Monthly Archives: March 2019

Episode 112: The Bullfrog and the Raven



I am sick and sound like a frog, or possibly a raven, so here’s a croaky episode about both!

Thanks to Corbin Maxey of Animals to the Max and Simon for their suggestions!

A bullfrog:

A common raven:

A baby raven:

NOT a baby raven (it’s probably a corncrake):

Show transcript:

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

Guess who has a cold! That’s right, I do! If this is the first episode you’ve ever listened to, I promise I don’t ordinarily sound like this.

Because my voice is such a mess, let’s have a short episode this week and learn about two animals that sound kind of like I do right now: the bullfrog and the raven. Thanks to Corbin Maxey of the great podcast Animals to the Max who suggested frogs, and friend of the pod Simon who suggested ravens, both of them in response to my complaining on Twitter that I had a sore throat. Little did they know what I would sound like a few days after that tweet!

Let’s start with the bullfrog. The American bullfrog is a species of frog. You probably figured that out without me needing to tell you. It originally only lived in eastern North America, but it’s been introduced in many other parts of the world. The reason it’s been introduced elsewhere is that it’s raised as food—specifically, it’s raised for its hind legs, which are considered a delicacy. It’s also sometimes kept as a pet. Sometimes it escapes from captivity and sometimes it’s just released into the wild by people who don’t know any better. In many places it’s become an invasive species that outcompetes native amphibians.

The bullfrog is a big, heavy frog. It can grow up to eight inches long from nose to butt, or 20 cm, but the hind legs are much longer. It can also be up to 1.8 pounds in weight, or 800 grams. Because the bullfrog has such long, strong legs, it can jump up to ten times the length of its own body.

The bullfrog is olive green in color, sometimes with darker blotches or stripes. The belly is pale and the lower part of the nose along the upper edge of the mouth is often bright green. Males usually have yellow throats, or technically yellow gular sacs. This is the sac the male inflates in order to make his loud croak.

Male bullfrogs have territories in swampy areas that they defend from other males, but the territories aren’t very large, maybe 20 feet apart from each other at most, or 6 meters. The males tend to move around and gather in groups during the breeding season, though, which is usually spring and early summer. The males croak loudly to attract females, and sometimes wrestle each other to show who’s stronger.

The female bullfrog lays her eggs in shallow water with plenty of plant cover. If the temperature isn’t too warm or too cold, the eggs hatch in about five days into tadpoles. The tadpoles have gills and teeth, although at first they don’t use their teeth for anything. They eat algae and other tiny food at first, and as they grow bigger, they start catching larger food.

In warmer climates, the tadpole starts to metamorphose into a frog in a few months. In colder climates, the tadpole can take up to three years to grow into a frog.

A full-grown bullfrog will eat anything it can swallow, not just insects. It’ll eat mice and other rodents, bats, birds, other amphibians, crawdads, snails, fish, and small reptiles. It uses its long sticky tongue to catch its prey, then clamps its jaws shut so the prey can’t escape. If part of the prey is sticking out of its mouth, like a tail or leg, the frog uses its thumbs to cram the bits in. If the prey won’t quit struggling, the frog may jump into the water and swim around until the animal drowns. They should call them sharkfrogs, not bullfrogs.

A lot of animals eat bullfrogs, though, like alligators and various snakes, birds like herons and kingfishers, and river otters. I have personally seen a snapping turtle attack a bullfrog. That was creepy. Sometimes when something attacks a bullfrog, it will actually scream. This sometimes startles the predator enough that it lets go, and the bullfrog can escape. Bullfrogs show some resistance to snake venom too.

The bullfrog gets its name from its voice, not its size. It sounds like this:

[bullfrog croaking]

Next, hopefully I will not lose my voice before I finish talking about the raven. There are a number of different raven species but they all look similar. They’re big black birds with heavy bills and deep, raspy voices. They look like a buff crow. We’ll talk about the common raven today, which lives throughout the northern hemisphere: that means North America, Greenland, and most of Eurasia.

The common raven can grow up to 26 inches long, from bill to tail, or 67 cm, with a wingspan over four feet wide, or 150 cm. Its feathers are glossy black, with purplish or blue iridescence in sunlight. Young ravens look similar but are not as glossy. Sometimes you’ll see a picture online of a little black poof of a baby bird labeled as a baby crow or raven, but that’s a mistake. Baby ravens have sleek feathers, not downy feathers. I’ll put pictures in the show notes so you can see the difference.

