Category Archives: North America

Episode 148: Gastric Brooding and Other Frogs

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Thanks for Merike for suggesting the gastric brooding frog and to Hally for suggesting newly-discovered frogs!!

The Gastric brooding frog:

Darwin’s frog, round boi:

The Surinam toad carries her eggs and tadpoles in the skin of her back:

Kermit the frog and a newly discovered glass frog:

Show transcript:

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

This week we have another fantastic listener suggestion, about frogs! Merike is a herpetologist from Estonia, who suggested the gastric brooding frog, and another listener, Hally, also wanted to learn about some of the new frog species discovered recently.

The gastric brooding frog is native to eastern Australia, specifically Queensland. There are two species, and both of them live in creeks in separate rainforests. The habitat is specific and small, and unfortunately both species went extinct less than forty years ago. Researchers aren’t sure why they went extinct, but it was probably due to pollution and habitat loss.

The gastric brooding frog was a slender frog, with the northern gastric brooding frog being about three inches long, or about 8 cm, while the southern gastric brooding frog was about half that size. Females were larger than males. It was grey or brown-gray in color with some darker and lighter patches on the back with a lighter belly. During the day it spent most of its time at the water’s edge, hidden in leaf litter or among rocks, although it generally only fully came out of the water when it was raining. It ate insects and may have hibernated in winter.

As you may have guessed from its name, the gastric brooding frog had a unique way of taking care of its eggs. After the eggs were fertilized, the female would actually swallow the eggs and keep them in her stomach while they developed. Even after the eggs hatched into tadpoles, they stayed in the mother’s stomach. As they grew larger, the stomach also grew larger, until it pretty much filled up the mother’s insides, to the point where she couldn’t even use her lungs to breathe. Fortunately many frogs, including the gastric brooding frog, can absorb a certain amount of oxygen through the skin. Finally the tadpoles metamorphosed into little frogs, at which point the mother regurgitated one or a few of them at a time, or sometimes all of them at once if she felt threatened.

So how did the mother keep from digesting her own eggs or tadpoles? How did she eat when her stomach was full of babies? How did the babies eat?

The jelly around the gastric brooding frog’s eggs contained prostaglandin E2, also called PGE2, which causes the stomach to stop producing hydrochloric acid. That’s a digestive acid, so once the eggs were inside the stomach, the stomach basically stopped stomaching. There is some speculation that the first eggs the mother frog swallowed actually got digested, but then the acid production stopped and the rest of the eggs remained. Once the eggs hatched, the tadpoles also produced PGE2 in the mucus in their gills.

The tadpoles continued to live off the yolk sac from their eggs as they developed, and in fact their mouths weren’t even connected to their gut yet. As for the mother, she just didn’t eat until the babies were developed and released into the water on their own, which took about six weeks.

The gastric brooding frog is the only frog known to raise its babies this way, but other frog species have interesting variations of the usual way frogs reproduce. Most female frogs lay their eggs, and then the male fertilizes them. But about a dozen species of frog have developed internal fertilization, where the female retains the eggs in her body until the male fertilizes them. The tailed frog from California in the United States, in North America, gets its name from a structure that looks like a tail, but is actually an extension of the cloaca. That’s the opening used for both excretion and reproduction. Only males have the tail, and it works like a penis to fertilize the female’s eggs without her needing to lay the eggs first. Once they’re fertilized, she can choose just the right spot to lay the eggs.

Another weird way frogs take care of their eggs is something that Darwin’s frog does. Darwin’s frog lives in Chile and Argentina in South America, and grows to a little over an inch long, or 3 cm. It has a pointy snout that gives its head a wedge  shape something like a leaf, which helps keep it camouflaged on the forest floor. The female lays her eggs in damp leaf litter, and after the male fertilizes them he guards them for several weeks. When they start to move as they develop, the male swallows them—but instead of his stomach, he stores them in his vocal sac. That’s the expandable sac in the frog’s throat that males use to make their croaking sounds by filling the sac with air.

The eggs hatch into tadpoles, which the male carries around as they grow. They live off their egg yolks, but they also eat secretions from the lining of the vocal sac. Once the tadpoles metamorphose into little frogs, they hop out of the male’s mouth and are on their own. Until then, the male doesn’t eat.

The Surinam toad is a species of frog. Remember that all toads are frogs but not all frogs are toads. It lives in wetlands and forests in northern South America, and has a radically different way of keeping its eggs safe. The Surinam toad is a flattened, broad toad that can grow up to 8 inches long, or 20 cm, and looks a lot like a dead leaf. It lives in slow-moving water. Unlike other frogs it doesn’t have a tongue, so instead of catching insects with its sticky tongue, it grabs them with its hands. It’s sometimes called the star-fingered toad because its long, thin fingers have tiny star-shaped appendages that help it catch prey. Instead of croaking, male Surinam toads make a clicking noise by moving a small bone in the throat back and forth.

When the female is ready to lay her eggs, a male clasps her around the middle like most frogs do while mating. But instead of just releasing her eggs and letting the male release sperm to fertilize them, the female makes a sort of flipping movement in the water as she releases a few eggs at a time. The male fertilizes them, then presses them onto her back. The skin of the female’s back grows up over the eggs, embedding them in the skin in little pockets. When the tadpoles hatch they stay in these little pockets as they develop. They only leave when they’ve metamorphosed into tiny toads, at which point they emerge and live on their own. The mother then sheds the layer of skin on her back where her babies lived.

