Category Archives: South America

Episode 437: Updates 8 and the Nutria

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

Further reading:

An Early Cretaceous Tribosphenic Mammal and Metatherian Evolution

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

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

Scientists Solve Mystery of Brown Giant Pandas

Elephant turns a hose into a sophisticated showering tool

New name for one of the world’s rarest rhinoceroses

Antarctica’s only native insect’s unique survival mechanism

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

The nutria has really orange teeth:

Show transcript:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Thanks for listening!

Episode 436: Red-Eyed Tree Frog

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Thanks to Trech for suggesting this week’s topic, the red-eyed tree frog!

Further reading:

Tadpoles hatch in seconds to escape predator

The colorful red-eyed tree frog [photo by Geoff Gallice]:

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 little frog, suggested by Trech.

The frog in question is the red-eyed tree frog, which is native to Central America, including parts of Mexico, and northwestern South America. It lives in forests, always around water. You might be thinking, “of course, frogs live in water,” but remember that this is a tree frog. It lives in trees. But it still needs water for its babies, just not quite in the way most frogs do.

Before we learn about that, let’s learn about the frog itself. A big female can grow about 3 inches long, or 7.5 cm, while males are smaller. It’s a cute frog, of course, because frogs are always cute, but it’s also brightly colored. It’s bright green with red eyes, blue and yellow stripes on its sides, and orange feet.

Ordinarily, a frog with such bright colors would warn potential predators that it’s toxic, but the red-eyed tree frog isn’t toxic at all. Its bright colors have a different purpose. When it’s sitting on a leaf, the bright colors are hidden and only the frog’s smooth green back is showing, which makes it look like just another leaf. Only its eyes are bright, but it closes its eyes when it’s resting. But if a predator approaches, the frog opens its eyes suddenly and jumps up, revealing all those bright colors. The predator is startled, and maybe even hesitates because it thinks the frog might be toxic, and by the time the predator decides it should try eating the frog after all, the frog is long gone.

Oh, and if you’re wondering, the red-eyed tree frog can see through its eyelids. They’re actually not eyelids like we have, but a membrane that it can move over its eyes. The frog is nocturnal and eats insects like mosquitoes, crickets, and moths. It has a good sense of smell, which helps it find insects in the dark.

The tree frog also has suction cups on its toes that help it stay put on smooth leaves. During the day it sticks itself to the underside of a leaf to sleep where it’s more hidden. The female also lays her eggs on the underside of a leaf. This protects them from heavy rain, since the frogs breed during the rainy season, and it also helps hide them from predators. The female chooses a leaf that’s growing above water, and if the leaf isn’t very big she’ll lay eggs on both sides of it and fold the leaf to help hide all the eggs. The eggs stick to the leaf with a type of jelly that also helps keep them from drying out.

The eggs hatch in about a week, but they can hatch a few days early if a predator approaches. The embryonic tadpoles in their eggs can sense vibrations, and if a predator like a snake shakes the leaf as it approaches the eggs, the tadpoles can hatch within seconds. They drop straight down into the water below the leaf.

Hatching early when in danger is called phenotypic plasticity, and it’s really rare. It’s especially unusual because the embryonic tadpoles can actually tell the difference between a typical predator of frog eggs and vibrations caused by other animals or the wind. They can hatch so quickly because the stress reaction causes the pre-tadpoles to secrete an enzyme from their little noses, which weakens the egg wall and allows them to push and wiggle their way out.

Tadpoles stay in the water for several weeks, or sometimes several months depending on conditions, during which time they eat algae and other tiny food in the water. As they grow bigger, the tadpoles can eat bigger food, including other tadpoles. They switch to tiny insects after they metamorphose into froglets.

At some point during its development, a red-eyed tree frog needs to eat enough food containing carotenoids in order to develop properly, and in order to develop brightly colored skin as an adult. The red-eyed tree frog is a popular pet, but captive-bred frogs sometimes aren’t as brightly colored because they didn’t get enough of the right foods as young frogs.

During breeding season, a male will claim a small branch and jump and bounce around on it, both to call attention to himself and to shake other males off the branch. He also croaks loudly to attract a mate. This is what he sounds like:

[frog 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. 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 433: Flamingos and Two Weird Friends

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Thanks to Ryder, Alexandria, and Simon for their suggestions this week! Let’s learn about three remarkable wading birds. Two of them are pink!

Bird sounds taken from the excellent website xeno-canto.

The goliath heron is as tall as people [picture by Steve Garvie from Dunfermline, Fife, Scotland – Goliath Heron (Ardea goliath), CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=12223810]:

The roseate spoonbill has a bill shaped like a spoon, you may notice [picture by Photo Dante – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=42301356]:

Flamingos really do look like those lawn ornaments [picture by Valdiney Pimenta – Flamingos, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=6233369]:

Show transcript:

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

This week we’re going to learn about three large birds with long legs that spend a lot of time wading through shallow water, suggested by Ryder, Alexandria, and Simon.

Wading birds tend to share traits even if they’re not closely related, because of convergent evolution. In order to wade in water deep enough to find food, a wading bird needs long legs. Then it also needs a long neck so it can reach its food more easily. A long beak helps to grab small animals too. Having big feet with long toes also helps it keep its footing in soft mud.

Let’s start with Ryder’s suggestion, the goliath heron. It’s the biggest heron alive today, standing up to 5 feet tall, or 1.5 meters. That’s as tall as a person! It only weighs about 11 lbs at most, though, or 5 kg, but its wingspan is over 7 ½ feet across, or 2.3 meters. It’s a big, elegant bird with a mostly gray and brown body, but a chestnut brown head and neck with black and white streaks on its throat and chest.

