Tag Archives: bats

BONUS! All about animal poop


A dung beetle rolling some poop:

Butterflies on poop:

Wombat poop is cubes!

Show transcript:

Welcome to a bonus episode made out of a bonus episode. Since this week’s topic is one that some adults may decide they don’t want their young kids listening to, because it goes into detail about hyena reproduction, I decided to unlock a Patreon bonus episode for everyone to listen to. But then I decided to actually release that episode so that listeners can download it normally in the main feed. Those of you who want time to pre-screen the hyena episode to see if it’s appropriate for your kids to listen to can listen to this episode together in the meantime, and those of you who decide the hyena episode isn’t right for your kiddos still have an episode this week as usual. The rest of you get two episodes this week! A special thanks to our Patreon subscribers who support the show and get twice-monthly bonus episodes like this one every single month. This is the only part of the episode that is new; the rest was originally recorded in late 2018. And here it is!

The topic for today’s episode was suggested by my aunt Janice. Janice doesn’t actually listen to the podcast, not even the main feed podcast, but she sends me topic suggestions every so often. Recently, she texted me out of the blue, saying, “I’ve decided that you need to do a podcast devoted to the topic of animal poop. Butterflies eat it, dung beetles roll it, owls leave pellets with tiny animal bones, guano has commercial uses, people make no-bake chocolate and peanut butter cookies and call them cow pie cookies. Goats are gumball machines! Why are so many animals’ poops little Raisinets, but others are long thick Tootsie rolls? Why do so many animals eat poop?” Only, she didn’t say poop. She said another word.

Then I texted her back, telling her how wombat poop is actually little cubes, which blew her mind.

If you listened to the spookiest owl episode recently in the main feed, you may remember about owl pellets. Those do indeed contain bones and other indigestible parts of the owl’s prey, like fur or feathers, but the pellets themselves aren’t the same thing as poops.

Poop, or more properly excrement or feces, is what’s left after food passes through an animal’s digestive system. It contains not just the remains of food that wasn’t fully digested, but secretions from the digestive system, bacteria that live in the digestive system, and of course water. The secretions include a chemical called stercobilin, which helps the body digest fat, and which is what makes your poop brown. Yes, I googled what poop is made up of. I googled it so you wouldn’t have to. I didn’t want to know this stuff. You’re welcome.

Incidentally, the bacteria in your digestive system actually help your digestion and do other good things for your body. People who have to take strong antibiotics or radiation treatment sometimes have trouble with their digestion because the antibiotics or radiation can accidentally kill a lot of the beneficial bacteria in the digestive system. Getting the bacteria back in such cases is simple, usually taking a doctor-prescribed supplement of probiotics, or in less acute cases, just eating a lot of yogurt or certain other foods, like sauerkraut or kimchi, which naturally contain probiotics.

Humans aren’t the only animals with beneficial bacteria in the digestive system. In fact, all animals have them. Some young animals, including horses, will eat their mother’s poop to gain digestive bacteria. Personally, I prefer yogurt.

Oh, and you know how dogs like to get into the cat’s litter tray and eat the cat poop? That’s because cats are obligate carnivores, which means they have to eat meat for almost all of their nutritional needs. That means cat poop is relatively high in protein, which makes it attractive to dogs. I can’t believe I’m talking about this. I hope you’re not snacking while you listen.

I’m sure a lot of us have seen butterflies gathered together on a hiking trail or in a pasture, their wings fluttering in the sunlight, and when you get too close they all fly up together and swirl around, making you smile and think about how wonderful it is that you live in a world with butterflies. Then you look at what the butterflies were gathered on, and it’s an animal poop. Why do they do that?

While butterflies do eat nectar, nectar doesn’t contain all the nutrients they need. It especially doesn’t contain much sodium—you know, salt. So butterflies get sodium and other nutrients from rotting fruit, rotting meat, and animal dung. Also, if a butterfly has ever landed on you, it was probably attracted to your sweat, which contains salt. A lot of times, male butterflies will collect nutrients from poop and other sources and offer them to the female as a gift, hoping she’ll choose him as her mate. I personally would rather have chocolate, but I’m not a butterfly.