A frog described in 2014 that lives in parts of South Asia gives birth to tadpoles instead of laying eggs. It’s a species of fanged frog, which are frogs that do actually have teeth unlike most frogs. Limnonectes larvaepartus grows about 1 ½ inches long, or just under 4 cm. The eggs are fertilized internally, but instead of laying them the female keeps them in her oviducts until they hatch. They remain inside her until they no longer have any yolk left to nourish them, at which point the mother releases them into a slow-moving stream.

Lots of other interesting frogs have been discovered recently. A new frog discovered in southern India in 2018 was recently determined to be a member of its own genus. It’s called the narrow-mouthed frog and had gone unnoticed even though it lives in an area that’s been extensively explored by scientists. It only comes out into the open for less than one week out of the year during the short breeding season, and the rest of the time it hides. Obviously, we don’t know much about it yet.

In 2016 in the same area as the narrow-mouthed frog, researchers discovered a new species of frog with a tadpole that burrows through sand. It’s a member of the Indian dancing frog family, and not only do the tadpoles burrow through wet sand at the bottom of streams, they have ribs that help them move around more easily. Tadpoles are usually just squidges without bones. Dancing frogs get that name because the males wave their feet to attract females during mating season.

There are so many recently discovered frog species that it’s hard to know which ones to highlight. You know, like the new glass frog from Costa Rica described in 2015 that honestly looks just like Kermit the Frog, if Kermit had a translucent belly that showed his organs. Scientists don’t know why glass frogs have no pigmentation at all on their bellies. Or the three tiny frog species discovered in Madagascar and described earlier in 2019, all of them smaller than your thumbnail, that belong to a new genus, Mini. Their scientific names are therefore Mini mum, Mini scule, and Mini ature. The three are related to one of Madagascar’s biggest frogs, which grows over four inches long, or 10.5 cm, as opposed to the Mini frogs which top out at about 15 mm long. Hally sent me an article about eleven new species of frog discovered recently in the Andes, including the multicolored rain frog. It’s sometimes yellow, sometimes brown, sometimes green, speckled, splotched, spotted–so variable that at first scientists thought they were different related species. All eleven of the Andes frogs lay their eggs on land, and instead of hatching into tadpoles the eggs hatch into tiny froglets.

Frogs and other amphibians are sensitive to environmental change, which means a lot of species have either recently gone extinct or are critically endangered. Habitat loss and an amphibian fungal disease that has spread around the world are also making things hard for frogs and their relations. Scientists have been working hard lately to find species that are rare, suspected to be extinct, or are unknown to science, to learn about them while we can and do our best to preserve the species, either in the wild or in captivity. There are even multiple genetic resource banks, or biobanks, to preserve genetic material of frogs and other animals so that future scientists might be able to clone them.

There’s always the possibility that the gastric brooding frog isn’t actually extinct. The southern gastric brooding frog hasn’t been seen since at least 1981 despite extensive searches, though, with the last captive individual dying in 1983. The northern gastric brooding frog was only discovered in 1984 but hasn’t been seen since 1985.

But even if there aren’t any left in the wild, all hope isn’t lost. The gastric brooding frog is a good candidate for de-extinction, and cloning has actually been successful to a limited degree already. In 2013 a living embryo was produced from preserved genetic material, although it didn’t survive. Researchers are still working to clone the frogs and keep them alive. With luck the attempt will be successful, and not only can a population of the frogs be kept in captivity, they can be reintroduced to their former habitat one day.

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 139: Skunks and Other Stinkers

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This week we’re commemorating my HOUSE getting SKUNKED by a SKUNK and it was STINKY

The skunk, stinky but adorkable, especially when it’s eating yellow jackets:

The stink badger looks like a shaved skunk with a bobbed tail:

The zorilla wants to be your stinky friend:

A woodhoopoe, most magnificent:

A Eurasian hoopoe, looking snazzy:

Show transcript:

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

This week we’re going to learn about some animals that are infamous for their stinkiness. This wasn’t the topic I had planned on for this week, but last week my house got skunked. That is, a skunk sprayed an animal very close to my house, which means I woke up at 4:45am gagging from the smell of point-blank skunk odor. And this was with the windows closed and the air conditioning going. It was so bad I thought I would throw up, so I yanked on my clothes, grabbed my purse, and fled the house at 5:30am. I went to work early—don’t worry, I got coffee on the way—and spent the whole day smelling skunk faintly where the smell clung to my hair and, oddly, my phone case. Also I spent the whole day complaining to my coworkers.

Fortunately, when I got home the smell had dissipated somewhat, so I opened all the windows and doors and by the next morning it was mostly gone. But it got me wondering why skunk spray smells so, so bad and how many other stinky animals are out there.

The skunk is native to North and South America, although there are two species of related animals that live in some of the islands of the Malay Archipelago, called stink badgers. No seriously, that’s really what they’re called. Skunks and stink badgers are related to actual badgers and to weasels, but not closely.

