Category Archives: birds

Episode 138: City Animals

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This week we’re going to learn about some animals that have made their homes in cities alongside humans. Thanks to Corianne who suggested this amazing topic!

Further reading:

The BBC’s Urban Fox FAQ

Toronto vs. Raccoons

The urban fox has a favorite coffee shop and knows where to find parking downtown:

The urban raccoon’s apartment is really small but it’s in a great location:

The urban (rock) pigeon can walk to work in good weather:

Show transcript:

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

This week we’re going to look at animals that live in cities. This is a great suggestion by Corianne, who especially suggested the pigeon. But pigeons aren’t the only animals that live in cities alongside people. In fact, in 2018 a large-scale camera trap study of animals in Washington DC and Raleigh, NC concluded that just as many mammal species live in cities as live in the countryside. That’s only mammals, though. There aren’t as many species of other animals in cities.

Different animals hang out in cities in different parts of the world. In parts of Africa and Asia, local monkeys have moved into cities and cause mischief by stealing food from markets and tourists. Gulls are also thieves of food, sometimes getting so bold as to snatch a sandwich from a person’s hands while they’re eating it, even in cities nowhere near the ocean. City parks attract squirrels and deer, decorative fountains and ponds attract geese and ducks as well as alligators, peregrine falcons move in to feast on pigeons, rats, and other small animals, and some cities have to deal with the occasional bear or leopard, wild boars, even penguins. But today we’re going to focus on three really common city dwellers, both because they’re interesting and because there are so many misconceptions out there about them.

We’ll start with urban foxes. We talked about foxes in episode 106, but while urban foxes are plain old red foxes and not a separate species or subspecies, they’ve adapted to city life easily since they’re omnivores and agile animals that can climb obstacles like fences.

Many cities throughout the world have urban foxes, but they’re especially common in the UK. They eat out of trash cans for some of their diet, but they also hunt rats and other small animals that live in cities too, along with earthworms, insects, and even plants. They especially like fruit and acorns. When a fox finds some food, it will often run off with it and bury it somewhere, then come back later to eat it.

Because an urban fox doesn’t have to worry about predators as much as ordinary countryside foxes do, it can grow larger on average than its country cousins. But it’s also in more danger of being hit by cars or infected with diseases common to dogs and other canids, like mange and distemper.

Urban foxes have a bad reputation for biting, attacking pets, and in general being a nuisance. But the fox is just being a fox and doing the best it can. In many parts of the world, the red fox’s natural habitat is fragmented more every year as cities grow larger and farmland and woodland is turned into houses. Besides, foxes have been reported in cities for a long time—over a century in London, England, where foxes are relatively common. They especially like areas with parks, or where people have gardens or lawns.

The biggest problem with urban foxes is people who treat them like they’re dogs. They’re wild animals, so while it’s okay to leave food out for them, don’t try to touch one or get too close to it. Foxes who get too used to people can become aggressive. Foxes usually don’t bother animals as large as cats, either, and they avoid dogs, but don’t leave small pets like guinea pigs or rabbits outside, especially at night, because that is just asking for trouble.

The urban fox doesn’t always live only in the city, though. One fox, nicknamed Fleet, was tagged by researchers in 2014 and tracked to see where he spent his time. To their surprise, Fleet lived up to his name and traveled from the city of Hove into the countryside across England. In 21 days he traveled 195 miles, or 314 km, and probably went farther but his GPS tracker stopped working so we don’t know how far.

This is what a fox sounds like:

[fox sound]

In the UK, foxes are frequent city animals, but in North America it’s much more common for raccoons to fill the same ecological niche. The raccoon is native to North and Central America although it’s been introduced in parts of Europe as a fur animal and briefly to Japan as a pet. The raccoon makes a really bad pet, by the way. It’s not domesticated and will tear your house up.

The raccoon is mostly gray or gray-brown with some lighter areas of fur, black rings on its bushy tail, and black markings over its eyes. It grows a little over two feet long, or around 70 cm, not counting its tail. Its legs are relatively short and it scurries instead of really running, although it can swim well. The raccoon is a great climber and can even climb down trees headfirst by turning its hind feet so that they point backwards, which gives it a better grip. It has sharp claws too, and dexterous hands although they don’t have opposable thumbs. The raccoon’s front paws have as many sensory receptors as human hands, which means it can learn a lot by just touching something. Like, for instance, how to unlock a trash bin.

The raccoon is well-known for getting into trash no matter what kind of bin it’s in. This is because raccoons are remarkably intelligent. By now you probably know that intelligence and social complexity are linked, but raccoons have a much different society than other intelligent animals. Groups of related females generally occupy the same territory and come together to eat and rest, while males usually live in small groups that are mostly separate from females.

Like the fox, the raccoon is an omnivore. It eats insects and worms, fruit and nuts as well as other plant material, bird and reptile eggs, frogs, fish, crustaceans, and other small animals. Raccoons in captivity are known to wash their food by dipping it in water, but this behavior hasn’t actually been documented in wild raccoons. Some researchers think the raccoons aren’t actually trying to clean the food, but are mimicking the motion of catching food in water, while others suggest the raccoons are stimulating the nerve endings in their hands with water to learn more about the food they’re touching.

Raccoons prefer open forests near water, since they like to catch fish and frogs. But they will eat pretty much anything, which means they raid trash bins. For years, the city of Toronto in Canada had trouble with raccoons getting into people’s trash bins. The bins were designed to be picked up and emptied by city trucks, but the raccoons had learned to break the locks. In 2015 the city redesigned the bins to be raccoon resistant, and in 2016 after extensive testing the new bins were distributed to residents. Before long the raccoons had figured out how to open them.

Researchers think that the daily puzzles urban raccoons solve to find food actually make them smarter. Since they’re pretty smart to start with, that’s kind of scary.

Like urban foxes, urban raccoons can get too used to humans. They’re rarely dangerous to people or pets, but they can cause a real mess if they get into your house and will bite if they feel threatened.

This is what a raccoon sounds like:

[raccoon sound]

We’ll finish with the ubiquitous city bird, the pigeon. It’s properly called the rock pigeon or rock dove and is native to parts of Eurasia and Africa. But these days it’s spread throughout much of the world, especially in cities.

Most people are familiar with the pigeon. It’s usually gray or brownish-gray with a white patch on its rump and two broad stripes of black on its wings. Both males and females have iridescent feathers on the neck that shine green and purple in sunlight, but the iridescence in males is much more pronounced. Pigeons with other markings are either feral domesticated pigeons or have feral domesticated pigeons in their ancestry. The domesticated pigeon was actually developed from the rock pigeon and it’s probable that most city pigeons are actually mostly feral domesticated pigeons.

The pigeon is a fairly large bird, up to 15 inches long, or 37 cm, with a wingspan over two feet, or 72 cm. It mostly eats seeds and other plant material, but will also eat small insects. City pigeons will eat bread and other foods too, but they would be happier with whole grains. Like many other birds, the pigeon stores food in its crop after swallowing it, which allows it to eat more food than it would otherwise be able to hold. The crop is a chamber at the bottom of the esophagus.

Not only do pigeons have a crop, which not all birds have, pigeon parents produce a food called crop milk or pigeon milk that they feed to babies. It’s not milk at all, of course, but the nutrient-rich lining of the crop that it sheds and regurgitates to feed its babies, which are called squabs. Both parents produce crop milk, which sort of looks like cottage cheese. The babies can’t digest anything except crop milk for the first week of life, so the parents may actually not eat anything during the first days after the eggs hatch to make sure there aren’t any seeds mixed in with the crop milk. After a few days the parents mix in food that’s been softened in the crop.

Pigeons and doves are almost the only birds that produce crop milk. The flamingo and the male emperor penguin do too, even though they aren’t related to pigeons. But that’s it, as far as we know. So if anyone asks you what the flamingo, the emperor penguin, and the pigeon have in common, now you know. Also, they’re all birds.

Pigeons live in flocks, although the flock may break up into smaller groups or pairs during part of the day. At night the birds usually roost together except for pairs who have eggs or babies in a nest. Pigeons mate for life and both parents take care of the eggs and squabs. Flock leaders find food and lead the rest of the birds to it, whether the food comes from plants growing in a park or from a person scattering birdseed.

Pigeons are actually clean animals when they have access to water. They like to bathe and preen to keep their feathers clean. If you’ve ever watched a typical bird drink water, maybe at a puddle or a birdbath, you might have noticed that the bird dips some water into its beak, then tilts its head back so the water runs down its throat. This is because most birds can’t actually swallow water the way most mammals can. I mean, if you had to you could drink water while you were upside down, although you might choke or get it in your sinuses. But some of the water at least would get into your stomach. Birds couldn’t. Except for the pigeon, which can actually drink like a mammal, keeping its head down as it swallows. The pigeon and its close relatives are the only birds known who can do this.

No one thinks of pigeons as especially smart birds, but guess what. They’re actually pretty bright. Pigeons can easily memorize images, even hundreds of them, and retain those memories for years. They not only recognize individual humans, they can learn to understand what human expressions mean. They also have keen vision and can differentiate between very similar items or pictures, which leads to pigeons being trained to do something unexpected. Wait for it. You’re not going to believe this. Pigeons can learn to identify malignant breast tissue in mammograms at least as well as humans can. Researchers train birds to identify the differences in mammogram slides, then use four birds in a team. The team can be 99% accurate in identifying malignancies that need to be treated. So pigeons can save human lives!

Not only that, but researchers can find sources of lead pollution by taking blood samples from sick or dead pigeons found in cities. Since city pigeons generally have small territories that only encompass a few blocks, researchers can measure the level of lead found in birds and know roughly where the lead exposure occurred. That helps the city find and clean up sources of lead pollution.

Pigeons are actually quite healthy birds, despite their reputation as diseased. They’re surprisingly resistant to a lot of bird diseases, including bird flu. Many people think of pigeons as dirty scavengers, but like other urban animals, they’re just living out their lives in an environment humans made. And if they’re scavengers, just think about where that food is coming from. People are dropping it on the ground, that’s where. Maybe people are the dirty ones, throwing food around. Pigeons are just cleaning it up for us.

This is what a pigeon sounds like:

[pigeon sound]

You can find Strange Animals Podcast online at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 136: Smallest of the Small

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Last week we learned about the smallest species of animals not typically thought of as small, like snakes and cetaceans. This week let’s look at some of the tiniest animals in the world, the smallest of the small!

Further watching:

A short video about jerboas. Really interesting and well-made!

A button quail:

Baby button quails are the size of BEES:

Kinglets are teeny birds even when grown up. Left, the golden-crowned kinglet. Right, the goldcrest. These birds MAY BE RELATED, you think?

The pale-billed flowerpecker, also teeny and with a cute name:

Moving on from birds, the pygmy jerboa is one of the smallest rodents in the world:

The Etruscan pygmy shrew is even tinier, probably the smallest known mammal alive today. Shown here with friend/lunch:

The Western pygmy blue butterfly is probably the smallest butterfly known:

But the pygmy sorrel moth is even smaller. Right: red marks left behind on a sorrel leaf eaten by its larvae:

One of the world’s teeniest frogs:

Show transcript:

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

Last week we learned about the smallest species of animals that aren’t typically thought of as small. But this week let’s learn about the smallest of the small animals. It’s like saying they’re the cutest of the cute animals. We’ll start with the bigger ones and get smaller and smaller as we go.

Let’s start with a bird. The smallest bird is the bee hummingbird, which we’ve talked about before. But there’s another bird that’s really small, the button quail. It’s about the size of a sparrow.

The button quail isn’t actually a quail, but it looks like one due to convergent evolution. There are a number of species in parts of Asia and Africa and throughout Australia. It generally lives in grasslands and is actually more closely related to shore and ocean birds like sandpipers and gulls than to actual quails, but it’s not very closely related to any other living birds. It can fly but it mostly doesn’t. Instead it depends on its coloring to hide it in the grass where it lives. It’s mostly brown with darker and lighter speckled markings, relatively large feet, and a little stubby nothing of a tail. It mostly eats seeds and other plant parts as well as insects and other invertebrates.

