Category Archives: South America

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 330: Vintana and Tiarajudens

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Thanks to Lorenzo for suggesting Tiarajudens! We’ll learn about it this week along with another extinct animal, Vintana.

Further reading:

Funky facial flanges [the skull picture below comes from this site]

First Postcranial Fossils of Rare Gondwanatherian Mammal Unearthed in Madagascar

The Earliest Saberteeth Were for Fighting, Not Biting [the skeleton picture below comes from this site]

Vintana’s skull had weird jugal flanges:

Tiarajudens had saber teeth as well as palatal teeth:

Show transcript:

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

Just last month we had an episode about the tenrec and an extinct animal called Adalatherium. At the end of that episode, I said something I say a lot, that we don’t know very much about it or the other ancient mammals that lived at the time, and that I hoped we would find some new fossils soon. Well, guess what! A paper about a newly discovered Gondwanathere fossil was published just a few days ago as this episode goes live. Rather than save it for the updates episode later this summer, let’s learn about an animal named Vintana sertichi, along with a suggestion from Lorenzo for another extinct animal.

As you may remember from episode 324, Adalatherium is a member of a group of animals called Gondwanatheria, which arose in the southern hemisphere around the time that the supercontinent Gondwana was breaking apart. We only have a few fossils of these animals so paleontologists still don’t know how they’re related, although we do know they’re not related to the mammals living today. Every new specimen found of these rare mammals helps scientists fill the gaps in our knowledge. That’s what happened with Vintana.

Vintana lived at the end of the Cretaceous, until the asteroid strike about 66 million years ago that killed off the non-avian dinosaurs and a whole lot of other animals, probably including Vintana. The first fossilized specimen was a skull found in Madagascar and described in 2014. It was really well preserved, which allowed scientists to learn a lot about the animal.

Vintana was an active animal that ate plants. It had large eyes and a good sense of smell and hearing, so its ears might have been fairly large too. Its face probably looked a lot like a big rodent’s face, but the skull itself had a weird feature. The cheekbones extended downward on each side next to the jaw, and these extensions are called jugal flanges. They would have allowed for the attachment of really big jaw muscles. That suggests that Vintana could probably give you a nasty bite, not that you need to worry about that unless you find a time machine. It might also mean that Vintana ate tough plants that required a lot of chewing.

Vintana probably looked a lot like a groundhog, or marmot, which we talked about recently in episode 327. It wasn’t related to the groundhog, though, and was bigger too. Scientists estimate it weighed about 20 lbs, or 9 kg.

The fossil specimen of Adalatherium that we talked about in episode 324 was discovered in Madagascar in 2020. When a tail vertebra from another mammal was found in the same area, researchers scanned and compared it to Adalatherium’s vertebrae. They were similar but not an exact match, plus the new bone was almost twice as large as the same bone in Adalatherium’s spine. It matched the size of Vintana and was assigned to that species. Vintana was probably related to Adalatherium but was bigger and had a shorter, wider tail. And as of right now, that’s just about all we know about it.

Next, let’s learn about another extinct animal, this one suggested by Lorenzo. Lorenzo gave me a bunch of great suggestions and I picked this one to pair with Vintana, because otherwise this episode would have been really short. Vintana lived at the end of the dinosaurs, but Tiarajudens lived long before the dinosaurs evolved, around 260 million years ago.

Tiarajudens was a therapsid, a group that eventually gave rise to mammals although it’s not a direct ancestor of mammals. Technically it’s an anomodont. We don’t have a complete skeleton so we don’t know for sure how big it was, but we do have a skull and some leg bones so we know it was about the same size or a little bigger than a big dog. There are only two species known, one from what is now South America and one from what is now Africa, but 260 million years ago those two landmasses were connected and were part of the supercontinent Gondwana.

Tiarajudens had weird teeth even compared to other anomodonts. It had a pair of saber teeth that resembled the tusks found in later anomodonts, but they weren’t really tusks. They were big fangs that grew from the upper jaw and jutted down out of the mouth well past the bottom of the jaw. Later anomodonts probably used their tusks to dig up plants, but there aren’t wear marks on Tiarajudens’s saber teeth that would indicate it used them for digging. Many paleontologists think it used them for defense and to fight other Tiarajudenses over mates or territory. We don’t know if the saber teeth were present in all individuals, since we’ve only found a few specimens.

Tiarajudens also had palatal teeth. These days palatal teeth are mostly found in amphibians, especially frogs. Palatal teeth grow down from the roof of the mouth and Tiarajudens’s were flat like molars. We haven’t found a lower jaw yet so we don’t know what the bottom teeth looked like, but from the wear marks on the upper teeth, it was clear that Tiarajudens was actually chewing its food. That was really unusual among all animals at the time, and in fact Tiarajudens is one of the first animals to really chew its food instead of giving it a chomp or two and swallowing it mostly whole. It ate plants, probably tough ones that required a lot of chewing.

So what did Tiarajudens look like beyond its teeth? It probably resembled a bulky four-legged dinosaur with a short tail, but it may have had whiskers. That’s as much as we know right now, because Tiarajudens was not only an early therapsid, it was different in many ways from most other therapsids known. For instance, it had what are called gastralia, or belly ribs, which were once common in tetrapods. Some dinosaurs had gastralia, including T. rex, but most therapsids didn’t. These days crocodiles and their relations still have gastralia, and so does the tuatara, but most animals don’t.

Both Tiarajudens and Vintana were unusual animals that we just don’t know much about. Let’s hope that changes soon and scientists find more fossils of both. I’ll keep you updated.

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 329: Manatees and a Surprise Sloth

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Thanks to Alexandra and Pranav for their suggestions this week! Let’s learn about manatees and sloths, including a surprising extinct sloth.

Further reading:

Sloths in the Water

A West Indian manatee:

A three-toed sloth:

Show transcript:

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

This week we have a suggestion from Alexandra and Pranav, who wanted an episode about manatees. We’ll also talk about another marine mammal, a weird extinct one you may never have heard of.

The manatee is also called the sea cow, because it sort of slightly resembles a cow and it grazes on plants that grow underwater. It’s a member of the order Sirenia, which includes the dugong, and sirenians are probably most closely related to the elephant. This sounds ridiculous at first, but there are a lot of physical similarities between the manatee and the elephant. Their teeth are very similar, for instance, even if the manatee doesn’t grow tusks. The elephant has a pair of big chewing teeth on each side of its mouth that look more like the bottoms of running shoes than ordinary teeth. Every so many years, the four molars in an elephant’s mouth start to get pushed out by four new molars. The new teeth grow in at the back of the mouth and start moving forward, pushing the old molars farther forward until they fall out. The manatee has this same type of tooth replacement, although its teeth aren’t as gigantic as the elephant’s teeth. The manatee also has hard ridged pads on the roof of its mouth that help it chew its food.