The goliath heron lives throughout much of sub-Saharan Africa, meaning south of the Sahara Desert, anywhere it can find water. It’s happy on the edge of a lake or river, in a swamp or other wetlands, around the edges of a water hole, or even along the coast of the ocean. It usually stands very still in the water, looking down. When a fish swims close enough, the heron stabs it with its bill, pulls it out of the water, and either holds it for a while until the bird is ready to swallow the fish, or sometimes it will even set the fish down on land or floating vegetation for a while. It’s not usually in a big hurry to swallow its meal. Sometimes that means other birds steal the fish, especially eagles and pelicans, but the goliath heron is so big and its beak is so sharp that most of the time, other birds and animals leave it alone.

The goliath heron will also eat frogs, lizards, and other small animals when it can, but it prefers nice big fish. It can catch much bigger fish than other wading birds, and eating big fish is naturally more energy efficient than eating small ones. If a goliath heron only catches two big fish a day, it’s had enough to eat without having to expend a lot of energy hunting.

This is what a goliath heron sounds like:

[goliath heron call]

Alexandria’s suggestion, the roseate spoonbill, is also a big wading bird, but it’s very different from the goliath heron. For one thing, it’s pink and white and has a long bill that’s flattened and spoon-shaped at the end. It’s only about half the size of a goliath heron, with a wingspan over 4 feet across, or 1.3 meters, and a height of about 2 ½ feet, or 80 cm. That’s still a big bird! It mostly lives in South America east of the Andes mountain range, but it’s also found in coastal areas in Central America up through the most southern parts of North America.

Unlike the goliath heron, which is solitary, the roseate spoonbill is social and spends time in small flocks as it hunts for food. It likes shallow coastal water, swamps, and other wetlands where it can find it preferred food. That isn’t fish, although it will eat little fish like minnows when it catches them. It mainly eats crustaceans like crabs and crayfish, along with frogs, aquatic insects, and mollusks, and some seeds and other plant material. Since most of its food lives on the floor of the waterway or hidden in mud or water plants, the spoonbill usually can’t see its prey. It depends on the sensitive nerves in its bill to know the difference between, say, a crab and a crab-shaped rock. It walks through shallow water, sweeping its bill back and forth through the mud at the bottom, and grabs any little animal it can. Other birds like egrets will sometimes follow foraging spoonbills so they can catch any animals that the spoonbills miss.

Baby spoonbills are born with ordinary pointy bills, but as the chicks mature, the ends of their beaks flatten and become more and more spoon-shaped. If the goliath heron’s bill is like a pair of kitchen knives, the spoonbill’s beak is like a set of salad tongs that can scoop up lots of salad and dressing at once.

The roseate spoonbill gets its pink coloration from the food it eats. A lot of crustaceans contain carotenoid pigments, which the spoonbill absorbs and expresses in its feathers.

There are other spoonbills in the world, but the roseate spoonbill is the only one found in the Americas. The other five species live in Africa and Madagascar, Australia and New Zealand, and much of Europe and Asia. All the other species are white with black, yellow, or pink facial markings. Only the roseate spoonbill is all pink.

This is what the roseate spoonbill sounds like:

[roseate spoonbill call]

Simon’s suggestion is another pink bird that you’ve undoubtedly heard of, the flamingo! It lives in parts of South America, Central and southern North America, Africa, southern Europe and the Middle East, and southwest Asia. The two most well-known and widespread species are the greater and lesser flamingos. The greater flamingo is the biggest, standing over 4 ½ feet tall, or 1.4 meters. That’s still not as tall as the goliath heron, although it’s close. Its wingspan can be five feet across, or 1.5 meters.

The flamingo is kind of a weird bird, even by wading bird standards. It rests by standing on one leg, which it can do without falling over and without expending any energy to keep itself upright. It can even sleep while standing on one leg. People are really good at walking on long legs, but it’s a lot harder for us to stand on one leg without swaying and eventually falling over when our muscles tire. On the other hand, we weigh a lot more than a flamingo, which is barely over 7 ½ lbs in weight, or 3.5 kg.

The most unusual aspect of the flamingo is its beak. It’s thick and famously bent downward halfway along its length, so that it’s shaped sort of like a boomerang. There’s really no way to describe it as a type of kitchen implement unless it’s a strainer basket, because that’s how the flamingo uses its beak.

The flamingo eats tiny animals like brine shrimp and other small crustaceans, insect larvae, and even algae, and it catches all these tiny foods by sifting them from the water with its beak. The beak is lined with lamellae, which look like little hairs or the teeth of a comb, and its tongue is rough. It lowers its head on its long neck until its head is actually upside down, scoops its beak back and forth through the water, and uses its tongue to push the water out through the lamellae. Whatever algae or tiny animals are left in its mouth, it swallows.

Flamingos are extremely social and live in huge flocks, sometimes consisting of thousands of birds. The female only lays a single egg in her mud nest, and both parents take care of the baby by feeding it crop milk. This isn’t actually milk but is a nutritious substance produced by glands in the throat and crop. Emperor penguins, pigeons, and doves are the only other birds known that produce crop milk for their babies. Flamingo chicks have ordinary straight beaks that develop the bend as they grow older.

Like the roseate spoonbill, the flamingo’s pink coloration is due to its diet. The algae it eats contains a lot of carotenoids, as do the brine shrimp it eats. The American flamingo tends to be the pinkest overall, but all flamingos are pink if they’re eating enough foods that contain these carotenoids.

This is what an American flamingo flock sounds like:

[flamingo call]

There are lots more wading birds than the ones we’ve covered here, and not all of them have long legs and long necks. Just, you know, the best ones do.

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

Thanks for listening!

Episode 429: Foxes!

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Thanks to Katie, Torin, and Eilee for suggesting this week’s topic, foxes!

Further reading:

Meet the Endangered Sierra Nevada Red Fox

Long snouts protect foxes when diving headfirst in snow

Black bears may play important role in protecting gray fox

The red fox:

A black and gold Sierra Nevada red fox [photo taken from the first link above]:

The extremely fluffy Arctic fox:

The gray fox [photo by VJAnderson – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=115382784]:

Show transcript:

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

This week we have an episode about foxes, a suggestion by Katie, and we’ll talk about fox species suggested by Torin and Eilee.