Moths also eat poop and other unsavory things, but some moths will cut out the middle-man, so to speak, and actually drink blood from living animals. Vampire moths mostly feed on fruit, piercing the fruit with their mouthparts to suck out the juice. But they’ll also use those same mouthparts to pierce animal skin and drink blood. Most vampire moths live in Asia and parts of southern Europe, but there is a species that lives in North America, although it hasn’t been observed drinking blood. Only male vampire moths eat blood, probably mostly for its salt content, which researchers think they pass along to the female during mating.

The size and shape of an animal’s dung depends on what it eats, how it digests its food, and the size and shape of its colon. Ruminants, like cows, evolved in areas where there was a lot of water, so their feces contain a lot of water. Ungulates, like sheep, goats, and deer, evolved in dryer conditions, so as much water is removed from the feces as possible and the animal excretes dry pellets.

But what about wombat poop? It really is shaped like little cubes, and it excretes 80 to 100 of the cubes every night, since it’s nocturnal. Why is it cube-shaped?

Wombats are territorial, and mark their territory by leaving their poop around their burrows and in areas where other wombats can easily find it. This includes on top of rocks and fallen logs, so having dung that won’t roll off these markers is beneficial for the wombat. The shape is caused by the wombat’s extremely long digestive process. It takes more than two weeks to digest the plants it eats, which allows it to absorb as much water and nutrients as possible. The upper part of its large intestine contains ridges that shape the excrement as it passes through, and the poop is so compacted from its long trip through the digestive system, that it retains its shape until it’s deposited where the wombat wants to leave it.

There are a number of different kinds of dung beetles throughout the world, and not all of them roll dung, but they all eat it. The dung beetles that roll poop are mostly those in the genus Scarabaeus. While poop-eating insects sound disgusting, they’re actually quite beneficial. Some species of dung beetles will bury the poop and lay eggs in it, which fertilizes the soil and helps disperse seeds that may be in the poop, and controls parasites. At least one dung beetle, Scarabaeus satyrus, rolls its dung balls quite a distance, and navigates by the stars and the Milky Way.

Guano is the term for both bat poop and sea bird poop, and it does indeed have commercial uses. It contains high levels of nitrogen, phosphate, and potassium, all of which are good for plants, so it’s used as a fertilizer. It also acts as a natural fungicide for plants. Bat guano was also once mined from caves to make gunpowder, which requires saltpeter, or potassium nitrate, which bat guano is full of.

The Thai Elephant Conservation Center, which you may remember from episode 23, non-human musicians, has developed a way to turn elephant dung into paper, which they then make into handmade notebooks. Since an elephant’s poop is mostly fiber from the plants it eats, and paper is made from plant fibers, it all makes sense. Don’t worry, the fibers are boiled to sterilize them before being used. Other companies have started using animal poop to make artisanal paper, including from pandas and sheep.

Scientists can learn a lot about an animal by studying its poop. Not only can a researcher get an idea of how healthy an animal is, they can learn what an animal is eating, what parasites it may have, and its reproductive cycle, since hormones are excreted with the poop too. Gathering poop doesn’t hurt the animal, and isn’t dangerous for the researcher, since they just pick it up off the ground. In zoos and other places where the animals are fed, researchers can mix additives in an individual animal’s food that help them identify which poop came from that animal. Additives include food dyes and glitter.

I think we’ve touched on everything my aunt Janice mentioned in her suggestion, except for cow pie cookies. I have no idea why people make them and call them that. That’s gross. Once I went to an office birthday party where the cake was made to look like it was made of poop. It was so realistic and disgusting-looking that half the office wouldn’t even try a piece. I don’t remember if I had any. Probably, knowing me. It was chocolate, after all.

Thanks for your support, and thanks for listening!

Episode 135: Smallest of the Large

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 109: Convergent Evolution

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

The adorable sucker-footed bat from Madagascar:

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

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

Show transcript:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!