Female manatees are larger than males on average, and a really big female manatee can grow over 15 feet long, or 4.6 meters. Most manatees are between 9 and 10 feet long, or a little less than 3 meters. Its body is elongated like a whale, but unlike a whale it’s slow, usually only swimming about as fast as a human can swim. Its skin is gray or brown although often it has algae growing on it that helps camouflage it. The end of the manatee’s tail looks like a rounded paddle, and it has front flippers but no rear limbs. Its face is rounded with a prehensile upper lip covered with bristly whiskers, which it uses to find and gather water plants.

Every so often a manatee will eat a little fish, apparently on purpose. Since most herbivorous animals will eat meat every so often, this isn’t unusual. Mostly, though, the manatee spends almost all of its time awake eating plants, often from the bottom of the waterway where it lives. It lives in shallow water and will use its flippers to walk itself along the bottom, and also uses its flippers to dig up plants. Its upper lip is divided in two like the upper lips of many animals, which you can see in a dog or cat as that little line connecting the bottom of the nose to the upper lip. In the manatee, though, both sides of the lips have a lot of muscles and can move independently.

There are three species of manatee alive today: the West Indian manatee that lives in the Gulf of Mexico down to the eastern coast of northern South America, the Amazonian manatee that lives exclusively in fresh water in the Amazon basin, and the West African manatee that lives in brackish and fresh water. Sometimes the West Indian manatee will also move into river systems to find food.

Back in episode 153 we talked about the Florida manatee, which is a subspecies of West Indian manatee. In the winter it mostly lives around Florida but in summer many individuals travel widely. It’s sometimes found as far north as Massachusetts along the Atlantic coast, and as far west as Texas in the Gulf of Mexico, but despite its size, the manatee doesn’t have a lot of blubber or fat to keep it warm. The farther away it travels from warm water, the more likely it is to die of cold.

In the 1970s there were only a few hundred Florida manatees alive and it nearly went extinct. It was listed as an endangered species and after a lot of effort by a lot of different conservation groups, it’s now only considered threatened, but it’s still vulnerable to habitat loss, injuries from boats, and getting tangled in fishing gear and drowning. Occasionally a crocodile will eat a young manatee, but for the most part it’s so big, and lives in such shallow water, that most predators won’t bother it. It basically only has to worry about humans, and unfortunately humans still cause a lot of manatee deaths every year with boats.

A lot of times, a manatee that’s hit by a boat is only injured. There are several rehabilitation centers in the United States, where an injured manatee can be treated by veterinarians until it’s healed and can be reintroduced into the wild.

One other detail that makes the manatee similar to the elephant is its flippers, which is probably not what you expected me to say. Most manatees have toenails on their flippers that closely resemble the nails on elephant feet. The exception is the Amazonian manatee that doesn’t have toenails at all.

A lot of the food the Amazonian manatee eats actually floats on the surface of the rivers where it lives, and it will also eat fruit that drops into the water. Because the Amazon basin is subject to a dry season where there’s not a lot of food, the manatee eats a lot when it can to build up fat reserves for later. During the dry season, it usually moves to the biggest lakes in the area as the rivers and shallower lakes dry up or get too shallow for the manatee to swim in. Since the manatee has a low metabolic rate, it can live off its fat reserves until the dry season is over.

One interesting thing about the manatee is that it only has six vertebrae in its neck. Almost all other mammals have seven, even giraffes. The exception is the two-toed sloth, which also has six, and the three-toed sloth, which has a varying number of neck vertebrae, up to nine in some species!

Pranav also wanted to learn about sloths, so let’s talk about them next. All sloths are native to Central and South America. The sloths living today live in forests, especially rainforests, and spend almost all their time in trees.

A sloth makes the manatee look like a speed demon. It spends most of its time hanging from its long claws beneath branches, eating leaves and other plant material, but when it does move, it does so extremely slowly. This helps it stay camouflaged from predators, because its fur contains algae that makes it look green, so a barely-moving green-furred sloth hanging from a tree just looks like a bunch of leaves. It does move from one tree to another to find fresh leaves, and once a week it climbs down from its tree to defecate and urinate on the ground. Yes, it only relieves itself once a week.

The sloth’s digestive tract is also extremely slow, which allows it to extract as much nutrition as possible from each leaf. It takes about a month for a sloth to fully digest one mouthful of food.

The three-toed sloth is about the size of a large cat while the two-toed sloth is slightly larger, maybe the size of a small to medium-sized dog. The two-toed sloth is nocturnal while the three-toed sloth is mostly diurnal. Even though they look and act very similar, the two types of sloth are not very closely related. Both have long curved claws and strong pulling muscles, although their pushing muscles are weak. This is why a sloth can’t walk like other animals; the muscles that would allow it to do so aren’t strong enough to support its own weight. And yet, it can hang from a branch and walk along it for as long as it needs to. I don’t think I could hang from a branch by my fingers for five minutes without having to let go.

Surprisingly, the sloth can also swim quite well, which allows it to find new trees even if there are streams or rivers in the way. But a few million years ago, a different type of sloth lived off the coast of western South America and did a whole lot of swimming. In fact, later species of Thalassocnus were probably fully marine mammals.

We talked about Thalassocnus briefly way back in episode 22. It was related to the giant ground sloths that were themselves related to the living three-toed sloths. The earliest Thalassocnus fossils are of semi-aquatic animals that grazed in shallow water. Fossils from more recent species show increasing adaptations to deeper water, including increased weight of the skeleton to help it stay underwater instead of bobbing up to the surface.

Thalassocnus eventually evolved a stiff, partially fused spine, which reflects the unusual way it moved around underwater. Instead of swimming the way a whale does, or even the way a dog or person does, it moved more like a hippopotamus. Hippos sort of bounce along underwater, using their feet to push off from the bottom. Thalassocnus probably did this too and used its long tail to help it maneuver.

Thalassocnus was a lot bigger than modern sloths. Even the smallest known species were the size of a big human, and the biggest species grew up to 11 feet long, or 3.3 meters. That biggest species was the one that lived most recently, up to about 1.5 million years ago, and researchers think it was fully aquatic. Its nostrils were on the top of its snout and it had prehensile lips to help it find plants underwater. Some researchers even think it could have had a short trunk something like a tapir. It had seven neck vertebrae, as in most other mammals.

There’s still a lot we don’t know about Thalassocnus, but because we have fossils of five different species that lived at different times, scientists are able to determine a lot about how it developed from a mostly terrestrial animal to a mostly or fully marine animal. The youngest species had smaller, weaker legs than the earlier ones, which suggests it didn’t use its legs to walk on land. It probably lived a lot like modern manatees, finding sea grasses and other plants on the sea floor in shallow water, but not able to swim very fast.

One last thing about the manatee is that it spends about half of its time asleep, and it sleeps underwater. It comes up for a breath every 15 minutes or so. Modern sloths sleep a lot too, around 15 hours a day. Chill sleepy friends.

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 326: The Harpy Eagle and Friends

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Thanks to Eva and Anbo for suggesting the harpy eagle!