Foxes are omnivorous canids related to dogs and wolves, and just to be confusing, male foxes are sometimes called dogs. Female foxes are vixens and baby foxes are cubs or kits. But even though foxes are related to dogs and wolves, they’re not so closely related that they can interbreed with those other canids. Plus, of course, not every animal that’s called a fox is actually considered a fox scientifically.

The largest species of fox is the red fox, which also happens to be the one most people are familiar with. It’s common throughout much of North America, Eurasia, and the Middle East, and even parts of northern Africa. It’s also been introduced in Australia, where it’s an invasive species. It’s a rusty-red in color with black legs and white markings, including a white tip to the tail. It has large pointed ears and a long narrow muzzle.

There are lots of subspecies of red fox throughout its natural range, including one suggested by Eilee, the Sierra Nevada red fox. It lives in the Sierra Nevada and Oregon Cascades mountain ranges in the western United States, in parts of California, Nevada, and Oregon. It’s smaller than the red fox and some individuals are red, some are black and gold, and some are a mix of red and gray-brown. Its paws are covered with long hair that protects the paw pads from snow, and its coat is thick.

The Sierra Nevada red fox was first identified as a subspecies in 1937, but it took more than half a century until any scientists started studying it. It used to be common throughout the mountain ranges where it lives, but after more than a century of trapping for fur and shooting it for bounty, it’s one of the rarest foxes in the world. Fewer than 100 adults are known to survive in the wild, maybe even fewer than 50.

For a long time, scientists thought the Sierra Nevada red fox had been extirpated from California, and that it might even be completely extinct. Then a camera trap got pictures of one in 2010. It’s fully protected now, so hopefully its numbers will grow.

Torin suggested we learn about the Arctic fox, which lives in far northern areas like Greenland, Siberia, Alaska, and parts of northern Canada. The Arctic fox’s muzzle is relatively short and its ears are rounded, and it also has a rounder body and shorter legs than other foxes. This helps keep it warm, since it has less surface area to lose body heat.

During the summer, the Arctic fox is brown and gray, while in winter it’s white to blend in with the snowy background. There are some individuals who are gray or brown-gray year-round, although it’s rare. The Arctic fox’s fur is thick and layered to keep it warm even in bitterly cold weather, and like the Sierra Nevada red fox, it has a lot of fur on its feet.

The Arctic fox is omnivorous like other foxes, although in the winter it mostly eats meat. In summer it eats bird eggs, berries, and even seaweed along with fish and small animals like lemmings and mice. It also eats carrion from dead animals and what’s left from a polar bear’s meal. It has such a good sense of smell that it can smell a carcass from 25 miles away, or 40 km. Its hearing is good too, which allows it to find mice and other animals that are traveling under the snow. Like other foxes, it will poke its nose into the snow quickly to grab the little animal, an activity called mousing. A study from 2024 revealed that the fox’s snout shape helps keep it from getting injured in deep and compacted snow.

The grey fox lives throughout North and Central America, although it’s less common than it used to be due to habitat loss and hunting by humans. It’s a grizzled gray in color with reddish or tan legs, and a black stripe down its tail ending in a black tail tip.

It’s actually not that closely related to what are called true foxes. Its pupils are rounded like a dog’s instead of slit like other foxes, which have eyes that resemble cats’ eyes. The grey fox also has hooked claws that allow it to climb trees like a cat, and when it’s in a tree it can climb around in it just fine. A vixen may make her den in the hollow part of a tree to have her babies, sometimes as much as 30 feet, or 9 meters, above the ground, although most of the time gray foxes den on the ground, in a burrow, hollow log, or even in an abandoned human building.

The gray fox is small, not much bigger than a domestic cat, and it eats a lot of the same things that coyotes eat. If a coyote feels like a grey fox is encroaching on its territory, the coyote will kill the fox. Naturally, foxes are cautious around coyotes as a result. A study published in 2021 discovered that in areas where black bears live alongside coyotes and gray foxes, the foxes spend a lot of time hanging out near bears. In winter when the bears are hibernating, the foxes leave because coyotes will move into the area until the bears re-emerge in spring. Coyotes are afraid of bears, so the presence of bears protects the foxes as long as the fox doesn’t annoy the bear. I feel like this would make a great basis for a cartoon.

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

Thanks for listening!

Episode 426 Lots of Little Birds

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Thanks to Murilo, Alexandra, and Joel for their suggestions this week!

The bird sounds in this episode come from xeno-canto, a great resource for lots of animal sounds!

A cactus wren [picture by Mike & Chris – Cactus WrenUploaded by snowmanradio, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=15876953]:

The sultan tit [photo by By Dibyendu Ash – CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=72070998]:

A female scarlet tanager [photo by Félix Uribe, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=81340425]. The male is red with black wings:

The Northern cardinal:

The yellow grosbeak [photo by Arjan Haverkamp – originally posted to Flickr as 2008-08-23-15h00m37.IMG_4747l, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=9596644]:

The purple martin isn’t actually purple [photo by JJ Cadiz, Cajay – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=4255626]:

The dusky thrush [photo by Jerry Gunner from Lincoln, UK Uploaded by snowmanradio, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=20762838]:

The European rose chafer, not a bird [photo by I, Chrumps, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2521547]:

Show transcript:

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

This week we’re going to learn about a lot of little birds that deserve more attention, because they’re cute and interesting. Thanks to Murilo, Alexandra, and Joel for their little bird suggestions!

All the birds we’ll talk about today are called passerines, because they belong to the order Passeriformes. They’re also sometimes referred to as perching birds or songbirds, even though not all passerines sing. Passerines are common throughout the world, with more than 6,500 species identified. I’ve seen about 150 of those species, so clearly I need to work harder as a birdwatcher.

Passerines are referred to as perching birds because of their feet. A passerine bird has three toes that point forward and another toe pointing backwards, which allows it to wrap its toes securely around a twig or branch to sit. Its legs are also adapted so that the toes automatically curl up tight when the leg is bent. That’s why a sleeping bird doesn’t fall off its branch.