The raven is an omnivore, which means it pretty much eats anything it can get. It will eat roadkill and other carrion, fruit and grain, insects, small animals, other birds, and eggs. It’s also extremely smart, which means it can figure out how to get into trash cans and other containers to find food humans think it secure. If a raven finds a good supply of food, it will call other ravens to join in the feast. This usually happens when a younger raven finds food and calls its friends, even if the food source is being guarded by a mated pair of adult ravens. Those pesky kids.

Ravens mate for life, but younger birds who haven’t paired off usually live in flocks. They’re devoted family birds, with grown young of a pair sometimes hanging around to help their parents raise the next nest. The raven lives a long time, up to 21 years in the wild and over 40 years in captivity.

The only animals that eat ravens are large owls and eagles, and even that’s rare. Ravens are big enough, strong enough, and smart enough to defend themselves.

Ravens are extremely intelligent birds. Research suggests that they may even have something approaching an actual language. They can certainly reason and deceive each other, and demonstrate empathy in their interactions with other ravens. They also use tools to help get food, and are well known to play with items, sometimes making toys out of twigs or other items to play with as a group. Young ravens in particular are curious and will steal shiny things.

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

But ravens also communicate nonvocally with other ravens. A raven will use its beak to point with the way humans will point with a finger. Incidentally, dogs understand what pointing means, but wolves don’t. Just throwing that in there. They’ll also hold something and wave it to get another raven’s attention, which hasn’t been observed in any other animal or bird besides apes.

I will soon be reduced to communicating nonvocally if I don’t stop and rest my voice. So I’ll shut up and let you listen to a real raven:

[raven sound]

You can find Strange Animals Podcast online at strangeanimalspodcast.com. blah blah blah I’m not saying it this week. My throat hurts.

Thanks for listening! Next week hopefully I’ll be all better and sound like a human again instead of like a frog or a raven.


Episode 111: Poisonous moths, venomous bugs



Let’s get gross and horrible this week! Are there any bugs with so much venom they could kill you? What would happen if you ate 5,000 moth digestive tracts? Why am I even talking about this stuff? Listen and find out! Thanks to Grady and Tania for today’s topic suggestions!

The giant silkworm moth caterpillar. Do not touch. No seriously, don’t! You might d i e

The southern flannel moth and its larva, a puss caterpillar. Fuzzy, yes, but don’t pet the caterpillar:

A luna moth and its caterpillar. It will not kill you:

A bullet ant. Look at those chompers!

The white-spotted assassin bug. At least you can see it coming:

Show transcript:

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

This week’s episode is a suggestion from Grady, who also sent several other really good suggestions we’ll hopefully get to soon. The one we’re looking at this week is poisonous bugs! And because another listener, Tania, suggested we cover moths, we’ll also make sure to talk about a lot of poisonous or venomous moths too.

Technically, if an insect is poisonous that means it will make you sick if you eat it. If an insect bites or stings you and it injects poison into the wound, it’s referred to as venomous. But you can call both poisonous because everyone will know what you mean. Also, you would probably get sick if you ate a venomous bug too, now that I think about it.

You might think I’m joking when I talk about eating bugs, but in many parts of the world people do. If you think about it, it’s no weirder than eating shrimp, lobster, oysters, or eggs. Remember that humans are omnivores, and that means we will eat just about anything. Those things don’t all have to be cookies and peanut butter sandwiches, although I haven’t had my lunch yet and if I had to choose between a PB&J with maybe a couple of Thin Mints afterwards, I’d choose that over a big bowl of deep-fried crickets. But lots of people would choose the crickets. It all depends on what you’re used to and what’s considered acceptable in your culture.

But even in areas where people eat lots of insects, they don’t eat every kind of insect. Some really are poisonous because they eat plants that contain toxins and store those toxins in the body. The monarch butterfly caterpillar eats milkweed, which contains poisons that can harm the heart, so don’t eat monarch butterflies. But because insects are generally quite small, the toxins one insect can hold aren’t usually enough to make you really sick unless you eat a whole bunch of them. That’s why children in some parts of Italy can eat a particular moth without dying even though it contains the deadly poison cyanide.

You know what? Let’s start with this moth, because what the heck, Italian children. Why are you eating these moths anyway, and why are you not dying of cyanide poisoning?

There are a number of closely related moth species that children in the Carnia region of Italy traditionally eat. The moth’s wingspan is only about an inch wide, or 30 millimeters. It’s most common in the Italian Alps and it flies around during the day, which makes it easy to find and catch. Its body is grayish, and one pair of its wings are greenish or gray with red spots, while the other pair of wings is mostly red. There’s also a variety with yellow wing markings instead of red. The reason it has such bright colors is because it stores a liquid containing cyanide in its digestive system, and the bright colors tell potential predators to leave it alone, it’s poisonous.