Further reading:

Crested Eagle Feeding a Post-Fledged Young Harpy Eagle

Harpy eagle with a food [By http://www.birdphotos.com – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=3785263]:

The harpy eagle has great big feet and talons:

The harpy eagle with its feather crown raised [photo by Eric Kilby]:

The New Guinea harpy eagle looks similar to its South American cousin [By gailhampshire from Cradley, Malvern, U.K – New Guinea Harpy Eagle. Harpyopsis novaeguineae, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=86187611]:

Ruppell’s griffon vulture:

Show transcript:

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

We’ve been talking about a lot of mammals lately, so let’s have an episode about birds. Anbo suggested the harpy eagle not too long ago, and a much longer time ago Eva suggested the harpy eagle and other raptors.

The word raptor can be confusing because it refers to a type of small theropod dinosaur as well as a type of bird. When referring to a bird, the term raptor includes eagles, hawks, vultures, owls, and other birds of prey. And that includes the harpy eagle.

The harpy eagle lives throughout much of Central and South America, although not as far south as Patagonia. It has a wingspan up to about seven feet across, or over 2 meters, and like other raptors, females are larger than males. This isn’t an especially big wingspan for an eagle, but that’s because the harpy eagle hunts in forests and needs short, broad wings that allow it to maneuver through branches.

The harpy eagle is a beautiful bird. It has a light gray head and darker gray or black body, and is white underneath with delicate black stripes on its leg feathers, with broader stripes on its tail and wings. It has a black ring around its neck, huge yellow feet with enormous talons, and a black bill. Each talon, which is the term for a raptor’s claws, can be over 5 inches long, or 13 cm, while its feet in general are bigger than a grown man’s hand, even if the man has especially big hands.

Most striking of all is the harpy eagle’s crest, also sometimes referred to as a crown. The crown is made of long, rounded feathers and most of the time they don’t show very much. When a harpy eagle is alarmed, it raises the feather crown and poofs out the feathers on its face, which makes its head look bigger and sort of owl-shaped.

The harpy eagle mostly lives in lowland rainforests. It mates for life and doesn’t have babies every year. Every two or three years a harpy eagle pair will build a huge nest out of sticks in the top of the tallest tree they can find. The female lays two eggs, which the parents care for together. The female spends most of her time incubating the eggs while the male brings her food, although he will also take a turn incubating while she goes out to stretch her wings and do a bit of hunting herself. When the first egg hatches, the parents bring the baby lots of food and give it lots of attention–but they ignore the other egg at that point, which usually doesn’t hatch as a result. A harpy eagle chick is all white at first, and although it can fly at around 6 months old, its parents will keep feeding it for almost another year.

The harpy eagle is increasingly threatened due to habitat loss and poaching. Because it’s such a big bird, many people shoot it because they think it’s dangerous to livestock or children. But it mostly eats monkeys, sloths, kinkajous and coatis, iguanas, and other medium-sized animals. It’s rare that it attacks livestock since it mostly hunts within the tree canopy for arboreal animals. If your lambs and chickens are sitting on tree branches, you already have a bigger problem than harpy eagles eating them.

A captive breeding program has been started in various zoos around the world, while conservationists work to protect the harpy eagle’s natural habitat so that individuals can be released back into the wild.

We don’t actually know all that much about the harpy eagle, but we know even less about its close relation, the New Guinea harpy eagle. It resembles the harpy eagle but instead of being mostly gray and white, it’s mostly brown and cream in color. It has longer legs and tail but is smaller overall than the harpy eagle, with a wingspan closer to 5 feet across, or 1.5 meters. It has a smaller crest than the harpy eagle too.

Like its South American cousin, the New Guinea harpy eagle hunts in forests, especially rainforests, and spends most of its time perched in a tree, watching for small animals to happen by. Sometimes it will shake a branch to startle any animals in the area to run or fly away, at which point the eagle flies after them. It will even climb around in a tree and poke around in any potential hiding places it finds. It eats tree kangaroos, possums, and other small to medium-sized mammals, but it also eats a lot of birds and reptiles.

While it’s closely related to the harpy eagle, the New Guinea harpy eagle is placed in a different genus. This is also the case for another closely related bird, the crested eagle, which lives in parts of South America. It’s a little smaller than the harpy eagle of South America, with a wingspan of not quite 6 feet across, or 1.8 meters, with a black mask marking over its eyes and a black spot on its crest. Other than that it’s mostly gray.

The two species look enough alike that sometimes people confuse the crested eagle for a young harpy eagle where their ranges overlap. But in at least one documented case, the birds seemingly got confused too.

In early 2004, a team of scientists observing a harpy eagle nest noticed something odd. The nest had one baby in it that was about a month old when the scientists first observed it, and they noticed a crested eagle perched nearby. Every time the scientists visited the nest, the crested eagle seemed to be nearby, although the harpy eagle parents were also around and seemed just fine. The scientists observed the crested eagle adding branches to the nest and even bringing food to the harpy eagle baby. This continued for almost a year. The baby actively solicited food from the crested eagle and happily ate what it brought. At the same time, the harpy eagle parents allowed the crested eagle to approach, although generally the crested eagle didn’t come very close when the harpy eagle parents were around.

The scientists published a short paper about these observations in 2006, including a few hypotheses about the crested eagle’s behavior. They suggested that the crested eagle might have lost her own chick and transferred her maternal instincts to another eagle chick nearby, or she might have just been responding to the eagle chick’s requests for food. She might even have wanted to use that tree for her own nest, but when the bigger, stronger harpy eagles moved in, she abandoned her nest but hung around. A male crested eagle wasn’t observed, so it’s also possible she had lost her mate.

Sometimes different species of raptor do feed each other’s nestlings, although we don’t know why. It also occasionally happens with other types of birds, often male birds whose own nests are still being incubated by the female or by birds whose nest is very close to another nest with babies in it.

Another raptor that hunts animals that live in trees is the crane hawk, also from South America. It lives in forests that are near water and usually hunts by sitting in a tree and watching for potential prey. A lot of the time, though, it hunts like the New Guinea harpy eagle, climbing around in a tree and poking through any nooks and crannies to find animals that are hiding. In the case of the crane hawk, though, it actually has double-jointed legs that allow it to reach a foot into a little hole in a tree to grab prey. Most birds don’t have legs that are flexible enough to allow this behavior. The crane hawk eats a lot of nestling birds, bats, frogs, and other small animals that hide in tree cavities, including some larger invertebrates like cicadas and snails. The only other raptor known to both hunt like this and have double-jointed legs is a genus of African harrier-hawks that aren’t related to the crane hawk. Yes, it’s convergent evolution, at it again!

Let’s get out of the trees now and finish with another raptor Eva suggested. We talked about Ruppell’s griffon vulture in episode 159, but only very briefly.

Ruppell’s griffon vulture is a critically endangered vulture that lives in parts of central and eastern Africa. Unlike the raptors we’ve talked about so far in this episode, it spends a lot of its time soaring at high elevations, so it has really big wings. Its wingspan is as much as 8 and a half feet across, or 2.6 meters. It’s mostly brown and black and like other vultures, it doesn’t have feathers on its head, just a little bit of thin fluff. It will travel enormous distances to find the dead animals it eats, sometimes following herds of migrating animals to scavenge individuals that die of injury or illness. It doesn’t just eat the yummy soft parts of a carcass, it will also eat bones and even the hide of a dead animal. It has a long neck that helps it get to the best bits of its food, uh, from the inside of the carcass. It sometimes even climbs completely inside the rib cage of a dead animal to more easily get every scrap of food.