Let’s start with one of Murilo’s suggestions, the wren. Wrens are birds in the family Troglodytidae, and are usually very small with a short tail, a pointy bill that turns slightly downward at the tip, and brown plumage. It mainly eats insects and larvae that it finds in nooks and crannies of trees, and many species will investigate dark places like hollow logs, the openings to caves, or your apartment if you leave the back door open on a warm day. Many sing beautiful songs and have very loud voices for such little bitty birds.

Most wrens are native to the Americas, including the canyon wren that’s native to western North America in desert areas. It’s cinnamon-brown with a white throat and an especially long bill, which it uses to find insects in rock crevices. It lives in canyons and has a more flattened skull than other wrens, which means it can get its head into crevices without hurting itself. No one has ever seen a canyon wren drink water, and scientists think it probably gets all the water it needs from the insects it eats. Where do the insects get the water they need? That’s an episode for another day.

This is what a canyon wren sounds like:

[bird sound]

Not every bird that’s called a wren is actually in the family Troglodytidae. Some just resemble wrens, like an unusual bird that Murilo brought to my attention. It’s called Lyall’s wren but it’s actually in the family Acanthisittidae, and it was once widespread throughout New Zealand. By the time it was scientifically identified and described in 1894, it was restricted to a single island in Cook Strait.

Lyall’s wren was flightless, and only five passerines are flightless as far as we know. All five were island birds who have since gone extinct, which is unfortunately the case with Lyall’s wren too. It was greenish-brown with a yellow eye stripe and its tail was just a little short nub. We don’t know much about it because between 1894 when a lighthouse was built and some families moved to the island to work at the lighthouse, bringing their housecats, and 1925 when the feral cat colony on the island was finally killed off, all the remaining Lyall’s wrens were eaten by cats or killed by people to sell as museum specimens. To be clear, it’s entirely the fault of people that the bird went extinct, because they brought the cats to the island and let them run loose. The bird probably actually went extinct in 1895, just one year after cats were introduced to the island.

Murilo also suggested some little birds called chickadees and tits, which belong to the family Paridae. They’re very small, often brightly colored or with bright white markings, with short bills that help them crack seeds open. They also eat insects. They’re not found in South America or Australia, but they’re very common in North America, Eurasia, and most of sub-Saharan Africa. Many species love to visit bird feeders, and since they’re cute and active little birds, people are happy to have them around.

Some species in this family have crests, which makes them even cuter. The tufted titmouse, which is found in eastern North America, has a little tufted crest on its head, for instance. It’s a soft gray-blue in color with patches of rusty-red under its wings, and white underneath. The gray crested tit lives in western Europe and also has a fluffy crest on its head. It’s gray-brown with a thin black and white ring around its neck and a buff-colored underside. The yellow tit lives only in forests in central Taiwan and is a gorgeous dark blue with bright yellow underneath and on its face, with a darker crest. It’s so beautiful that it’s becoming rare, since people trap the birds to sell to disreputable collectors. The sultan tit is even more spectacular, if that’s possible, since the male is black with bright yellow underparts and a bright yellow crest. It lives in parts of south Asia and some subspecies have a black crest instead.

This is what a sultan tit sounds like:

[bird sound]

Another spectacular bird is one Alexandra suggested, the summer tanager. It’s a common summer visitor in the eastern and southwestern United States that winters in Central and northern South America. The male is a bright, cheerful red all over while the female is yellow. The western tanager is a close relation that lives in western North America, wintering in Mexico. The male has a mostly black back with a yellow rump and yellow underneath, with red and orange on his face. Females are yellowy-green and gray. The scarlet tanager is also similar, although the male is red with black wings and the female is yellowy-green and gray. They eat insects and fruit, and spend a lot of time in the very tops of trees.

This is what a scarlet tanager sounds like:

[bird sound]

Despite their names, all three of these tanagers aren’t actually tanagers. Tanagers are members of the family Thraupidae and are native to central and South America. Many of them are brightly colored and absolutely gorgeous, like the red-legged honeycreeper that’s common in Central and parts of South America. The male has a black back and tail and is bright blue on the rest of his body, except for a black mask over his eyes. His long curved bill is also black, but his legs are bright red. The female has red legs but she’s mostly greeny-yellow.

The North American tanagers are actually more closely related to the cardinal than to other tanagers, and are placed in the family Cardinalidae. The family is named after the northern cardinal, which is common throughout most of the United States and parts of Mexico. The male is bright red with black around his bill, while the female is more of a rosy brown color. Both have red bills and tufted crests. In North America, the cardinal appears on a lot of Christmas cards because its bright red plumage against a snowy background is so cheerful in winter.

This is what a northern cardinal sounds like:

[bird sound]

Alexandra also suggested the blue grosbeak, while Joel suggested the yellow grosbeak. Both are also members of the family Cardinalidae. The blue grosbeak lives in much of the United States in summer and spends the winter in Mexico and Central America. The male is blue with black and rufous markings and a silvery-gray beak, while the female is rufous-brown and gray. The yellow grosbeak lives along the Pacific slope of Mexico and may be the same as the golden grosbeak that lives in western South America, or a very close relation. Scientists aren’t sure yet. The male is a bright golden yellow with black and white wings and a black bill, while females are a less conspicuous green-yellow. The yellow grosbeak is larger than the blue but they’re both pretty big and robust. They eat insects and lots of other small animals like snails and spiders, along with fruit and seeds. Sometimes a yellow grosbeak will show up farther north, in the United States, and birdwatchers lose their minds with excitement.

This is what a yellow grosbeak sounds like:

[bird sound]

Joel also suggested the purple martin, a type of swallow that’s common throughout the Americas. It’s not purple but it is a dark blue-black color with iridescence that reflects light. This makes the bird look anywhere from dark purple to blue depending on the angle of the light. The male is much darker than the female, who is more gray-blue in color. It spends the summer in North America, raising babies and eating lots of insects, then migrates to South America to spend the winter.