The problem is, the moth’s digestive system also contains sugars called glucosides, which makes it taste sweet. And before you laugh at little Italian children catching moths to eat because they’re sweet-tasting, think about how much effort you may have put into extracting a tiny bead of nectar from honeysuckle blossoms.

But honeysuckle doesn’t contain cyanide. Why don’t those little moth-eating kids get sick?

Researchers have studied this, mostly because they were worried about the children. It turns out that there’s so little cyanide in each moth that even a small child would have to eat at least 170 moths whole in a short period of time to die. Since most of the time the kids pull the moths apart and only eat the tiny piece of the digestive tract that contains sugar, that reduces the amount of cyanide they ingest. A kid would have to eat 5,000 moth digestive tracts to die, and frankly if a kid was that determined to have that much sugar, they’d probably be more likely to spend their time doing odd jobs for money to buy candy instead of catching thousands of moths.

Well, that was gross. I feel like we’re off to a really good start in this episode.

So, eating 5,000 moth digestive tracts aside, are there any bugs out there that are so venomous that they could kill you?

Yes there are. But you’re probably not going to run across them, and even if you do, you’re probably going to be just fine. It’s rare that someone dies after touching Lonomia moth caterpillars, although it does happen. But if you do touch one of the caterpillars, even if you don’t die, you’re not going to feel very good.

There are a number of Lonomia species. The adult moths are brown or grayish, with the males sometimes yellow. It has delicate darker brown markings to help it mimic small dead leaves. The species that is most venomous is sometimes called the giant silkworm moth, Lonomia obliqua, and it lives in South America. It’s especially well known in southern Brazil. The caterpillar grows to about two inches long, or 5.5 cm, and is either green or brown with lots of hair-like spines growing from the back and sides.

A lot of caterpillars have these hair-like spines, and most of them aren’t venomous. They can cause a rash, though, since the spines are very thin, detach easily, and can irritate the skin. But the caterpillar of the giant silkworm moth has spines with powerful venom. The venom contains an anti-clotting agent that causes internal bleeding that can eventually lead to death. But one little caterpillar doesn’t contain enough venom to kill a person all by itself. The trouble comes when the caterpillars are gathered in groups on leaves or tree trunks, because then it’s easier for someone to accidentally touch a bunch of caterpillars at once, receiving hundreds or even thousands of tiny stings from the venomous hairs. Fortunately, the mortality rate for people who are stung by these caterpillars is only a little over 2%. That means almost 98% of people stung by one survive.

Another moth with a venomous caterpillar lives in the United States, especially the southeastern states. It’s called the southern flannel moth and it’s really pretty and fuzzy, yellow and white with some brown markings. The caterpillar is often called the puss caterpillar because it’s also fuzzy and somewhat resembles the end of a cat’s tail or a cat’s paw. But don’t touch it! The puss caterpillar has spines with venom sacs at the base just like the giant silkworm moth caterpillar has. If someone brushes against the spines, they inject venom into the skin. The puss caterpillar isn’t deadly, and most people who touch it only end up with a painful swelling at the injection site that feels like an extra bad bee sting. But some people have a more severe reaction, including fever, vomiting, and heart trouble.

Incidentally, in case you were wondering if caterpillars poop, of course they do. Some caterpillars, though, including the puss caterpillar, actually eject fecal pellets so that they fly away like tiny bullets of poop. This is partly so the caterpillar doesn’t make a mess on the leaf it’s eating, but mainly so that predators aren’t able to find the caterpillar after seeing or smelling its poop. But sometimes the puss caterpillar will fire fecal pellets at predators, so that’s yet another reason not to touch one.

Puss caterpillars build really tough cocoons, so tough that they can stay on a tree or bush for years after the moth is long gone. Some ant species actually move into puss caterpillar cocoons to raise their eggs. Spiders also sometimes live inside empty puss caterpillar cocoons.

There are other venomous moth caterpillars, but they’re all pretty similar to the ones we’ve discussed already. But while we’re on the subject of moths, let’s talk about just how amazing and weird they are. This goes for butterflies too, of course, which are very similar.

As an example, let’s discuss a type of moth that isn’t venomous or poisonous or dangerous in any way, the luna moth.

The luna moth is one of the largest moths in North America, and it’s fairly common in the eastern part of the continent. It’s beautiful, with pale green wings and a white body. Its wingspan can be as much as seven inches across, or 18 cm. The wings have yellow eyespots and long swallowtails that confuse bats’ echolocation by fluttering as the moth flies, scattering the reflections of the bat’s echolocation calls. The bat attacks the swallowtail instead of the moth’s body, allowing the moth to fly away.