The stink badger is black or dark brown with a white stripe that runs from its head down the back of its neck and along its spine, and finishes at its little short tuft of a tail. The skunk is black or dark brown with one or two white stripes or white spots, depending on the species, which continues down its long fluffy tail. In all cases, though, these stinky animals are vividly patterned with dark fur and bright white markings as a warning to other animals. Do not get too close or there’s a world of stink coming your way. Also, I can verify from my own experience that the white markings of a skunk make it much easier to see in the darkness and therefore avoid. Since the skunk is crepuscular, meaning it’s most active around dusk and dawn, that’s important. The stink badger is more nocturnal than the skunk.

Both the skunk and the stink badger have relatively short legs with sharp claws. Both are relatively small, about the size of a cat. Both are also good diggers and spend the daytime asleep in their burrows. In winter the skunk doesn’t hibernate but it does stay in its burrow more, spending most of its time asleep. This is the best way to deal with winter cold, if you ask me.

Female skunks share a den in the winter but males are usually solitary. This means the females retain a higher amount of body fat when the weather warms up, since they didn’t need to burn that fat to keep themselves warm. Researchers think this helps the females stay in better condition for a spring pregnancy. Meanwhile, males are skinnier at the beginning of the winter but by staying alone they’re less likely to contract disease or parasites.

Mating season for skunks is in spring and babies are born in early summer. They mostly stay in the burrow for about two months, then start accompanying their mother when she goes out foraging. The mother is really protective of her babies and will spray any animal that approaches.

Although the skunk can hear and smell well, it has poor vision. That’s why so many are killed by cars. The skunk’s biggest predator is the great horned owl, because owls don’t have much of a sense of smell and don’t care about being sprayed.

The skunk and the stink badger are both omnivorous and will dig up grubs and earthworms, will sometimes eat carrion, and also eat frogs, crustaceans, and other small animals, leaves and other plant parts, especially berries and nuts, and insects. The skunk especially likes bees. It has thick fur that helps protect it from stings, and will eat all the bees it can catch.

The skunk also eats other stinging insects, including the dreaded yellow jacket. That’s a type of wasp that’s common where I live, with incredibly painful stings. A few years ago I noticed a yellow jacket nest in the ground behind my garage, and that night when the yellow jackets were asleep I carefully trimmed the long grass around the nest opening to see how extensive it was. Then I made a mental note to get some yellow jacket poison the following day. When I went back out to deal with the nest the next night, it was gone. A skunk had discovered it, probably because I’d exposed it by trimming back the grass, and had dug the whole nest up to eat the yellow jackets. There wasn’t a single one left. Ever since I have been lowkey fond of skunks, although I do wish they wouldn’t spray so close to my house.

So what is skunk spray and why is it so stinky? The skunk has two anal glands that contain an oily liquid made up of sulfurous chemical compounds. If a skunk feels threatened, it will raise its tail and fluff it out as a warning. It may also hiss, stomp its feet, and pretend to charge its potential attacker. The skunk doesn’t actually want to spray if it can avoid it, though. Its anal glands only hold enough of the oil to spray a few times, and when the skunk runs out it can’t spray again for almost two weeks. But if its warnings don’t work, it will use muscles to contract the glands and spray the oily liquid more than ten feet, or 3 meters.

If you’ve only ever smelled skunk spray in the distance, you may not think it’s so bad. But the smell is horrific up close, strong enough to induce vomiting, and it can cause irritation to the skin or even temporary blindness if it gets in the eyes. And the skunk is really accurate when spraying, aiming at the face. Not only that, because it’s an oil, the spray clings to skin, hair, or fur, and it won’t just wash off. It can literally take weeks to wear off normally. If your clothes get sprayed, or your dog’s collar, the smell will never come out and you will have to throw the clothes away.

Domestic dogs get sprayed by skunks a lot. Some dogs just never learn. I once had a cat who was sprayed by a skunk too. You may have heard that you can remove the smell by washing your pet in tomato juice, but this actually doesn’t work. I asked a veterinarian how to clean up my cat, and this is what she told me. This worked great, by the way.

Mix hydrogen peroxide about half and half with warm water and add about a spoonful of dishwashing liquid. Rub the mixture into the fur thoroughly, making sure to work it in well right down to the skin. If you can tell where the spray is, concentrate on that part. Do your best not to get the mixture into your pet’s eyes, and make sure to use good warm water. Part of the reason animals hate getting bathed is because they get cold really easily once their fur is wet, so using really warm water helps. Then rinse your pet thoroughly, making sure to get all the soap out so they won’t get itchy. You may need to mix up another batch of the hydrogen peroxide, water, and soap and give the stinkiest areas another wash. After you’ve rinsed your pet thoroughly, wrap them up in a towel and gently squeeze as much of the water out of the fur as you can. Then make sure you have a dry towel to put in your pet’s bed or basket or wherever it wants to hide after its horrible bath.

In July of 2019 a research team published a report about a type of fungus that makes a chemical called pericosine A that neutralizes noxious chemicals. The researchers tested pericosine on skunk spray and discovered that it neutralized the smell harmlessly. So it’s probably just a matter of time before pericosine is marketed to veterinarians to help pet owners. Let’s hope so.

Even skunks don’t like to be sprayed, incidentally. Males fight each other during mating season and will sometimes spray each other. A skunk reacts like any other animal when it gets sprayed.