The button quail is especially interesting because the female is more brightly colored than the male, although not by much. In some species the female may have bright white markings, in some their speckled markings are crisper than the males. The female is the one who calls to attract a male and who defends her territory from other females. The female even has a special bulb in her throat that she can inflate with air to make a loud booming call.

The male incubates the eggs and takes care of the chicks when they hatch. Baby button quails are fuzzy and active like domestic chicken babies but they’re only about the size of a bumblebee. In many species, as soon as the female has laid her eggs, she leaves them and the male and goes on to attract another male for her next clutch of eggs.

People sometimes keep button quails as pets, specifically a species called the painted buttonquail or the Chinese painted quail. It’s about five inches long, or 12 cm. The female has black and white stripes on her face and throat. The birds can become quite tame and can live several years.

Button quails make a lot of different noises. This is what a button quail sounds like:

[button quail calls]

One of the smallest birds in the world that isn’t a hummingbird is the kinglet, with several species that live in North America and Eurasia. The goldcrest is a type of kinglet and the smallest European bird. It’s only 3.3 inches long, or 8.5 cm, although some individuals are larger. It looks a lot like the North American bird the golden-crowned kinglet, which is just a shade smaller at 3.1 inches, or 8 cm. Both species have a golden patch on the top of the head. The male also has an orangey spot in the middle of the golden patch. Both live in coniferous forests and eat insects and spiders.

Because kinglets are so small and active, they can starve to death quickly—in only an hour in some cases. Females lay up to 12 eggs at a time. TWELVE EGGS. That is a lot of eggs. The nest is too small to hold a dozen eggs in one layer so they end up in a pile. The female keeps all of them warm by pushing her legs down into the pile of eggs. Since her legs have a lot of blood vessels near the surface, they’re much warmer than most birds’ legs.

When the babies hatch, they stay in a pile. The ones on the top of the pile get fed first, naturally, but then they burrow down into the pile and push their siblings up toward the top. They’re not just being nice, though, since birds in the bottom of the pile stay warmer.

This is what a golden-crowned kinglet sounds like:

[bird call]

The pale-billed flowerpecker is even smaller than the kinglets and are among the smallest birds in Asia. It lives in parts of India and nearby areas and mostly eats berries, although it also eats flower nectar. It grows to only 3 inches long, or 8 cm, and is plain brownish-green in color with a short tail and shiny black eyes. It lives in forests but often visits gardens. It doesn’t lay a dozen eggs at a time, just an ordinary two or three.

This is what a pale-billed flowerpecker sounds like. These are some teeny sounds from teeny birds:

[bird call]

There are several rodents that are considered the smallest rodent, but we’re only going to learn about one of them today, the pygmy jerboa. On average it’s only 1.7 inches long, or 4.4 cm, not counting its extremely long tail.

The pygmy jerboa lives in the deserts of Pakistan and possibly in nearby areas too. It has very long hind legs and very short front legs so it hops like a tiny kangaroo, using its long tail as a way to balance and maneuver at high speeds. Its tail is twice as long as its body. Its large hind feet and the end of its tail are very furry to give it more surface area so it can easily maneuver through loose sand.

It mostly eats seeds and leaves, and it gets all the moisture it needs from the food it eats. It’s nocturnal and spends its days in the burrow it usually digs under bushes. Like many other tiny animals, when it rests it slows its metabolism drastically so it won’t starve to death while it’s asleep. Life is rough for tiny animals.

We don’t know a whole lot about the pygmy jerboa except that it’s endangered due to habitat loss, so let’s move on to an even smaller mammal.

The Etruscan shrew grows to about 1.6 inches long, or 4 cm, on average, not counting its short tail. The tail is about a third of the length of its body. It lives in southern Europe, parts of Asia, parts of the Arabian Peninsula, and northern Africa and prefers warm, moist climates. It’s the same size and weight as the bumblebee bat we talked about last week, so it’s one of the smallest mammals known.

The Etruscan pygmy shrew is pale brown with a lighter colored belly, a long nose, and short whiskers around its mouth that it uses to help it find its prey. It’s incredibly active and makes clicking noises almost constantly, as a way to alert other shrews that it’s there and is willing to defend its territory. It makes its nest among rocks and in the abandoned burrows of other animals.

Like the kinglets and other highly active, tiny animals, it has to eat a lot to keep its metabolism going—up to twice its own weight in food every day. It can also enter a torpid state where it reduces its body temperature and metabolism the same way the pygmy jerboa does, in order to not starve while it sleeps. But the Etruscan shrew doesn’t rest very often.

It mostly eats insects and other invertebrates like earthworms, but it will eat anything it can kill. This includes lizards, small rodents, and frogs. It especially likes grasshoppers and crickets, which are often as large as it is. In order to kill prey its own size, the shrew is incredibly fast. If you remember episode 82 where we talked about the star-nosed mole, the Etruscan shrew primarily hunts by touch and can react in barely 25 milliseconds when it touches something it wants to eat. It takes something like 300 milliseconds for a human to blink their eyes, if that gives you an idea of how fast the shrew is. It can touch a cricket and kill it in less time than it takes to blink.

So that’s as small as mammals get, as far as we know. What’s the smallest amphibian?

Well, it’s really, really small. The smallest known frog is only 7.7 mm long. Paedophryne amauensis isn’t just the smallest frog, it’s the smallest vertebrate known. It was only discovered in 2009 in Papua New Guinea.

It sounds like an insect and lives in the damp leaf litter on the forest floor, and it’s dark brown and black in color to blend in with dead leaves, so it was hard to find. Researchers only found it by using sensitive microphones to triangulate on its call, then quickly scooping up lots of leaf litter and stuffing it into plastic bags so anything living in the leaves couldn’t escape. Its eggs hatch into tiny froglets instead of tadpoles.

The tiniest frog is just about the same length as the tiniest fish, the stout infantfish that lives in a few coral reefs near Australia, including the Great Barrier Reef. It also grows 7.7 mm long on average, although females are typically longer and it can grow as much as 10 mm long. But the smallest known fish is the male of an anglerfish species that only grow 6.2 mm long. This doesn’t really count, though, since females grow up to two inches long, or 50 mm. Like other deep-sea anglerfish species, when a male of Photocorynus spiniceps finds a female, he bites her and stays there. Eventually his mouth actually fuses to her body and he lives the rest of his life as a sort of parasitic extension of the female. He supplies her with sperm to fertilize her eggs before she lays them, and she supplies him with nutrition and oxygen since he’s basically part of her body at that point. A female can have more than one male fused to her.

So, we seem to have reached the smallest vertebrates. What about the smallest insects and other invertebrates?

Butterflies are generally pretty small, but the smallest butterfly known is really, really small. The Western pygmy blue butterfly only has a wingspan of 20 mm at most but usually more like 12 mm across. That’s less than an inch. It lives in western North America and parts of the middle east, and has even been found on Hawaii. Its wings are a pretty coppery brown color with rows of black and white spots. It likes deserts and waste places where you wouldn’t expect to find anything as delicate as a tiny butterfly. Its caterpillars eat various types of weed plants.

That is pretty much it. There’s not much to this tiny butterfly. The real mystery is why it’s called the western pygmy blue when it’s not actually blue.

Compared to the smallest moth known, the western pygmy blue butterfly is a giant. The smallest moth is the pygmy sorrel moth and its wingspan is barely four millimeters. Its wings shade from silvery with a metallic bronze tint to purply with a white stripe, and gray along the ends. It’s really pretty but so tiny that it’s hard to spot. It lives in much of Europe and its larvae leave distinctive spiral shapes on sorrel leaves as it eats.

We’ll come back to insects in a minute or two, but let’s look at a few snails first. The smallest land snail is the Borneo snail. Its shell is only .7 of a mm high. It was only discovered in 2015. We don’t know a lot of about it yet, but it probably eats bacterial film growing on limestone in caves. So far researchers haven’t even found a living Borneo snail, though, just its shells.

The smallest water snail is even smaller than the Borneo snail. It’s from North America and its shell is only half a millimeter across at the most. Some individuals are only .3 mm across. Ammonicera minortalis lives in shallow water off the coast of southern Florida and around Cuba and other islands in that area. And that’s pretty much all we know about it. It’s a lot easier to study bigger animals just because they’re easier to find.

Small as that is, on average the smallest beetle is smaller than the smallest snail. It’s a type of featherwing beetle only described in 1999, and on average it’s .338 mm long. So far it’s only been found in Central America and it eats fungus. It’s yellowish-brown in color but that doesn’t really matter because it’s so small that you need a magnifying glass to really see it.

Once you start dividing millimeters, you’re getting into ridiculously tiny territory. But the smallest insect is a type of wasp known as a fairyfly. Kikiki huna is so small it’s measured in micrometers, sometimes called microns, and is smaller than some single-celled organisms. It’s only 150 micrometers long, which is shorter than an ordinary piece of printer paper is thick. It’s been found on Hawaii, Costa Rica, and Trinidad but it probably lives in other places but just hasn’t been found yet. Some researchers suspect that it’s as small as a flying animal can become without losing the ability to fly under its own power instead of just floating on the wind.

At this point anything smaller than Kikiki huna and its close relatives are made up largely of bacteria, which are frankly not as cute or as interesting as, say, button quail. So let’s finish with what may be the very smallest living organism ever found. Or it may not be. Because researchers are literally not even sure if the nanobe is even alive.

In 1996 researchers found what looked like filiments growing among rock samples collected from wells off the Australian coast. Some of them were only 20 nanometers in diameter. To put that into perspective, a nanometer is one billionth of a meter. That’s billion with a B. It’s one thousandth of a micrometer. A nanobe is a tenth of the size of the smallest known bacteria.

The researchers weren’t sure what they’d found so they did a lot of tests. They thought they might have discovered a new kind of crystal, but when they stained the nanobes with a type of dye that binds to DNA, the results indicated the nanobes might be living organisms. But no DNA has been successfully recovered from nanobes.

There’s still a lot of research to be done to determine what they are and if they’re actually alive, though. The main problem is that nanobes appear to be too small to contain all the things that living organisms need. But they do resemble fungi in some ways, just much, much smaller. If nanobes are alive, they’re extremely different from any living animal ever known and presumably live and reproduce in ways completely unlike all other life.

But here’s an interesting note. In 1996 researchers found structures inside a meteorite from Mars that look a lot like nanobes.

You can find Strange Animals Podcast online at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 134: The Magpie

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Thanks to Emma for this week’s suggestion about the magpie! We’ll learn all about the magpie and also about the mirror test for intelligence and self-awareness.

The black-billed magpie of North America (left) is almost identical in appearance to the Eurasian magpie (right):

Not all magpies are black and white. This green magpie is embarrassed by its goth cousins:

The beautiful and altruistic azure-winged magpie:

Chimps pass the mirror test. So do magpies:

The Australian magpie, or as Emma calls it, MURDERBIRD:

Show transcript:

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

This week let’s learn about the magpie, a frighteningly intelligent bird. Thanks to Emma for the suggestion!

The magpie is a member of the corvid family, so it’s related to crows, ravens, jackdaws, jays, rooks, and a few other kinds of birds. Most magpies are native to Europe and Asia, but there are a couple of species found in western North America. There are also two species found in Australia, but we’ll come back to those later on. People think of magpies as black and white, but some Asian species are green or blue. They look like parrots at first glance.

The most well-known magpie is the Eurasian or common magpie. Its body and shoulders are bright white and its head, tail, wings, beak, and legs are a glossy black. It has a very long tail for its size, a little longer than its body, and its wingspan is about two feet across, or 62 cm. It looks so much like the black-billed magpie of western North America that for a long time people thought the two birds were the same species.

Like most corvid species, the magpie is omnivorous. It will eat plant material like acorns and seeds, insects and other invertebrates, the eggs and babies of other birds, and roadkill and other carrion. It will also hunt small animals in groups. It mates for life and is intensely social.

