Tag Archives: amphisbaenian

Episode 158: Legless Lizards and Other Not-Snakes

Posted on by

Podcast: Play in new window | Download (Duration: 12:58 — 13.1MB)

Subscribe: RSS | More

What’s the difference between a snake and a legless lizard? Find out this week and learn about all kinds of interesting reptiles without legs that aren’t actually snakes!

The slow-worm. Not a snake:

Burton’s legless lizard. Not a snake:

The excitable delma. Not a snake:

The Mexican mole lizard. Not a snake or a worm:

The red worm lizard (Amphisbaena alba). Also not a snake or a worm, but honestly, it looks a lot like I imagine the Mongolian death worm to look:

The giant legless skink. Not a snake:

Stacy’s bachia. Not a snake:

Further reading (and this is where I got the Stacy’s bachia picture above):

Bachia lizards–look, no hands!

An Explosive Enigma from Kalmykia—the ‘Other’ Mongolian Death Worm?

Show transcript:

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

A couple of weeks ago we discussed the Mongolian death worm and the possibility that it was an animal called an amphisbaenian, which is a reptile without legs that’s not a snake. But there are lots of other legless reptiles that aren’t snakes. So this week we’re going to learn about legless lizards and their friends.

Researchers have determined that leglessness evolved in reptiles many different times in species that aren’t related, often in species that spend at least part of their time underground. If the legs get in the way of burrowing or other movement, over time individuals born without legs or with much smaller legs end up finding more food than those with legs. That means they’re more likely to reproduce, and their offspring may inherit the trait of no legs or smaller legs.

Some legless lizards look so much like snakes at first glance that it can be hard to tell them apart. The common slow-worm, for instance, lives throughout most of Europe and part of Asia. It grows to about a foot and a half long, or 50 cm, and is brown. It mostly eats slugs and worms so it spends most of its time in damp places or underground. But while it looks superficially like a snake, it’s not a snake. It’s a lizard with no legs. Like some other lizard species, including many legless lizards, it can even drop its tail if it’s threatened and then regrows a little tail stump.

So how can you tell the difference between a legless lizard and a snake? The one big clue is if the reptile blinks. Snakes don’t have eyelids; instead, their eyes are protected by a transparent scale that covers the eye completely. Lizards have eyelids and blink. Legless lizards have a different head shape from snakes too, usually more blocky and less flattened. The tongue is not so much forked as just notched, and shorter and less slender than a snake’s tongue.

Species of one family of legless lizards do sometimes have legs. Honestly, this is almost as confusing as the whole deer and antelope mix-up from episode 116. The family is Pygopodidae and they’re actually most closely related to geckos although they don’t look much like geckos. They look like snakes, and to make things even more complicated, geckos and Pygopodids don’t have eyelids. I know I know, I just said lizards have eyelids but geckos are an exception. Pygopodids don’t have front legs at all, but some do have vestigial hind legs that look more like little flaps than actual legs. They’re sometimes called flap-footed lizards as a result. They live in Australia and New Guinea.

One Pygopodid is Burton’s legless lizard, which does actually have vestigial hind legs. It lives in parts of Australia and Papua New Guinea and is kind of a chunky reptile with a pointed nose. It’s brown or gray, sometimes with long stripes, and can grow to more than three feet long, or one meter. It eats other lizards, especially skinks, but will also sometimes eat small snakes.

Burton’s legless lizard mostly stays in leaf litter in forests. Sometimes it will twitch the end of its tail to attract a lizard, which it then grabs by the neck. It will swallow small lizards whole, but if it’s too big to swallow, it will just hold onto its neck until the lizard suffocates or just gives up out of exhaustion. It can also retract its eyes so they’re less likely to be injured if its prey fights back.

The excitable delma is another pygopodid, this one without any legs at all. It lives in many parts of Australia and can grow nearly two feet long, or 54 cm, but almost half that length is tail. It’s shy and nocturnal, so even though it’s very common, it’s seldom seen. It’s brown or grayish with darker stripes on its head. The reason it’s called the excitable delma is because it uses its long tail to jump, twisting and changing directions as it jumps repeatedly up to six inches off the ground, or 15 cm. It does this to escape from predators but it also sometimes just jumps around for the heck of it, according to observations of excitable delmas in captivity. It can also make a squeaky sound. It likes dry, rocky areas and eats insects.