This is the life cycle of the luna moth, which is similar to most moths’ life cycles. A female moth will lay several hundred eggs on the undersides of leaves the caterpillars will eat, usually only one or a few eggs per leaf spread across many trees. The luna moth caterpillar especially likes persimmon, sweet gum, wild cherry, hickory, willow, black walnut, and white birch trees. The eggs hatch into little green caterpillars after about a week. The caterpillars eat leaves, grow big enough to molt, eat and grow some more, molt again, and so on. The period between molts is called an instar, which in the luna moth is about a week, give or take. After five instars, the caterpillar is as big as it will get, generally around 3 ½ inches long, or 9 cm. It’s not dangerous, but if a predator approaches, it will rear up, clack its mandibles, and puke up the contents of its digestive system, which stinks.

Finally, the caterpillar leaves the tree where it’s lived its whole life and crawls around in the leaf litter underneath the tree. There it spins a cocoon out of silk, wrapped inside leaves to hide it, expels any water or food still in its intestines, and transforms within the cocoon into a pupa. The pupal stage takes about two or three weeks, and let’s find out what’s going on inside the cocoon during that time.

First, the pupa is encased in a sort of exoskeleton called a chrysalis, which is inside the cocoon. Within the chrysalis, the caterpillar’s body starts to digest itself using its own digestive juices. This breaks its body down into cells in a sort of soup inside the chrysalis, and the cells then reform into the adult moth or butterfly.

Clearly, if you go through a metamorphosis like this that requires all your cells to turn into cell soup, you aren’t going to retain any memories from before you ensouped. Right? Well, according to a 2008 study with a moth called the tobacco hornworm, caterpillars that learned to avoid a particular odor retained those memories as full-grown moths. The moths would also avoid that odor. Researchers aren’t sure how this happens and I wasn’t able to find any follow-up studies, but it’s pretty mind-blowing. My brother sent this article to me ages ago, so thanks, Richard!

So, the luna moth has developed from a caterpillar into caterpillar soup and then into a newly-formed luna moth. The moth has serrated spurs made of chitin at the base of the front wings, which it uses to tear its way out of the cocoon. Its new wings are soft and wet, so it will spend a couple of hours waiting for the wings to harden before it can fly.

Male luna moths usually hatch first and fly away to find females. When a female luna moth hatches, she flies around until she finds a tree she likes, and then she stays in the tree and releases pheromones once it grows dark. Pheromones are chemicals that attract males, which is why the male moth has wider antennae than the female. He detects pheromones with his antennae, and can sense them up to six miles away from the female, or about 11 km. After he finds her, the pair mate, and within a day or so she starts laying eggs.

Like many moth species, adult luna moths don’t eat. They only have vestigial mouths and no digestive system at all. They mate, lay eggs, and die within about a week of hatching.

The luna moth is harmless even if you eat it or pet it—please don’t do either—but it is related to the deadly giant silkworm moth of South America. Fortunately, they look totally different and live in different places.

One last note before we leave moths behind and look at some other venomous insects. Back in episode 93 where we talked about some of the biggest insects in the world, I mentioned the queen alexandra’s birdwing butterfly. I put a picture of it in the show notes, or so I thought. Listener Judith caught my mistake and pointed out that the picture I’d posted was actually of an atlas moth. The atlas moth is in fact bigger than the queen alexandra’s birdwing butterfly, with a wingspan just shy of a foot across, or 30 cm. I swapped out the picture so it’s correct, so thank you to Judith for letting me know!

Now let’s take a look at some venomous insects that aren’t moths. Let’s just skip right over the ones you know about, like bees, and talk about a few interesting ones you might not have heard of. Like the bullet ant. It gets its name because its bite is so painful it feels like you’ve been shot with a gun.

The bullet ant lives in the rainforests of Central and South America. Worker ants are about an inch long, or 3 cm, which is pretty darn big for an ant. The queen ant is about the same size as the worker ants. It’s not closely related to any other ants alive today, but an ant discovered in amber dated to at least 15 million years old was determined to be the bullet ant’s closest relative. The bullet ant looks more like a wasp without wings than an ant, in fact. It’s black in color with massive jaws.

The bullet ant’s bite is considered the most painful of any insect. The ant injects venom with the bite that causes a burning pain throughout the body that lasts for a solid 24 hours without fading. It won’t kill you, but you may wish you were dead. The venom is a neurotoxin that can cause temporary paralysis of the part of the body that was bitten too.

An indigenous people of Brazil, the Sateré-Mawé, use the bullet ant bite in an initiation rite for warriors. That’s how much the ant’s bite hurts.