The big thing about the magpie is how intelligent it is. It’s a social bird with a complex society, tool use, excellent memory, and evidence of emotions usually only attributed to mammals, like grief. An experiment with a group of Azure-winged magpies, a species that lives in Asia, shows something called prosocial behavior, which is incredibly rare except in humans and some other primates. Prosocial behavior is also called altruism. In the experiment, a magpie could operate a seesaw to deliver food to other members of its flock, but it wouldn’t get any food itself. All the magpies tested in this way made sure their bird buddies got the food. When access to the food was blocked for the other birds, the bird operating the seesaw didn’t operate it.

The magpie also passes what’s called the mirror test. The mirror test is when a researcher temporary places a colored dot on an animal’s body in a place where it can’t see it, usually the face. Then a mirror is introduced into the animal’s enclosure. If an animal sees the dot in the reflection and investigates its own body to try to examine or remove the dot, the researcher concludes that the animal understands that the reflection is itself, not another animal.

This sounds simple because most humans pass the mirror test when we’re still just toddlers. But most animals don’t. Obviously researchers haven’t been able to try the test with every single animal in the world, but even so, the results they’ve found have been surprising. Great apes pass the test, bottlenose dolphins and orcas have passed, and the European magpie has passed the test. Cleaner wrasse fish also passed the test.

You know what else passed the mirror test? Ants.

The mirror test is supposed to be a test of self-awareness, but that’s not necessarily what it’s showing. Dogs fail the mirror test but pass other tests that more clearly indicate self-awareness. But in dogs, the sense of smell is much more important than sight. Humans don’t even usually think of smell since we’re more attuned to sight and hearing, so we’ve constructed a flawed test without realizing it.

Gorillas also don’t always pass the mirror test, but researchers think this may be because in gorilla society, it’s an act of aggression to look into another gorilla’s eyes. So the gorilla looking in the mirror may literally not see the dot that was painted on its forehead while it was asleep, since it automatically avoids looking at another gorilla’s face, even its own reflection. As far as I can find, no one has tried painting the dot on bottom of the gorilla’s foot or something instead of its face.

Parrots, monkeys, lesser apes, and octopuses don’t pass the test, but all these animals express intelligence in many other ways. Not only that, but some animals that don’t technically pass the test because they don’t give any attention to the dot painted on them will use the mirror for other purposes, like looking at parts of the body they can’t ordinarily see. Asian elephants do poorly on the mirror test, but do well in other tests that measure self-awareness.

Also, most of the animals given the mirror test have never looked in a mirror before. Maybe they don’t realize that dot wasn’t always on their cheek. Or maybe they just don’t care if they’ve got a dot on their face.

That brings us to a final criticism of the mirror test. Some animals live in environments where they’re likely to see reflections. An animal that frequently sees its own reflection in still water when it drinks is more likely to understand that this is a reflection of itself. An animal that has never seen its own reflection won’t necessarily understand what it is. Even humans have this trouble. People who have been blind since birth but who regain vision later in life often don’t know what a reflection is at first. This doesn’t mean they’re stupid or not self-aware, it’s just something new that they have to learn.

But it’s still interesting that magpies pass the mirror test. Okay, let’s move on.

There are a lot of folklore traditions and superstitions about magpies. In Britain, seeing a single magpie is sometimes said to be bad luck, a sign of bad weather to come, or even an omen of death. Seeing two magpies is good luck or a good omen. In parts of Asia all magpies are considered lucky. The nursery rhyme “one for sorrow, two for joy” is originally about magpies, although as a kid I learned it about crows since I live in a part of the world where we don’t have magpies. The rhyme varies, but the version I learned is “one for sorrow, two for joy, three for a girl, four for a boy, five for silver, six for gold, and seven’s a secret that’s never been told.”

Magpies are supposed to be attracted to shiny objects and are thought of as thieves. There’s a whole opera about this, Rossini’s La Gazza Ladra, about a girl who’s accused of stealing a silver spoon. The girl is convicted and condemned to death, but just in time the spoon is discovered in a magpie’s nest and the girl is pardoned. You’ve probably heard the overture to this opera without knowing it, since it appears in a lot of movies.

But do magpies really steal shiny things like jewelry, coins, and silver spoons? Results of a study of wild common magpies indicate that they don’t. A few of the magpies investigated the shiny objects, but none took any and most birds were wary of getting too close to items they’d never seen before.

Many people think magpies are pests who chase off or kill other songbirds, steal things, and are basically taking over the world. That’s actually not the case. The magpie is an important part of its ecosystem, and areas with plenty of magpies actually have healthier populations of other songbirds. The black-billed magpie of North America will hang around herds of cattle, cleaning the animals of ticks and other insects.

Let’s return now to the Australian magpies I mentioned earlier. The black magpie is mostly black with white on its wings. It’s actually not closely related to the magpie at all but is a species of treepie. Other treepies are found in southeast Asia. Treepies are corvids, but they’re not closely related to magpies although they look similar.

The Australian magpie also looks similar to the common magpie, but it’s not a corvid, although its family is distantly related to the corvid family. It’s mostly black with white markings and a heavy silvery-white bill with a black tip. It lives in Australia, southern New Guinea, and has been introduced to New Zealand, where it’s an invasive pest that displaces native birds. It’s about the size of the common magpie, but more heavily built with a shorter tail. It mostly eats insects and other invertebrates, but it is omnivorous. Researchers have noticed that some Australian magpies dunk insects in water before eating them, a practice seen in many species of birds. It doesn’t just dip the insect in the water, though, it thrashes it around. Researchers theorize that this helps rid certain insects of toxins and therefore improves the taste.

If someone gets too close to an Australian magpie’s nest, it will divebomb them, especially the male. It may also peck at the face, sometimes causing injuries. Sometimes people will paint eyes on the back of a hat to try and fool a magpie into attacking the painted face instead of their actual face, although this generally doesn’t work. The magpie especially attacks people who are moving fast, like joggers and bicyclists, so some bike helmets have spikes on them to stop magpies from diving at them. But since a magpie will also sometimes land on the ground in front of a person, then fly up and attack their face from that angle, it doesn’t really matter what kind of hat you wear. It’s probably safest to avoid magpies who are nesting. The babies will be grown and flown away soon enough and then you can have your public park back.

Australian magpies also chase off predatory birds, mobbing them the same way crows and other birds mob hawks.

The Australian magpie is also an intelligent bird. Researchers think intelligence in birds and animals of all kinds is linked to sociability, and Australian magpies are just as social as their far-distant Eurasian and North American cousins. Magpies who grow up in larger groups score higher on tests of intelligence than magpies from smaller groups. The larger a group, the more complex the social interactions required of an individual bird, which drives cognitive development.

The Australian magpie has an amazing singing voice and can mimic other birds and animals. It even sometimes imitates human speech. A magpie may sing constantly for over an hour at a time, and pairs often call together. These duets actually indicate to other birds that the pair is working together to defend their territory, so maybe if you hear it it’s time to put on the bike helmet with spikes.

This is what an Australian magpie sounds like:

[magpie call]

You can find Strange Animals Podcast online at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 131: Paleontological Mistakes

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Part of the scientific method involves making mistakes and correcting them. Here are some interesting and sometimes goofy mistakes made by paleontologists through the years, and how the mistakes were corrected.

Iguanodon did not actually look like this (left). It looked like this (right):

Pterosaur did not actually look like this (left). It looked like this (right):

Elasmosaurus did not actually look like this (left). It looked like this (right):

Apatosaurus/brontosaurus did not actually look like this (left). It looked like this (right):

Stegosaurus did not actually look like this (left). It looked like this (right):

Gastornis did not actually look like this (left). It looked like this (right):

Those are Gastornis’s footprints:

Show transcript:

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

Paleontology is the study of fossils, and really it’s only been a discipline for a little over a century. Back in the 19th and early 20th centuries, even experts made major mistakes in preparing and assembling fossil skeletons, and dishonest amateurs made deliberate errors so their fossil animals looked bigger or scarier. Many of these mistakes or hoaxes were displayed in museums, sometimes for decades.

I found so many interesting examples during my research that I decided to split the episode into two. This week we’ll learn about some paleontological mistakes and what the fossil animals really looked like when they were alive. Next week we’ll look at the frauds and hoaxes.

We’ll start with Iguanodon, a dinosaur that lived around 125 million years ago in what is now Europe. It ate plants and was fairly common, with a number of species now known to science. The biggest could grow as much as 43 feet long, or 13 meters. It had teeth that resemble an iguana’s, which is how it gets its name, and a beak probably covered in keratin that it used to clip through tough plants. It probably mostly walked on two legs and browsed from trees, but its front legs were long and it might have spent at least some of its time on all fours. But the most interesting thing about Iguanodon was its hands. Its little finger was slender and usually longer than the others and many researchers think it was used for handling food and other objects. The first finger, which is equivalent to a thumb, wasn’t so much a digit as just a big spike. It’s called a thumb spike and no one’s sure what it was for. It might have been used for defense, but it might also have been used to help dig up plants. Maybe it was used for both. But it was the source of an embarrassing mistake that many paleontologists made for years.

Iguanodon came to the attention of science in 1822 when a medical doctor in Sussex, England found some fossilized teeth. No one was sure what kind of animal the teeth belonged to, although guesses ranged from a crocodile to a rhinoceros. In 1824 the doctor, Gideon Mantell, noted the teeth’s resemblance to iguana teeth, but so big that he estimated Iguanodon must have been almost 60 feet long, or 18 meters. He also thought Iguanodon looked like an iguana.

In 1834 more Iguanodon fossils came to light in a quarry and Mantell bought them. This incomplete skeleton included a thumb spike, but Mantell didn’t know where it belonged. He thought it was a horn, so when he made a drawing of the living animal, he placed the thumb spike on the nose.

And there it stayed, despite other fossils found with the thumb spike in place on the hand, and despite other scientists pointing out that they didn’t think Iguanodon had a horn on its nose. It wasn’t until 1882 that the nose horn vanished for good and Iguanodon started looking more like itself.

Similarly, pterosaurs have been misunderstood since the very beginning, with a lot of frankly ridiculous suggestions made about them. To be fair, they are really strange animals and nothing like any animal living today. The first pterosaur was described in 1784 by an Italian naturalist, but he thought it was a swimming animal and that its wing bones were actually flippers. Zoologist Georges Cuvier pointed out it was a flying reptile in 1801, but the swimming hypothesis wasn’t abandoned for decades after that. Even after the flying part was accepted by other researchers and the general public, many people believed they were related to bats for a remarkably long time. In 1843 one scientist suggested pterosaurs were not only bats, but specifically marsupial bats. (There are no marsupial bats. Bats are placental mammals.) The notion that pterosaurs and bats were related hung around a really long time, right up to the 1930s, although experts had more or less figured it out by then.

Elasmosaurus lived around 80 million years ago and was a type of plesiosaur. We talked about Elasmosaurus in episode 92 about marine reptiles. It wasn’t a dinosaur but it lived at the same time as dinosaurs, and could grow up to 34 feet long, or over 10 meters. It had a very long neck containing 72 vertebrae, a short tail, and four paddle-like legs. These days we know that the neck wasn’t very flexible, but for a long time Elasmosaurus and its relatives were depicted with flexible, serpentine necks. But the real mistake came when it was first discovered.

The first Elasmosaurus fossil was found in Kansas in 1867 and given to Edward Cope, a well-known paleontologist who discovered many fossil species found in North America.

The problem was, Cope was the bitter rival of another well-known paleontologist, Othniel Marsh. The two men were so frantic to publish more descriptions of new animals than the other that it sometimes led to sloppy work. That may have been why, when Cope described Elasmosaurus in 1869, he placed its head at the end of its tail so that it looked like it had a short neck and a really long tail instead of the other way around. The bones were all jumbled together and the jaws had ended up at the wrong end of the skeleton when it was covered over with sediment and the fossilization process began.

Another paleontologist pointed out Cope’s mistake only a few months later. Cope tried to buy up all the copies of the article and reissued a corrected version. But Cope’s nemesis Marsh got hold of a copy of the original article and was absolutely gleeful. He never would let Cope forget his mistake, and in fact it was the final straw in the relationship between the two. Cope and Marsh had started out as friends but their friendship soured, and by 1870 they pretty much loathed each other.