This is what a purple martin sounds like:

[bird sound]

Another Joel suggestion is the dusky thrush, which is another passerine that migrates a long distance. It spends the summer in Siberia and nearby areas to nest, then flies south to spend the winter in southern China, Japan, India, Vietnam, Korea, and other nearby areas. It’s mostly brown on its back and white underneath with lots of speckles, and a light stripe over its eye. Males and females look very similar. It eats insects, spiders, worms, seeds, and berries and spends a lot of its time on the ground. Every so often a dusky thrush will get lost during migration and end up in western Europe or Alaska, and again, birdwatchers in those areas go nuts trying to catch a glimpse of it.

This is what a dusky thrush sounds like:

[bird sound]

Let’s finish this episode with another of Joel’s suggestions, the European rose chafer. You may be wondering what kind of bird this is, and that is exactly what I was wondering. It sounds very pretty! Then I looked it up, and it’s not a bird at all, it’s a type of beetle!

The rose chafer is a big metallic-green beetle related to scarabs that grows up to 20 mm long. It’s common in Europe and some parts of southeast Asia, and is often found on rose bushes in summer. It eats flowers, including the petals, nectar, and pollen, and really likes roses.

The female rose chafer lays her eggs in the ground and the larvae eat decaying vegetation. There’s also a related beetle called the rose chafer that lives in parts of North America, but it’s sort of a muddy tan color, and while it likes to eat roses and other flowers, it also likes to eat fruit like peaches and grapes. Its larvae eat roots and can damage plants.

Since the European rose chafer is such attractive beetle, with an iridescent bronze shimmer to its emerald-green carapace, you’d think people who grow roses would like to have them on their rose bushes, but this isn’t actually the case. I guess people who grow roses want to see the roses without them being all chewed up by beetles. To bring it back to birds, birds don’t eat the rose chafer because the beetle contains toxins that make it taste awful. But they’re still really pretty.

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

Thanks for listening!

Episode 418: Animals Discovered in 2024

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

Further reading:

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

New Species of Dwarf Deer Discovered in Peru

Hylomys macarong, the vampire hedgehog

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

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

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

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

A new mini tarantula [photo by David Ortiz]:

Show transcript:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Thanks for listening!

Episode 417: The Hoatzin

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I’m a bit under the weather this week, so here’s a Patreon episode about a weird bird!

Further reading:

Hoatzin nestling locomotion: acquisition of quadrupedal limb coordination in birds

Show transcript:

Welcome to the Patreon bonus episode of Strange Animals Podcast for mid-November, 2019!

We’re going to learn about a mystery bird today. When I say mystery bird, I don’t mean that people aren’t sure if it exists. It definitely exists. You can go to South America and look at it if you like, because fortunately it’s not rare or endangered. But scientists aren’t completely sure what it’s related to, because it’s a really weird bird.

The hoatzin [pronounced what-seen] is a large bird, over two feet long, or 65 cm. It’s shaped sort of like a pheasant, with a chunky body, long neck and small head, and a long tail made of stiff feathers like a hawk’s. Its face has no feathers and blue skin, it has red eyes, and it has a spiky feather crest on its head. It’s black and chestnut brown with some darker and lighter streaks, and is a softer brown underneath. It’s a really pretty bird, in fact, with a strong bill. But it really doesn’t resemble any other bird alive today.

The hoatzin is the only species in its genus, and the only genus in its family, and the only family in its order. It’s basically not really related to any other bird alive today, although in 2012 its genome was sequenced and found to be most closely related to cranes and plovers—but only very distantly. In fact, a 2015 study determined that the hoatzin started evolving separately from other birds 65 million years ago, right after the Cretaceous-Paleogene extinction event that killed off the non-avian dinosaurs.

We only have a few fossils of hoatzin ancestors, but they show that it was much more widespread in the past and lived in what is now North America and Europe. But these days it only survives in northern and central South America. It likes swampy areas and forests near rivers or other water.

The hoatzin eats plants—specifically leaves and buds, although it also eats some flowers and fruit. And leaves require a lot of digesting before the body can make use of the nutrients. The hoatzin’s digestive system is unlike any other living bird’s, because the hoatzin is a foregut fermenter. Its crop, which most birds only use to store extra food temporarily when the stomach is full, acts as a bacterial fermentation chamber—two chambers, in fact, since it’s divided into two sections. This acts like the rumen of a cow. Its crop is so big it doesn’t have room on its body for big flight muscles, so it’s not a strong flyer. It mostly stays in trees and bushes, eating leaves, flapping its big wings for balance and display, and hanging out with other hoatzins.

The hoatzin’s digestive system has a weird side effect. It smells bad. It’s supposed to smell like manure. It’s sometimes called the stinkbird and, fortunately for the hoatzin, almost no one wants to eat it as a result.

As you probably know, birds developed from dinosaurs. It’s easy to forget that, since birds have evolved structures like toothless beaks and front legs modified for flight and they no longer have lizard-like tails. But the hoatzin retains something from its dinosaur ancestry that is a startling reminder.

The hoatzin is a social bird that lives in small flocks. It breeds during the local rainy season and builds its nest over water when the forest floods due to rain. The female lays two or three eggs, and when the babies hatch, they can climb around in the branches near the nest right away. This means they can hide from predators instead of being helpless in the nest. And the reason a hoatzin chick can climb so well is partly because it has big feet, and partly because it has finger claws on its wings: specifically a thumb claw and one finger claw, which are fully functional and make it look a lot like a fuzzy baby dinosaur.

Not only does the baby hoatzin use these claws for climbing, a study published in May 2019 shows that the baby hoatzin uses its wings differently when climbing than it does as an adult bird. Obviously, birds fly by flapping both wings at the same time. But the baby hoatzin climbs by using its limbs in an alternating motion. You know, the way you would climb a tree. Or the way a small dinosaur would climb a tree.