Finally, let’s learn about an insect with a terrifying name, the assassin bug. There are a lot of assassin bug species throughout the world, and while they sound scary, they can’t actually kill you. Their bite might hurt, but compared to a bullet ant bite, pffft. Easy peasy. But the white-spotted assassin bug of Africa does something the bullet ant only wishes it could do. If something disturbs a white-spotted assassin bug, it can spit venom. And if any of the venom gets into your eyes, it can temporarily blind you.

Assassin bugs mostly eat other insects. Some specialize in hunting spiders, some in hunting bedbugs or cockroaches. The assassin bug has a strong proboscis, or rostrum, that it uses to stab its prey and inject venom containing digestive enzymes. The venom paralyzes the insect and the digestive enzymes liquefy its insides. The assassin bug slurps up the liquefied insect insides. But if a predator attacks the assassin bug, it will inject a different kind of venom that causes intense localized pain and kills off the tissue around the injection site. No other insects are known to produce two different types of venom.

Some people keep assassin bugs as pets. What is wrong with those people?

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!


Episode 110: Three mystery animals from India



Thanks to Pranav for this week’s suggestion! We’re going to look at three mystery animals from India, ones you may not have heard of.

A photograph reportedly of a kallana pygmy elephant, although scale is hard to tell:

A pink-headed duck, deceased:

Show transcript:

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

It’s time for a mystery animals episode, and this one was a suggestion from Pranav, who suggested mystery animals from India. Pranav also gave me lots of other excellent suggestions that I’ll hopefully get to pretty soon.

When I got the suggestion, I realized the only mystery animal from India I really knew about was one we talked about in episode 55, the buru. I had no idea what else might be hiding in the forests and mountains of India. Apologies in advance for undoubtedly mangling names and places from India. I tried to look up pronunciations to at least make an effort to get them right.

India is in south Asia, and it’s a huge country. The area is often referred to as the Indian subcontinent because it mostly sits on its own tectonic plate. Around 100 million years ago it was connected with Madagascar, then split off around 75 million years ago and for many millions of years it was a giant island. But it moved northward slowly—and we’re talking only around 8 inches a year, or 20 cm, which is actually pretty fast for a tectonic plate—and slowly crashed into Eurasia, shoving beneath the Eurasian plate and causing it to crumple upwards, creating the Himalayas.

About half of India’s landmass projects southward into the Pacific Ocean like someone dipping their foot into a bath to see if it’s too hot. As a result, the country has a lot of coastland. So there are amazingly high mountains to the north, tropical coasts to the south, and everything from desert to tropical rainforest in between. It even has some volcanic islands off its coast. It pretty much has everything you could want in a country, and that means it has an amazing variety of animal life too.

Many of India’s animals are ones everyone is familiar with from zoos and storybooks: elephants, tigers, rhinoceroses, cobras, pangolins, and lots lots lots more. But it also has its share of mystery animals. We’ll look at three of those mystery animals today. I think you’re going to like all three of them.

Let’s start with the mande burung. It’s supposed to be a giant ape-like animal as much as 8 or 10 feet tall, or up to 3 meters, with black hair. It lives in the remote forests of northeast India—specifically, in Meghalaya.

The mande burung has long been a creature of folklore in the area, until November 1995 when someone saw one. But I can’t find any information at all about what that sighting entailed. Interest in the mande burung has increased steadily since then, with cryptozoologists from India and other parts of the world mounting expeditions to look for it. They report finding footprints up to 15 inches long, or 38 cm, hair from unidentified animals, and nests made from leaves and grass. But there are no photographs of the animals, no mande burung feces, no dead bodies, and very few sightings, all of them within the last few decades and some of them decidedly questionable.

It’s certainly possible that there’s a mystery animal living in the area. Meghalaya is heavily forested outside of the cities and farmland. Some areas of forest are considered sacred, so they’ve never been logged, no one’s ever lived there, and no one hunts there. As a result, these sacred forests contain some of the richest habitats in all of Asia, containing plants and animals that live nowhere else. Meghalaya also has wildlife sanctuaries. So it’s pretty much guaranteed that there are animals living in Meghalaya that are unknown to science.

But while Meghalaya is primarily an agricultural region, tourism is becoming more and more important. A 2007 press release even talks about how the mande burung legend will bring more tourists to the area, and that a local group had started offering tours for people looking for the mande burung. That doesn’t mean the sightings aren’t genuine—I think most of them are—but as I’ve said many times, people see what they expect to see. The more people talk about the mande burung, the more likely people will think of it when they see a large animal they can’t identify. And there are lots of big animals living in the forests of Meghalaya, including an endangered species of gibbon, four species of macaque, and three species of bears. Any of these might resemble a bigfoot type of creature if seen in low light or poor conditions.