The way vultures eat is gross, which makes it fun for me to talk about, but vultures are incredibly important. They actually help stop the spread of diseases like rabies and anthrax by eating animals that died of the diseases. The vulture’s digestive tract is so effective that it kills off any viruses that caused the animals to die.

Ruppell’s vulture mates for life. It nests in cliffs, with hundreds of vulture pairs nesting very close together. The female lays one egg, and both parents take care of the baby when it hatches. Even after it can fly, the parents take care of their chick for almost a year while it learns how to find food on its own. Most vultures have relatively weak feet since they don’t use them to catch prey like other raptors, but Ruppell’s vulture has strong feet to help it perch on the cliffs where it nests.

Ruppell’s griffon vulture is one of the highest-flying birds known. It’s been recorded flying as high as 37,000 feet, or 11,300 meters, and we know it was flying at 37,000 feet because unfortunately it was sucked into a jet engine and killed. There’s so little oxygen at that height that a human would pass out pretty much instantly, but the vulture’s blood contains a variant type of hemoglobin that’s more efficient at carrying oxygen than ordinary hemoglobin.

As if all that weren’t enough for one bird, Ruppell’s vulture can also live to be 50 years old. That’s pretty good for an animal that mostly eats rotting and diseased meat.

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 323: The Kinkajou

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Thanks to Lincoln for suggesting this week’s subject, the kinkajou!

Further reading:

Early Primates Groomed with Claws

Not actually a monkey:

Not actually a bear [photo 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 an animal suggested by Lincoln. It’s the kinkajou, an adorable but weird little animal from Central and South America.

In episode 302 we talked about the coatimundi and the olingo, and both those animals are closely related to the kinkajou. So is the raccoon. But the kinkajou is the only member of its own genus that probably started evolving separately from its closest relations around 22 million years ago.

When the kinkajou was first described scientifically in the late 18th century, it was considered to be a type of lemur, which is a primate. At first glance, the kinkajou really does look like a primate in many ways. It’s arboreal, meaning it lives in trees, and it has a long prehensile tail. Its head is rounded with a short snout, and its large eyes are forward-pointing. Its ears are also low on the sides of its head. All these features resemble features common in primates, but the kinkajou isn’t related to primates at all. Eventually biologists figured it out and it was reclassified.

You can tell the kinkajou isn’t a primate if you know what to look for. It has fur on the bottoms of its feet, while primates always have bare skin on the bottoms of our feet and hands. Its fingers also all have long claws, whereas all primates have fingernails. The only exception is what’s called a toilet claw that some primates retain, including lemurs, where one toe has a claw instead of a nail that the animal uses to groom its fur. But no modern primates have claws on all their digits.

The kinkajou is covered with thick, plush fur that keeps it warm in cold weather. Some populations live in high elevations where it can get cold at night, and since it’s a nocturnal animal it needs to stay warm while it’s out looking for food. It’s yellowish-brown in color but some of its hairs are tipped with darker brown. Even though the darker hairs are mixed in with the lighter ones and the kinkajou doesn’t actually have a pattern of darker spots, the dark hairs absorb more light than the lighter hairs and can make it look spotted in low light. This helps it blend in with the dappled shade in the trees where it lives.

The kinkajou and its close relations make up the family Procyonidae, which is classified in the order Carnivora. Carnivora means “meat-eaters,” but Procyonids are all omnivores that don’t eat a lot of meat. The kinkajou mostly eats fruit, and its favorite fruit is the fig. It also eats other plant parts, insects, and honey, but it mostly just wants lots of yummy ripe figs. (Same.)

The kinkajou lives in family groups, typically one female and her young offspring, a dominant male, and a subordinate male. During the day the family members sleep in a tree hollow or in a tangle of branches that give them plenty of shade. When it starts getting dark, the kinkajous wake up and go out looking for food. Sometimes the family forages together but more often they split up and forage on their own. When there’s a lot of food available in one place, like a bunch of fig trees, a whole lot of kinkajous may gather to eat and play together.

Because it spends just about all its life in the treetops, the kinkajou is well adapted to arboreal life. It can turn its hind feet around backwards to help it climb headfirst down a tree trunk, which is another trait it shares with the raccoon. Other animals have evolved the same ability, though, even ones that aren’t closely related to the kinkajou.

The kinkajou’s prehensile tail is strong and thick, and it often hangs from its tail to eat. It’s not a very large or heavy animal, only 10 lbs in weight at the most, or 4.6 kg, and usually less than half that. Because it’s only about the size of a cat, it can climb onto thin branches to pick fruit. It also has an extremely flexible spine, so flexible that it can twist its head and shoulders 180 degrees from its pelvis.

A female kinkajou usually only has one baby at a time, sometimes two. She mostly takes care of the baby herself, although occasionally its dads will play with the baby or help it collect fruit. The baby stays with the family even after it’s able to care for itself, until it grows old enough that it leaves to find its own territory. The kinkajou can live a long time, 30 or 40 years, partly because it doesn’t have very many predators in its treetop habitat.

One other interesting detail about the kinkajou is its tongue. It has a surprisingly long tongue that it can stick far out of its mouth to lick up insects like ants. It also likes nectar and honey, so its long tongue helps it gather both. The kinkajou is sometimes called the honey bear since it likes honey and its fur is the color of honey, but it’s not related to bears any more than it’s related to primates.

One local name for the kinkajou translates to “bear-monkey,” and that’s honestly probably the best name for it–as long as we can remember that it’s not a bear and not a monkey!

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 310: The Crab-Eating Fox

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Thanks to Dean for this week’s suggestion, the crab-eating fox!

Further reading:

Jaguars could prevent a not-so-great American biotic exchange

The crab-eating fox is not actually a fox:

Show transcript:

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

I’m happy to report that I’m feeling healthy and testing negative for covid now. Even my lingering cough has pretty much cleared up! I hope you’re healthy too. Anyway, this week let’s learn about an unusual animal suggested by Dean, the crab-eating fox.

The crab-eating fox lives in parts of South America east of the Andes Mountains. It likes forests and open woodlands, and sometimes lives in savannas too although it prefers areas with a lot of tree cover and rivers. It’s a fairly small animal that rarely weighs more than 18 pounds, or 8 kg, and stands about 16 inches tall at the shoulder, or 40 cm. It has a thick coat that’s mostly gray or brown with reddish ears and paws, black markings on the ears, tail, and legs, and a black stripe down its spine. It also has a bushy tail and a relatively short muzzle.

There are two important questions we need to answer about the crab-eating fox. First, does it actually eat crabs? Second, is it actually a fox?

The crab-eating fox does indeed eat crabs, although it’s an omnivore and will eat pretty much anything it can find. This includes insects, eggs, fruit, carrion, and small animals of various kinds, especially rodents. But during the wet season, when it rains a whole lot and rivers flood and ebb repeatedly, the crab-eating fox eats a whole lot of crabs and other crustaceans.