There are other reptiles that look like snakes but aren’t, in addition to the legless lizards. We talked about the amphisbaenians in the Mongolian animals episode a few weeks ago, and also in episode 10. Amphisbaenians are sometimes called worm lizards because they look less like snakes than they do worms. They’re related to both legless lizards and snakes but lost their legs independently.

The amphisbaenian moves like a worm, not a snake. Its skin is loosely attached to its body so that it can move freely, and it bunches up its skin the way a worm bunches up its body, then extends it to move forward or backward. This kind of action is called peristalsis, by the way. Unlike worms, the amphisbaenian has scales because it’s a reptile, but the scales are often arranged in rings that make it look even more like an earthworm. Many amphisbaenians are pink like many earthworms, too.

Most amphisbaenians live underground their entire lives, hunting worms, insect grubs, and other small animals. In most cases they only come to the surface at night or after a heavy rain. Most have no legs at all, but one family consisting of four species, all of them native to Mexico, has little front legs. One of these species is the Mexican mole lizard, which can grow over a foot long, or more than 30 cm. It mostly eats soft-bodied animals like worms and termites, but it will occasionally eat small lizards. It’s pink and has little black dots for eyes and is actually really cute, but don’t let that fool you. If you are a worm, the Mexican mole lizard is a murder machine. It has sharp little teeth that it uses to bite pieces from its prey instead of swallowing them whole.

All the other known amphisbaenians have no legs at all, and for most species we know very little about them. The red worm lizard, for instance, lives throughout much of western South America and appears to be common, but it lives underground and is hardly ever seen. It’s the largest amphisbaenian known and can grow nearly three feet long, or 85 cm, although it’s only a few inches thick, or around 6 cm. It’s brown, reddish, or yellowish in color with a white belly and has tiny eyes that are barely visible. Its tail is blunt and rounded like other amphisbaenian tails, but its tail is tough enough to withstand bites from predators without being injured. If the red worm lizard feels threatened, it raises its head and tail and bends itself into a U shape so that it looks like it has two heads.

That’s why the amphisbaenian has that name, by the way. In ancient mythology, the amphisbaena was a serpent with a head on each end of its body. It was said to mostly eat ants, and that’s actually a good observation of the real amphisbaenian, which often eats ants, termites, and other insects.

Legless skinks are another group of lizards that either have no legs at all or just little flaps instead of hind legs. The males are the ones with the hind leg flaps, which they use to hold onto the female while mating. Most legless skinks look sort of like amphisbaenians, with a blunt-ended tail that’s sometimes hard to tell from the head, but more snakey than wormy for the most part.

One example is the giant legless skink, which is dark gray or black with no legs, and which lives in South Africa. It grows almost a foot and a half long, or 42 cm, and is a little bit of a chonk. We still don’t know much about it but it probably eats insects and other invertebrates like most legless skinks do.

A while back, Llewelly sent me a link to an article about Stacy’s bachia, a lizard that lives in the tropics of South America. It’s a member of the spectacled lizards, which all have lower eyelids that are transparent. That way the lizard can see even if its eyes are closed. I put a link to the article in the show notes if you want to read it.

Stacy’s bachia usually has no hind legs, although it may have little stubby ones, but it hatches with small front legs. But it spends most of its life burrowing in soil and in leaf litter as it hunts termites, ants, and other small animals, and eventually all its legs wear away to nothing.

Let’s finish with a mystery animal. Kalmykia is a small region of Russia, and the native people of the area are called Kalmyks. The Kalmyks report that there’s an animal that lives in both the steppes and in sand dunes in the desert that looks like a snake but isn’t a snake, which they actually call the short gray snake. It grows around 20 inches long, or 50 cm, and has smooth skin and a tail that’s short and rounded at the end. It has no legs. This report is from zoologist Karl Shuker’s blog, and check the show notes for a link. The person who told him about this animal also says it’s about six to eight inches thick, or up to 20 cm, so if that’s correct it’s even more of a chonk than the giant legless skink.