Episode 088: Megabats and the Ahool

Our next Halloween monster is the ahool, a mystery bat from Indonesia and Java, but along the way we’ll learn about megabats in general–especially the hammerhead bat! Thanks to Grace, Grace’s sons, and Tania for the hammerhead bat suggestion!

I’ve unlocked a Patreon bonus episode about burrowing bats, which you can listen to here.

A hammerhead bat (male) from side and front. DAT SNOOT. (Photos by Sarah Olson and swiped off the web, because I have no shame.)

The Egyptian fruit bat (Photo by Amram Zabari and swiped etc etc):

Great flying foxes, sleepin (photo by Lars Petersson and swiped etc etc):

Golden-crowned flying fox, flyin (photo by Dave Irving and swiped etc etc):

Show transcript:

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

This week we’re going to learn about bats—some real, some mysterious, and all of them awesome, because bats are awesome! Listeners Grace and Grace’s sons requested an episode about hammerhead bats recently, which made me realize two things. One, I had never actually done a bats episode even though bats are one of my favorite animals, and two, back when listener Tania suggested hammerhead worms and other hammerhead animals, I totally forgot hammerhead bats were a thing!

As a special Halloween treat, I’ve unlocked a Patreon episode about burrowing bats that anyone can now listen to. I’ll put a link in the show notes, which you can click to listen on your browser. You don’t need a Patreon login or anything.

Bats are grouped into two basic types, microbats and megabats. Microbats are typical bats, usually small, flat-faced with big ears, that use echolocation to catch insects at night. Megabats are typically larger, with limited echolocation abilities and longer muzzles, and they often eat fruit. They’re sometimes called fruit bats collectively. We’re going to focus on megabats in this episode.

Let’s start with the hammerhead bat. It lives in parts of Africa near the equator, in forests and swamps, and mostly eats fruit. It especially likes figs. So do I, big flappy bat friend. It’s a big bat, with a wingspan over three feet wide, or 97 cm. Males are larger than females, and males tend to fly farther to find fruit while females generally stick to areas they know.

During the day the hammerhead bat roosts high up in trees. Researchers think it’s nocturnal mostly because it tends to overheat while flying. Naturally it prefers to nap when it’s hottest out and is only active at night when it’s cooler.

The hammerhead bat’s body is furry, with leathery wings and a mostly bare nose, although it also has long whiskers. Its fur is mostly brown or gray-brown, but its shoulders are white and it has a tuft of white fur at the base of its ears. Its tail is short and its eyes are large.

Most of what a hammerhead bat does is typical for other fruit bats. But it differs from other fruit bats in a big way. The hammerhead bat gets its name from the male’s face, which looks sort of mooselike with a big snoot, big lips, cheek pouches, a split lower lip, and a larynx that’s really big for the size of the throat. All these features allow the male hammerhead bat to make really loud honking noises to attract females. Females have smaller faces that resemble a fox or dog rather than a moose.

Often, males gather at night to honk and flap their massive wings, showing off for the females. Females fly around, checking the males out and probably giggling with each other about which ones they like best and who’s got the best voice.

This is what the hammerhead bat sounds like, although it’s not a great audio clip. At least it gives you an idea of what these bats sound like:

[hammerhead bats honking]

There are reports of the hammerhead bat attacking chickens and other birds to eat them. Fruit isn’t all that high in protein, so it could be that a bat occasionally needs nutrients it can’t get from its usual diet. This is not that uncommon in herbivorous animals, as it happens. Cows will occasionally eat chickens, deer and sheep will eat baby birds when they find them, and so forth.

Fruit bats of all kinds also visit mineral licks, especially pregnant females. But researchers have found that fruit bats don’t actually need those trace minerals. Fruit is rich in minerals. Researchers think the mineral-rich clay actually acts as a detoxifier for the bats, helping reduce the toxic effects of secondary plant compounds—leaves and unripe sections of the fruit, and so forth—that the bats eat every night that could otherwise make them sick.