The crab-eating fox is not, in fact, a fox. It’s definitely related to foxes, since it’s a canid and the family Canidae includes foxes as well as wolves, dogs, coyotes, and all their relations, and it looks like a fox. It’s the only member of its own genus, but it’s grouped together with some other South American canids that look like foxes but are more closely related to wolves. But they’re not all that closely related to either foxes or wolves. Another member of this group is the maned wolf, the one with super long legs, which we talked about most recently in episode 167.

Scientists think that the crab-eating fox’s closest relation is another South American canid called the short-eared dog, which we talked about in episode 195. Unlike the crab-eating fox, the short-eared dog likes heavy forests and lives in the Amazon rainforest. We know so little about it that researchers sometimes refer to it as the ghost dog.

The crab-eating fox is nocturnal and spends most of the daytime sleeping in a den. Sometimes it makes a den by burrowing into thick grass, sometimes it will dig a burrow, but it prefers to find a den made by another animal and move into it if it’s empty. It may have several dens in its territory, which it often shares with its mate. Both parents help take care of the babies, and a female may have two litters a year.

I’m happy to report that the crab-eating fox is not endangered. It’s doing just fine in most places. It’s an adaptable, intelligent animal, which helps it thrive in a changing environment the same way coyotes do in North America. In fact, it fills the same ecological niche in South America that the coyote fills in North America, and this has led to a really weird potential problem.

The crab-eating fox is native to South America, but it has been spreading northward into Central America. Likewise, the coyote is native to North America, but it has been spreading southward into Central America. Neither species likes thick forested areas, but as more rainforests are cleared for agriculture and housing, people have inadvertently made a sort of corridor for both species. Having people around doesn’t bother either the crab-eating fox or the coyote. Coyotes have made it as far south as Panama, almost to South America.

If this continues, with crab-eating foxes migrating north and coyotes migrating south in ever greater numbers, eventually they’ll start to compete with each other. This isn’t good for either of them.

The only thing stopping coyotes from migrating farther south at this point is a thick strip of tropical forest called Darien National Park in Panama, where jaguars live. Unlike coyotes and crab-eating foxes, jaguars are very shy of humans and need a lot of dense forest to live in. This is exactly the kind of place that coyotes and crab-eating foxes like least, not to mention that a jaguar would be more than happy to catch and eat either species of canid. So as long as the forest in the national park remains intact, it acts as a barrier to keep both canid species apart, and that’s good. It’s also good for the jaguars and lots of other animals. Hooray for protected forests!

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 307: Coquí Frogs and Glass Frogs

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Thanks to Miranda and Henry for this week’s frog suggestions!

Further reading:

Shattering the Glass Frog Ceiling

The Puerto Rican wetland frog, AKA coquí llanero:

The golden coquí in happier times:

Glass frog from above and below:

A female granulosa glass frog named Millie (in one of the few successful breeding programs of these frogs), looking demure:

Laura’s glass frog, rediscovered after almost 70 years [photos from this article]:

Show transcript:

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

This week we have suggestions from Henry and Miranda, so we’re going to learn about some weird but cute frogs!

First, Miranda listened to episode 270 about the tapir frog and commented about a little frog native to Puerto Rico that sounds very similar. It’s call the coquí frog and it has an adorable beep! It sounds like this:

[frogs beeping]

You can definitely hear why the coquí frog is called that. It sounds like it’s saying “coquí.”

The coquí is a type of tree frog although most species prefer to live on or near the ground. Instead of webbed toes, their toes have discs that act sort of like suction cups that help them stick to leaves. Different species of coquí frogs are different colors, including brown, green, gray, and yellow. Their tummies are usually white or yellow. Most species are quite small, although a few species grow as big as 3 inches long, or about 8 cm.

There are at least 17 species of coquí frog known in Puerto Rico, with more species found in other parts of the Caribbean and in Central and South America. New species are discovered from time to time, including the tiniest species, the Puerto Rican wetland frog. It was only discovered in 2005 and described in 2007. It’s about 15 mm long from nose to butt, or more properly snout to vent, and while males are bright yellow, females are browner. It lays its eggs on the leaves of a plant called the bulltongue arrowhead, and it only lays one to five eggs at a time. Instead of hatching into tadpoles, the eggs hatch into miniature frogs which are ready to hop out and eat lots of ticks, because that’s mainly what this species of coquí eats. And that’s about all we know about this particular species except that it only lives in one small area of Puerto Rico and is critically endangered.

Another species of coquí is the golden coquí, which is almost as small as the Puerto Rican wetland frog. It’s yellow or golden in color, or sometimes a more olive green. Instead of laying eggs that hatch into tadpoles that develop into frogs, the golden coquí skips most of these steps and just gives birth to fully developed teeny baby frogs, three to six of them at a time.

The golden coquí lives in a small, specific habitat, a moist subtropical forest where bromeliad plants grow. Bromeliads are shrubby plants with succulent-type leaves that retain water. Pineapples are a type of bromeliad, although not the ones the golden coquí lives in. Unfortunately, the golden coquí is also critically endangered and may actually be extinct. No one has seen one since 1981.

Most species of coquí lay their eggs on leaves instead of in water. The eggs still need to stay moist, though, so in many species the male will bring water to the eggs. He does this by just dunking himself in water, then returning to the leaf where the eggs are and plunking himself down on the eggs. He will also guard the eggs from potential predators. The eggs of all coquí species hatch into frogs instead of tadpoles.

A few species of coquí have been introduced to other parts of the world, either by accident or on purpose, and have become invasive species. This is especially true in Hawaii, where the coquí has become incredibly common and as a result is causing some native frogs to decline in numbers, along with other animals. But in Puerto Rico, where the coquí belongs, people are naturally proud of their loud little frogs. The indigenous people of Puerto Rico, the Taíno, incorporated the frog into their legends, and there’s even 700-year-old cave art on nearby Mona Island that includes paintings of coquí frogs.

The coquí frog mostly eats small invertebrates, including lots of cockroaches and other beetles, so they’re good to have around. Unfortunately, as is the case with so many frog species around the world, their numbers are in decline due to habitat loss, climate change, pollution, introduced predators, and a deadly fungus that we talked about in episode 250. Studies have shown that some populations of the coquí show a natural resistance to the fungus, so if we can just protect their habitats, the frogs will be okay.

Next, Henry wanted to learn more about the glass frog, which lives in Central and South America. We’ve talked about it very briefly in episode 148 and a couple of old Patreon episodes, but we’ve never really gone in-depth about it. Let’s do that now, because this is a really weird and interesting frog!

The glass frog lives in forests of Central and South America, mostly in treetops. They’re small frogs, no longer than about three inches, or 7.5 cm, from snout to vent. Most species are bright green, and in many species, the belly skin is almost completely transparent. You can see right through to their insides: guts, blood vessels, even bones. One newly discovered species from the Amazon also has a translucent chest so you can see its heart. In some species, even the organs are translucent. Some species even have green bones.

The blue-green color of the bones comes from high levels of biliverdin [bill-uh-ver-din] in the blood, which has evolved at least 40 times in 11 different frog families, with more species that have blue-green blood and bones discovered all the time.