Kalmykia is west of Kazakhstan, which is west of Mongolia, so there’s always the possibility that this legless animal is related to or the same animal as the Mongolian death worm that we talked about in episode 156. But Kalmykia is actually pretty far away from Mongolia, and the short gray snake is different from the death worm in two important ways. One, reports say it has no bones. If this is true, it must be some kind of invertebrate, not a reptile. It’s also supposed to move like a worm, although remember that the amphisbaenian does too and it’s a reptile.

But the other thing reported about the short gray snake is much weirder than having no bones. Apparently if someone hits the animal in a particular place on its back—presumably with a stick—it EXPLODES. It explodes into goo that spreads for several feet in every direction, or about a meter, leaving nothing else behind.

It’s possible this isn’t a real animal but a folktale, something like American tall tales about the hoop snake that’s supposed to grab its tail in its mouth and roll itself along like a hoop. The hoop snake is not a real animal, in case you were wondering. There’s no way of telling whether the exploding boneless short gray snake is a real animal, a folktale, or reports of more than one real animal that have gotten mixed up in translation. Hopefully someone who lives in Kalmykia will investigate and find out more. In the meantime, don’t hit any animals with sticks. For one thing, that’s mean. For another, it might explode and leave you covered in goo.

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.

Thanks for listening!

Episode 156: Animals of Mongolia

Posted on by

Podcast: Play in new window | Download (Duration: 20:41 — 21.0MB)

Subscribe: RSS | More

In honor of my new favorite band, The Hu, let’s learn about some animals from their country, Mongolia! (You can also watch the “Wolf Totem” video with English lyrics.)

The Hu. Oh my heart:

If you need the podcast’s feed URL, it’s https://strangeanimalspodcast.blubrry.net/feed/podcast/

A handsome prize-winning domesticated yak and rider (photo taken from this site):

The saiga, an antelope with a serious snoot:

A Bactrian camel (photo by *squints* Brent Huffman, looks like):

The taimen, a fish that would swallow you whole if it could:

Further watching:

A clip from the TV show Beast Man showing how moist the soil is in parts of the Gobi

Show transcript:

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

Recently, podcaster Moxie recommended a band she liked on her excellent podcast Your Brain on Facts. The band is called The Hu, spelled H-U, and she mentioned they were from Mongolia. I checked the band out and FELL IN LOVE WITH THEM OH MY GOSH, so not only have I been recommending them to everyone, I also want to learn more about their country. So let’s learn about some interesting animals from Mongolia.

But first, a quick note. About six months ago I had to migrate the site to an actual podcasting host, since I’d run out of memory on my own site. Well, there doesn’t seem to be any point to keep the old site open anymore since all the podcasting apps I checked appear to have the new feed and everything is on the new website. So in another week or two, the old site will close. If you suddenly stop receiving new episodes, please email me at strangeanimalspodcast@gmail.com and let me know what app you use for podcast listening, so I can get it updated. In the meantime, if your app gives you the option of entering a podcast feed manually, I’ve made a new page on the website, strangeanimalspodcast.blubrry.net, where you can copy and paste the feed URL. It’s also in the show notes. Feel free to contact me if you have any questions or if something isn’t working. Now, back to Mongolia and its animals.

Mongolia is located in Asia, north of China and south of Russia, with the Gobi Desert to the south and various mountain ranges to the north and west. You actually probably know some Mongolian history without realizing it. You’ve heard of the Great Wall of China, right? Well, it was built to keep out the Mongols, who would ride their horses into China and raid villages. Genghis Khan was the most famous Mongol in history, a fearsome warrior who conquered most of Eurasia in the early 13th century.

While you’re thinking about that, here’s a short clip of my favorite Hu song, called “Wolf Totem.” There’s a link in the show notes if you want to watch the official video.

Oh my gosh I love that song.