The zorilla is another stinky animal related to the skunk, although it lives in parts of Africa. It’s brown with white markings and is sometimes called the striped polecat or African skunk. It’s about the same size as a skunk or stink badger and looks and acts very similar, although it’s a carnivore and much more social than the skunk. It’s also related to the honey badger, which we talked about in episode 62. If you remember, the honey badger is also black with a broad white or silvery stripe down its back, and it can invert its anal sacs and discharge a stinky oil, although it doesn’t spray like a skunk.

It’s not really surprising that all these animals are related, since most members of the weasel family, known as mustelids, have anal scent glands that produce a strong odor. Most species just use the glands to mark their territory, though.

But are there animals who spray like skunks but aren’t related to the skunk? Many animals have anal glands for marking territory, and if threatened some animals will empty the anal glands as a form as defense. The king ratsnake will sometimes do this, as will the lesser anteater, the opossum, and others.

But there’s another animal that actually sprays a smelly substance for defense, and it’s not one you’d expect. It’s a bird called the hoopoe, along with its relative the woodhoopoe.

The woodhoopoe lives in woods, savannah, and rainforests of Africa. It looks something like a cuckoo, with a very long tail marked with white spots. It’s mostly a metallic black in color, although some species have markings in other colors. Males have longer, more curved bills than females because they eat larger insects that live in bark and rotten wood while females eat smaller insects that live mostly on leaves. In this way, mated pairs don’t compete with each other for food.

The hoopoe lives across Eurasia and parts of Africa, and while it’s related to the woodhoopoe, it looks very different. It has a long crest that it can raise and lower like a crown, and it’s a pretty tan or brown color with black and white markings. Both males and females have long, slightly curved bills that they use to catch insects and other small animals.

Female hoopoes and woodhoopoes are picky about nesting spots. The female likes to nest in dead trees in rotting wood, or sometimes in a gap in a rock wall. The female incubates her eggs alone. But animals find dead trees and crumbling walls easy to climb, so to protect her nest the female can spray a foul-smelling liquid from the gland that most birds just use to secrete preening oil. This is the case for the female hoopoe and woodhoopoe too most of the time, but after she lays her eggs the gland becomes weaponized. Not only that, when the babies hatch, they develop the same gland. The female rubs the stinky oil on her babies and on the nest to deter predators, and researchers think it may also deter parasites. If an animal approaches the nest anyway, the female can spray the oil at it. And if the female is off catching food for her babies, the babies will hiss, peck, and squirt liquid poop at the predator. At that point, most predators probably just decide to go hunt something else. After they clean up.

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 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 135: Smallest of the Large

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This week we’re looking at some very small animals–but not animals that we think of as small. Join us for a horrendously cute episode!

Further reading:

The Echinoblog

Further listening:

Animals to the Max episode #75: The Sea Panda (vaquita)

Varmints! episode #49: Hippos

Further watching:

An adorable baby pygmy hippo

The Barbados threadsnake will protecc your fingertip:

Parvulastra will decorate your thumbnail:

Berthe’s mouse lemur will defend this twig:

The bumblebee bat will eat any bugs that come near your finger:

The vaquita, tiny critically endangered porpoise:

The long-tailed planigale is going to steal this ring and wear it as a belt:

He höwl:

A pygmy hippo and its mother will sample this grass:

This Virgin Islands dwarf gecko will spend this dime if it can just pick it up:

Show transcript:

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

I talk a lot about biggest animals on this podcast, so maybe it’s time to look at the very smallest animals. I don’t mean algae or bacteria or things like that, I mean the smallest species of animals that aren’t usually considered especially small.

We’ll start with the smolest snek, the Barbados threadsnake. It only lives on a few islands in the Caribbean, notably Barbados. The very largest individual ever measured was only 4.09 inches long, or 10.4 cm, but most are under four inches long. But it’s an extremely thin snake, not much thicker than a spaghetti noodle.

The Barbados threadsnake mostly eats termites and ant larvae. It spends most of its time in leaf litter or under rocks, hunting for food. The female only lays one single egg, but the baby is relatively large, about half the mother’s length when it hatches.

That’s so cute. Why are small things so cute?

Remember the starfish episode where we talked about the largest starfish? Well, what’s the smallest starfish? That would be Parvulastra parvivipara, which is smaller than a fingernail decoration sticker. It grows to about ten millimeters across and is orangey-yellow in color. It lives on the coast of Tasmania in rock pools between low and high tide, called intertidal rock pools.

If you remember the Mangrove killifish from a few episodes ago, you’ll remember how killifish females are hermaphrodites that produce both eggs and sperm, and usually self-fertilize their eggs to produce tiny clones of themselves. Well, Parvulastra does that too, although like the killifish it probably doesn’t always self-fertilize its eggs. But then it does something interesting for a starfish. Instead of releasing its eggs into the water to develop by themselves, Parvulastra keeps the eggs inside its body. And instead of the eggs hatching into larvae, they hatch into impossibly tiny miniature baby starfish, which the parent keeps inside its body until the baby is big enough to survive safely on its own.