In 2001, a hair found in what’s called a “cedar tree root den” was DNA tested. Bear and human DNA was ruled out, and the DNA results didn’t match any known animals. But a follow-up test in 2008 gave a result that was just as surprising to scientists: the hair belonged to a Himalayan goral, a bovid that wasn’t known to live in the area until the DNA results came in. The goral is a small antelope-like animal with short horns that lives in the southern slopes of the Himayalas. It’s dark gray or gray-brown in color with a darker eel stripe along the spine. Generally, websites that like to talk about Bigfoots mention the first DNA test but don’t mention the follow-up, but I think the discovery of Himalayan goral hairs in Meghalaya is exciting. Who knows what else might be hiding in the forests too?

For instance, maybe a pygmy elephant! Well, okay, reports of a suspected dwarf elephant species called the kallana come from southern India, not northeastern. But it’s definitely a mystery animal.

The Indian elephant is a subspecies of Asian elephant that lives throughout much of mainland Asia. It’s smaller than the African elephant but still pretty big, with males standing as much as 11.3 feet at the shoulder, or 3.4 meters, although most are much smaller than this. Females are smaller than males and have smaller tusks, or sometimes no tusks. It was once common throughout India but is now endangered due to habitat loss and poaching. Tame elephants help with farming and with carrying heavy items and human riders across uneven terrain, but the elephants aren’t actually domesticated.

The kallana elephant reportedly only grows to around five feet high, or 1.5 meters, and while it looks like an ordinary Indian elephant except for its size, it doesn’t mix with Indian elephants and even appears to avoid them. It lives in rocky hills in and around the Peppara Wildlife Sanctuary in southern Kerala. It’s shy and can move much faster than regular elephants, and it doesn’t appear to have trouble with steep slopes the way elephants usually do.

In 2005, a wildlife photographer named Sali Palode got pictures of two kallana elephants, one alive, one a dead one they found by a lake. He took more photos in 2010, and in 2013 he got brief video footage. But there are no photos of a herd of kallana elephants, just solitary animals. Without being able to examine a kallana elephant in person, researchers don’t know if the elephant photographed is a new species or subspecies, or just an Indian elephant with a genetic anomaly similar to dwarfism in humans. The photos might even just be of young elephants that haven’t grown to their full size yet.

Until someone gets definitive footage of a herd of Kallana elephants, an individual is captured and studied, or someone takes samples of the elephant dung found throughout the hills and sends it for DNA testing, there’s no way of knowing if the small elephants Sali Palode has photographed and the local tribespeople report seeing are something special. Not that regular elephants aren’t special enough already, but if there is a population of anomalous elephants in the area, it’s important to learn about them so they can be further protected.

Our final mystery animal of India is the pink-headed duck. It lives in wetlands in parts of eastern India and a few nearby countries, and it gets its name because the male has a pink head and neck. It builds its nests in dense elephant grass and its eggs are almost completely round. It’s shy and prefers remote, isolated areas with deep ponds or lakes and thick grass.

So why are we talking about the pink-headed duck in a mystery animals episode? Well, unfortunately, there hasn’t been a single confirmed sighting of the duck since 1949. Some researchers push this back ever farther to 1935. The main reason it hasn’t been classified as extinct is that the occasional report of one occasionally trickles in.

The difficulty in knowing whether there really are pink-headed ducks still alive out there is that the areas where they are known to have lived are really hard to get to. I mean, unless you’re a duck. Then they’re great. The decline of the species started in the 19th century when British big game hunters would come through and basically just shoot everything that moved. It was already considered rare by the turn of the 20th century, which made hunters even more eager to shoot it so they’d have a rare trophy. Habitat loss and trophy hunting drove it nearly to extinction even if it’s not actually already extinct.

Recent expeditions by conservationists and birders hoping to find some pink-headed ducks haven’t found any definitive proof that any are still alive. A 2017 expedition to Myanmar didn’t find any of the ducks, but the team did interview locals who said they’d seen the ducks as recently as 2010.

We don’t know a whole lot about the pink-headed duck. Researchers think it was a diving duck, but it may have been a dabbler. A dabbling duck tips its body forward, head underwater and tail sticking up, to forage in shallow water, often on plants. A diving duck dives for its food, usually small animals of various kinds. We know the pink-headed duck ate snails and plants, but it probably ate other things too that we don’t know about.

A study of a taxidermied pink-headed duck’s feathers in 2016 determined that the pink color came from carotenoids, a pigment that also gives the flamingo its pink color. The only other duck with feathers pigmented by carotenoids is the pink-eared duck of Australia, which is only distantly related to the pink-headed duck. It has a tiny pink spot on each side of its head.