Anyway, Mongolia has short summers but long, bitterly cold winters. Many people are still nomadic, a traditional culture that’s horse-based. A lot of Mongolia is grassland referred to as the steppes, which isn’t very good for farming, but which is great for horses. Domesticated animals include horses, goats, and a bovid called the yak. Let’s start with that one.

The yak is closely related to both domestic cattle and to bison, and is a common domesticated animal in much of Asia. The wild yak is native to the Himalaya Mountains in Eurasia. It’s a different species from the domesticated yak and is larger, with a big bull wild yak standing up to 7.2 feet at the shoulder, or 2.2 meters. A big bull domesticated yak is closer to 4 ½ feet high at the shoulder, or almost 1.4 meters. The wild yak is usually black or brown, but domesticated yaks may be other colors and have white markings. Occasionally a wild yak is born that has golden fur.

Both male and female yaks have horns, although the males usually have larger horns with a broader spread than the females. The male also has a larger shoulder hump than the female, much like bison, and males are also larger and heavier. The reason the domesticated yak is so popular in the mountains and in areas where winters are long and cold, like Mongolia, is that it has long, dense hair with a soft undercoat that keeps it warm. It’s also naturally adapted to high altitudes where there’s less oxygen, with large lungs and heart. As a result, it doesn’t do well in lower altitudes and can even die of heat if it gets too warm, since it can’t sweat.

The yak is domesticated for its meat and milk, to pull plows, as a riding animal, and for its soft undercoat which is combed out in spring and used to make yarn. Even the yak’s droppings are useful, since they’re mostly undigested plant fibers that burn really well once they’re dry, so they can be used instead of wood to build fires.

In Mongolia, yak milk is used to make butter, cheese, and yogurt. And vodka. Yak races and yak festivals are increasingly popular as tourist attractions, but yak herding is a tradition dating back thousands of years.

The wild yak is a protected species where it still lives, mostly in China, India, and Tibet, but it’s still threatened by poaching and habitat loss due to domesticated yak herds pushing out their wild cousins. In the wild, the yak prefers to live in elevations too high for trees to grow. It eats grass and other plant material and can survive on a diet too poor to sustain cattle. This is because it has a larger rumen and the plants it eats can stay in its digestive tract for longer to extract as many nutrients as possible.

It’s rare for a domesticated animal to also be endangered, but yak herding in Mongolia is in steep decline, with 70% fewer yaks raised now than there were twenty years ago. There are a number of reasons for the decline. More people are moving to cities in Mongolia since they can make more money there instead of farming. Some farmers have started raising cattle or yak-cattle hybrids instead of yaks, since cattle and cattle hybrids produce more milk and meat even though they eat considerably more than yaks do. Worse, cloth made of sheep’s wool and other fibers is being exported by Chinese farmers labeled as Mongolian yak wool, which has caused the market for actual yak wool to crash. Yak wool is as soft and warm as cashmere, which comes from goats, but yaks are much better for the fragile mountain environment in Mongolia than goats are. Hopefully, increased tourism, including yak festivals, will help farmers make money from their traditional ways of life.

Instead of mooing like a cow, the yak grunts, although wild yak are usually silent. This is what a domesticated yak sounds like:

[yak grunting]

Another bovid, this one found only in Mongolia, is the Mongolian saiga. Some researchers consider it a subspecies of the saiga that was once found throughout Eurasia while others consider it a separate species. It’s critically endangered, possibly with as few as 5,000 animals left in the wild, threatened by poaching and competition with livestock. But the saiga frequently has twins instead of just one baby at a time, which helps its numbers increase quickly as long as people stop shooting the males for their horns. Some people think have medicinal qualities. They don’t, of course. The saiga almost went extinct back in the 1920s, but it recovered, so it can recover again as long as people leave it alone.

The saiga stands nearly three feet tall at the shoulder, or 81 cm, and its coat is usually a sandy pale brown in color. In winter it grows a long coat to keep warm. It’s also rather stocky in shape compared to other antelopes, which helps keep it warm too. But the main adaptation it has for cold weather is its nose. The saiga has a remarkable snoot. It almost looks like it has a little trunk. Its muzzle is considerably enlarged to make plenty of room for large nasal passages, which warms air before it reaches the lungs and also filters dust from the air. The nostrils point downward. The males have pale-colored horns that can grow nearly nine inches long, or 22 cm, although the closely related Russian saiga has horns that are almost twice that long. The horns grow upward and slightly back. The saiga migrates across the steppes and lives in herds that are sometimes quite large.

