more about it.

We talked about deep-sea isopods just a few weeks ago, in episode 311. They’re crustaceans related to crabs and lobsters, but also related to roly-polies that live on land. The deep-sea species often show deep-sea gigantism and are referred to as giant isopods, and that’s what this newly discovered species is. It was first found in 2017 in the Gulf of Mexico and is more slender than other giant isopods. The largest individual measured so far is just over 10 inches long, or 26 cm, which is almost exactly half the length of the longest giant isopod ever measured. It’s still pretty big, especially if you compare it to its roly-poly cousins, also called pillbugs, sow bugs, or woodlice, who typically grow around 15 mm at most.

Before we get out of the water, let’s talk about one more marine animal. This one’s a mystery that I covered in the October 2022 Patreon episode. It was suggested by my brother Richard, so thank you again, Richard!

On August 30, 2022, a research team was off the coast of Puerto Rico, collecting data about the sea floor. Since the Caribbean is an area of the ocean with high biodiversity but also high rates of fishing and trawling, the more we can learn about the animals and plants that live on the sea floor, the more we can do to help protect them.

When a remotely operated vehicle dives, it sends video to a team of scientists who can watch in real time and control where the rover goes. On this particular day, the rover descended to a little over 1,300 feet deep, or around 407 meters, when the sea floor came in view. Since this area is the site of an underwater ridge, the sea floor varies by a lot, and the rover swam along filming things and taking samples of the water, sometimes as deep as about 2,000 feet, or 611 meters.

The rover saw lots of interesting animals, including fish and corals of various types, even a fossilized coral reef. Then it filmed something the scientists had never seen before. It was a little blue blob sitting on the sea floor.

The blue blob wasn’t moving and wasn’t very big. It was shaped roughly like a ball but with little points or pimples all over it and a wider base like a skirt where it met the ground, and it was definitely pale blue in color.

Then the rover saw more of the little blue blobs, quite a few of them in various places. The scientists think it may be a species of soft coral or a type of sponge, possibly even a tunicate, which is also called a sea squirt. All these animals are invertebrates that don’t move, which matches what little we know about the blue blob.

The rover wasn’t able to take a sample from one of the blue blobs, so for now we don’t have anything to study except the video. But we know where the little blue blobs are, so researchers hope to visit them again soon and learn more about them.

It wouldn’t be a newly discovered species list without at least one new frog. Quite a few frogs were discovered in 2022, including a tree frog from Vietnam called Khoi’s mossy frog. It lives in higher elevations and is pretty big for a tree frog, with a big female growing over 2 inches long, or almost 6 cm, from snout to vent. Males are smaller. It’s mostly brown and green with little points and bumps all over that help it blend into the moss-covered branches where it lives. That’s just about all we know about it so far.

Our next discovery is an invertebrate, a spider that lives in bamboo. Specifically it lives in a particular species of Asian bamboo in Thailand, and when I say it lives in the bamboo, I mean it really does live inside the bamboo stalks. Also, when I say it’s a spider, specifically it’s a small tarantula.

It was first discovered by a YouTuber named JoCho Sippawat, who travels around his home in Thailand and films the animals he sees. I watched a couple of his videos and they’re really well done and fun, and he’s adorable even when he’s eating gross things he finds, so I recommend his videos even if you don’t speak the language he speaks. I’m not sure if it’s Mandarin or another language, and I’m not sure if I’m pronouncing his name right either, so apologies to everyone from Thailand for my ignorance.

Anyway, Sippawat found a tarantula where no tarantula should be, inside a bamboo stalk, and sent pictures to an arachnologist. That led to a team of scientists coming to look for more of the spiders, and to their excitement, they found them and determined right away that they’re new to science. It was pretty easy to determine in this case because even though there are more than 1,000 species of tarantula in many parts of the world, none of them live in bamboo stalks. The new spider was placed in a genus all to itself since it’s so different from all other known tarantulas.

It’s mostly black and dark brown with narrow white stripes on its legs, and its body is only about an inch and a half long, or 3 1/2 cm. It can’t make holes into the bamboo plants itself, so it has to find a hole made by another animal or a natural crack in the bamboo. It lines its bamboo stalk with silk to make a little home, and while there’s a lot we don’t know yet about how it lives, it probably comes out of its home to hunt insects and other small animals since tarantulas don’t build webs.