But what do the baby starfish eat while they’re still inside the mother? Well, they eat their SIBLINGS. The larger babies eat the smaller ones, and eventually leave through one of the openings in the parent’s body wall, called gonopores. Researchers theorize that one of the reasons the babies leave the parent is to escape being eaten by its siblings. And yes, occasionally a baby grows so big that it won’t fit through the gonopores. So it just goes on living inside the parent.

Next, let’s look at the smallest primate. The primate order includes humans, apes, monkeys, and a lot of other animals, including lemurs. And the very smallest one is Berthe’s mouse lemur. Its body is only 3.6 inches long on average, or 9.2 cm, with a tail that more than doubles its length. Its fur is yellowish and brownish-red.

Berthe’s mouse lemur was only discovered in 1992. It lives in one tiny area of western Madagascar, where it lives in trees, which means it’s vulnerable to the deforestation going on all over Madagascar and is considered endangered.

It mostly eats insects, but also fruit, flowers, and small animals of various kinds. Its habitat overlaps with another small primate, the gray mouse lemur, but they avoid each other. Madagascar has 24 known mouse lemur species and they all seem to get along well by avoiding each other and eating slightly different diets. Researchers discover new species all the time, including three in 2016.

Last October we had an episode about bats, specifically macrobats that have wingspans as broad as eagles’. But the smallest bat is called the bumblebee bat. It’s also called Kitti’s hog-nosed bat, but bumblebee bat is way cuter. It’s a microbat that lives in western Thailand and southeast Myanmar, and like other microbats it uses echolocation to find and catch flying insects. Its body is only about an inch long, or maybe 30 millimeters, although it has a respectable wingspan of about 6 ½ inches, or 17 cm. It’s reddish-brown in color with a little pig-like snoot, and it only weighs two grams. That’s just a tad more than a single Pringle chip weighs.

Because the bumblebee bat is so rare and lives in such remote areas, we don’t know a whole lot about it. It was only discovered in 1974 and is increasingly endangered due to habitat loss, since it’s only been found in 35 caves in Thailand and 8 in Myanmar, and those are often disturbed by people entering them. The land around the caves is burned every year to clear brush for farming, which affects the bats too.

The bumblebee bat roosts in caves during the day and most of the night, only flying out at dawn and dusk to catch insects. It rarely flies more than about a kilometer from its cave, or a little over half a mile, but it does migrate from one cave to another seasonally. Females give birth to one tiny baby a year. Oh my gosh, tiny baby bats.

So what about whales and dolphins? You know, some of the biggest animals in Earth’s history? Well, the vaquita is a species of porpoise that lives in the Gulf of California, and it only grows about four and a half feet long, or 1.4 meters. Like other porpoises, it uses echolocation to navigate and catch its prey. It eats small fish, squid, crustaceans, and other small animals.

The vaquita is usually solitary and spends very little time at the surface of the water, so it’s hard to spot and not a lot is known about it. It mostly lives in shallow water and it especially likes lagoons with murky water, properly called turbid water, since it attracts more small animals.

Unfortunately, the vaquita is critically endangered, mostly because it often gets trapped in illegal gillnets and drowns. The gillnets are set to catch a different critically endangered animal, a fish called the totoaba. The totoaba is larger than the vaquita and is caught for its swim bladder, which is considered a delicacy in China and is exported on the black market. The vaquita’s total population may be no more than ten animals at this point, fifteen at the most, and the illegal gillnets are still drowning them, so it may be extinct within a few years. A captive breeding plan was tried in 2017, but porpoises don’t do well in captivity and the individuals the group caught all died. Hope isn’t lost, though, because vaquita females are still having healthy babies, and there are conservation groups patrolling the part of the Gulf of California where they live to remove gill nets and chase off fishing boats trying to set more of the nets.

If you want to learn a little more about the vaquita and how to help it, episode 75 of Corbin Maxey’s excellent podcast Animals to the Max is an interview with a vaquita expert. I’ll put a link in the show notes.

Next, let’s talk about an animal that is not in danger of extinction. Please! The long-tailed planigale is doing just fine, a common marsupial from Australia. So, if it’s a marsupial, it must be pretty big—like kangaroos and wallabies. Right? Nope, the long-tailed planigale is the size of a mouse, which it somewhat resembles. It even has a long tail that’s bare of fur. It grows to 2 ½ inches long not counting its tail, or 6.5 cm. It’s brown with longer hind legs than forelegs so it often sits up like a tiny squirrel. Its nose is pointed and it has little round mouse-like ears. But it has a weird skull.

The long-tailed planigale’s skull is flattened—in fact, it’s no more than 4 mm top to bottom. This helps it squeeze into cracks in the dry ground, where it hunts insects and other small animals, and hides from predators.

The pygmy hippopotamus is a real animal, which I did not know until recently. It grows about half the height of the common hippo and only weighs about a quarter as much. It’s just over three feet tall at the shoulder, or 100 cm. It’s black or brown in color and spends most of its time in shallow water, usually rivers. It’s sometimes seen resting in burrows along river banks, but no one’s sure if it digs these burrows or makes use of burrows dug by other animals. It comes out of the water at night to find food. Its nostrils and eyes are smaller than the common hippo’s.