Another animal that’s domesticated but still lives wild in some parts of southern Mongolia and northern China is the Bactrian camel. That’s the camel that has two humps instead of just one. Like the yak, the domesticated and wild Bactrian camels are different species although they’re closely related. The wild Bactrian camel is smaller with a flatter head. A domesticated Bactrian camel can stand up to 7 ½ feet high at the shoulder, or 2.3 meters.

The wild Bactrian camel is critically endangered due to poaching and habitat loss, although it’s protected in both Mongolia and China. There may be only 1,000 of them left in the wild, and some of those are hybrids of wild and feral domesticated Bactrian camels. Since they’re different species, offspring of wild and domesticated Bactrian camels are often infertile. A wild Bactrian captive breeding program in Mongolia is underway and has been successful so far.

When you think of a camel, you probably think of a hot desert. Camels of all kinds are well adapted to desert life. The one-hump camel is a dromedary, which is a domesticated animal native to the Sahara Desert in northern Africa and other arid regions. But the two-humped Bactrian camel is adapted to a different kind of desert, the cold desert. Although it can get hot in the Gobi Desert in summer, winters are long and very cold, but mainly a desert just doesn’t get much rain. In the case of the Gobi, what little moisture it receives in winter is mainly from snow and frost, although it also gets an average of almost 8 inches of rain in the summer, or 19 cm.

The wild Bactrian camel, therefore, has to be able to survive without a lot of water. Some people think camels store water in their humps, but the humps are actually made up of fat. Fat is full of water, though, and when the camel can’t find any food or water, its body will reabsorb the fat to keep itself alive. If you see a camel with floppy or skinny humps, you know it’s not had much to eat recently and has had to use up its fat stores.

The wild Bactrian camel grows thick fur in winter to keep it warm in temperatures that can drop to -27 degrees Fahrenheit in winter, or -32.8 Celsius, but it sheds a lot of this heavy coat in summer when temperatures can soar to 99 F, or 37 C. Unlike most animals, it can safely eat snow without risking hypothermia, where the body core temperature falls to dangerous levels. It can also safely drink water that’s even saltier than the ocean. It lives in small herds that travel across the desert from one water source to another, since if it stayed in one area it would soon eat all the food available. It eats any plants it can find.

Mongolia has several rivers and lakes, so naturally it has some interesting water animals too. The taimen [TIE-min] is a large fish sometimes called the Eurasian river trout or Siberian giant trout, but it’s actually more closely related to the salmon. It lives in parts of Mongolia and Russia but is threatened by overfishing and water pollution. Until recently in Mongolia, people didn’t eat much fish, plus the taimen was considered the offspring of an ancient river spirit so was left alone. These days, unfortunately, not only are more people eating fish in Mongolia, sport fishing has become a big tourist draw. Conservationists are encouraging anglers to practice catch and release to save the remaining population.

The taimen grows up to six feet long, or two meters, and is a vicious predator. It will eat anything it can catch, including smaller taimen, and in fact will occasionally try to swallow a fish that’s too big, and will suffocate and die as a result. It lives in swift-moving water but is sometimes found in lakes. It grows slowly and lives a long time, and there are rumors of it hunting in packs. As a result, it’s sometimes called the river wolf. Stay away from anything called the river wolf, that’s my advice.

It wouldn’t be an episode about Mongolian animals if we didn’t talk about a mystery animal called the Mongolian death worm. We talked about it once before way back in episode ten, about electric animals, but that was a long time ago so let’s look at it again now.

The story goes that a huge wormlike creature lives in the western or southern Gobi Desert, and most of the time it stays below ground. During the rains of June and July it sometimes comes to the surface. It’s generally described as looking like a sausage or an intestine, red or reddish in color, as thick as a person’s arm, and as long as three or four feet, or up to about 1.5 meters. Its head and tail look alike, sort of like a giant fat earthworm, although some reports say it has some pointy bristles or spines at one end. Touching a death worm is supposed to lead to a quick, painful death, because why would you name something a death worm if it didn’t kill you? Some people report that it can even spit venom or emit an electrical shock that can kill people or animals at a distance.