Not a whole lot is known about the hammerhead bat or other megabats, for that matter. A recent discovery about how fruit bats navigate in the darkness suggests they actually use a rudimentary form of echolocation, but it’s very different from the echolocation used by microbats. For one thing, the clicking sounds they make aren’t vocalizations, they’re produced by the wings as the bat flies. For another, while the echolocation does help bats navigate, it’s not very accurate. Bats still sometimes crash into things. Researchers think echolocation has evolved separately in bats and that the megabat echolocation is not related to microbat echolocation.

The Egyptian fruit bat uses a more sophisticated version of echolocation, clicking its tongue to produce the signals it uses. It’s a relatively small megabat, with a wingspan of about two feet, or 60 cm, and it eats fruit, especially wild dates. Its echolocation is more like dolphin and whale sonar than microbat echolocation. It also has good eyesight and can easily switch between visual navigation and echolocating depending on how much light it has available.

Fruit bats are amazing flyers. Their wings are modified arms, with the fingers enormously elongated. The fingers are connected with tough but flexible skin called a membrane. Researchers have found that the membrane contains tiny muscles barely thicker than a hair that help the bat fine-tune the stiffness and shape of the membranes. This allows it to fly efficiently and quickly.

Many farmers think megabats destroy fruit crops, so they try to kill or drive off the bats. But while fruit bats do sometimes visit fruit farms, they are most likely to eat overripe fruit that was missed by pickers. This helps keep fungus and insect pests to a minimum, so it’s actually beneficial to fruit farmers. Unfortunately, many people just don’t like bats and blame them for damage to crops that’s actually done by other animals and by birds.

For instance, in Australia the flying fox is blamed for fruit crop destruction and the spreading of the Hendra virus and other diseases. But the flying fox mostly eats blossoms, especially of gum trees, along with insects, leaves, nectar, and some fruit. Birds are much more damaging to orchards. And while all bats can carry diseases, just as all mammals can, it’s not proven that the Hendra virus is spread by flying foxes at all. Domestic cats, on the other hand, do spread the virus. Keep your cats indoors. But the flying fox has been systematically persecuted in Australia for the last century, with several species having gone extinct as a result. This is a shame for many reasons, but especially because fruit bats of all kinds are important to the environment as seed dispersers and pollinators.

The biggest bat alive today is probably the great flying fox, which lives in New Guinea, Indonesia, and other nearby areas. Its wingspan can be nearly six feet across, or 1.8 meters. The golden-crowned flying fox, which lives in the Philippines, is very nearly as large, with a wingspan of over five and a half feet across, or 1.7 meters.

But there are reports of bats much larger than these. And that brings us to the ahool, a monstrous batlike creature reported from Java, Indonesia, and other areas.

The first official report of an animal called the ahool comes from western Java in 1927. Naturalist Dr. Ernst Bartels was in bed but still awake when he heard a loud call that sounded something like “a-hool!” Bartels rushed outside with a flashlight in hopes of seeing what animal had made the call, but he heard it again farther away, then again almost out of earshot.

As it happens, Bartels had grown up in western Java and knew about the legend of the ahool. It was supposed to be a monstrous bat, its wingspan some 12 feet across, or 3.6 meters. Its face was monkey-like with large eyes, and it was supposed to have feet that pointed backwards. During the day it was supposed to live in caves hidden behind waterfalls, but at night it flew out and scooped fish from the river.

Bartels did more research into the ahool legend, and eventually Ivan Sanderson, a cryptozoologist who had his hand in everything back in the day, contacted him with his own account. In 1932 Sanderson said he had seen a gigantic black bat in western Africa one night. He and his companion, naturalist Gerald Russell, had been searching for tortoises in a river when the bat flew over them. They both estimated its wingspan as 12 feet, and Sanderson said he could even see the sharp teeth in its open mouth.

Now, I can’t help but be skeptical of Sanderson’s sighting just because Sanderson was always having remarkable cryptozoological sightings with no proof but his own say-so. No one’s that lucky and unlucky at the same time. Dude should have carried a camera with him at all times, you know? Also, Bartels’ story was documented by Sanderson and is therefore a little bit suspect too.

But the ahool is an interesting cryptid because its description sounds so plausible. Even the backwards feet make sense, as bat feet have evolved to allow bats to hang upside down easily, which means when they’re right side up, their feet do appear to be backwards.