But Marsh made his own mistakes. In 1877 he found a dinosaur he named Apatosaurus, although the specimen was missing a skull. He used the skull of a different dinosaur when he prepared the specimen. Then in 1885 his workers found a similar-looking skeleton with a skull. He named it Brontosaurus.

Guess what. They were the same animal. Marsh was so eager to describe a new dinosaur that Cope hadn’t described yet that he didn’t even notice. But for some reason the name Brontosaurus stuck in pop culture, which is why you probably know what a Brontosaurus was and what it looked like, while you may never have heard of Apatosaurus. The mistake has been corrected and the dinosaur’s official scientific name is Apatosaurus, but Marsh’s Apatosaurus skeleton from 1877 didn’t get the right skull until 1979. The skeleton had been on display with the wrong skull for almost a century, but researchers found the correct skull that had been unearthed in 1910 and stored away.

Apatosaurus lived in North America around 150 million years ago and was enormously long, growing on average 75 feet long from head to tail, or 23 meters. It ate plants, and some researchers suggest that it used its incredibly long tail as a whip to scare predators by cracking the whip and making a loud noise. This sounds absurd but the physiology of the tail’s end supports that it could probably withstand the pressures involved in a whip-crack. The neck was also quite long and researchers are still debating how flexible it was. The reason so much old artwork of Apatosaurus/Brontosaurus shows the animal standing in water eating swamp plants is because scientists used to think it was such a heavy animal that it couldn’t even support its own weight out of the water, much like whales. Not true, of course. It had strong, column-like leg bones that had no trouble supporting its weight on dry land, and it lived on what are referred to as fern savannas. Grass hadn’t yet evolved so the main groundcover was made up of ferns.

The name Brontosaurus has been retained for some Apatosaurus relations, fortunately, because it’s a pretty nifty name. It means thunder lizard.

Marsh is also responsible for the notion that some of the larger dinosaurs, specifically Stegosaurus, had a second brain at the base of their tails. This isn’t actually the case at all. Marsh just couldn’t figure out how such a large animal had such a small brain. Then again, Marsh also thought Stegosaurus’s tail spikes, or thagomizer, belonged on its back while its back plates belonged on its tail.

If you want to learn more about the Stegosaurus, check out episode 107 where we learn about it and Ankylosaurus. It’s too bad a paleontologist named Charles Gilmore couldn’t listen to that episode, because in 1914 he decided the back plates were osteoderms that lay flat on its skin. This was an early idea of Marsh’s that he had rejected early on but which Gilmore liked. Gilmore also thought the thagomizer spikes grew between the back plates so that the Stegosaurus was covered in both big plates like armor with spikes in between the plates.

A man named Henry Fairfield Osborn made a couple of mistakes too. He was the guy who named Oviraptor, which means “egg thief.” That was a reasonable assumption, really, since the first specimen was found in 1923 in a nest of Protoceratops eggs…but the Protoceratops eggs were later found to actually be Oviraptor eggs, and Oviraptor was just taking care of its own nest.

In 1922 Osborn was the president of the American Museum of Natural History when a rancher sent him a fossil tooth he’d found in Nebraska in 1917. Paleontologists often have to extrapolate an entire animal from a single fossil, and teeth are especially useful because they tell so much about an animal. So Osborn examined the tooth carefully and published a paper describing the ape that the tooth came from.

If you remember, though, there are no apes native to the Americas, just monkeys. The media found out about the discovery and wrote articles about the missing link between humans and apes, which was a popular topic back before people fully understood how evolution worked and when so little was known about human ancestry. The papers called the fossil ape the Nebraska man.

Then, a few years later, paleontologists went to Nebraska to find the rest of the fossilized ape bones. And while they did find them, they didn’t belong to an ape. The tooth came from a species of extinct peccary. You know, a type of pig relation. Peccaries do evidently have teeth that look a lot like human teeth, which is kind of creepy, plus the fossil tooth was badly weathered. Osborn retracted his identification in 1927.

All this wouldn’t have been a big deal except that people who didn’t believe evolution was real decided that this one relatively small mistake, quickly corrected, meant ALL scientists were ALL wrong FOREVER.

We’ll finish with a bird fossil, a bird you’ve probably never heard of although it’s massive. The first Gastornis fossil was found in the mid-19th century near Paris and described in 1855. More fossils were found soon after, and in the 1870s there were enough Gastornis bones that researchers were able to reconstruct what they thought it looked like, a gigantic crane. They were wrong.

Gastornis was as big as a big moa, over six and a half feet high, or 2 meters. It had a heavy beak and a powerful build that for over a century led many paleontologists to think it was a predator. But these days, we’re pretty sure it only ate tough plant material. Its bill could have crushed nuts but wasn’t the right shape to strip meat from bones, and a carbon isotope study of Gastornis bones indicate that its diet was entirely vegetarian.

Gastornis had vestigial wings that probably weren’t even visible under its body feathers. It was actually related most closely to modern waterfowl like ducks and geese. We have some fossilized Gastornis eggs and they were bigger than ostrich eggs, although they were shaped differently. They were oblong instead of ovoid, about ten inches long, or over 25 cm, but only four inches in diameter, or 10 cm. Only the elephant bird of Madagascar laid bigger eggs. We even have two fossil feather impressions that might be from Gastornis, and some fossil footprints in Washington state that show Gastornis had three toes with blunt claws. The bird went extinct around 40 million years ago.

At about the same time that Gastornis was being described in Europe as a kind of giant wading bird, our old friend Edward Cope found some bird fossils in New Mexico. He described the bird in 1876 as Diatryma gigantea and recognized that it was flightless. Cope’s deadly enemy Othniel Marsh also found a bird’s toe bone and described it as coming from a bird he named Barornis regens in 1894. As more and more fossils were found, however, it became clear that Cope’s and Marsh’s birds were from the same genus, so Barornis was renamed Diatryma.

By then, some paleontologists had already suggested that Diatryma and Gastornis were the same bird. In 1917 a nearly complete skeleton, including the skull, was discovered in Wyoming in the United States, but it didn’t really match up to the 1881 reconstruction of Gastornis.

But in the 1980s, researchers looked at that reconstruction more closely. It turned out that it contained a lot of mistakes. Some of the elements weren’t from birds at all but from fish and reptiles, and some of the broken fossil bones had been lengthened considerably when they were repaired with plaster. A paper published in 1992 highlighted these mistakes, and gradually the use of the term Diatryma was changed over to Gastornis.

So remember, everyone, don’t be afraid to make mistakes. That’s how you get better at things. And for the same reason, don’t make fun of other people who make mistakes. Other people get to learn stuff too. And even if you don’t think you’ve made a mistake, maybe double check to make sure you didn’t accidentally include a fish fossil in your extinct flightless bird reconstruction.

You can find Strange Animals Podcast online at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. 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 127: New World Vultures

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This week we’ll learn about some vultures from North and South America–some living, some extinct, and one mystery! Thanks to Maureen and Grady for their suggestions!

Thanks also to Kat White for the Turkey Vulture Song that opens the podcast! If you’d like to buy her album “In the Eye of the Owl,” visit her website at katwhitemusic.com/

Further listening:

CritterCast episode 35 Turkey Vultures

How to tell a turkey vulture apart from a black vulture:

The king vulture has a very bright head:

The Andean condor soaring:

The painted vulture:

Show transcript:

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

Way back in episode 40 we learned about the bearded vulture and some of its close relatives. This was a suggestion from Maureen, and I always meant to revisit vultures so we could learn about more vulture species. Then Grady wanted to know how long buzzards stay in the sky until they come down for food, and why do they soar for so long? That’s a great question that shows some good observation skills, so let’s go back to vultures and learn more about them.

Those of you listening in Europe may be wondering why I’m talking about buzzards in a vulture episode. That’s because we’re going to learn about new world vultures today, and in North America the general term for a vulture is a buzzard. In Europe, a buzzard is actually a type of eagle.

Before we get into the episode, though, I should mention that the intro music we heard is by Kat White, who was kind enough to let me use a snippet. It’s from the album “In the Eye of the Owl,” which is all about animals and so much fun I wanted to let everyone know about it. I’ll put a link in the show notes so you can find out more about the songs.

Kat also let me know about a turkey vulture named Lord Richard who lives in a park called Lindsay Wildlife Experience in California. Lord Richard just turned 45 years old and got a huge birthday party! So as you can see, vultures can live a long time in captivity, although usually not as long in the wild. Then again, the oldest verified vulture is an Andean condor born in captivity in 1930 who died in 2010 at the age of 79. Andean condors in the wild can live more than 50 years. This makes Lord Richard sound like a positive youngster.

New World vultures are native to the Americas and all of them are pretty big. In fact, condors are vultures and they’re extremely large birds. The New World vultures aren’t very closely related to each other but they all share some traits.

Vultures are scavengers that find dead animals to eat. The meat from dead animal carcasses is referred to as carrion. Vultures will also eat rotting fruit and garbage sometimes. Because they eat meat that is often spoiled, vultures have an extremely acidic digestive system that helps the bird digest its food quickly and kills off any bacteria that might make it sick. It also has beneficial bacteria in its digestive system that neutralize toxins.

But that’s not where the adaptations to eating carrion end. The vulture is a highly specialized bird. Most vultures don’t have many feathers on their heads, unlike other birds. If you’re snacking right now, you might want to pause this until you’re done. Quite often a vulture will actually stick its head into a rotting animal carcass to get at the, uh, softer parts. This means its head gets covered in rotting gunk and a lot of bacteria. If it had head feathers, they would be destroyed by bacteria.

One interesting thing about vultures of all kinds is that they actually help stop the spread of diseases like rabies and anthrax. Their digestive tract is so effective that it kills off viruses that caused the animal to die, so it’s actually beneficial to the environment in general and to farmers. Unfortunately, farmers don’t always know this and think vultures spread disease. Many vultures are protected species in most countries to stop farmers and other people from shooting them.

Quite often you’ll see a vulture perched somewhere up high with its wings spread. It does this to dry them when it’s been rainy or foggy, but also so that sunlight will help kill off any bacteria on the feathers. That’s another reason the vulture has no feathers on the head, so that sunlight can kill off any bacteria on its skin.

Vultures do some other gross stuff, like pee on their own legs. They do this to cool down in hot weather, since as the liquid droppings evaporate it cools the legs, and therefore cools the blood flowing through the legs, and therefore cools the vulture’s body temperature overall. But vultures also like to bathe in shallow water, which helps clean the skin and the feathers, and which of course washes any droppings off their legs.

Vultures also puke up what they’ve eaten if they feel threatened. This serves two purposes. The vulture is immediately much lighter and can fly away more easily, and the horrible stench of partially digested rotting meat may drive away a potential predator.

There are seven species of new world vulture alive today. The most common one is the turkey vulture, which lives throughout most of North and South America. The next most common is the American black vulture, which lives in South America up to the southern parts of North America. From a distance it can be hard to tell the two apart, but the black vulture has silvery tips on its wings.

The turkey vulture is the vulture most often referred to as a buzzard. It has a wingspan of about six feet, or over 1.8 meters, although it doesn’t weigh more than about five pounds at most, or 2.4 kg. It’s kind of a picky eater, surprisingly, and doesn’t like really rotten meat. It often hangs out with black vultures, but black vultures are more aggressive even though they’re a little smaller, and the turkey vulture will wait until the black vultures are done eating before it moves in to finish off what’s left.

Black vultures and turkey vultures aren’t very closely related and don’t really look very similar if you see them up close. The turkey vulture has a red head that looks a lot like a male turkey’s, which is where it gets its name. The black vulture has a gray head.

Unlike the turkey vulture, which almost exclusively eats carrion and rotting fruit and sometimes vegetables, the black vulture will also eat eggs and sometimes kills small animals, especially baby animals. It hunts in groups and can even kill newborn calves.

If you want to learn more about the turkey vulture, the Critter Cast Podcast has a really good episode all about it. I’ll put a link in the show notes in case you don’t already listen to Critter Cast.