The National Geographic Channel has a show called Beast Man, or used to, I don’t know, but in 2018 it aired an episode about the Mongolian death worm. I didn’t watch the whole episode, just clips, and while they didn’t actually find one, it was interesting. One lady they interviewed, who saw a death worm when she was a little girl, said it was about two feet long, or 60 cm, reddish in color, and its head and tail looked the same. This matches up with what other people have reported. In one clip, the show’s host tests the soil moisture content in the southern Gobi and is surprised that underneath the dry surface, the ground is actually quite moist. I’ll put a link to that one in the show notes.

There are actually earthworms that live in parts of the Gobi, including two species described in 2013. The earthworms don’t resemble reports of the Mongolian death worm, but if an earthworm can survive, other soft-bodied creatures can too. That’s assuming that the death worm is actually a worm and not a reptile or amphibian of some kind.

The best suggestion for what the death worm might be is an animal called the amphisbaenian. It’s sometimes also called the worm lizard, and while it’s not any kind of lizard, it is a reptile. Amphisbaenians live in many parts of the world, including most of South America and parts of North America, parts of Africa, southern Europe, and the Middle East. But since amphisbaenians live almost all of their lives underground, it’s very likely that species unknown to science live in other places. And much of Mongolia is extremely remote and probably not very well explored by scientists.

Amphisbaenians resemble snakes but they also resemble worms. The eyes are tiny and can be hard to spot, and the head and tail look very similar as a result. Many species are pink or reddish in color, although some are blue or other colors, including spotted, and many have scales that grow in a ringed pattern that make it look even more like an earthworm. But they’re not big animals, generally around six inches long, or 15 cm. Also, they’re slender like an earthworm, not as big around as someone’s arm. And they’re completely harmless to humans and large animals.

That doesn’t mean there can’t be a big amphisbaenian living in the remote parts of the Gobi, rarely seen even by the people who live there. Or, of course, the Mongolian death worm might be a completely different kind of animal, one totally unknown to science—maybe one that’s related to the amphisbaenian but radically different in appearance. Or it might be a mythical monster, although there are enough plausible-sounding witness sightings to think there’s something in the Gobi that looks like a big fat red horrible worm, even if it’s not actually dangerous.

What worries me, though, is that there don’t seem to be any sightings from recent times. Only old people report having seen a death worm back when they were young. Considering that so many Mongolian animals are endangered, it could be that the death worm is also declining in numbers so that fewer of them are around to be seen. Let’s hope Mongolian scientists are out there looking for the death worm and that they figure out what it is so it can be protected and studied in its natural habitat.

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.

Thanks for listening!

Episode 010: Electric Animals

Posted on by

Podcast: Play in new window | Download (Duration: 14:02 — 14.2MB)

Subscribe: RSS | More

This week’s episode is about electric animals! There are so many of them that I could only touch on the highlights.

We start with the electric eel. It’s not actually an eel but it is most definitely electric. This one has just read some disturbing fanfic:

The oriental hornet is a living solar panel:

The platypus’s bill is packed with electricity sensors. I couldn’t make this stuff up if I tried:

Amphisbaenids are not electric AS FAR AS WE KNOW. Bzzt.

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.

This week we’re looking at electric animals! You’ve probably heard of the electric eel, but you may not know there are a lot of fish, insects, and even a few mammals that can sense or generate electric impulses. This is a re-record of the original episode with some updated information.

All animals generate electric fields in their nerves and the contracting of muscles. Animals that can sense these fields are called electroreceptive. An electroreceptive animal can find hidden prey without using its other senses.

To take that a step further, many electroreceptive animals can also generate weak electrical fields, usually less than a single volt—small electrical pulses or a sort of wave, depending on the species, that can give them information about their environment. Like a dolphin using echolocation, a fish using electro-location can sense where potential prey is, where predators, plants, and rocks are, and can even communicate with other fish of its same species. Of course, those same electric pulses can also attract electroreceptive predators. It’s hard being a fish.