Conservationists and birdwatchers hold out hope that the pink-headed duck is still alive, hiding its round eggs in clumps of elephant grass far away from humans. Some researchers have even suggested it might be nocturnal, which would explain why it’s always been hard to find. It was never much of a duck for moving around, preferring to stay put instead of flying off to other areas. Hopefully someone will discover a healthy population one day, possibly somewhere no one’s even looked yet, and we can protect it and learn about it before it’s too late. Once a duck is gone, a duck is gone forever.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!


Episode 109: Convergent Evolution



I mention convergent evolution occasionally, but what is it really? This week we learn about what it is and some animals that demonstrate it. Thanks to Richard E. and Llewelly for their suggestions this week! Jaguars and leopards look so similar I’m not 100% sure this picture actually shows one of each:

The adorable sucker-footed bat from Madagascar:

The equally adorable TOTALLY UNRELATED disk-winged bat from South America:

Metriorhynchus looked a lot like a whale even though it was a crocodile ancestor:

Show transcript:

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

This week we’re going to learn about some animals that represent convergent evolution. That’s a term that I mention every so often, so it’s time to really dig into it and see what it’s all about. We’ll start with animals that are fairly closely related, then work our way backwards to those that aren’t related at all.

Basically, when unrelated organisms develop similar form, structure, or functions as each other, that’s called convergent evolution. One simple example is bats and birds. They’re not related, but both can fly using forelimbs that have been modified into wings.

This topic idea was sparked by an idea from Richard E., who suggested an episode about evolution and how it doesn’t “improve” anything, just adapts. That’s an important distinction. Evolution is a reactive force, not a proactive. Sometimes we use terms like advanced to describe certain animals, and primitive to describe others with traits that haven’t changed in a long time. That implies that some animals are “better” than others, or better adapted. In actuality, one trait is not better or worse than another, as long as both traits help the animal survive and thrive. If an animal has traits that haven’t changed in millions of years but it’s still doing well, it’s as adapted as it needs to be. An animal that’s extremely specialized to an environment can sometimes be much more vulnerable to environmental change than a more generalized animal, too.

From a scientific point of view, while it may look like species become more advanced as time goes on, all it means is that a lot of animals have evolved to occupy specific ecological niches. One example Richard gives is the panda, which we talked about in episode 42 about strange bears.

The panda is an extremely specialized animal. It’s a bear that is no longer a carnivore, for one thing, and not only does it not eat meat, or hardly any meat since it will eat small animals and bird eggs when it finds them, it mostly just eats one type of plant. That plant, of course, is bamboo, which is low in nutrients. The panda has adapted in all sorts of ways to be able to digest bamboo, and one of the most obvious adaptations is what looks like a sixth toe on its forefeet. It’s not a toe but a projecting sesamoid bone that acts as a toe and helps the panda grasp bamboo.

But the panda’s sixth toe evolved because of selective pressures, because pandas born with the toe were able to eat more bamboo and were therefore healthier and more likely to have babies than pandas without the toe.

Richard also mentioned the similarities between jaguars and leopards. They are related, but not closely. The jaguar is more closely related to the leopard than to the lion, but the leopard is more closely related to the lion than to the jaguar. That’s not confusing at all. But both cats look very similar, tawny or golden in color with black spots called rosettes, and both frequently demonstrate an all-black coloring called melanism. But the jaguar lives in the Americas while the leopard lives in Asia and parts of Africa. Why do they look so similar?

In this case, a big part of the similarities between jaguars and leopards are that they share a common ancestor that lived around three and a half million years ago. The jaguar migrated from Africa into Europe and then into North America on the land bridge Beringia, while the leopard mostly stayed put but expanded its territory into Asia. New research into feline genetics suggests that the jaguar interbred with lions at some point, which gave it a heavier build and stronger jaws than the leopard.

But leopards and jaguars look very different from other big cats, and very similar to each other. This is where convergent evolution comes in. Leopards and jaguars live in similar habitats, dense forests and jungle where light is dim and filtered through leaves. A spotted animal is harder to see where there’s a lot of dappled shade, and an all-black animal is harder to see when there’s not a lot of light. Melanistic jaguars, those that are all-black, are extremely common, and melanistic leopards are more common in populations living in thicker forests than in populations that live in more open forests with more light.

Leopards and jaguars share a genus, Panthera, which means they’re pretty closely related. But Llewelly suggested we talk about sucker-footed and disk-winged bats, and while they’re both microbats, they’re much less closely related than jaguars and leopards. And they share a really weird adaptation for climbing on smooth leaves.