Finally, let’s wrap around to the sea anemone again, at least sort of. If you remember episode 129, we talked about the Venus flytrap sea anemone, which is an animal that looks kind of like a carnivorous plant called the Venus flytrap. We then also talked about a lot of other carnivorous plants, including the pitcher plant. Well, in 2022 a new species of pitcher plant was discovered that has underground traps.

The pitcher plant has a type of modified leaf that forms a slippery-sided pitcher filled with a nectar-like liquid. When an insect crawls down to drink the liquid, it falls in and can’t get out. It drowns and is dissolved and digested by the plant. Almost all known carnivorous plants are pretty small, but the largest are pitcher plants. The biggest pitcher plant known is from a couple of mountains in Malaysian Borneo, and its pitchers can hold over 2 ½ liters of digestive fluid. The plant itself is a messy sort of vine that can grow nearly 20 feet long, or 6 meters. Mostly pitcher plants just attract insects, especially ants, but these giant ones can also trap frogs, lizards, rats and other small mammals, and even birds.

The newly discovered pitcher plant grows in the mountainous rainforests of Indonesian Borneo and is relatively small. Unlike every other pitcher plant known, its pitchers develop underground and can grow a little over 4 inches long, or 11 cm. Sometimes they grow just under the surface, with leaf litter or moss as their only covering, but sometimes they grow deeper underground. Either way, they’re very different from other pitcher plants in other ways too. For one thing, scientists found a lot of organisms actually living in the pitchers and not getting eaten by the plant, including a new species of worm. Scientists aren’t sure why some animals are safe in the plant but some animals get eaten.

The new pitcher plant is found in parts of Indonesian Borneo that’s being turned into palm oil plantations at a devastating rate, leading to the extinction or threatened extinction of thousands of animal and plant species. The local people are also treated very badly. Every new discovery brings more attention to the plight of the area and makes it even more urgent that its ecosystems are protected from further development. The fastest way to do this would be for companies to stop using so much palm oil. Seriously, it’s in everything, just look at the ingredients list for just about anything. I try to avoid it when I’m grocery shopping but it’s just about impossible. I didn’t mean to rant, but the whole palm oil thing really infuriates me.

You know what? Let’s have one more discovery so we don’t end on a sour note.

A biodiversity survey of two of Australia’s marine parks made some really interesting discoveries in 2022. This included a new species of hornshark that hasn’t even been described yet. It’s probably related to the Port Jackson shark, which grows to around five and a half feet long, or 1.65 meters, and is a slow-moving shark that lives in shallow water off the coast of most of Australia. Instead of a big scary mouth full of sharp teeth, the Port Jackson shark has a small mouth and flattened teeth that allow it to crush mollusks and crabs. The newly discovered shark lives in much deeper water than other hornsharks, though, around 500 feet deep, or 150 meters.

Another thing they found during the survey wasn’t a new species of anything, but it’s really cool so I’ll share it anyway. It was a so-called shark graveyard over three miles below the ocean’s surface, or 5400 meters. The scientists were trawling the bottom and when they brought the net up to see what they’d found, it was full of shark teeth–over 750 shark teeth! They were fossilized but some were from modern species while some were from various extinct species of shark, including a close relative of Megalodon that grew around 39 feet long, or 12 meters. No one has any idea why so many shark teeth are gathered in that particular area of the sea floor.

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!

Episode 313: The Wolverine and the Kakapo

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This week we learn about two interesting animals from opposite parts of the world! Thanks to Felix and Jaxon for suggesting the wolverine and the kakapo.

Further reading:

Study: Wolverines need refrigerators

Kakapo Comeback [this article has some fantastic pictures!]

The wolverine likes cold weather:

So many young kakapos!

The kakapo is a really big bird:

(Photo by Matu Booth)

Show transcript:

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

This week we’re going to cover two animals suggested by listeners who spell their names with an X. I had already picked out these topics from the list and just now noticed both suggesters have X’s in their names. Thanks to Jaxon and Felix for these suggestions!