Unlike the common hippo, the pygmy hippo lives in deep forests and as a result, mostly eats ferns, fruit, and various leaves. Common hippos eat more grass and water plants. The pygmy hippo seems to be less aggressive than the common hippo, but it also shares some behaviors with its larger cousins. For instance, the pooping thing. If you haven’t listened to the Varmints! Episode about hippos, you owe it to yourself to do so because it’s hilarious. I’ll put a link in the show notes to that one too. While the hippo poops, it wags its little tail really fast to spread the poop out across a larger distance.

Also like the common hippo, the pygmy hippo secretes a reddish substance that looks like blood. It’s actually called hipposudoric acid, which researchers thinks acts as a sunscreen and an antiseptic. Hippos have delicate skin with almost no hair, so its skin dries out and cracks when it’s out of water too long.

The pygmy hippo is endangered in the wild due to habitat loss and poaching, but fortunately it breeds successfully in zoos and lives a long time, up to about 55 years in captivity. For some reason females are much more likely to be born in captivity, so when a male baby is born it’s a big deal for the captive breeding program. I’ll put a link in the show notes to a video where you can watch a baby pygmy hippo named Sapo and his mother. He’s adorable.

Finally, let’s finish where we started, with another reptile. The smallest lizard is a gecko, although there are a lot of small geckos out there and it’s a toss-up which one is actually smallest on average. Let’s go with the Virgin Islands dwarf gecko, which lives on three of the British Virgin Islands. It’s closely related to the other contender for smallest reptile, the dwarf sphaero from Puerto Rico, which is a nearby island, but while that gecko is just a shade shorter on average, it’s much heavier.

The Virgin Islands dwarf gecko is only 18 mm long not counting its tail, and it weighs .15 grams. A paperclip weighs more than this gecko. It’s brown with darker speckles and a yellow stripe behind the eyes. Females are usually slightly larger than males. Like other geckos, it can lose its tail once and regrow a little stump of a tail.

The Virgin Islands dwarf gecko lives in dry forests and especially likes rocky hills, where it spends a lot of its time hunting for tiny animals under rocks. We don’t know a whole lot about it, but it does seem to be rare and only lives in a few places, so it’s considered endangered. In 2011 some rich guy decided he was going to release a bunch of lemurs from Madagascar onto Moskito Island, one of the islands where the dwarf gecko lives. Every conservationist ever told him oh NO you don’t, rich man, what is your problem? Those lemurs will destroy the island’s delicate ecosystem, drive the dwarf gecko and many other species to extinction, and then die because the habitat is all wrong for lemurs. So Mr. Rich Man said fine, whatever, I’ll take my lemurs and go home. And he did, and the dwarf gecko was saved.

Look, if you have so much money that you’re making plans to move lemurs halfway across the world because you think it’s a good idea, I can help take some of that money off your hands.

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 133: The mangrove killifish and the unicorn pig

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This week’s (short) episode is about two animals that should have been in the strangest small fish and weird pigs episodes, respectively. I left them out by accident but they’re so interesting that they deserve an episode all to themselves anyway. Thanks to Adam for suggesting the mangrove killifish!

Further reading:

25 Years in the Mud: How a Quirky Little Fish Changed My Life

The mangrove killifish just looks normal:

Not a unicorn pig (okay yes technically a unicorn pig):

Unicorn pig skull:

Show transcript:

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

A few weeks ago we had an episode about strange small fish. Shortly after that episode released, I was going through my disorganized ideas and suggestions file and realized I’d left out one of the best weird small fish ever, a suggestion by Adam. I also discovered I’d missed an extinct pig I’d planned to include in the recent weird pigs episode. So let’s play catch up in a short episode and learn about both this week.

The fish Adam suggests is called the mangrove killifish, also called the mangrove rivulus, which lives in parts of Florida and Mexico, down to Central and South America. It’s technically a marine fish, meaning it lives in salt-water, but it also likes brackish water, that’s less salty than the ocean, and occasionally it even lives in freshwater. It especially likes mangrove swamps. It grows up to 3 inches long, or 7.5 cm and is a mottled brown in color with an eye spot on its tail. It doesn’t look like anything special.

But the mangrove killifish has a lot in common with amphibians, especially the lungless salamanders. Many types of salamander absorb air through the skin instead of through lungs or gills. The mangrove killifish does this too. It often lives in abandoned crab holes, which may not have very high quality water. But that’s okay, because it can absorb air through its skin and can live out of the water for well over a month as long as its skin stays damp. It’s sometimes found in places where you wouldn’t expect to find a fish, like the inside of rotting logs or buried in damp dead leaves.

So how does the killifish get into the rotting logs or the leaf litter or the crab burrows that aren’t connected to waterways? It actually uses its tail to flip itself out of the water and onto land, and then it continues to flip here and there until it finds a place where it wants to live for a while. It can direct this jumping, not just flop around like most fish out of water, and can jump several times its own length.

A lot of times when the tide goes out, fish get trapped in crab holes, dimples in the sand or mud, and other shallow water. That’s okay if the tide comes back in far enough to re-submerge the holes, but if the water doesn’t quite reach, it’s not long before fish start to suffocate as all the oxygen in the water is used up. But the killifish doesn’t have that problem. It just flips itself out of the water. It can also leave the water if it gets too hot.