There are some discrepancies, though. Megabats all have long muzzles compared to microbats. The ahool is specifically described as having a flat face like a human or a monkey. While megabats aren’t all 100% frugivorous—that is, they don’t all eat nothing but fruit—none of them are known to eat fish. Some microbats do specialize in catching fish, though, and those bats all have longer snouts than typical insectivorous bats, although not as long as megabat snouts. And the ahool is said to stand or sit upright on the ground occasionally. While microbats sometimes do stand upright, megabats never do.

Sanderson proposed that the ahool may actually be an enormous microbat. Some microbats are actually pretty big, including the carnivorous ghost bat, also called the false vampire bat, which lives in parts of northern Australia. Its wingspan is almost 20 inches, or 50 cm. This is much larger than the smallest megabat, the spotted-winged fruit bat, which has a wingspan of only 11 inches, or 28 cm.

But microbats don’t make a lot of noise. It’s megabats who honk and call to each other rather than just squeaking. The ahool is supposedly named for its loud cry, the one Bartels heard. And remember that Bartels never saw the animal he heard.

So we have a few possibilities here.

Possibility one: the ahool is a real animal, exactly or mostly as described, with aspects of both megabats and microbats. It’s either incredibly rare or extinct these days, which would explain why there aren’t more sightings. If this is the case, it’s undoubtedly an animal completely new to science.

Possibility two: the ahool is a real animal, but it’s not well known because it’s so seldom seen. It seems to be a mixture of microbat and megabat because people who saw it made assumptions of its appearance based on what they know about bats. But some of those details are from microbats and some from megabats, and the actual animal may not look anything like its description in folklore. In this case, it’s probably a megabat.

Possibility three: the ahool is an animal entirely of folklore and myth, described as similar to various bats familiar to locals but enormously large. In this case, the myth may have grown up around the call, if the ahool’s call is that of a rare or migratory bird, seldom heard and therefore mysterious.

I can’t even make a guess as to which possibility might be the most likely, and that’s pretty awesome.

Let’s go back to the hammerhead bat for another mystery. A few years ago people started pointing out that the hammerhead bat looked a lot like drawings of the Jersey Devil, a cryptid supposedly seen in the southern New Jersey pine barrens. Newspaper accounts of the Jersey devil started circulating in the early years of the 20th century, although it may have been an established folktale before then. It’s usually described as having the head of a goat, bat wings, cloven hooves, and a forked tail, although its description varies from story to story. It’s more of an urban legend than a real cryptozoological mystery, to be honest. In 1909 a couple of guys bought a circus kangaroo, glued fake bat wings on it, and claimed they’d captured the Jersey devil.

So could someone have brought a male hammerhead bat to New Jersey and released it, where it subsequently inspired reports of the Jersey devil? I’m going to say no. The hammerhead bat can’t survive in cold weather, and if temperatures drop below 55 degrees F, or about 13 degrees C, it can’t even fly. Even if someone had captured one and somehow managed to keep it alive during the journey from equatorial Africa, how and why did it end up in the pine barrens of New Jersey? A bat that big would have excited comment even if only glimpsed in a cage on the docks, and would probably have been a big draw in traveling menageries. But there are no records of any giant bats in the area, and the theory that the Jersey devil was inspired by a hammerhead bat is a modern one. It’s still pretty cool, though.

Because bats are nocturnal and look scary, a lot of superstitions have grown up around them. Some cultures consider bats lucky, some unlucky. Some say you have to kill a bat to cancel out its bad luck, some say harming a bat will bring bad luck. But bats would avoid people completely if they could, and you don’t have anything to fear from them, not even bad luck.

I mean, except for the kind that can turn into actual vampires. Those are scary. Fortunately they only exist in horror movies.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 011: The Vampire Squid and the Vampire Bat

This week we’re going all goth in April for the vampire squid and the vampire bat. They’re so awesome I want to die.

The vampire squid looking all menacing even though it’s barely a foot long.

“I love you, vampire bat!!” “I love you too, Kate.”