First, Felix suggested we learn about the wolverine. We’ve talked about it before in episode 62, but there’s a whole lot more to learn about this uncommon animal.

The wolverine is a mustelid, which is a family that includes weasels, ferrets, and other small, long, skinny animals with short legs. But the wolverine is big and broad, although its legs are pretty short. It kind of looks like a small bear and stands about 18 inches tall at the shoulder, or 45 cm. It’s light brown with darker brown or black legs, muzzle, tail, and back, and some have silvery-gray markings too. Its tail is short but fluffy. It lives in cold, mountainous areas, including northern Canada and Alaska, Siberia, and parts of Norway, Sweden, and Finland.

The wolverine is mainly a scavenger of animals that are already dead, but it will also kill and eat pretty much anything it can catch. This includes rabbits, mice, rats, porcupines, geese, and other small or relatively small animals, but it sometimes kills animals a lot bigger than it is, like deer. It will also eat eggs, berries, seeds, and anything else it can find. It’s not a picky eater.

The wolverine nearly went extinct in the 19th century due to overhunting for its fur, which is mostly waterproof and frost-proof. People used it to line winter clothes. The wolverine is also vulnerable to habitat loss and climate change, since it needs deep snow and cold temperatures to survive.

Because the wolverine lives where winters are harsh, when it finds a lot of food, it will sometimes bury it in snow to eat later. It chooses a protected area between boulders or a natural crevice in rocks to put the dead animal, then covers it with deep snow to keep it fresh for longer, just like putting meat in a freezer. Females in particular need this stored food, because they give birth in winter and need lots of food so they can produce milk for their babies.

But if you’ve ever taken food out of the freezer, you know it’s hard as a rock. How does the wolverine eat meat that’s frozen solid? Not only does the wolverine have strong jaws and teeth, it actually has a special tooth in the back of the mouth that points inward, one on each side of the upper jaw. The inward-pointing tooth allows the wolverine to tear off chunks of frozen meat more easily. Other mustelids have this arrangement of teeth too.

A male wolverine roams widely through a large territory, which can sometimes be hundreds of square miles. Pairs often mate for life although they don’t spend a lot of time together, and sometimes a male will have two or three mates. In winter, the female digs a den deep into the snow to have her babies, and while she mostly takes care of them by herself, the father wolverine will visit from time to time and bring everyone food. The babies stay with their mother for up to a year, and sometimes the half-grown wolverines will go traveling with their dad for a while.

The wolverine is sometimes called the nasty cat because it has a strong smell, which it uses to mark its territory. “Nasty cat” is the funniest name for an animal I’ve ever heard.

Next, Jaxon suggested the kakapo, which is a weird and adorable bird. It’s flightless and nocturnal, lives only in New Zealand, and is a type of parrot. A flightless, nocturnal parrot!

The kakapo is really big even for a parrot. It can grow over two feet long, or 64 cm, but since it’s flightless its wings and tail aren’t very big. Its legs are relatively short considering it has to walk everywhere. It has green feathers with speckled markings, blue-gray feet, and discs of feathers around its eyes that make its face look a little like an owl’s face. That’s why it’s sometimes called the owl parrot. Males are almost twice the size of females on average.

The kakapo evolved on New Zealand where it had almost no predators. A few types of eagle hunted it during the day, which is why it evolved to be mostly nocturnal. Its only real predator at night was one type of owl. As a result, the kakapo was one of the most common birds throughout New Zealand when humans arrived.

The Maori discovered New Zealand around 700 years ago. They killed the kakapo to eat and to use its feathers in clothing, and they also brought dogs and the Polynesian rat that also liked to kill and eat the kakapo. Then a few hundred years ago Europeans arrived, bringing all sorts of invasive animals with them, and they also chopped down forests to create more farmland.

By the end of the 19th century, the kakapo was becoming increasingly rare everywhere. When Resolution Island was declared a nature reserve in 1891, early conservationists brought kakapos and kiwis to the island in an attempt to save them. But stoats and feral cats killed them all. Attempts to establish captive breeding programs weren’t successful either. By 1970, scientists worried that the kakapo was already extinct.