In most animals, high levels of biliverdin are a result of liver disease, since it’s a toxin, but in these frogs, the biliverdin is retained in the blood instead of filtered out by the kidneys. Researchers think the biliverdin serves two purposes. Because it makes the frog green all the way through, it helps camouflage the frog among the leaves where it lives, even in infrared light. Researchers recently discovered that at least two species of glass frog reflect infrared light, which may also help keep them concealed from predators that can see in infrared. The high levels of biliverdin may also make the frog taste bad. Some researchers also think it may help protect the frog from parasites.

This doesn’t appear to be related to their see-through tummies, though. No one’s sure why glass frogs are see-through from underneath. Most species have green backs, which helps them blend in to the leaves they live on. Since the glass frog’s legs are usually partially transparent along with its belly, one study has determined that it’s actually the legs that help with camouflage. When the frog sits on a leaf with its legs folded up on either side, the way frogs often sit, the color of the leaf is partially visible through the legs. This helps make the frog look less frog-shaped since its edges sort of blend in with the leaf.

Most of the time glass frogs live high in the treetops, but during breeding season they come down closer to the ground. The female lays her eggs on leaves hanging over running water, which the male fertilizes. In some species, males guard the eggs until they hatch. When the eggs hatch, the tadpoles drop into the water.

Not all glass frogs have translucent undersides, though. Most are ordinary-looking frogs that may be green or occasionally brown or orangey in color, sometimes with little spots. There are also probably a whole lot more of these frogs than scientists know about, since they live in such hard-to-study areas. Several new species have been discovered in just the last few years, including one rediscovery of a species called Laura’s glass frog.

Until a few years ago, the only specimen of Laura’s glass frog was a male collected in 1955 in the foothills of the Andes Mountains in Ecuador. Then a team of scientists studying frogs in the Colonso-Chalupas Biological Reserve, also in Ecuador, found two frogs that weren’t familiar to them. One was male and the other a young female, both living near small creeks where lots of other frog species were common. They were green with tiny yellow spots surrounded by black rings, and were only a few centimeters long, or less than an inch. After several years of study, the team determined that the frogs were Laura’s glass frogs, and they published their findings almost exactly one year ago, in December 2021.

Hopefully, in 2023 scientists will discover and rediscover even more frog species, and we’ll be able to learn more about them so they and their habitats can be protected.

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 304: Animals of the Paleogene

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Thanks to Pranav for suggesting this week’s topic, animals of the Paleogene, the period after the Cretaceous! Thanks also to Llewelly for suggesting the horned screamer, now one of my favorite birds.

Further watching:

Southern Screamers making noise

Horned Screamers making noise

Further reading:

The Brontotheres

Presbyornis looked a lot like a long-legged goose [art by Smokeybjb – CC BY-SA 3.0]

The southern screamer (left) and horned screamer (right), probably the closest living relation to Presbyornis:

Megacerops was really really big:

All four of these illustrated animals are actually megacerops, showing the variation across individuals of nose horn size:

Uintatherium had a really weird skull and big fangs:

Pezosiren didn’t look much like its dugong and manatee descendants:

Show transcript:

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

This week we’re going to look at some strange animals of the Paleogene period, a suggestion from Pranav. Pranav also suggested the naked mole-rat that we talked about in episode 301, but I forgot to credit him in that one.

As we talked about in episode 240, about 66 and a half million years ago, a massive asteroid smashed into the earth and caused an extinction event that ended the era of the dinosaurs. The geologic time period immediately after that event is called the Paleogene, and paleontologists study this era to learn how life rebounded after the extinction event. We’re going to learn about a few animals that evolved to fill ecological niches left vacant after dinosaurs went extinct.

These days, mammals fill a whole lot of these ecological niches, so it’s easy to assume that mammals have been successful for the last 66 million years. But while that’s true now, birds were incredibly successful for a long time. Basically for millions of years after the non-avian dinosaurs died out, it was dinosaurs 2.0 as the avian dinosaurs, better known as birds, spread throughout the world and evolved into some amazing organisms.

This included terror birds, which we talked about in episode 202. They lived in South America, except for one species from North America, and evolved really soon after the dinosaurs went extinct, appearing in the fossil record about 60 million years ago. They lasted a long time, too, only going extinct around 2 million years ago.

The earliest known terror bird was about three feet tall, or 91 cm, but its descendants became larger and more fearsome until they were apex predators throughout South America. The biggest species grew up to ten feet tall, or three meters, with a massive beak and sharp claws on its toes. It couldn’t fly but was a fast runner. You would not want a terror bird chasing you.

Lots of other birds evolved throughout the Paleogene, but most of them would look pretty familiar to us today. Paleontologists have found fossils of the ancestors of many modern birds, including penguins, hummingbirds, and parrots, which shows that they were already specialized some 25 or 35 million years ago or even more. In the case of penguins, we have fossils of penguin ancestors dating back to the late Cretaceous, before the extinction event. Those ancient penguins could probably still fly, but it didn’t take too long to evolve to be a fully aquatic bird. The species Waimanu manneringi lived around 62 million years ago in what is now New Zealand. It resembled a loon in a lot of ways, with its legs set well back on its body, and it probably spent much of its time floating on the water between dives. But unlike a loon, it had lost the ability to fly and its wings were already well adapted to act as flippers underwater.

Another bird would have looked familiar at first glance, but really weird when you gave it a second look. Presbyornis lived between about 62 and 55 million years ago in what is now North America, and it lived in flocks around shallow lakes. It was the size of a swan or goose and mostly shaped like a goose, with a fairly chonky body and a long neck. It had a large, broad duckbill that it used to filter small animals and plant material from the water and its feet were webbed…but its legs were really long, more like a heron’s legs.

When the first Presbyornis fossils were found in the 1920s, the scientists thought they’d found ancient flamingos. But when a skull turned up, Presbyornis was classified with ducks and geese. It wasn’t very closely related to modern ducks and geese, though. Researchers now think its closest modern relation is a South American bird called the screamer. Llewelly suggested the horned screamer a long time ago and now that I have learned more about these birds, I love them so much!

The screamer looks sort of like a goose but has long, strong legs and a sharp bill more like a chicken’s. It lives in marshy areas and eats pretty much anything, although it prefers plant material. It has two curved spurs that grow on its wings that it uses to defend its territory from predators or other screamers, and if a spur breaks off, which it does pretty often, it grows back. The screamer mates for life and both parents build the nest together and help take care of the eggs and chicks when they hatch.

The horned screamer has a long, thin structure that grows from its forehead and looks sort of like a horn, although it’s not a horn. It’s wobbly, for one thing, but it’s also not a wattle. It grows throughout the bird’s life and may break off at the end every so often, and it’s basically unlike anything seen in any other bird. Maybe presbyornis had something similar, who knows?