But primitive and dinosaur-like as this trait is, researchers have discovered that it developed relatively recently. That is, as the hoatzin’s distant ancestors evolved from a small dinosaur into a primitive bird, it lost the claws on its front legs as they became more and more modified into wings. But at some point, the hoatzin re-developed those claws. Researchers think it’s what is called an atavistic trait, which you may remember from way back in the Patreon episode where we talked about horses with extra toes. In other words, the genes to grow claws on the front limbs are still present in birds, but are suppressed by other genes, since claws just get in the way when you’re flying. But occasionally a small mutation causes the claws to grow anyway, and in the case of the hoatzin, it proved so useful that those babies with claws survived better than those without claws, and therefore lived to pass on their genes. But the claws are no longer useful once the babies grow up and learn how to fly, so they lose them as adults.

Hoatzin chicks climb using alternating motions of the wings, but swim by moving both wings together. Oh, didn’t I mention that the babies swim? They have to, because sometimes a predator attacks and they have to get away fast. They can’t fly yet, and they can’t climb all that quickly, so they drop out of the branches and fall into the water below. That’s why the parent birds build the nests over water. The babies can swim just fine, and they swim to safety and climb back up into the branches where their parents can find them.

The hoatzin isn’t the only bird that has wing claws as a baby. Some species of turaco do too. The turaco lives in Africa and shares many traits with the hoatzin, so for a long time people thought the two were related. But now we know they’re not and that the similarities are due to convergent evolution.

Thanks for your support, and thanks for listening!

Episode 416: The heaviest tarantula and the bitey-est ant

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Thanks to Siya, Sutton, Owen, and Aksel for suggesting this week’s topic, the Goliath birdeater tarantula and the fire ant!

Further listening:

The TEETH Podcast

Further reading:

Tropical fire ants traveled the world on 16th century ships

The Goliath birdeater tarantula, bigger than some kittens:

Fire ants:

Show transcript:

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

This week we’re going to talk about two invertebrates, a spider and an insect. Thanks to Siya, Sutton, Owen, and Aksel for suggesting them!

We’ll start with the spider, which Siya and Sutton both suggested. It’s the goliath tarantula, also called the goliath birdeater. You know it has to be a big spider if it’s called a birdeater. We’ve talked about it before, but not in a long time.

The goliath birdeater is the heaviest spider in the world. If you think of the usual spider, even a big one, it’s still pretty lightweight. Let’s use a wolf spider as an example, which is found just about everywhere in the world. It’s a hunting spider that doesn’t spin a web, and while different species vary in size, the biggest is the Carolina wolf spider found in many parts of North America. A big female can have a legspan of four inches across, or 10 cm, with a body up to an inch and a half long, or 35 mm—but it weighs less than an ounce. That’s barely 28 grams, or just a little heavier than five sheets of printer paper.

In comparison, the goliath birdeater tarantula can weigh over 6 ounces, or 175 grams. That’s heavier than a baseball, or two packs of cards. Its legspan can be as much as 12 inches across, or 30 cm with a body length of about 5 inches, or 13 cm. It’s brown or golden in color and lives in South America, especially in swampy parts of the Amazon rainforest. It’s nocturnal and mostly eats worms, large insects, other spiders, amphibians like frogs and toads, and occasionally other small animals like lizards or even snakes. And yes, every so often it will catch and eat a bird, but that’s rare. Birds are a lot harder to catch than worms, especially since the Goliath birdeater lives on the ground, not in trees.

Because it’s so large, the goliath looks like it would be incredibly dangerous to humans. It does have fangs and can inflict a venomous bite, but it’s not very strong venom. The danger comes from a very different source, because the goliath birdeater is famous for its urticating spines.

Many species of tarantula have special setae, hairlike structures called urticating spines, that can be dislodged from the body easily. If a tarantula feels threatened, it will rub a leg against its abdomen, dislodging the urticating spines. The spines are fine and light so they float upward away from the spider on the tiny air currents made by the tarantula’s legs, and right into the face of whatever animal is threatening it. The spines are covered with microscopic barbs that latch onto whatever they touch. If that’s your face or hands, they are going to make your skin itch painfully, and if it happens to be your eyeball you might end up having to go to the eye doctor for an injured cornea. Scientists who study tarantulas usually wear eye protection.

The goliath birdeater tarantula is considered a delicacy in northeastern South America. People eat it roasted. Apparently it tastes kind of like shrimp.

Next, Owen and Aksel wanted to learn about fire ants. I couldn’t believe that we’ve never talked about fire ants before!

Fire ant is the name for any of the more than 200 species in the genus Solenopsis, but it’s typically used to refer to the species Solenopsis invicta. It’s native to tropical South America but has been introduced to parts of North America, Australia, China, Taiwan, India, Africa, and many other places where the climate is tropical or sub-tropical.

The fire ant initially became so invasive due to Spanish galleons in the 16th century, which carried trade goods around the world. A ship that’s meant to carry a lot of cargo is built so that it needs to be weighted down to a certain degree to sail safely. A lot of times if a Spanish ship didn’t have enough goods in its hold to make it weigh enough, the captain would bring a few tons of soil onboard to make up the difference. Then, when the ship got to its next port where it was supposed to pick up new cargo, it would just dump the dirt wherever it was. It didn’t matter to the fire ant if the dirt was dumped into the water, because fire ants are prepared for their nests getting flooding. They cling together and form huge rafts that the wind pushes to shore. But more often, the dirt would get dumped on land for other ships to re-use.

A team of scientists figured out where the invasive fire ant populations came from by comparing the genetic signatures of 192 different populations. They hypothesized that the ants with the highest genetic diversity were the original population, and that as the ants were moved around the world by ship, genetic diversity would get lower and lower, since all the ants were descendants of the original colony or colonies transported accidentally in the dirt. They mapped out the genetics, then compared the results to Spanish trade routes in the mid-1600s, and it all matched up.

The fire ant made it to the United States in the late 1930s or early 1940s, the West Indies around 1980, and Australia around 2001. These days a lot of fire ants end up transported to new areas in golf course sod imported from Florida.