Fortunately, a few of the birds survived in remote areas. By now conservationists understood that they had to provide a safe environment for the birds, and that took a lot of effort. Several islands were chosen as kakapo refuges, and then all the introduced mammals on the islands had to be eradicated or relocated. This included animals like deer that ate the same plants that the kakapo relied on, as well as predators. Then native plants and trees had to be transplanted to the islands since they’d been mostly killed off by deer and other introduced animals.

Then, finally, all the kakapos scientists could find were relocated to the islands. There weren’t very many, and most of them were males. 65 birds were introduced to four islands and monitored carefully, both to make sure they settled in well and to make sure no predators found their way to the islands.

Kakapo females only lay eggs when they have plenty of high-protein food, especially the fruit of the rimu tree that only ripens every four or five years, so the females were given extra food to encourage them to breed more often. The extra food helped, but it turns out that when the females were allowed to eat as much as they wanted, most of the eggs they laid hatched male chicks. That was the opposite of what the kakapo needed, so conservationists experimented with the amounts of extra food they gave the birds until finally the eggs were hatching equal numbers of females and males.

Many parrot species mate for life and both parents help take care of the eggs and babies, but the kakapo handles things differently. Males gather on hilltops during breeding season and each male digs out a shallow bowl well apart from other males, sometimes several bowls connected with little trails. If a male gets too close to another male, they’ll fight. Each male stands in his bowl and makes a booming call by inflating a special sac in his throat. The bowl helps amplify the sound and often the male will construct his bowl near a surface that reflects sound, like rock. His calls can be heard three miles away in good conditions, or 5 km, and the sound attracts females.

This system of males competing in one area to attract females is called lekking, spelled L-E-K. We’ve actually talked about lekking before but I don’t remember if I specifically mentioned the term. The area where the males gather is called a lekking ground or an arena or sometimes just a lek. The females walk around inspecting each male, who booms and struts to show how strong and fit he is. If a female is especially interested in one male, she’ll approach him and he starts his courtship dance. This sounds fancy but for the kakapo, it basically means he turns his tail with his wings spread, then walks backwards towards the female. Weird dance, but the female kakapo thinks it’s cool.

After a female chooses a male, they mate and then the female leaves him and walks home. She builds a nest in a hollow tree or in a hidden crevice among roots or rocks, and lays one to four eggs. She takes care of the eggs and the babies by herself, and may continue to feed the babies until they’re around six months old.

The kakapo eats nuts, seeds, fruit, leaves, and other plant material. Its legs are short but strong, and it will jog for long distances to find food. It can also climb really well, right up into the very tops of trees. It uses its strong legs and its large curved bill to climb. Then, to get down from the treetop more efficiently, the kakapo will spread its wings and parachute down, although its wings aren’t big enough or strong enough for it to actually fly. A big heavy male sort of falls in a controlled plummet while a small female will land more gracefully.

While the kakapo is doing a lot better now than it has in decades, it’s still critically endangered. The current population is 249 individuals according to New Zealand’s Department of Conservation. Scientists and volunteers help monitor the birds, especially newly hatched chicks. If a mother bird is having trouble finding enough food for all her babies, or if any of the babies appear sick or injured, a team of conservationists will decide if they need to help out. They sometimes move a chick from a nest where the mother bird has a lot of other babies to one where there are only one or two babies. Some chicks are raised in nurseries if necessary and reintroduced to the wild when they’re old enough.

The kakapo can live for a long time. This isn’t unusual for parrots, which can live as long as a human, but the kakapo is especially long-lived. There are reports of individuals who have reached 120 years old. This means that potentially, only six kakapo generations ago, the first East Polynesian sailors, ancestors of the modern Maori, became the first humans ever to set foot on the shores of New Zealand. And there were some weird parrots there.

This is what the male kakapo sounds like when it’s booming:

[booming call]

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!

Episode 312: Little Bouncy Animals

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Thanks to Zachary and Oran for this week’s topic, some little animals that bounce around like tiny kangaroos!