The other new world vultures are mostly restricted to South America, except for the California condor. We’ll talk about condors in a minute. The king vulture is most common in South America although it also lives in parts of southern Mexico and in Central America. Unlike most vultures, which are mostly black, its feathers are mostly white with some gray and black markings. The skin of its bald head is brightly colored, with different individuals having different coloration—red, orange, yellow, purple, even blue, with an orange crest on its bill in adult birds. It also has a white eye with a red rim, and short bristles on the head. The ancient Maya people considered the king vulture a messenger of the gods, which is pretty neat.

The king vulture is big even for a vulture, with a wingspan of up to about 7 feet, or 2 meters, which makes sense since it’s most closely related to the Andean condor. It has a stronger bill than most vultures, which helps it tear open an animal carcass that other vulture species might not be able to access. Often, other vulture species will wait until a king vulture has opened a carcass and eaten its fill before they move in and eat too. It especially likes the skin and tougher meat of a carcass, and its tongue is raspy to help it pull meat off bones.

The king vulture’s ancestors lived farther north, into parts of North America, but went extinct around 2 ½ million years ago. We don’t really know all that much about the ancestors of the New World vultures, though, because they’re not very common in the fossil record. But the New World vultures are related to the terratorns, huge birds that are extinct now. We’ve discussed terratorns once before way back in episode 17, about the Thunderbird, but let’s discuss them again because they were incredible birds.

We have a decent number of terratorn remains from the La Brea Tar Pits and a few other places. The terratorns were bigger even than condors. A number of species lived throughout the Americas, with even the smaller species having an estimated wingspan of around 12 feet, or 3.8 meters. The largest species known, Argentavis magnificens, lived in South America around six million years ago. It’s estimated to have a wingspan of at least 20 feet, or 6 meters, and possibly as much as 26 feet, or 8 meters. That’s the size of a small aircraft.

Researchers think Argentavis was an efficient glider, hardly needing to flap its wings. But it wasn’t very maneuverable, so researchers also think it was probably a scavenger like modern vultures. Smaller terratorns may have been active hunters, more like eagles than vultures. Argentavis had strong legs and probably took off by running into the wind with its massive wings spread, sort of like an airplane taking off, so it didn’t have to flap its wings at all.

That brings us to Grady’s question about why and how buzzards soar for so long. Argentavis would have spent most of its time soaring, hardly ever needing to flap its wings. Its wings weren’t even very strong, and it might not even have been able to flap them when they were extended. The turkey vulture, or buzzard, is especially good at soaring for long periods of time, sometimes for hours, without needing to flap its wings.

If you’ve noticed, soaring birds like vultures, eagles, and hawks tend to fly in circles. There’s a reason for this. When the wind blows over a hill or mountain, it creates an updraft, a breeze that blows directly upward. Similarly, air rises from land that’s been warmed by the sun, causing columns of warm air called thermals. A soaring bird stays in these updrafts and thermals by flying in circles. Vultures also have wingtips where the feathers are spread out, so that each flight feather is separated from the next by a small space. Each of these feathers acts like a tiny wing of its own, which helps keep the vulture gliding forward and not downward. All this wind over the wingtip feathers causes a lot of pressure, though, and vultures have a special bone at the wingtip that helps strengthen and support the flight feathers. Soaring instead of flapping conserves a lot of energy, which is why vultures will soar for as long as they can, looking for food.

Most New World vultures have a good sense of smell, which is unusual for birds. The turkey vulture finds a lot of its food by smell. The black vulture doesn’t have nearly as good a sense of smell, though, and as a result it often follows turkey vultures to find carcasses, then bullies the turkey vultures out of the way to eat first. That’s not very nice, birds. In addition, the turkey vulture has keen eyesight, which helps it find dead animals that might not have started to smell yet.

So let’s talk about those condors now. There are two species of condor alive today, the California and the Andean. We covered the California condor in episode 44, extinct and back from the brink. The California condor actually went extinct in the wild in 1987, with only 22 birds alive in captivity, but an ongoing captive breeding program saved it from extinction and captive-bred birds started to be released into the wild in 1991. But there are still fewer than 500 individuals alive today, so it’s still in danger of extinction. The California condor only lives in a few small areas of western North America today, but around 40,000 years ago it lived throughout North America. Part of the reason it’s still so rare is that it reproduces very slowly. A pair doesn’t nest every year, and even when they do, the female only lays one egg. A young condor depends on its parents for a full year, both for food and to learn how to fly. It can take a young condor months to learn how to fly properly, and researchers sometimes observe awkward crash landings that are probably pretty funny, although maybe not so funny to the condor.

The California condor’s wingspan can be up to almost ten feet, or 3 meters. This is huge, but the Andean condor is even bigger. Its wingspan is nearly eleven feet, or 3.3 meters. The Andean condor lives in and near the Andes Mountains along the western coast of South America. It’s mostly black with silvery patches on the wings and a white ruff around the neck, and its head is gray in color but can flush reddish to communicate with other condors. The male also has a comb on the top of its head.

The Andean condor’s feet are adapted for walking, not fighting. Its feet aren’t very strong and its talons aren’t very sharp. It does sometimes kill small animals like rabbits, but its feet are so weak that it can’t use them to attack. Instead, it stabs the animal to death with its beak.

Like Argentavis, the Andean condor’s wings are built for soaring, not flapping. It can soar for hours without needing to flap its wings once, sometimes traveling hundreds of miles in a day to find food.

It’s a social bird that mates for life, and one of its courtship rituals is a hopping, flapping dance. Keep in mind that this is a bird with wings over five feet long. That would be a pretty impressive dance. The Andean condor nests high in the Andes Mountains on cliffs that predators can’t reach and lays one or two eggs.

Let’s go back to the king vulture now to finish up, because there’s a mystery associated with the king vulture. In the 1770s, a man named William Bartram traveled through Florida and took notes about the animals and plants he saw. He published a book of his travels in 1791 and in it, he included information about a bird he called a painted vulture. He said it was fairly common in Florida and that he’d even shot one himself. The description he gave sounds like a king vulture except that Bartram described its tail as white with a black tip, not entirely black.

But remember, the king vulture primarily lives in South America. It is known in the very southern parts of North America in Mexico, but not Florida. What’s going on?

Some people think Bartram included the painted vulture as a hoax. Some people think he got it mixed up with a different bird, the Northern caracara, a bird of prey which only looks slightly like a king vulture. Some people think there may have been a small population of king vultures in Florida at the time that later went extinct, possibly a subspecies of king vulture with a mostly white tail instead of all black.

Bartram wasn’t the only person who reported seeing the painted vulture. In 1734 an English naturalist and artist, Eleazar Albin, painted a vulture that looked almost identical to the one Bartram described 30-odd years later, tail and all. It’s not completely clear where Albin saw his bird, but as far as researchers can determine Bartram wasn’t aware of the painting. So it’s possible that a subspecies of king vulture once lived in Florida but went extinct soon after Bartram saw it. If he and Albin hadn’t documented it, no one alive today would have any idea the painted vulture ever existed.

You can find Strange Animals Podcast online at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. 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 124: Updates 2 and a new human

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It’s our second updates and corrections episode! Thanks to everyone who sent in corrections and suggestions for this one! It’s not as comprehensive as I’d have liked, but there’s lots of interesting stuff in here. Stick around to the end to learn about a new species of human recently discovered on the island of Luzon.

The triple-hybrid warbler:

Further reading:

New species of ancient human discovered in the Philippines: Homo luzonensis

Show transcript:

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

Yes, it’s our second updates episode, but don’t worry, it won’t be boring!

First, a few corrections. In episode 45 I talked about monotreme, marsupial, and placental mammals, and Tara points out that the placenta and bag of waters are different things. I got them mixed up in the episode. The bag of waters is also called the amniotic sac, which protects and cushions the growing baby inside with special amniotic fluid. The placenta is an organ attached to the lining of the womb, with the bag of waters inside the placenta. The umbilical cord connects the baby to the placenta, which supplies it with all its needs, including oxygen since obviously it can’t breathe yet.

Next, I covered this correction in in episode 111 too, but Judith points out that the picture I had in episode 93 of the Queen Alexandra’s birdwing butterfly was actually of an atlas moth. I’ve corrected the picture and if you want to learn more about the atlas moth, you can listen to episode 111.

Next, Pranav pointed out that in the last updates episode I said that the only bears from Africa went extinct around 3 million years ago–but the Atlas bear survived in Africa until the late 19th century. The Atlas bear was a subspecies of brown bear that lived in the Atlas Mountains in northern Africa, and I totally can’t believe I missed that when I was researching the nandi bear last year!

Finally, ever since episode 66 people have been emailing me about Tyrannosaurus rex, specifically my claim that it was the biggest land carnivore ever. I don’t remember where I found that information but it may or may not be the case, depending on how you’re defining biggest. Biggest could mean heaviest, tallest, longest, or some combination of features pertaining to size.

Then again, in 1991 a T rex was discovered in Canada, but it was so big and heavy and in such hard stone that it took decades to excavate and prepare so that it can be studied. And it turns out to be the biggest T rex ever found. It’s also a remarkably complete fossil, with over 70% of its skeleton remaining.

The T rex is nicknamed Scotty and was discovered in Saskatchewan. It lived about 68 million years ago, and turns out to not only be the biggest T rex found so far, it was probably the oldest. Paleontologists estimate it was over 30 years old when it died. It was 43 feet long, or 13 meters. This makes it bigger than the previously largest T rex found, Sue, who was 40 feet long, or 12.3 meters. Scotty also appears to be the heaviest of all the T rexes found, although estimates of its weight vary a lot. Of course some researchers debate Scotty’s size, since obviously it’s impossible to really know how big or heavy a living dinosaur was by just looking at its fossils. But Scotty was definitely at least a little bigger than Sue.

Scotty is on display at the Royal Saskatchewan Museum in Canada.

Way back in episode 12, I talked about snakes that were supposed to make noises of one kind or another. Many snakes do make sounds, but overall they’re usually very quiet animals. A snake called the bushmaster viper that lives in parts of Central America has long been rumored to sing like a bird. The bushmaster can grow up to ten feet long, or 3 meters, and its venom can be deadly to humans.

Recently, researchers discovered the source of the bushmaster’s supposed song. It’s not a snake singing. It’s not a bird singing. It’s not even a single animal–it’s two, both of them tree frogs. One of the frogs is new to science, the other is a little-known frog related to the new one.

I tried so hard to find audio of this frog, and I’m very bitter to report that I had no luck. The closest I could find was not great audio of this frog, whose name I forgot to write down, which I think is related to the new frogs.

[frog sound]

Now let’s do some quick, short updates, mostly from recent articles I’ve happened across while researching other things.

A triple-hybrid warbler, its mother a golden-winged/blue-winged hybrid (also called a Brewster’s warbler) and its father a warbler from a different genus, chestnut-sided, was sighted in May of 2018 by a birder in Pennsylvania. Lowell Burket noticed it had characteristics of both a blue-winged and a golden-winged warbler but sang like a chestnut-sided warbler. He contacted the Cornell Evolutionary Biology Lab about the bird with photos and video of it, and they sent a researcher, David Toews, out to look at it. Toews caught the bird, measured it, and took a blood sample for analysis. I think a listener told me about this article but I didn’t write down who, so thank you, mystery person.

Red-fronted lemurs chew on certain types of millipedes and rub the chewed-up millipedes on their tails and their butts. They also eat some of the millipedes. Researchers think the millipedes secrete a substance called benzoquinone, which acts as an insect repellant and may also help the lemurs get rid of intestinal parasites. Other animals rub crushed millipedes on their bodies for the same reasons.

A recent study of saber-toothed cat fossils show that many of the animals with injuries to their jaws and teeth that would have kept them from hunting properly survived on softer foods like meat and fat. Researchers think the injured cats were provided with food by other cats, which suggests they were social animals. The study examined micro-abrasions on the cats’ teeth that give researchers clues about what kinds of food the animals ate.

Simon sent me an article about a 228 million year old fossil turtle, Eorhynchochelys [ay-oh-rink-ah-keel-us]. It was definitely a turtle but it didn’t have a shell. Instead, its ribs were wide, which gave its body a turtle-like shape. Turtle shells actually evolved from widened ribs like these. Researchers are especially interested because Eorhynchochelys had a beak like modern turtles, while the other ancient turtle we know of had a partial shell but no beak. This gives researchers a better idea of how turtles evolved. Oh, and in case you were wondering, Eorhynchochelys grew over six feet long, or over 1.8 meters.