A fire ant colony consists of a queen, thousands of worker ants, and larger soldier ants that protect the workers and especially the queen. Some colonies have more than one queen. The ants eat anything, including seeds and insects, and even small animals, but also including dead animals they find. The colony can have as many as a quarter million ants. The nest is underground and entrances can be far from the nest itself, and nests can be so large that they can cause structures built over them to collapse.

Invasive animals of any kind aren’t good for the native animals, and the same is true for the fire ant. The fire ant specializes in colonizing areas where humans have disturbed the ground, whereas native ants often have trouble surviving in disturbed areas. The fire ants crowd out native ants and can destroy some native plants.

But the main reason why people don’t like fire ants is that they bite and they’re venomous. The bites cause a burning sensation and painful swelling, but some people are allergic to the venom and can actually die from ant bites. Luckily, that’s rare, but the bites are still painful.

Some countries have spent millions of dollars trying to eradicate the fire ant, including Australia and New Zealand. New Zealand seems to have succeeded, but Australia is still struggling to get the invasion under control. Fortunately, a lot of animals eat fire ants, which helps. One of the animals that especially loves to eat fire ants is the wolf spider, so now we’ve come full circle in this episode.

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

Thanks for listening!

If you are wishing that I’d gone into more detail about fire ant attacks, you might like the TEETH podcast. It’s the only podcast where you’ll hear wild animal attack stories directly from the survivors, hosted by a wilderness guide and attack survivor himself. I’ll put a link in the show notes so you can go listen. It’s appropriate for all ages. I don’t think they’ve actually covered a fire ant attack, but they’ve got lots of other fascinating accounts.

Episode 415: Animals with Names

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This week we’re going to learn about some animals that seem to have individual names!

Further reading:

Bottlenose dolphins can use learned vocal labels to address each other

How Do Dolphins Choose Their Name?

Vertical transmission of learned signatures in a wild parrot

Baby Parrots Learn Their Names from Their Parents

Study: African Elephants Address Each Other With Name-Like Calls

Marmoset Monkeys Use Names to Communicate with Each Other

The green-rumped parrotlet (photo by Rick Robinson, taken from this site):

Show transcript:

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

This week we’re going to learn about some animals that seem to be using names to refer to other individuals or themselves.

Let’s start with bottlenose dolphins, because they’re well-studied and scientists have known about this particular aspect of their society for over a decade. Every bottlenose dolphin has a signature whistle that identifies it to other dolphins. The signature whistles can be complex and the dolphin may add or change details to indicate its mood or other information. It’s not precisely a name in the way humans would think of it, but it is an identifier.

The dolphin creates its own signature whistle when it’s young. Some dolphins pattern their whistles on their mother’s signature whistle, while others mimic their siblings or friends. Some seem to pattern theirs on a distant acquaintance, which sounds to me like they just like something about an unusual whistle and decide to incorporate it into their own whistle. As dolphins grow up, females typically don’t change their whistles, but males often do. Male dolphins often pair up together and remain bonded, and a pair may change their signature whistles to be similar.

When a dolphin is trying to find a friend it can’t see, it will mimic that friend’s signature whistle. If a mother can’t see her calf and is worried, she’ll do the same, and her calf will answer by repeating its signature whistle. A lost calf will imitate its mother’s whistle. But it’s even more complicated than it sounds, because a group of dolphins who get together to forage may choose a shared whistle that the whole group uses. This helps them coordinate their behaviors to work together. Each member of the group uses a slightly different version of the group whistle, which means that each member can identify who’s speaking.

Other cetaceans seem to use a similar kind of name. Sperm whales, for instance, have a unique click sequence that they use to announce themselves when approaching other whales. The signature clicks always appear at the beginning of a sequence and don’t vary.

Bottlenose dolphins and many other cetaceans are extremely social animals. So are parrots. Studies of parrot calls indicate that parrots appear to have signature calls that they use the same way as dolphins do, to identify themselves to other parrots and as a way for other parrots to call for them. A study of wild green-rumped parrotlets in Venezuela discovered that the birds give a unique signature call to each baby while it’s still in the nest, and the baby continues to use its call its whole life, often with small changes.

The study set up video cameras to monitor 16 nests of a large wild population of the parrots. The population has been well studied and is used to using nesting tubes that scientists have set up for them. This makes it easier for the scientists to monitor nesting behaviors. In this case, to test whether the names had something to do with genetics or not, the scientists sneakily moved half of the eggs from one nest to another, so that half the parents unknowingly raised some chicks that weren’t actually related to them.

Despite the egg switcharoo, all the chicks were given names that were similar to the parents’ signature calls. The parents started using a specific signature call soon after the eggs hatched, and the babies started imitating it. Gradually each baby added its own specific flourish to the call that made it their own, so while you can say that the parents named their babies, it’s just as true to say that the babies named themselves. The parrots use the signature calls to announce themselves, but also to call for friends, siblings, and parents.

Elephants are also extremely social animals. Recent studies of African savanna elephant calls indicate that elephants also have an identifying rumble sound that acts as a name. In fact, it acts more like a name as humans use names than the signature sounds made by dolphins and parrots. An elephant will use a specific rumble when addressing another elephant, but the rumble isn’t the speaker’s name, it’s the recipient’s name. It’s the difference between me saying, “Hi, I’m Kate. How are you?” and me saying, “Hi, Kelly, how are you?” when I’m talking to my friend Kelly. Dolphins and parrots seem to be saying something like, “Kate here, I’m swimming this way.”

Marmosets seem to use names the same way that elephants do. Marmosets are a type of small monkey native to Central and South America, which live in treetops and eat fruit and other plant material, and the occasional insect. A 2024 study found that marmosets that know each other address individuals with specific sounds, whether or not they’re related.

All the animals we’ve talked about today are incredibly social, just like humans are. In the case of dolphins, parrots, and marmosets in particular, it’s easy for individuals to travel and forage together but be out of sight of one other. Having a way to track friends and family members when you can’t see them is important to keep a group together.