The sucker-footed bat lives in Madagascar, the big island off the coast of Africa that’s full of lemurs. Madagascar is also home to a tree called the traveler’s palm, although it’s not actually a palm tree. It’s an amazing tree with huge leaves that grow in a fan shape. I don’t mean the tree has a lot of leaves growing in fan shapes, I mean the main part of the tree is one giant fan of enormous leaves. The leaves can be 36 feet long, or 11 meters, and some trees can grow 100 feet high, or 30 meters. It’s supposedly called the traveler’s palm because the fan tends to grow along an east-west line so it gets the most sun, or possibly because the stems catch and hold rainwater that thirsty travelers could drink. Its white flowers are pollinated by ruffed lemurs and it has bright blue seeds. But the traveler’s palm also has extremely smooth leaves, and the sucker-footed bat roosts on the leaves. But the leaves are so slick and smooth that most insects can’t even hold on to them. How does a bat manage it?

As you may have guessed from the name, the sucker-footed bat has little cuplike pieces of skin on its thumb joint and its feet that excrete lots of sweat-like fluid. The bat presses the cups against the leaf and they act just like suction cups, although the main suction comes from wet adhesion. You know how a suction cup holds better if you lick it first? That’s pretty much how it works. Also, hey kids, don’t lick suction cups, they’re dirty. Also don’t drink rainwater out of leaves, that sounds clean but it’s full of dirt and drowned bugs.

The sucker-footed bat roosts head-up instead of hanging upside-down, only one of six species known to roost head-up. It’s about two inches long, or 5 cm, and eats insects. Because it mostly only roosts in the traveler’s palm and is mostly solitary, it doesn’t carry any parasites in its fur or on its skin. Parasites can’t walk across those slick leaves.

The disk-winged bat, meanwhile, lives in the tropical parts of Central and South America. Like the sucker-footed bat, it has cuplike discs made of skin and cartilage on its thumbs and feet that act as suction cups. It roosts head-up in smooth curled-up leaves, generally in small groups. But its suction cups are different from the sucker-footed bat’s. They actually use suction to stay in place, whereas the sucker-footed bat’s suction cups mostly just use wet adhesion from the sweat it produces, with the actual suction being weak and not really necessary.

So let’s back it up some more and look at two animals that have evolved in similar directions that aren’t related. Like crocodiles and whales, or at least a crocodile relative and modern dolphins.

Metriorhynchids [met-ree-oh-rink-id] were croc relatives that lived around 150 million years ago, about 100 million years before whales and their relatives evolved. Metriorhynchids were marine animals, and while we don’t know a whole lot about them since we don’t have very many fossils, we do know that they grew up to ten feet long, or three meters, and lived in the ocean.

Metriorhynchus ate fish, ammonites, and whatever else it could catch, and it was a fast swimmer. It was streamlined with a long snout, smooth skin instead of armored, and even had a finned tail sort of like a shark’s that probably provided its propulsion through the water. It had four long flippers to help it maneuver.

In other words, in a lot of ways it looked like a dolphin, because it was so well adapted to live in the same environment. Whales and their relations have streamlined shapes, smooth bodies to reduce drag in the water, fluked tails, and flippers. Even the shape of metriorhynchus’s snout mirrors the longer rostrums that some dolphins have evolved to help them catch prey.

Finally, let’s look at convergent evolution between two animals that look totally different, are totally unrelated, but which share one similar feature. If you guessed primates and parrots, you are correct!

Specifically, this is about how the brain manages higher-order processing. In other words, intelligence. Primates, including humans, have an enlarged section of the brain called the pontine nuclei that transfers information between the brain’s cortex and cerebellum, allowing primates to process information in a more sophisticated way than most other mammals studied. But parrots and a lot of other birds are also intelligent, and researchers have recently discovered how their brains do the same thing.

Instead of a big pontine nuclei, birds use a part of the brain called the medial spiriform nucleus that performs the same transfer of information from the cortex and the cerebellum. In intelligent birds like parrots, that part of the brain is very large, five times larger than it is in chickens. I’m sorry, chickens, you’re very pretty birds and taste delicious, but you’re not known for your high-level reasoning abilities.

So convergent evolution is more than just two animals that evolve to look or act similar because they live in the same environment. In fact, there’s so much to convergent evolution that there’s no way I can do more than brush along the surface of the topic in a single episode. It might be a fun topic to revisit now and then.

In the meantime, now you know a little bit about what convergent evolution is. Just remember that if you explain it to a parrot, it’s processing your information with a totally different part of its brain than you are. That’s pretty awesome.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. 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 whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!