The killifish is also territorial in water, which requires a lot of energy. When it’s out of the water, or in a little temporary pool or a crab burrow where it doesn’t have to worry about other killifish, it can relax. On the other hand, it loses a lot of weight while it’s out of the water since it doesn’t eat as much. So there are trade-offs.

Even the killifish’s eggs can survive out of water. The fish usually lays its eggs in shallow water, sometimes even on land that’s just near water. The eggs continue to develop just fine, in or out of water, but they delay hatching until they’re submerged.

And that leads us to the most astonishing thing about the mangrove killifish. In most populations, almost all killifish are females, and most of the time they don’t need a male fish to fertilize their eggs. Females produce eggs but they also produce sperm that fertilize the eggs before they’re even laid. The eggs hatch into genetic duplicates of the parent—clones, basically. The term for an organism that produces both eggs and sperm is hermaphrodite, and while it’s common in some invertebrates, the killifish is the only known vertebrate hermaphrodite. Vertebrate, of course, is an animal with a backbone.

But while most killifish are females, there are occasionally males. Male killifish are orangey in color. When a male is around, females suppress their ability to self-fertilize eggs and they lay the eggs for the male to fertilize, just like any other fish. This helps keep the species genetically diverse and able to adapt to external pressures like increased numbers of parasites.

Next, let’s talk about the unicorn pig. Or pigicorn, if you like. It’s called Kubanochoerus [koo-ban-oh-ko-rus] and there were several species. It was related to modern pigs and lived throughout most of Eurasia and parts of Africa around 10 million years ago.

It was big, up to four feet tall at the shoulder, or 1.2 meters, and had tusks like other pigs. It probably looked a lot like a wild boar. But its skull is longer than modern pig skulls and it had horns. Three horns, specifically. Two of the horns were small and grew above the eyes, while a bigger horn grew forward from its forehead. The forehead horn wasn’t very long and was probably blunt. Researchers used to think males used these forehead horns to fight each other, but females had them too so they may also have been used for defense from predators.

That is literally all I can find out about this fascinating animal. I can’t even speculate about the horns since literally no other pig has horns, at least that I can find. Presumably the warty protrusions that many modern pig species have are similar to the horns that Kubanochoerus had. The eyebrow horns might have had the same purpose as the facial protrusions on warthogs and other pigs, as a way to protect the eyes when the pigs fight. The forehead horn, though…well, that’s just weird. It probably wasn’t covered with keratin, but we don’t know. My own guess is that it was something more like an ossicone and was covered with skin and hair. But again, we don’t know. Not until we invent a working time machine and go back to look at one.

That’s it, a very short episode. I’m actually in Dublin, Ireland right now attending WorldCon, so while I’m here I will keep an eye out for leprechauns, fairies, and pigicorns, just in case.

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 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 125: Triceratops and other ceratopsids

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It’s time to learn about some more dinosaurs, ceratopsids, including the well-known Triceratops!

Triceratops:

An artist’s frankly awesome rendition of Sinoceratops. I love it:

A Kosmoceratops skull:

Pachyrhinosaurus had a massive snoot:

Protoceratops:

Fighting dinos!

Show transcript:

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

Back in episode 107, about ankylosaurus and stegosaurus, I mentioned that one day I’d do an episode all about triceratops and its relations. Well, that day is today. It’s the ceratopsid episode!

Ceratopsids are a family of dinosaurs with elaborate horns on their faces and frills on the back of their heads. They almost all lived in what is now North America and most of them lived in the late Cretaceous. Triceratops is the most well known, so we’ll start with it.

The name triceratops, of course, means three face horns, and it did indeed have three face horns. It had one on its nose and two on its brow, plus a frill that projected from the back of its skull.

Triceratops was a big animal, around 10 feet high at the shoulder, or 3 meters, and about 30 feet long, or 9 meters. Its body was bulky and heavy, sort of like a rhinoceros but, you know, even bigger and more terrifying.

Like the rhinoceros, triceratops was a herbivore. It had a horny beak something like a turtle’s that it probably used to grab plant material, and it had some 40 teeth on each side of the jaw. These teeth were replaced every so often as the old ones wore down, sort of like crocodilians do. Back when triceratops lived, around 68 million years ago, grass hadn’t developed yet. There were prairies in parts of western North America the same way there are today, but instead of grass, the prairies were covered in ferns. Many researchers think triceratops mostly ate ferns, grazing on them the same way bison graze on grass today.

In fact, the first paleontologist to study a triceratops fossil thought it was an extinct type of bison. This was a man called Othniel Charles Marsh. To his credit, Marsh only had a little piece of a triceratops skull to examine, the piece with the brow horns. And since the brow horns of a triceratops do look a little like the horn cores of a bovid, and since this was 1887 before a lot was known about dinosaurs, and since the fossil was found in Colorado where the buffalo roam, it’s understandable that Marsh would have assumed he was looking at a gigantic fossil bison skull. He figured it out the following year after examining another skull with the nose horn intact, since bovids are not known for their nose horns, and he naturally named it Triceratops.

It’s tempting to assume that Triceratops was a herd animal, but we don’t have any evidence that it lived in groups. It was common and we have lots of fossil triceratops, especially the thick-boned skulls, but it seems to have mostly been a solitary animal.