Further reading:

Evolution of Kangaroo-Like Jerboas Sheds Light on Limb Development

Supposedly extinct kangaroo rat resurfaces after 30 years

High-Speed Videos Show Kangaroo Rats Using Ninja-Style Kicks to Escape Snakes

Williams’s jerboa [picture by Mohammad Amin Ghaffari – https://www.inaturalist.org/photos/177950563, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=115769436]:

A drawing of a jerboa skeleton. LEGS FOR DAYS:

The San Quintin kangaroo rat lives! [photo from article linked above]

Show transcript:

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

This week we’re going to learn about two cute little animals suggested by Zachary and Oran! Both of these animals are rodents but although they look remarkably alike in some unusual ways, they’re not actually all that closely related.

First, Zachary suggested the jerboa. We talked about the pygmy jerboa in episode 136, but we haven’t talked about jerboas in general. It’s a small rodent that’s native to the deserts of Asia, north Africa, and the Middle East. It’s usually brown or tan with some darker shading on the back and tail. It looks sort of like a gerbil with long ears, long hind legs, and a tuft at the end of the tail. Its front legs are short and it has an adorable whiskery nose.

The reason the jerboa’s hind legs are so long while its front legs are really short is that it jumps around on its hind legs like a kangaroo. Not only can it jump really fast, up to 15 mph, or 24 km/h, it can change directions incredibly fast too. This helps it evade predators, because most animals are fastest when running in a straight line. The jerboa bounces in all sorts of directions, hopping or just running on its long hind legs, with its long tail held out for balance. It can also run on all fours with its short front legs helping it maneuver, but for the most part it’s a bipedal animal. It has tufts of stiff hairs under its toes that help it run through loose sand.

The jerboa eats plants, although sometimes if it finds a nice juicy insect it will eat it too. Mostly it just eats leaves, bulbs, roots, and some seeds. It gets all of the moisture it needs from its diet, which is good because it lives in the desert where there’s not much water available.

Some species of jerboa mainly eat insects and spiders, and some have short ears instead of long ears. This is the case for the thick-tailed pygmy jerboa that lives in parts of China, Mongolia, and Russia. Its head and body only measures about two inches long, or almost 5 cm, but its tail is twice that length. The reason it’s called a thick-tailed jerboa is because it stores fat at the base of its tail, which makes the tail look thick compared to many rodent tails.

The jerboa is mostly active at dawn and dusk, although some species are fully nocturnal. It spends the day in a burrow it digs in sand or dirt. A jerboa will usually have more than one burrow in its territory, with the entrances usually hidden under a bush or some other plant. Different burrows have different purposes. Some have numerous entrances and lots of side tunnels but are relatively shallow, which is useful if the jerboa lives in an area with a rainy season. A shallow burrow won’t flood if it rains a lot. Some burrows are temporary, which the jerboa may dig if it’s out and about during the day looking for food. A mother jerboa will dig a burrow with a roomy nesting chamber to raise her babies, and a jerboa’s winter burrow has a nesting chamber that’s deep underground to help it stay warm. Some species of jerboa construct unusual burrows, like the lesser Egyptian jerboa that has spiral-shaped burrows with storage chambers. Most jerboas are solitary animals, although sometimes a group will hibernate together in winter to help everyone stay warmer.

Scientists have been studying the jerboa to learn how different animals have evolved radically different leg lengths. The jerboa’s incredibly long hind legs are very different from its very short front legs, but it evolved from animals that had four short legs. But jerboas are born with four short legs, and as the babies grow up their hind legs grow longer and longer.

The jerboa is an incredibly efficient runner. Some species can jump as far as six feet in a single bound, or 1.8 meters, and up to three feet, or 90 cm, straight up.

The jerboa isn’t the only rodent that hops on its hind legs like a kangaroo. The kangaroo rat does too, and it’s Oran’s suggestion. Oran pointed out that a long time ago, I think in the humans episode, I said that humans are the only fully bipedal mammal, meaning we only ever walk on our hind legs. (Crawling when you’re a baby or trying to find something under the couch don’t count.) I was wrong about that for sure, because the kangaroo rat, the jerboa, and a few other mammals are also bipedal.

The kangaroo rat is native to parts of western North America. It looks a lot like a jerboa, with long hind legs and a long tail, although its ears are smaller. But the kangaroo rat and the jerboa aren’t closely related, although both are rodents. Their similarities are due to convergent evolution, since both animals live in very similar environments with the same selective pressures.