The screamer gets its name from its habit of screaming if it feels threatened or if it just encounters something new or that it doesn’t like. The screaming is actually more of a honking call that sounds like this:

[screamer call]

People sometimes raise screamers with chickens to act as guard birds. It can run fast but it can swim faster, and it can also fly although it doesn’t do so very often. Although it’s distantly related to ducks, its meat is spongy and full of air sacs that help keep it afloat in the water, so people don’t eat it. It is vulnerable to habitat loss, though.

One organism that evolved early in the Paleogene was grass. You know, the plant that a whole lot of animals eat. There are lots and lots of different types of grass, not just the kind we’re used to mowing, and as the Paleogene progressed, it became more and more widespread. But it wasn’t as ubiquitous as it is now, so even though the ancestors of modern grazing animals evolved around the same time, they weren’t grazers yet. The word graze comes from the word grass, but ancient ancestors of horses and other grazing animals were still browsers. They ate all kinds of plants, and didn’t specialize as grazers until grasses really took off and huge grasslands developed in many parts of the world, around 34 million years ago.

Because the Paleogene lasted so long, between about 66 and 23 million years ago, there’s literally no way we can talk about more than a few animals that lived during that time, not in a single 15-minute episode. We’ve also covered a lot of Paleogene animals in previous episodes, like paraceratherium in episode 50, the largest land mammal known. It probably grew up to about 16 feet tall at the shoulder, or 5 meters, and taller if you measured it at the top of its head. Other examples are moeritherium, an ancient elephant relation we talked about in episode 18, the giant ground sloth that we talked about in episode 22, and the ancient whale relation basilosaurus that we talked about in episode 132. Patrons also got a bonus basilosaurid episode this month. But I’m pretty sure we’ve never talked about brontotheres.

Brontotheres first appear in the fossil record around 56 million years ago and they lived until at least 34 million years ago. All animals in the family Brontotheriidae are extinct, but they were closely related to horses. They didn’t look like horses, though; they looked a lot like weird rhinoceroses, although remember that rhinos are also related to horses. They were members of the odd-toed ungulates, along with tapirs and the gigantic Paraceratherium.

Fossil remains of brontotheres have been found in North America, a few parts of eastern Europe, and Asia, although they might have been even more widespread. The earliest species were only about three and a half feet tall at the shoulder, or about a meter, but later species were much larger. While they looked a lot like rhinos, they didn’t have the kind of keratin hose horns that rhinos have. Instead, some species had a pair of horns made of bone that varied in shape and size depending on species. The horns were on the nose as in rhinos, but were side-by-side.

Brontotheres developed before grasslands became widespread, and instead they were browsers that mostly ate relatively soft vegetation like leaves and fruit. Grass is really tough and animals had to evolve specifically to be able to chew and digest it. In fact, the rise of grasslands as the climate became overall much drier around 34 million years ago is probably what drove the brontotheres to extinction. They lived in semi-tropical forests and probably occupied the same ecological niche that elephants do today. This was before elephants and their relations had evolved to be really big, and brontotheres were the biggest browsing animals of their time.

Brontotheres probably lived in herds or groups of some kind. They were widespread and common enough that they left lots of fossils, so many that they were found relatively often in North America even before people knew what fossils were. The Sioux Nation people were familiar with the bones and called them thunder horses. When they were scientifically described in 1873 by Othniel Marsh, he named them after the Sioux term, since brontotherium means “thunder beast.”

Two of the biggest brontotheres lived at about the same time as each other, around 37 to 34 million years ago. Megacerops lived in North America while Embolotherium lived in Asia, specifically in what is now Mongolia. Megacerops is the same animal that’s sometimes called brontotherium or titanotherium in older articles and books.

Megacerops and Embolotherium were about the same size, and they were huge, although Embolotherium was probably just a bit larger than Megacerops. They stood over 8 feet tall at the shoulder, or 2.5 meters, and were more than 15 feet long, or 4.6 meters. This is much larger than any rhinos alive today and as big as some elephants. Their legs would probably have looked more like an elephant’s legs than a rhinoceros’s.

Brontothere nose horns weren’t true horns, since they don’t seem to have been covered with a keratin sheath, but they were formed from protrusions of the nasal bones. They might have been more like ossicones, covered with skin and hair. Megacerops had a pair of nose horns that were much larger in some individuals than others, and scientists hypothesize that males had the larger horns and used them to fight each other.

But this can’t have been the case for embolotherium. It had even bigger nose horns that were fused together in a wedge-shaped plate sometimes referred to as a ram, but they contained empty chambers inside that were a continuation of the nasal cavities. They wouldn’t have been strong enough to bash other embolotheriums with, but they might have acted as resonating chambers, allowing embolotherium to communicate with loud sounds. All individuals had these nose horns, even juveniles, and they were all about the same size, which further suggests that they had a purpose unrelated to fighting.

At about the same time the brontotheres were evolving, another big browsing animal also lived in what are now China and the United States. Two species are known, one in each country, and both stood about 5 feet tall at the shoulder, or 1.5 meters. It looked sort of like a brontothere in some ways, but very different in other ways, especially its weird skull, and anyway it was already big around 56 million years ago when brontotheres were still small and unspecialized.

Scientists aren’t sure what uintatherium was related to. It’s been placed in its own genus, family, and order, although some other uintatherium relations have been discovered that share its weird traits. Most scientists these days think it was probably an ungulate.

Uintatherium’s skull was extremely strong and thick, which didn’t leave a whole lot of room for brains. But what uintatherium lacked in brainpower, it made up for in sheer defensive ability. It had huge canine teeth that hung down like a sabertooth cat’s fangs, although males had larger fangs than females. Males also had three pairs of ossicones or horns on the top of the skull that pointed upwards. One pair was on the nose, one pair over the eyes, and one pair almost on the back of the skull. They could be as much as 10 inches long, or 25 cm, and paleontologists think that males wrestled with these horns the same way male deer will lock antlers and wrestle.

Uintatherium lived in the same habitat and probably ate more or less the same type of plants that later brontotheres did. They went extinct around the time that brontotheres evolved to be much larger, which suggests that brontotheres may have outcompeted uintatherium.

We’ll finish with one more Paleogene mammal, Pezosiren. It was only described in 2001 from several incomplete specimens discovered in Jamaica in the 1990s, and it lived between 49 and 46 million years ago.

Pezosiren was about the size of a pig, although it had a longer, thicker tail compared to pigs. It wasn’t any kind of pig, though, and in fact it was distantly related to elephants. It was the oldest known ancestor of modern sirenians. Pezosiren is also called the walking siren, because it still had four legs and probably spent at least part of the time on land, although it could swim well. Scientists think it probably swam more like an otter than a sirenian, propelling itself through the water with its hind legs instead of its tail.

Pezosiren was probably semi-aquatic, sort of like modern hippos, and already shows some details specific to sirenians, especially its heavy ribs that would help it stay submerged when it wanted to. It ate water plants and probably stayed in shallow coastal water. At different times in the past, Jamaica was connected to the North American mainland or was an island on its own as it is now, or occasionally it was completely submerged. About 46 million years ago it submerged as sea levels rose, and that was the end of Pezosiren as far as we know. But obviously Pezosiren either survived in other areas or had already given rise to an even more aquatic sirenian ancestor, because while Pezosiren is the only sirenian known that could walk, its descendants were well adapted to the water. They survive today as dugongs and manatees.