The elephant bird, featured in episode 51, was a giant flightless bird that lived in Madagascar. Recently new research about elephant birds has revealed some interesting information. For one thing, we now know what the biggest bird that ever lived was. It’s called Vorombe titan and grew nearly ten feet tall, or 3 meters, and weighed up to 1,800 lbs, or 800 kg. It was first discovered in 1894 but not recognized as its own species until 2018.

There’s also some evidence that at least some elephant bird species may have been nocturnal with extremely poor vision. This is the case with the kiwi bird, which is related to the elephant bird. Brain reconstruction studies of two species of elephant bird reveal that the part of its brain that processed vision was very small. It resembles the kiwi’s brain, in fact. One of the species studied had a larger area of the brain that processed smell, which researchers hypothesize may mean it lived in forested areas.

Another study of the elephant bird bones show evidence that the birds were killed and eaten by humans. But the bones date to more than 10,000 years ago. Humans supposedly didn’t live in Madagascar until 4,000 years ago at the earliest. So not only is there now evidence that people colonized the island 6,000 years earlier than previously thought, researchers now want to find out why elephant birds and humans coexisted on the island for some 9,000 years before the elephant bird went extinct. Hopefully archaeologists can uncover more information about the earliest people to arrive on Madagascar, which may help us learn more about how they interacted with the elephant bird and other extinct animals of the island.

Speaking of humans, humans evolved in Africa and until very recently, evolutionarily speaking, that’s where we all lived. Scientists rely on fossils, archaeological materials, and studies of ancient DNA to determine when and where humans spread beyond Africa. But at the moment, the DNA that researchers have studied doesn’t overlap entirely with what we’ve learned from the other sources. Basically this means that there are big chunks of data we still need to find to get a better picture of where our ancestors traveled. Part of the problem is that DNA preserves best in cold, dry areas, so most of the viable DNA recovered is from middle Eurasia. Fortunately, DNA technology is becoming more and more refined every year.

This brings us to a suggestion by Nicholas, who told me about a newly discovered hominin called Homo luzonensis. Homo luzonensis lived on an island called Luzon in the Philippines at least 50,000 years ago. It wasn’t a direct ancestor to Homo sapiens but was one of our cousins, although we don’t know yet how closely related.

No one thought humans could reach the island of Luzon until relatively recent times, because of how remote it is and because it hadn’t been connected to the mainland for the last 2 ½ million years. But when Homo floresiensis was discovered in 2004 on the island of Flores in Indonesia, which you may remember from episode 26, suddenly scientists got interested in other islands. Researchers knew there had been human settlements on Luzon 25,000 years ago, but no one had bothered to search for older settlements. In 2007 a team of paleoanthropologists returned to the island and found a foot bone that looked human. In 2011 and 2015 the team found some teeth and more bones from at least three different individuals.

We don’t know a whole lot about the Luzon humans yet. The discoveries are still too new. The Luzon hominins have a combination of features that are unique, a mixture of traits that appear more modern and traits that are seen in more ancient hominins. They’re also smaller in stature than modern humans, closer to the size of the Flores people. Homo luzonensis apparently used stone tools since researchers have found animal bones that show cut marks from butchering.

Researchers are starting to put together a picture of South Asia in ancient times, 50,000 years ago and more, and it’s becoming clear that there were a surprising number of hominins in the area. It’s also becoming clear that hominins lived in the area a lot longer ago than we thought. Researchers have found stone tools on the island of Sulawesi that date back at least 118,000 years. Even on Luzon, in 2018 researchers found stone tools and rhinoceros bones with butcher marks that date back over 700,000 years ago. We don’t know who those people were or if they were the ancestors of the Luzon people. We just know that they liked to eat rhino meat, which is one data point.

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 121: Cave Dwelling Animals

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This week let’s learn about some animals that live in caves!

The dipluran Haplocampa:

Oilbirds and their big black eyes:

A swiftlet:

The angel cave fish that can walk on its fins like a salamander walks on its feet:

Leptodirus, carrying around some air in its abdomen in case it needs some air:

The cave robber spider and its teeny hooked feet:

The devils hole pupfish:

Show transcript:

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

Way back in episode 27 we learned about some animals that live deep in caves. Cave dwelling animals are always interesting because of the way they’ve adapted to an unusual environment, so let’s learn about some of them!

We’ll start with an invertebrate. Diplurans are common animals that are related to insects but aren’t insects. They live all over the world, with hundreds of species known to science, but most people have never seen one because of where they live. They like moist, dark areas like soil, dead leaves, and caves. They’re also small, usually only a few millimeters long, although a few species grow larger, up to two inches long, or five cm.

Diplurans have long bodies with a number of segments, six legs, long antennae, and a pair of tail appendages called cerci. Depending on the species, the cerci may just be a pair of straight filaments like an extra pair of antennae, or they may look like pincers. Diplurans with pincer-like cerci use them to help capture prey, while ones with antennae-like cerci eat fungi and plant material.

Diplurans also don’t have eyes. They don’t need eyes because they live underground where there’s little or no light. A lot of species are pale in color or lack pigment completely.

Diplurans have been around for something like 350 million years, although we don’t have very many fossil diplurans. But recently, a new species of dipluran was discovered in North America that has raised some interesting questions.

Vancouver Island is a large island on the west coast of Canada, near the city of Vancouver. It’s prone to earthquakes and contains a lot of caves, and last summer, in June of 2018, a party of cavers and scientists explored two of the caves and found a new dipluran, which has been named Haplocampa wagnelli. This dipluran is chunkier than most other known diplurans, with shorter antennae, which researchers think points to a more primitive body plan. Since the dipluran is so different from most other diplurans known, and because the caves where it was found were under a thick ice sheet until around 18,000 years ago, researchers are trying to figure out if it found its way into the caves after the ice sheet melted or if it survived in the caves while they were buried under ice.

Haplocampa seems to be most closely related to a few diplurans found in Asia. Asia was connected to western North America during the Pleistocene when sea levels were much lower, since so much of the world’s water was frozen, so it’s possible the ancestors of Haplocampa migrated from Asia after the ice sheets started to melt but before the Bering Land Bridge was completely submerged. Possibly its eggs were accidentally transported by birds who foraged in leaf litter where its ancestor lived.

A lot of animals that live in caves are only found in one particular cave system. This happens when a species of animal that lives near a cave moves into the cave, either full-time or part-time. As its descendants grow up, they become more and more adapted to cave life, until eventually they couldn’t live outside of the cave. Since there’s no way for them to travel from one cave system to another, they are confined to that single cave. And since caves are largely difficult for humans to explore, that means there are lots and lots and lots of animals unknown to science living out their quiet lives deep within caves where humans have never visited. Every so often a group of adventurous and brave scientists explore a cave and discover new animals, usually with the help of experienced cavers.

Animals that are endemic to a specific cave system are rare to start with and vulnerable to any changes in the cave environment. The Tumbling Creek cave snail is only found in a single stream in Tumbling Creek Cave in Missouri, in the United States. It lives its whole life in the water and is only about 2 millimeters in size, with a pale yellowish shell. When it was first discovered in 1971 it was common. Thirty years later, researchers could only find about forty of the snails due to water pollution.

Caves aren’t very friendly environments. Most of the animals that live in caves are very small as a result. Lots of insects and spiders live in caves, some snails, lots of fish, lots of crustaceans that live in fresh water, like crawdads and amphipods, and some salamanders. But the only mammals and birds that live in caves leave the cave to hunt or forage outside of it, like bats. There just isn’t enough food inside a typical cave to sustain a population of larger animals.

So what do cave animals eat? Obviously they eat each other, but without plants a cave system is definitely lacking in organic matter that can sustain populations of animals. Nutrients enter a cave primarily in two ways. Water flowing into a cave brings nutrients from outside, and animals that mainly live outside but sleep in caves also bring nutrients in. In the case of animals, their poop is a major source of organic material, with dead animals also contributing to the cave’s ecosystem. Bats in particular support a lot of cave animals with their poop, which is called guano, but bears, hyenas, and various other animals, birds, and insects also spend time in caves, either to sleep or to hibernate, and bring nutrients in from outside in one way or another.

There are two birds that spend time in caves, and I’m going to talk about both of them briefly even though technically they don’t live in caves, because they’re so interesting. Both birds are nocturnal and can echolocate like bats. The oilbird lives in parts of northern South America and is related to nightjars. I have a whole episode planned about nightjars and their relatives, but the oilbird is the only one that echolocates (as far as we know). The other bird that echolocates is the swiftlet.

The oilbird nests in caves and also roosts in caves during the day, then flies out at night and eats fruit. Some oilbirds roost in trees during the day instead. Its wings have evolved to allow it to hover and to navigate through tight areas, which helps it fly through caves. It sees well in darkness, with eyes that are arranged more like those of deep-sea fish rather than typical bird eyes.

Several species of swiflet echolocate. These are the birds that make their nests from saliva, and which humans gather to make bird’s nest soup from. They mostly live in Asia. They nest in caves and roost in caves at night, then fly out during the day to catch insects.

Researchers don’t know a lot yet about either bird’s echolocation. It’s audible to human ears, unlike most bat echolocating, and some researchers think it’s less sophisticated than bats’. It’s always possible there are other birds that echolocate, but we don’t know about them yet because maybe we can’t hear their echolocating.

This is what oilbirds sound like. The clicking noises are the echolocation calls.

[oilbird calls]

Cave fish are especially interesting. There isn’t one kind of cave fish but hundreds, mostly evolved from ordinary fish species that ended up in a cave’s water system and stayed. Sometimes the species of fish that gave rise to cave fish are still around, living outside the cave, but most cave fish species have evolved so much that they’re no longer very closely related to their outside ancestors.

Cave fish are considered extremophiles and they tend to have similar characteristics. They usually have no pigment, no scales, and often have no eyes at all, or tiny eyes that no longer function. They’re usually only a few inches long, or maybe 10 cm, and have low metabolic rates. They typically eat anything they can find.

Some cave fish have evolved in unusual ways to better fit their specific habitats. The cave angel fish lives in a single large cave system in Thailand, in fast-moving water. It’s about an inch long, or not quite 3 cm, and gets its name from its four broad fins, which look feathery like angel wings.

It was discovered in 1985 but it wasn’t until 2016 that researchers verified a persistent rumor about the fish, which is that it can WALK on its fins. It has a robust pelvis and vertebral column, and strong fin muscles that allow it to climb rocks to navigate waterfalls.

Other fish navigate waterfalls and other obstacles by squirming and wriggling, using their fins to push them along. But the cave angel fish walks like a salamander. Scientists are studying the way it walks to learn more about how the ancestors of four-legged animals evolved.

The largest cave dwelling animal is the blind cave eel, which grows up to 16 inches long, or 40 cm, although it’s very slender. Since it appears pink due to a lack of pigment in its skin and it has no eyes or fins, it looks a lot like a really long worm. But it’s actually a fish. Not much is known about it, but it’s widespread throughout western Australia and is sometimes found in wells. It lives in caves or underground waterways that are connected to the ocean.

The first insect that was recognized as living only in caves is a beetle called Leptodirus hochenwartii. It was discovered in 1831 deep in a cave in Slovenia, and researchers of the time found it so intriguing that they invented a whole new discipline to study it and other cave animals, known as biospeleology.

Leptodirus has some interesting adaptations to cave living. It has no wings and no eyes, its antennae and legs are long, but the real surprise is its body. Its head is small and the thorax, the middle section of an insect, is slender. But the abdomen is relatively large and round, and the insect uses it to store moist air. Caves tend to be humid environments and Leptodirus has evolved to need plenty of moisture in the air it breathes. But some parts of a cave can be dry, so not only does Leptodirus keep a supply of breathable air in its abdomen, its antennae can sense humidity levels with a receptor called the Hamann organ.