Thanks for listening! We now have a Patreon if you’d like to subscribe! Rewards include patron-only episodes and stickers!

Show transcript:

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

I thought about waiting to run this episode in October, but that’s a really long way away. So we’ll have Halloween in April and talk about the vampire squid and the vampire bat.

The vampire squid has one of the coolest Latin names going, Vampyroteuthis infernalis, which means “vampire squid from hell.” It’s a deep-sea squid and until recently, not a lot was known about it. It was discovered in 1903 and originally classified as an octopus. Its body is about six inches long [15 cm], with another six inches or so of tentacles, which are connected with webbing called a cloak. Actually I’m not sure if scientists refer to this as a cloak, but if you’ve called your animal the vampire squid from hell, you can’t complain if podcasters, for instance, refer to web-connected octopus legs as a cloak.

So is it an octopus or a squid? It’s both, in a way. The vampire squid is the last surviving member of its own order, Vampyromorphida, which shares similarities with both.

The vampire squid’s color varies from deep red to velvety black. The inside of its cloak is black and the parts of its legs inside the cloak are studded with spines. Its beak is white. Basically the only thing this little guy needs to be the world’s ultimate goth is a collection of Morrissey albums.

It lives in the lightless depths of the ocean below 3,000 feet [914 meters]. There’s not a lot of oxygen down there so there aren’t very many predators. The vampire squid doesn’t need oxygen because it’s a vampire—or at least it can live and breathe just fine with oxygen saturations as little as 3%. Its metabolic rate is the lowest of any cephalopod.

The vampire squid doesn’t move a lot. It drifts gently, aided in buoyance because its gelatinous tissues are roughly the same density as seawater. Adults have two small fins sticking out from their mantle, which they flap to propel them through the water.

If something threatens a vampire squid, it brings its legs up to expose the spiny insides of its cloak and hide its body. If something really threatens a vampire squid, even though it doesn’t have ink sacs, it can eject a cloud of bioluminescent mucus, and can flash its photophores in a dazzling display of lights. These photophores are concentrated on the outside tips of its arms. If the end of an arm is bitten off, the vampire squid can regenerate it.

So we have a creepy-looking, if small, cephalopod that lives in the deep, deep sea called a vampire squid. WHAT. DOES. IT. EAT?

I hate to disappoint you, but the vampire squid eats crap. In fact, it eats the crap of animals that eat crap. There’s not a lot of food in the ocean depths. Mostly there’s just a constant rain of fish poop, algae, bits of scales and jellyfish, and other waste. Lots of little creatures live on this stuff and their poop joins the rain of barely-food that makes it down to the abyssal depths where the vampire squid waits.

The squid had two retractable filaments—not the same thing as the two feeding tentacles true squids have, but used for feeding. The filaments are extremely long, much longer than the vampire squid itself. It extends the filaments, organic detritus falls from above and sticks to them, and the vampire squid rolls the detritus up with mucus from its arm tentacles into little sticky balls and pops the balls into its mouth.

That’s not very goth. Or it might be incredibly goth, actually.

Most cephalopods only spawn once before they die. A 2015 paper in Current Biology reports that the vampire squid appears to go through multiple spawning phases throughout its life. It may live for a long time too, but we don’t know for sure. There’s still a lot we don’t know about the vampire squid.

Because squids and octopuses are soft bodied, we rarely find them in the fossil record. In 1982, though, a beautifully preserved octopus body impression was found in France in rocks dating to 165 million years ago. And guess what kind of octopus it turned out to be! Yes, it’s related to the vampire squid.

If the vampire squid is the kind of pensive goth who listens to The Smiths and reads Poe in cemeteries, the vampire bat is out clubbing with its friends, blasting Combichrist, and spending its allowance in thrift shops. There are three species of vampire bat, but they’re different enough from each other that each belongs to its own genus. They’re native to the Americas, especially tropical and subtropical environments, although they haven’t been found any further north than Mexico. And yes, vampire bats do actually feed on blood. It’s all they eat.