Studies about animals using names are becoming more common, with both the marmoset study and the elephant study published in 2024. It may not seem like a big deal, but using a specific vocal label for a specific individual is a huge indicator of linguistic intelligence. We haven’t known a lot about it before recently because the recordings of animals communicating was time-consuming and difficult to categorize. Now we have sophisticated computer programs that can compile the information for us, so that scientists can study it more easily. I wouldn’t be a bit surprised if more and more studies start finding animals that use names.

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

Thanks for listening!

Episode 414: Two Marvelous Frogs

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Thanks to Eilee and Alexis for their suggestions this week, two amazing frogs!

Further reading:

Paradoxical frog: The giant tadpole that turns into a little frog

Fungus is wiping out frogs. These tiny saunas could save them.

How to build a frog sauna

The paradoxical frog [photo by Mauricio Rivera Correa – http://calphotos.berkeley.edu, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=6703905]:

The Vietnamese mossy frog [photo by H. Zell – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=81804225]:

Show transcript:

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

Let’s start 2025 off right with an episode about frogs! Thanks to Alexis and Eilee for their suggestions.

Let’s start with Eilee’s suggestion, the paradoxical frog. The paradoxical frog is a type of tree frog that lives in South America. Like other frogs, it likes ponds and shallow lakes. Some individuals are green and some are brown, and a frog may have darker stripes or splotches, or might just be plain. The tadpoles eat algae and other tiny food, while the adults eat insects.

As with most frogs, the paradoxical frog hatches into a larval stage called a tadpole or pollywog, which is fully aquatic. It later metamorphoses into its adult form as a frog. Most tadpoles start out very small and grow larger, then metamorphose into a juvenile frog which then grows to fully adult size. But while the paradoxical frog’s tadpole starts out small, it can grow to as much as 11 inches long, or 28 centimeters! It’s the largest tadpole in the world as far as we know.

So how big is the adult frog if the tadpole is so enormous? About 3 inches long, or 7.5 cm, from snout to vent. That’s why it’s called the paradoxical frog, because a paradox is something that seems contradictory to expectations. Instead of the ordinary way of things, where a small tadpole grows into a bigger frog, in this case a big tadpole grows into a smaller frog. It’s sometimes called the shrinking frog.

One interesting detail is that not all of the tadpoles are that big. If a female lays her eggs in a small body of water that’s likely to dry up, or that doesn’t have a lot of food available, or if there are a lot of predators in the water, the tadpole metamorphoses quickly and doesn’t grow very big. But if the tadpole is in a better location it matures much more slowly, which allows it to reach much larger size before metamorphosing.

I should also mention that the 11-inch-long tadpole that is the largest ever measured was actually raised in captivity. In the wild, the largest paradoxical frog tadpole ever measured was 6 ½ inches long, or almost 17 cm. That’s still really big, but not that ridiculously big. But the confusing thing is that the tadpole is big and bulky, up to four times the size of the adult frog. Where does all that mass go after it transforms?

Early scientists who learned about the paradoxical frog wondered the same thing. They were so confused that they suggested that the frog actually came first and later metamorphosed into the tadpole, which then metamorphosed into a fish. But the main reason the tadpole is so long is its tail. When it metamorphoses into a frog, it absorbs the tail and therefore appears to shrink. The bulkiness of the tadpole’s body matches the bulkiness of the frog’s body. And unlike most frogs, which metamorphose into juvenile frogs that still have some growing to do, the paradoxical frog metamorphoses into a completely adult frog. It’s as big as it will ever get and fully mature, ready to mate and lay eggs.

Next, Alexis wanted to learn about the Vietnamese mossy frog. It lives in parts of Vietnam, Laos, and other nearby areas. It prefers mountainous rainforests and the female often chooses to lay her eggs in a tree hollow or even a rock cavity where water has collected. Instead of laying her eggs in the actual water, though, she lays them on rocks or branches above the water. The eggs don’t dry out because of the high humidity in rainforests, and when they hatch, the tadpoles fall into the water.

The tadpoles take a long time to mature, anywhere from four to eight months depending on how warm it is while they’re developing. They grow quite large, although not anywhere near the size of the paradoxical frog tadpole.

A big female Vietnamese mossy frog can grow up to 3 ½ inches long, snout to vent, or 9 cm, and is chubby and round. It’s nocturnal and spends the day hiding on mossy rocks or among plants in the water, then comes out at night to hunt insects like crickets as well as other small animals like worms.

The reason it’s called the mossy frog is because it looks for all the world as though this frog is covered in moss, or maybe is just made out of moss. It’s green and brown in color and its skin is covered in little bumpy structures called tubercules. This helps it blend in incredibly well in the rainforest, where moss is pretty much everywhere. If it feels threatened and it can’t jump into the water to hide, it will play dead.

This is what a Vietnamese mossy frog sounds like:

[frog beeping]

As we’ve talked about in other frog episodes, frogs throughout the world are declining in numbers because of a fungus that infects their skin. The effects of this fungus are worse in cold weather, so a team of scientists speculated that helping the frogs stay warm might help them stay healthier in winter and even help them recover from the infection. They tested their hypothesis by offering infected frogs a variety of temperatures in their enclosure. The frogs could pick where they wanted to spend their time. The frogs liked the warm areas but didn’t spend all their time in them, but they all recovered from the infection. Frogs who were given an overall warm environment also recovered, but not as fast. Frogs who had an ordinary enclosure without warmer areas remained infected with the fungus. Even better, frogs who had recovered from infection with the warm environment also showed resistance to later infections.

The team worked to develop plans that allow people to easily build what they call frog saunas. They don’t require electricity or fuel, just sunshine. When the saunas are placed near ponds or other areas with frogs, the frogs find them quickly and use them. There’s a link in the show notes if you want to learn how to make a frog sauna for your own back yard.

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

Thanks for listening!