Some spiders live in caves and like other cave dwellers, they’ve evolved to look strange compared to ordinary spiders. The cave robber spider was only discovered in 2010 in a few caves in Oregon. Researchers suspect there are more species of cave robber spider in other cave systems that haven’t been explored yet by scientists.

The cave robber spider is so different from other spiders that it’s been placed in its own family, Trogloraptoridae, which means cave robber. It has hook-like claws on the ends of its legs which it probably uses to capture prey. It spins small, simple webs on the roofs of caves and researchers think it probably hangs upside down from its web and grabs its prey as it passes by. But since no one knows what the cave robber spider eats, it’s anyone’s guess. Researchers have even tried raising the spider in captivity to learn more about it, but it wouldn’t eat any of the insects or other small invertebrates it was offered as food. It starved to death without ever eating anything, so it’s possible it only eats specific prey. It’s a yellowish-brown spider with two rows of teeth, called serrula in spiders, which researchers say is unique among spiders.

It’s also pretty big for a cave dweller. Its body is up to 10 millimeters long, or about a third of an inch, and it has a legspan of about 3 inches, or 7.6 cm. But it’s very shy and rare, and of course it’s not going to hurt you. It literally wouldn’t even hurt a fly to keep itself from starving.

One of the scientists who discovered the spider and is studying it, Charles Griswold, points out that there are stories in the area of giant spiders living in caves. He suggests the cave robber spider might be the source of the stories, since a three inch spider looks much bigger when it’s hanging down from the roof of a cave right in your face, with hooked claws.

Let’s finish with a remarkable cave fish known as the devil’s hole pupfish. Devil’s hole is a geothermal pool inside a cavern in the Amargosa Desert in Nevada, which is in the southwestern United States. It’s not far from Death Valley. The cavern is more than 500 feet deep, or 150 meters, with water that stays at about 92 degrees Fahrenheit, or 33 degrees Celsius. There’s a single small opening into the cavern at the surface, which geologists estimate opened about 60,000 years ago. The cavern and cave system are more than half a million years old.

The geothermal pool is home to the devils hole pupfish, which is barely an inch long, or 25 millimeters, and looks pretty ordinary. It mostly stays around the opening to the surface, where there’s a limestone shelf just below the water’s surface that measures about 6 ½ by 13 feet, or 2 by 4 meters. While the pupfish does swim deeper into the cavern at times, it mostly eats algae that live on and around the shelf, and tiny animals that live within the algae. It also depends on the shelf for laying eggs and spawning.

So the shelf is really important. But it’s also really small and close to the surface. It can only support so many pupfish, so the average devil’s hole pupfish population is about 200 or 300 fish, although this fluctuates naturally depending on many factors. In the 1960s, a farming corporation drilled wells in the area and pumped water out for irrigation, and the water in devil’s hole started to drop and drop. Devil’s hole is part of Death Valley National Monument, and conservationists were well aware of how fragile the pupfish’s environment was. As the water level dropped, threatening to expose the limestone shelf that the pupfish depended on for their entire lives, conservation groups sued to stop the pumping of groundwater in the area. After a series of court cases that went all the way up to the Supreme Court, the water rights were acknowledged to be part of the national monument status. Pumping of groundwater was limited and the pupfish was saved.

The water level in devil’s hole is monitored daily, which has led to a lot of information about how the water is affected by seismic events. Earthquakes as far away as Alaska, Japan, and South America have all affected the water level.

Researchers aren’t sure how long the pupfish have lived in devil’s hole. Some researchers think they’ve been there for 20,000 years, others think it’s more like a few hundred. Researchers aren’t sure how such a small population of fish has stayed healthy for so long, since such a restricted number of individuals should be so inbred they’re no longer viable. The most recent genetic analysis of the pupfish suggests they became isolated from other pupfish species in the area less than a thousand years ago. But if that’s the case, no one’s sure how they got into devil’s hole in the first place. Flooding of the area hasn’t happened in the last thousand years.

Because the pupfish’s habitat is so fragile, the U.S. Fish and Wildlife Service has moved some of the fish into captive populations that mimic the fish’s original habitat. It’s nice to think that these tiny silvery-blue fish with big eyes have so many people working to keep them safe.

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 120: Hybrid Animals

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If you’re a subscriber on Patreon, you may recognize some of the information in this episode, but I’ve updated it and added a whole bunch. Thanks to Pranav for the topic suggestion!

A cama, llama/camel hybrid:

A swoose, swan/goose hybrid:

Motty the Asian/African elephant hybrid and his mother:

A zorse, zebra/horse hybrid:

Show transcript:

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

This week we’ve got another listener suggestion. Pranav really really wants me to do an episode about hybrid animals, but I’ve been dragging my feet on it because I actually already did an episode on the topic back in 2017—but only for Patreon subscribers. It wasn’t my best episode so for various reasons I’d decided not to unlock it. But Pranav really really wants to learn about hybrids! So I’ve taken part of the Patreon episode and added a lot of newer information to it to bring it up to date and make it more interesting.

The term for an animal with parents of different species is hybrid. Crossbreed is also a common term, although technically a crossbred animal is one with parents of the same species but different breeds, like a labradoodle is a crossbreed of a Labrador and a poodle. Both parents are domestic dogs.

A mule, on the other hand, is a hybrid between a horse and a donkey, specifically a mare and a jack, which is what a male donkey is called. The offspring of a stallion and a lady donkey, known as a jenny, is a hinny.

So why can a horse and a donkey breed while, for instance, a possum and a rat can’t? The two species must belong to the same family, and with very few exceptions, they must also belong to the same genus. The genus is indicated in an animal’s scientific name. Equus caballus is a horse and Equus africanus is a donkey, while a Labrador and a poodle are both Canis familiaris, or Canis lupus familiaris depending on who you ask. The Virginia opossum is Didelphis virginiana while the brown rat is Rattus norvegicus. They’re not even slightly related, although superficially they look alike.

If the hybrid’s parents are from species with different numbers of chromosomes, hybrid males will almost always be sterile. You can’t cross two mules to get more mules, for instance, because male mules can’t make babies. Female mules are sometimes fertile but very rarely conceive. Horses have 64 chromosomes while donkeys have 62. Mules end up with 63. Hinnies are much rarer than mules because if the female of a pair of related species has fewer pairs of chromosomes than the male, it’s less likely that any offspring will result.

More closely related species can have fertile offspring. Killer bees, for instance, are hybrids of a European honeybee and an African honeybee. The two are actually subspecies of the honeybee, Apis mellifera, so it’s less like creating a hybrid and more like crossing a Labrador and a poodle to get an adorable happy pup with curly hair. It seemed like a really good idea. The result was supposed to be a tropical bee that would produce more honey. What actually happened was killer bees. Which do actually kill people. Hundreds of people, in fact, since they escaped into the wild in 1957 and started spreading throughout the Americas.

When animals hybridize even though they aren’t of the same genus, it’s called an intergeneric hybrid. That’s the case with sheep and goats. While sheep and goats are related on the subfamily level, they belong to separate genuses. Sheep have 54 chromosomes while goats have 60. That’s enough of a difference that most hybrid babies don’t survive long enough to be born alive, but it does happen occasionally. Usually the babies have 57 chromosomes, and sometimes the babies survive and even prove to be fertile when crossed with either a goat or a sheep. So that’s weird.

Just because someone wants to find out what you get when you cross, say, a sheep and a goat, doesn’t mean the sheep and goat in question are willing to make that effort. The less closely related the two animals are, the less interested they are in mating. Occasionally hybrids are produced by artificial insemination, or rarely by genetic manipulation of embryos, although genetic manipulation technically results in a chimera, not a hybrid.

Another intergeneric hybrid is a cross between a male camel and a female llama. In this case it’s accomplished by artificial insemination and has only produced a handful of living babies, called camas. Researchers were hoping to produce a camel-sized animal with a llama’s more cooperative temperament, but camas turn out to act like camels. So basically they’re just camels that aren’t as big or strong as camels.

In the 1970s, Chester Zoo in Cheshire in the UK kept a female Asian elephant and a male African elephant together in the same enclosure. The pair mated but no one thought they could produce a hybrid calf, since Asian elephants and African elephants aren’t that closely related. They’re another pair of animals that don’t share a genus. But a calf named Mottie was born in 1978. Surprise!

Many hybrids resemble one or the other of their parents. Motty was a fascinating blend of both. He had five toenails on his forefeet and four on the hind feet like his mom. African savannah elephants like his dad have four front toenails and three hind toenails. But he had longer legs and bigger ears than an Asian elephant. His trunk was wrinkled like his dad’s, but had only one digit at the tip like his mom’s. African elephants have two digits at the tip of their trunks. Even the shape of Motty’s head and back were a mixture of his parents’ characteristics.

So why would anyone want to cross species to get a hybrid? I mean, you might end up with killer bees.

A lot of times hybrids show what is known as hybrid vigor. This is more common in hybrid plants, but some hybrid animals combine the best features of their parents. Mules, for instance, have more stamina than horses and are stronger than donkeys. A hybrid of a domestic cow and an American bison is called a beefalo, which is bred to produce leaner meat in an animal that is better for the environment than a cow but easier to handle than a bison. But a lot of times, hybrids are the result of human ignorance, such as keeping related animals together without realizing babies might result, or human curiosity. We just want to see what might happen.

Unfortunately, for every healthy mule-like hybrid, there’s an unhealthy, malformed, or stillborn animal from parents who should have never produced offspring. Motty the elephant was premature and died of infection when he was only eleven days old, probably because his immune system was weakened due to his hybridized genetics.

Lions, tigers, leopards, and other big cats can all interbreed, but the resulting babies sometimes have unusual health issues. When a male lion and a female tiger breed, the resulting babies are known as ligers, and ligers are enormous. They’re much bigger and heavier than both their parents. This sounds neat, but it happens because of a genetic anomaly that means the animals just grow and grow much faster and longer than a normal tiger or lion cub. This puts stress on the body and can lead to health problems. Ligers can sometimes weigh over 1200 pounds, or over 550 kg, and grow up to 12 feet long, or 3.6 meters, bigger than a full-grown tiger or lion. The offspring of a puma and a leopard, often called a pumapard, has the opposite problem, with cubs usually inheriting a form of dwarfism. The cubs are only half the size of the parents.

The savannah cat is now accepted as a domestic cat breed by some organizations, but it was first developed in 1986 by crossing a female domestic cat and a male serval. The serval is a wild cat from Africa with large ears, long legs, and a spotted and striped coat pattern. It’s a little larger than a domestic cat and is sometimes kept as an exotic pet, although it’s not domesticated. The hybrid babies inherited their mother’s domesticated nature and turned out to be mostly sociable with humans, although some are less tame. But while Savannah cats are pretty, the kittens of a serval and domestic cat are often stillborn or premature, and many male offspring are infertile. Savannah cats are also prone to certain health issues, especially heart problems. Some areas have banned savannah cats since they’re not considered fully domesticated.

The more closely related the parents, the more likely a hybrid baby will result, and the more likely it will be healthy. Many wolf-like canids can and do easily hybridize with other wolf-like canids, since they have 78 chromosomes in the same arrangement and are closely related. Offspring are usually fertile. The wolf-like canids include wolves, domestic dogs, coyotes, jackals, and dholes. Where the ranges of these various species overlap in the wild, hybrids are not uncommon. But canids that are less closely related to the wolf-like canids, like foxes and raccoon dogs, can’t and don’t hybridize with their cousins.

Some whales will hybridize in the wild, including the fin whale and the blue whale, which are closely related. Dolphins of different species sometimes hybridize when they’re kept together in captivity, such as the false killer whale and the bottlenose dolphin. The resulting babies don’t usually live very long. Occasionally dolphins also hybridize in the wild too. In 2017 a hybrid baby of a rough-toothed dolphin and a melon-headed whale, which is actually a species of dolphin, was spotted off the coast of Hawaii. Researchers were able to get a small tissue sample from the young hybrid to DNA test, which confirmed its parentage. The melon-headed whale mother was also spotted with her calf in a pod of rough-toothed dolphins.