The largest species of kangaroo rat, the giant kangaroo rat, grows around 6 inches long, or 15 cm, with a tail about 8 inches long, or 20 cm. It can jump even longer than the jerboa although it doesn’t move as fast on average.

Like the jerboa, the kangaroo rat can change directions quickly, and it’s also mostly nocturnal and spends the day in a burrow. Some species spend almost all the time in burrows, only emerging for about an hour a night to gather seeds. Since owls like to eat kangaroo rats, you can’t blame them for wanting to stay underground as much as possible.

Snakes also like to eat kangaroo rats, especially the sidewinder rattlesnake. It’s a fast predator with venom that can easily kill a little kangaroo rat, but the kangaroo rat isn’t helpless. A study published in 2019 filmed interactions in the wild between the desert kangaroo rat and the sidewinder, using high-speed cameras. They had to use high-speed cameras because the snakes can go from completely unmoving to a strike in under 100 milliseconds. That’s less time than it takes you to blink. But the kangaroo rat can react in even less time, as little as 38 milliseconds after the snake starts to move. A lot of time the kangaroo rat will completely leap out of range of the snake, but if it can’t manage that, it will kick the snake with its long hind legs, which are strong enough to knock the snake away. Little fuzzy ninjas.

Unlike the jerboa, the kangaroo rat mostly eats seeds. The jerboa’s teeth aren’t very strong so it can’t bite through hard seeds, but the kangaroo rat’s teeth are just fine with seeds. The kangaroo rat also has cheek pouches, and it will carry lots of seeds home to its burrow. It keeps extra seeds in special burrow chambers called larders.

The kangaroo rat sometimes lives in colonies that can number in the hundreds, but it’s still a mostly solitary animal. It has its own burrow that’s separate from the burrows of other members of its colony, and it doesn’t share food or interact very much with its neighbors. It will communicate with other kangaroo rats by drumming its hind feet on the ground, including warning its neighbors to stay away and alerting them to predators in the area.

The kangaroo rat is vulnerable to habitat loss, since it mostly lives in desert grassland and humans tend to view that kind of land as useless and in need of development. An example of this is the San Quintin kangaroo rat, which is only found in western Baja California in Mexico. Only two large colonies were known when it was discovered by science in 1925, although it used to be much more widespread. But in the decades since 1925, the land was developed for agriculture until by 1986 the two colonies were completely wiped out. Scientists worried the species had gone extinct. Then, in 2017, a colony was discovered in a nature preserve and everyone breathed a sigh of relief. Other colonies have been discovered on farmland that has been abandoned due to drought. Still, the San Quintin kangaroo rat is critically endangered.

The kangaroo rat is actually helpful for the environment. Because it stores seeds underground, and sometimes forgets where it put them, it helps native plants spread. Its burrows help increase soil fertility and the spread of water through the soil. This is similar to the jerboa, which also eats enough insects to help reduce the number of agricultural pests in some areas.

There are also two species of kangaroo mouse, which are closely related to kangaroo rats. They mostly live in the state of Nevada in North America. There are also jumping mice that look like ordinary mice but with long hind legs. It also has cheek pouches. While some jumping mice live in western North America, some live in northeastern North America and Canada and are adapted to cold weather and long winters. One species of jumping mouse lives in the mountains in parts of China. There’s also a larger jumping rodent called the springhare that lives in parts of Africa, and which is about the size of a squirrel or a small rabbit. Like all these other rodents, it’s bipedal and hops on its hind legs like a little kangaroo, using its long tail for balance and to prop itself up when it’s standing. It mostly eats plants but will sometimes eat insects, and it spends most of the day in burrows. There’s also a hopping mouse native to Australia, which is a rodent with long hind legs and a long tail and long ears. It’s not closely related to the jerboa or the kangaroo rat, but it looks a lot like both because of convergent evolution. It mostly eats seeds.

All these animals are rodents, but Australia also has another animal called the kultarr that looks a lot like the kangaroo rat and the jerboa. It’s not a rodent, though. It’s actually a marsupial that’s completely unrelated to rodents although it looks like a rodent. That’s definitely what you call convergent evolution.

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