But in some cases, the animal can generate an electric shock so strong it can stun or kill other animals. The most famous is the electric eel, so let’s start with that one.

The electric eel isn’t actually an eel. It’s a type of knife-fish related to carp and catfish. Some other species of knife-fish generate electric fields, but the electric eel is the only one that uses it as a weapon.

The electric eel is a weird fish even without the electric part. It can grow over eight feet long, or 2.5 m, lives in freshwater in South America, and gets most of its oxygen by breathing air at the surface of the water instead of through its gills. It has to surface for air about every ten minutes or it will drown. That’s a weird habit for a fish, but it makes sense when you consider that many electric eels live in shallow streams or floodplains with a tendency to dry up between rains. Oh, and electric eels frequently swim backwards.

A male electric eel makes a foam nest for females with his spit, and the female lays her eggs in it—as many as 17,000 eggs, although 1,200 is more common. The male defends the nest and hatchlings until the rainy season starts and the young electric eels can swim off on their own.

The electric eel has rows of some 6,000 specialized cells, called electrocytes, that act like batteries to store energy. When all the electrocytes discharge at the same time, the resulting shock can be as much as 860 volts, although it’s only delivered at about one amp. I have no idea what that means because I don’t understand electricity.

Since the electrocytes are all found in the animal’s tail, and electric eels are mostly tail, the fish will sometimes curl up and hold its prey against its tail to increase the shock it receives. This honestly sounds like something a villain from a superhero movie would do. The electric eel will also sometimes leap out of the water to shock an animal it perceives as a threat.

You do not want to be in the water when an electric eel discharges. It probably won’t kill you unless you have a heart problem, but it could stun you long enough that you drown. And if more than one electric eel discharges at the same time, the danger increases. There’s a River Monsters episode about electric eels that shows a whole bunch of them in water so shallow that they’re barely covered. Walking through that pond would probably be deadly. I also really love that show.

How does the electric eel not shock itself? Well, it probably does. All of its vital organs are in the front fifth of its body, and well insulated by thick skin and a layer of fat. But its discharges are extremely fast. Think taser, not sticking a fork in a wall socket, which by the way is something you should not do. The charge naturally travels away from its tail and into the nearest object, usually its prey.

There are three known species of electric eel, all of which live in the Amazon basin in South America. Two of the three species were only identified in 2019 after DNA studies of 107 specimens. One of the new species, Electrophorus voltai, can discharge up to 860 volts of electricity, higher than the well-known E. electricus. Researchers think E. voltai has evolved to generate higher jolts because it lives in the highlands of the Brazilian Shield, where the water is clear and doesn’t conduct electricity as well as the mineral-rich water in other electric eel habitats.

One last thing about the electric eel. It can shock people who touch it up to eight hours after it dies.

Most electric animals are fish since water conducts electricity well. Some other notable electric fish are the stargazer, a venomous bottom-dwelling ocean fish that generates shocks from modified eye muscles; the paddlefish; the electric catfish; and of course sharks.

Sharks are the kings of electroreceptive animals. Some sharks can sense voltage fluctuations of ten millionths of a volt. Sharks only sense electricity; they can’t generate it. But some of their cousins, the electric rays, can generate an electric shock equivalent to dropping a toaster in a bathtub, which by the way is another thing you shouldn’t do although why would you even have a toaster in the bathroom?

Scientists are only just discovering electric use in insects. It’s probably more widely spread than we suspect, and it’s used in ways that are very different from fish. The oriental hornet, for instance, converts sunlight into energy like a tiny flying solar panel. Researchers think the hornet uses that extra energy for digging its underground nests.

Flying insects generate a positive charge from the movement of air molecules, which is basically what static electricity is. It also happens to moving vehicles, and which is why you should touch the metal of your car to discharge any static electricity before pumping gasoline so you don’t spark a fire. This episode is full of safety tips. In the case of bees, this static charge helps pollen adhere to their bodies. You know, like tiny yellow socks stuck to a shirt you’ve just taken out of the dryer. When a bee lands on a flower, its charge also temporarily changes the electrical status of the flower. Other bees can sense this change and don’t visit the flower since its nectar has already been taken.