It’s pretty obvious that the triceratops’ horns must have been for defense. It lived at the same time as Tyrannosaurus rex, which preyed on triceratops often enough that we have a lot of Triceratops fossils with T rex tooth marks in the bones. We also have some triceratops fossils with T rex tooth marks in the bones that show signs of healing, indicating that the triceratops successfully fended off the T rex and lived. But what was the frill for?

Researchers have been trying to figure this out for years. There were a lot of different ceratopsid species, many of which may have overlapped in range and lived at the same time, so some researchers suggest the frill’s size and shape may have helped individuals find mates of the same species. Triceratops has a rather plain frill compared to many ceratopsid species, which had frills decorated with points, spikes, scalloped edges, lobes, and other ornaments.

But the ornamental elements of the frills change rapidly through the generations, which suggests that they weren’t for species recognition. If that was the case, the frills would have stayed about the same to minimize confusion. Instead, they get more and more elaborate, which suggests that they were a way to attract mates who liked fancy head frills. You know, like a snazzy hairstyle.

Of course, the frill could have more than one use. It could be attractive to potential mates and also could have protected the back of the skull from T rex bites, just like a snazzy hairstyle still keeps your head warm in cold weather. Then again, in many species of ceratopsid the frill is thin and rather fragile, so it’s more likely to be just for display. It’s very likely that the frills were brightly colored or patterned.

So what were some of these other ceratopsids with strange shaped frills? I’m SO glad you asked! There were so many ceratopsids, and they all had bodies shaped roughly the same but with head frills and horns that looked very different from each other. Some had no horns, just a frill. Some just had a nose horn, some just had brow horns. The horns were shaped differently in different species, too. Researchers group ceratopsids into two major groups: the chasmosaurines, which have longer frills and usually long brow horns and short nose horns; and the centrosaurines, which typically had larger nose horns and small brow horns, and snouts that were thicker top to bottom.

Almost all the ceratopsids have been found in North America, where they were super common in the Cretaceous. But Sinoceratops was discovered in 2008 in China. It wasn’t as big as Triceratops, topping out at about 6 ½ feet tall, or 2 meters, but what it lacked in bulk it made up in head frill ornamentation. Its frill was relatively short and was edged with small horns that curve forward. Its frill also had knobs along its edge and down the middle, which is unique among all ceratopsids and may have been the base for small keratin horns. Since keratin doesn’t fossilize, we have no way of knowing. It also had two holes in the frill that made it lighter, but they would have been covered with skin (no matter what a certain movie may have led you to believe). Its single nose horn pointed almost straight up, and in front of the nose horn it had a bony knob. It basically had no brow horns, just what may have been bony knobs above its eyes.

Kosmoceratops had probably the most ornamented skull of any known ceratopsid, and maybe any known dinosaur, with 15 horns growing from it. The rear of its frill curled forward like a collar, edged with flat, pointed projections. The frill was scalloped along its sides. Its brow horns were long, pointy, and arched sideways and slightly downward. Kosmoceratops also had a cheek horn under each eye and a flattened nose horn just in front of the brow horns. It lived in what is now Utah, in the United States, some 76 million years ago, and was only described in 2010.

Pachyrhinosaurus had flattened bony nose and brow horns more properly called bosses, since they aren’t actually horns. But Pachyrhinosaurus did have horns on its frill, although the size, shape, and number of the frill horns vary from individual to individual.

These bosses resemble the base of rhinoceros horns, which as you may recall are made of keratin. Some researchers think the bosses found in Pachyrhinosaurus and other ceratopsids may have also had keratin horns growing from them.

Remember how I said Triceratops didn’t appear to be a herd animal? Triceratops is considered a chasmosaurine, and chasmosaurines all seemed to be fairly solitary animals. But the other big group of ceratopsids, centrosaurines, may have been herd animals. Pachyrhinosaurus was a centrosaurine, for instance, and several bonebeds containing dense collections of fossil pachyrhinosaurus have been found where the individuals appear to have died at the same time. The biggest found so far is in Alberta, Canada, where paleontologists have excavated thousands of bones, from full grown adults to babies. Researchers suggest a herd of the animals may have died trying to cross a flooded river. The species of Pachyrhinosaurus found in the Alberta bonebed had both bosses and short brow horns.

Even though only one species of ceratopsid has been discovered in Asia so far, earlier basal forms were common in Asia. Protoceratops, which only stood about two feet tall, or 60 cm, lived in what is now the Gobi Desert in Mongolia around 80 million years ago. Researchers think some of these early species in the genus Protoceratops migrated into North America on the Bering land bridge, where they evolved into ceratopsids.

Protoceratops looked like a mini ceratopsid with a simple neck frill and no horns. We have a lot of Protoceratops fossils and some of them are frankly amazing.

For instance, a Protoceratops fossil found in 1965 was preserved with its own footprint in the ground near it. The fossils of baby protoceratopses have been found together in one nest, which suggests the parents cared for their young. We even have a fossil of a protoceratops and a Velociraptor that both died together while fighting. The velociraptor’s hind leg is extended where it kicked protoceratops with its vicious claws, but the velociraptor’s arm is in protoceratops’s jaws, broken.

Fighting dinosaurs. It’s one of those things that makes life worth living, you know?

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 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!