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 302: The Coatimundi and a Mysterious Friend

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Thanks to Oceana, Leo, and Alexandra for suggesting the coatimundi this week!

Further reading:

Caught red handed: The mystery of an unusual Panamanian plant’s dispersal

The coatimundi has a long tail and a long nose:

The olingo sitting on a cloud cycad seed pod. Mystery solved!

The olingo in daylight:

My new podcasting studio!

Show transcript:

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

This week we’re going to talk about an animal suggested by several people. Thanks to Oceana, Leo, and Alexandra for suggesting the coatimundi, also called the coati! We’re also going to learn about a related animal mystery that was the subject of a Patreon episode earlier this year, because it ties in so well.

The coatimundi looks superficially like a type of monkey, or maybe a lemur, but it’s not a primate at all. It belongs to the family Procyonidae, which includes raccoons, kinkajous, and a few others. Procyonids are native to the Americas, and some scientists think they may be very distantly related to canids. Since a lot of Procyonids have bushy ringed tails, at one point the red panda was classified as a relation, but it’s since been reclassified into a family all its own that doesn’t appear to be related.

The coati lives in much of South America, Central America, and southern North America, including Mexico and parts of the American southwest. It’s mostly gray-brown or reddish-brown in color, with some white markings around the eyes and muzzle. Males are much bigger than females on average, but in general the coati isn’t that much bigger than a domestic cat. It has a long, thick tail that sort of resembles a cat’s tail except that it’s even longer in relation to its body. Some coatis have rings around the tail but some don’t. It depends on the species and the individual.

The coati uses its long tail to help it balance in trees, since it does a lot of climbing. Its hind feet can rotate so that they’re backwards, which means it can climb down trees headfirst. Procyonids can all do this, but so can some unrelated animals like weasels, due to convergent evolution. The coati also uses its long tail to keep track of its friends when they’re traveling through long grass. It sticks its tail straight up so that it’s visible above the grass. Since female coatis live in social groups of up to 40 individuals, keeping track of friends is important.

The coatimundi doesn’t worry too much that predators might see its tail sticking up and run over for a coati-sized snack. While jaguars, cougars, large eagles, and a few other predators do eat coatis, for the most part other animals leave them alone. The coati has sharp teeth, sharp claws, and it’s strong and fast for its size. It can be ferocious when it needs to, and of course it has its equally ferocious friends to help out. Plus, the coati is intelligent. In a 2013 study, the female coati’s brain was found to have a very large frontal cortex, which is the part of the brain that handles sociability. Male coatis had smaller frontal cortexes, since males spend most of the time by themselves or in small bachelor groups except during mating season. And as we’ve learned when talking about other animals, the more complex an animal’s social structure, the more intelligent it’s likely to be.

The coati’s ears are small and its snout is long and thin and turns slightly upwards, which makes it look a little like a piggy nose. But unlike a pig’s nose, the coati’s is extremely flexible. It uses its nose to root around in leaf litter and dirt to find food. It’s an omnivore that’s happy to eat pretty much anything, from fruit and other plant material, to insects and other invertebrates, including tarantulas, to eggs and small animals. It has a strong sense of smell and clever front paws that help it dig up grubs, termites, and other yummy things. It sleeps with its nose tucked into its belly fur and its long tail wrapped around it.

When a female coati is ready to have babies, called kits, she leaves her group and builds a little nest in a tree. She gives birth there and takes care of her kits alone for about six weeks. At that point the babies can travel well and the whole family rejoins the other females and their offspring. The females take turns babysitting younger kits and watching for danger.

Next, let’s learn about another Procyonid, this one associated with a mystery. But to learn about the mystery we need to start not with an animal, but with a plant. Zamia pseudoparasitica is a type of cycad that only lives in the montane cloud forests in western Panama, in Central America. Even though the cycad is a plant that resembles a palm tree, this particular plant grows in the treetops instead of on the ground.

Because Z. pseudoparasitica is a mouthful, I’m going to call it the cloud cycad.

The cloud cycad has a short trunk without branches, but its leaves are almost 10 feet long, or 3 meters. They look like palm fronds. It grows on other trees, clinging to the branches with its roots, but it doesn’t actually parasitize the tree. That’s why its name is pseudoparasitica: pseudo means false, so it only looks like a parasitic plant growing on a bigger plant.

The cloud cycad starts out by growing upward from a branch as much as 65 feet above the ground, or 20 meters, but as it gets bigger and heavier, it slips down around the branch and hangs upside down. Then its trunk starts bending upward to get more light, so it grows in a sort of U shape.

The term for a plant that lives on other plants without being a parasite is epiphytic. Many epiphytic plants get their nutrients from rain, decomposition of leaves and other organic material near their roots, and other external sources since they don’t have access to soil. They’re often really good at absorbing water quickly too. Spanish moss, some ferns, lichens, and orchids are all good examples, but only one cycad is epiphytic, our cloud cycad.

The cloud cycad produces large yellow or orange seeds in cones, and when the seeds are ripe they have a pungent smell. But here’s the mystery about this strange plant: how do its seeds get dispersed to other trees? The cloud cycad never grows on the ground, and researchers think any seeds that fall to the ground just lie there until something eats them.

An animal has to be helping in some way, possibly by eating the seeds and pooping them out somewhere else. That’s why so many seeds are encased in sweet-tasting tissues. People suspected that fruit bats were the main seed disperser, but no one knew for sure.

In late 2019, a team of young scientists decided to get to the bottom of the mystery. They climbed trees and placed cameras pointing at cloud cycads to see what animals visited them. This was hard work, as you can probably imagine, because those trees are really big; but finally they got the cameras set up. Then, in early 2020, right before Panama went into lockdown due to Covid-19, they had to go back and climb the same trees to retrieve the cameras. Then they had to download the photographs from each and go through them.

Lots of animals were caught on camera, including seven species of mammal. Monkeys, kinkajous, and opossums all gave the seed cones a sniff or two, but only one animal actually collected the seeds. And that animal was the olingo!

The northern olingo is a Procyonid, and is probably the coatimundi’s closest relation. It’s gray-brown in color with a rounded face and short muzzle, small round ears that are low on its head, and claws that help it climb around in trees. It’s mostly nocturnal and mostly eats fruit, and it spends most of its time in the treetops. It’s a slender animal that grows about 20 inches long, or 50 cm, not counting its tail, which is about as long as its body and which it uses for balance. If you look closely, its tail has very faint rings of dark and light fur.

We don’t know a whole lot about the olingo, but we now know it probably eats the seeds of the cloud cycad because it’s been caught on camera grabbing up to four of the seeds at a time and carrying them off.

The scientists still have a lot of work to do to find out more about how the olingo helps disperse the cloud cycad’s seeds, assuming it actually does. The team thinks the olingo might cache seeds like some squirrels do, hiding them in various places around its treetop territory until it’s hungry. If so, in at least some cases, just like with squirrels, some of the seeds are forgotten and germinate to grow new plants.

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!