Spiderwebs are statoelectrically charged too, which actually draws insects into the web, along with pollen and other tiny air particles. This helps clean the air really effectively, in fact, so if you have allergies you should thank spiders for helping keep the pollen levels down. The webs only become electrically charged because the spider combs and pulls at the thread during the spinning process.

Only three living mammals are known to be electroreceptive. The South American Guiana dolphin has a row of electroreceptors along its beak, visible dots called vibrissal crypts. They’re basically pores where whiskers would have grown, except that marine mammals no longer grow whiskers. The vibrissal crypts are surrounded by nerve endings and contain some specialized cells and proteins. Researchers think the dolphins use electroreception to find fish and other prey animals in murky water when the animals are so close that echolocation isn’t very effective. A lot of toothed whales, including other dolphins, show these dots, and it’s possible that the Guiana dolphin isn’t the only species that is electroreceptive.

The platypus and its cousin the echidna are the other two electric-sensing mammals. These two are both such odd animals that they’re getting their own episode one day—and that episode is # 45! They are weird way beyond being the mammals that lay eggs deal. So I’ll just mention that their bills are packed with electroreceptors. The platypus in particular uses electroreception as its primary means of finding prey in the mud at the bottom of ponds.

There are undoubtedly more animals out there that make use of electrical fields in one way or another. One possible addition to the list, if it exists at all, is called the Mongolian death worm.

Nomadic tribes in the Gobi Desert describe a sausage-like worm over a foot long, or 30 cm, and the thickness of a man’s arm. Its smooth skin is dark red and it has no visible features, not even a mouth, which makes it hard to tell which end is the head and which is the tail. It squirms or rolls to move. It spends most of its life hidden in the sand, but in June and July it emerges, usually after rain, and can kill people and animals at a distance.

In his book The Search for the Last Undiscovered Animals, zoologist Karl Shuker discusses the death worm at length, including the possibility that it might be able to give electric shocks under the right conditions. Among the reports he recounts are some that sound very interesting in this regard, including that of a visiting geologist poking an iron rod into the sand, who dropped dead with no warning. A death worm emerged from the place where the geologist had been prodding the sand. I’m going to add “don’t poke an iron rod into the sand of the Gobi Desert” to my list of warnings.

The Gobi is a cold desert and has bitter winters, but it’s still a desert, which means it’s arid, which means the death worm probably isn’t a type of earthworm or amphibian—nothing that needs a lot of moisture to stay alive. On the other hand, two types of earthworms have recently been discovered in the Gobi, and there are a few amphibians, especially frogs, that have evolved to live in areas that don’t receive much rain. In episode 156, about some animals of Mongolia, we talk about the Mongolian death worm again if you want to know a little more. Some parts of the Gobi get more moisture than others and may be where the death worm lives.

Shuker suggests it might be a kind of amphisbaenid. Amphisbaenids are legless lizards that look more like worms than snakes. They move more like worms than snakes too, and spend a lot of their lives burrowing in search of worms or insects. No known species of amphisbaenid can generate electric shocks, but then again, only one of the over 2,000 known species of catfish generates electricity.

It’s not completely out of the realm of possibility that electrogenesis might develop in a reptile, assuming that’s what the death worm is. Sand isn’t a good conductor of electricity, but wet sand is. The death worm might ordinarily use weak electrical pulses to stun its small prey, but if it emerges after rain because its tunnels are temporarily flooded, it might feel vulnerable above ground and be more likely to discharge electrically as a warning when approached.

Of course, as always, until we have a body—until we know for sure that the Mongolian death worm is a real animal and not a folktale, we can’t do more than speculate. But it is interesting to think about.

As far as I can find, no living reptiles or birds show any electrical abilities akin to those in fish and other aquatic animals. But electroreceptors in fish were only discovered in the 1950s. There’s a lot we still don’t know. Always another mystery to solve!

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.

Thanks for listening!