Vampire bats are small, active, and lightweight. They’re only about 3 ½ inches long [9cm] with a 7-inch wingspan [18 cm], and weigh less than two ounces [57 grams]. They live in colonies that consist of big family groups: a small number of males and many more females and their babies. Males without a colony hang out together and probably never clean up their apartments.

Vampire bats belong to the leaf-nosed bat family, and like other leaf-nosed bats they sleep during the day and hunt at night. But the vampire bat doesn’t actually have a nose leaf. That’s a structure that aids with echolocation, and vampire bats don’t need the high level echolocation ability that insect-eating bats do. They get by with a reduced ability to echolocate, but they have another highly developed sense that no other mammal has: thermoreception. They use it to determine the best place to bite their prey. The warmer, the better. That’s where the blood is.

The vampire bat also has good eyesight, a good sense of smell, and hearing that’s attuned to the sound of breathing. A bat frequently remembers the sound of an individual animal’s breathing, and returns to it to feed night after night. What vampire bats don’t have is a very good sense of taste. They don’t really need it. In fact, they don’t have the kind of bad food avoidance that every other mammal has. In a study where vampire bats were given blood with a compound that tasted bad and made them throw up, the next time they were offered the bad-tasting blood, they ate it anyway.

Most bats are clumsy on the ground. They’re built for flying and for hanging from perches. But vampire bats are agile. They crawl around and even run and jump with no problems.

Two species of vampire bat prey mainly on birds, while the third—the common vampire bat—feeds on mammals. Bird blood has a much higher fat content than mammal blood, which is higher in protein. But results of a study released in January 2017 found that hairy-legged vampire bats, which usually prey on large wild birds, had started feeding on domestic chickens as their wild prey became scarcer—and then they started feeding on human blood.

A vampire bat doesn’t suck blood. It makes a small incision with extremely sharp fangs and laps up the blood with its grooved tongue. It may even trim hair from the bite site first with its teeth. Its saliva contains an anti-coagulate called draculin that keeps the blood flowing. The bat doesn’t eat much, because let’s face it, it’s just a little guy. In order to hold more blood, as soon as it starts to feed its digestion goes into overdrive. Within some two minutes after it starts to eat, the bat is ready to urinate in order to get rid of the extra fluid so it can hold more blood. A feeding session may last about 20 minutes if the bat isn’t disturbed, and the bat may drink about an ounce of blood in all.

A vampire bat needs to eat at least every two days or it will starve. A bat that hasn’t found prey in two nights will beg for food from its colony mates, which often regurgitate a little blood for the hungry bat to eat. New mother bats may be fed this way by her colony for as much as two weeks after she’s given birth so that she doesn’t have to hunt. Baby vampire bats drink their mother’s milk just like any other mammal.

If a mother bat doesn’t return from hunting, other colony members will take care of her baby so it won’t die. Colony members groom each other and are generally very social. Even the male bats that aren’t part of the colony are allowed to roost nearby. Nobody fights over territory. These are nice little guys.

Vampire bats do sometimes carry rabies, but it’s pretty rare compared to infection rates in dogs. They are more dangerous to livestock than to humans. Attempts to kill off vampire bat colonies to stop the spread of rabies actually has the opposite effect, since bats from a disturbed colony will seek out another colony to join.

Vampire bats have considerable resistance to rabies and frequently recover from the disease, after which they’re immune to reinfection, and there’s some preliminary evidence to suggest that native human populations in areas where vampire bats are common may also have developed some resistance to rabies. Researchers hope that this finding will lead to better treatment of rabies in the same way that the draculin anticoagulant in vampire bat saliva led to advances in blood-thinning medications.

I like to imagine a vampire bat hanging out with a vampire squid. The bat would sip blood from a tiny wineglass and fidget with its jewelry while it tries to conversation. The squid would just stare at the bat. Then it would eat a globule of crap. The bat would pee on itself and the whole evening would just be a bust. Also, one of them would drown but if I can imagine a tiny wineglass I can imagine a tiny bat-sized bathysphere or something. Never mind.

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 at patreon.com/strangeanimalspodcast if you’d like to support us and get twice-monthly bonus episodes for as little as one dollar a month.

Thanks for listening!