Birds also sometimes hybridize in the wild. This happens occasionally where the range of two closely related species overlap. Since the resulting babies may look very different from both their parents, this makes bird-watching even more challenging. Some warbler species hybridize so often that the hybrid offspring are well-known to birders, such as Brewster’s warbler and Lawrence’s warbler. These two birds are both offspring of a golden-winged warbler and a blue-winged warbler mate, with the appearance different depending on which traits the babies inherit from which parent.

Occasionally a domestic chicken will mate with a wild pheasant and produce babies, since chickens and pheasants are related. Very rarely, a swan and goose will mate and produce babies, although the babies don’t usually survive very long. One swan-goose hybrid that did survive was hatched in 2004 in Dorset in the UK, with a mute swan mother and a domestic goose father. The baby was referred to as a swoose and it was the only of the offspring to survive. It looks like a goose but with a longer, more swan-like neck and head.

If you’ve listened to episode 25, part one of the humans episode, you’ll recall that human DNA contains traces of DNA from our extinct cousins, including Neandertals. If Neandertals were still around, we could undoubtedly produce hybrids with them. But what about our living cousins, the other great apes? Humans are closely related to chimpanzees, but could a human produce a hybrid with a chimp? It’s possible but very unlikely. We belong to different genuses and have different numbers of chromosomes, not to mention the enormous ethical issues involved.

Let’s finish up with my favorite hybrid animal, the zebroid. This is a term for any hybrid where one parent is a zebra and the other parent is a horse, a donkey, or a pony, which also leads to the terms zorse, zedonk, and zony. These all crack me up, especially zedonk.

Zebroids are usually at least partially striped, frequently on the legs and neck but sometimes all over. The mane may stand up like a zebra’s or fall over the neck like a horse’s. The zebroid is adorable because of the stripes, but it’s also ornery and can be aggressive. There goes my dream of having a stripy horse.

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 118: The Hummingbird

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This week’s episode is about the world’s tiniest birds, the hummingbird! Thanks to Tara for the suggestion!

The bee hummingbird:

The giant hummingbird:

The giant giant hummingbird:

If you’re interested in my little side project, Real Life Cooking Podcast, here’s the URL (or you can just search for it in your regular podcast app): https://reallifecooking.blubrry.net/

Show transcript:

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

This week is another listener suggestion, this one from Tara! Tara’s favorite bird is the hummingbird, and I can’t believe I didn’t know that before she texted me, because I’ve known Tara for a long long time and in fact she is married to my brother. Tara, I hope you are ready for hummingbird-themed birthday gifts for the rest of your life!

The smallest birds in the world are hummingbirds, but not all hummingbirds are the smallest birds in the world. If that makes sense. The very smallest hummingbird, and definitely the smallest bird alive today and possibly alive ever, is the bee hummingbird.

The bee hummingbird is literally the size of a bee. Males are slightly smaller than females and barely grow more than two inches long, or 5.5 cm, from the tip of its long bill to the end of its tail. It weighs less than an ounce, or 2 grams. A penny weighs more than this bird does.

The bee hummingbird lives in Cuba and parts of the West Indies. Males are iridescent green and blue while females are more green and gray. During the breeding season, in spring and early summer, males also have red or pink spots on the head and throat.

Just like other birds, the bee hummingbird builds a nest and lays one or two eggs. The female takes care of the eggs and babies by herself. But her nest is so incredibly small! It’s barely an inch across, or 2.5 cm, lined with soft items like dandelion fluff and cobwebs. And the bee hummingbird’s eggs are the size of peas. I have some peas in my lunch today. Peas are really small. Can you imagine the smallness of an egg the size of a pea, and the smallness of the baby that hatches from the egg? I just died. I literally just died because it’s so cute and tiny I can’t stand it. Don’t worry, I came back to life to finish telling you about hummingbirds.

The largest hummingbird is called the giant hummingbird. It’s just over 9 inches long, or 23 cm, which sounds enormous, especially compared to the bee hummingbird. But keep in mind that its long bill is included in that length, so if you go by actual body size it’s only about the size of a sparrow. It has relatively long, pointed wings and sometimes actually glides instead of flapping its wings, which is practically unheard-of among hummingbirds. The giant hummingbird lives in the Andes Mountains in western South America, with some populations even living in high altitudes where the air is thinner. You know the so-called Nazca lines, the giant geoglyphs created by the ancient Nazca people that are shaped like animals? One of the geoglyphs is a hummingbird that’s 305 feet long, or 93 meters. It’s based on the giant hummingbird that lives in the area, so I guess you could say it’s a GIANT giant hummingbird.

*rimshot!* [it’s actually called a sting, and I played this one myself. Years of drum lessons have finally paid off!]

All hummingbirds are specialized to eat nectar from flowers. A hummingbird has a long, slender bill that can reach down into a flower to get at the nectar. In the process, the hummingbird gets pollen on its feathers that it then transfers to the next flowers it visits, helping pollinate the flowers. So the hummingbird gets a good meal and the flowers get pollinated, so everyone wins. Some hummingbird species have co-evolved with certain plant species so that only the bird can reach the nectar and only the bird can pollinate the flowers.

But the hummingbird’s bill isn’t a straw. It can open its bill just like other birds, and in fact hummingbirds eat a lot of tiny insects they find while foraging for nectar. They need to eat insects because while nectar provides a ton of energy, since it’s mostly just sugar, it doesn’t supply many nutrients. The upper part of the bill is much longer than the lower part, and the lower bill actually fits tightly inside the upper bill. That’s why it looks like a hummingbird’s bill is a tiny needle-like tube, since even if the bird has its mouth open it’s hard to tell.

A hummingbird actually uses its tongue to lap up nectar. The hummingbird’s tongue is extremely long, up to twice the length of the bill, and has a forked end. The tongue also contains grooves. When a hummingbird puts its bill into a flower, it sticks its tongue out and laps up the nectar rapidly, something like 13 licks a second. The nectar travels up the grooves into the bird’s mouth.

If you were wondering, a mother hummingbird feeds her babies nectar and tiny insects. Also, the reason hummingbirds use so much spiderweb silk in their nests is because it will expand as the babies grow. I’m sorry, I just died again. Give me a second to stop dying of cute. A baby hummingbird grows quickly and some species learn to fly at only two weeks old, although the mother bird continues to feed the babies for a little longer.

Hummingbirds move fast, which is why they need all that energy from nectar. Their energy needs are incredibly high. When a hummingbird flies, its metabolic rate increases to the highest ever measured in an animal that’s not an insect. Its heart can beat over 1,200 times per minute and it may breathe 250 times per minute. At night, or if there’s not a lot of food around, the hummingbird’s metabolism slows dramatically and the bird enters a state called torpor. Its body temperature falls, its heartrate can drop to only 50 beats per minute—which is on the slow side for a human—and its breathing rate drops too. Torpor is basically a very short hibernation where the bird will sleep deeply until morning or until it needs to go out and find more food. Even so, a hummingbird can lose up to 10% of its body weight overnight as its body burns fat reserves to keep it alive.

So that makes it all the more amazing that some species of hummingbird migrate long distances, including over the ocean. All hummingbird species are native to the Americas, but many species that spend the summer in North America migrate south to spend winter in Central America or Mexico. Some species in South America migrate north to winter in warmer areas too. The rufous hummingbird migrates from Alaska to Mexico, about 3,900 miles, or almost 6,300 km, and then it migrates back up the western coast of North America in spring.

The hummingbird doesn’t fly like other birds. It flaps its wings in a figure 8 motion that provides lift, which allows it to hover. Its wings beat incredibly quickly, up to 80 times a second. Even the slowest-moving hummingbird, the giant hummingbird, beats its wings 12 times a second. I don’t know about you, but I’m pretty sure I can’t do anything 12 times a second except maybe flutter my eyelashes, and even then my eyelids would get tired after a few seconds. Also, that’s not going to help me fly. Not even if I wear really long false eyelashes.

The hummingbird gets its name from the humming sound its wings make as they beat so incredibly fast. But the hummingbird’s feathers also make other sounds as the bird flies. In some species of hummingbird, the male grows special feathers that vibrate as he flies and make a whistling or chirping sound. This helps females find a male and helps the male defend his territory by announcing his presence to other males.

Oh, you didn’t know hummingbirds were territorial? They sure are. They may be tiny and pretty, but they’re fierce too. A male will chase other males away from his flowers, even stabbing other males with his long bill.

My aunt likes to tell a story of a cat she had years and years ago who liked to go into her garden and lie in the sun. One day the cat leaped at what my aunt thought was a bee. The cat stopped with a startled look on his face and opened his mouth. A hummingbird backed up out of the cat’s mouth and flew away and the cat never bothered a bird or a bee again, since the hummingbird’s beak had stabbed him in the back of the throat.

Needless to say, the hummingbird is the only bird that can fly backwards.

It’s one thing to think, “Oh, hummingbirds are so small” but it’s another thing to see a hummingbird in the wild and really understand how small they are. When I’m out birdwatching I almost always mistake hummingbirds for bees when I first see one. The hummingbird is so small, in fact, that it’s eaten by some larger insects, like the preying mantis, and by larger spiders. Anything that will eat an insect will eat a hummingbird, and that includes some other birds.

Fortunately, the hummingbird is so fast that it can usually get away from predators. It can fly up to 30 mph, or 48 km per hour. Its tail feathers also come out easily and grow back quickly, so anything that grabs it by the tail is probably just going to end up with a few feathers to eat.

The hummingbird flies so quickly through dense vegetation that its brain processes images in a different way from other birds so it doesn’t run into things. It has excellent vision, too, since it finds flowers by sight.

You can attract hummingbirds to your garden by planting flowers they like, such as bee balm, hollyhocks, petunias, trumpet vine, and lots more. You can also put out hummingbird feeders that you fill with imitation nectar. It’s important to keep the feeders cleaned, since the nectar will spoil after a while, mold will grow inside the feeder, and insects may get into the nectar and drown. Also make sure to hang the feeder where the birds will be safe from predators like cats and snakes.

Some of you may have heard that I’ve started a little side project, another podcast called Real Life Cooking where I share recipes and explain how to make them. So as a sort of crossover event, I’ll give you a recipe for making hummingbird nectar.

You don’t need anything expensive, just plain tapwater and plain white sugar. Use one part sugar to four parts water. So if you use one cup of water, add ¼ c sugar. Put them together in a small pot on the stove and heat the water, stirring occasionally, until the water is boiling. Let it boil for about a minute, then remove it from the heat and let it cool to room temperature. Once it’s cool, you can pour it into your hummingbird feeder. Don’t add red food coloring or any kind of flavoring, and don’t use any sugar except regular white sugar. Brown sugar and natural-colored sugars can contain iron, which is toxic to hummingbirds. If the feeder you use isn’t attracting hummingbirds, you can tie a red ribbon around it to make hummingbirds notice it. Make sure to change out the nectar every couple of days so it won’t go bad.

Sugar-water sounds like a horrible thing to feed a wild animal, but it’s exactly what hummingbirds need and what they eat naturally.

Hummingbirds are such unusual birds that it’s hard to imagine what they’re related to. There are birds that resemble hummingbirds in some ways, especially the sunbird that lives in Africa, parts of Asia, and Australia. But the hummingbird and the sunbird aren’t related. They just share a very specific ecological niche, which has resulted in similarities due to convergent evolution.

No, the hummingbird is most closely related to the swift! Not closely related, of course, because the two started evolving separately as much as 42 million years ago. The first ancestral hummingbird is found in the fossil record in South America around 22 million years ago, where they spread throughout the Americas and evolved into the hundreds of species we have today. In the Andes Mountains alone, there are 140 species of hummingbird and researchers keep finding new ones. The blue-throated hillstar was only discovered in 2017, for instance, since it lives in a very small area of the Andes in Ecuador and is very rare.

Researchers keep finding out more about hummingbirds, too. The black Jacobin hummingbird from the mountains of eastern Brazil makes complex sounds that are so high-pitched that the researchers have to record them using equipment developed to record bat calls. So who knows what else we’ll learn about hummingbirds next? I can definitely see why they’d be anyone’s favorite bird.

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 112: The Bullfrog and the Raven

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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.