Episode 010: Electric Animals

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!

Episode 006: Sea Monsters

This week’s episode is all about sea monsters: mysterious sightings, possible solutions, and definitely discovered monsters of the world’s oceans!

The giant oarfish! Try to convince me that’s not a sea serpent, I dare you.

The megamouth shark. Watch out, krill and jellyfish!

The frilled shark. Watch out, everything else including other sharks!

A giant isopod. Why are you touching it? Stop touching it!

Sorry, it’s just a rotting basking shark:

Recommended reading:

In the Wake of Bernard Heuvelmans by Michael A. Woodley

In the Wake of the Sea-Serpents by Bernard Heuvelmans

The Search for the Last Undiscovered Animals by Karl P.N. Shuker

Episode 002: The Mokele Mbembe and the Coelacanth

People have been searching for the so-called African brontosaurus, mokele mbembe, for a century without any luck. No one was looking for the extinct coelacanth until a museum curator saw one in a pile of recently caught fish. In this episode of Strange Animals Podcast we discuss the hunt for both creatures. (re-recorded episode)

Recommended reading: Abominable Science!: Origins of the Yeti, Nessie, and Other Famous Cryptids by Daniel Loxton and Donald R. Prothero.

The beautiful coelacanth:

Show transcript:

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

It looks like when I upload a new version of an old episode, it doesn’t spam everyone’s feed! So I’m going to try and get the first dozen or so episodes re-recorded and uploaded as quickly as possible. Here’s the new version of episode two, where I sound like a human being and not a robot reading out loud.

This week’s episode is about a couple of so-called living fossils, one that possibly never existed and one that exists like WHOA.

Legends of “lost worlds” full of dinosaurs have been around ever since people recognized that fossilized bones belonged to once-living animals. Early science fiction like Jules Verne’s Journey to the Center of the Earth and Arthur Conan Doyle’s The Lost World featured explorers encountering living prehistoric creatures.

Europeans looked at a map of the world, saw that Africa was still largely unexplored—by other Europeans, anyway—and suggested maybe dinosaurs were living somewhere on that vast continent. After all, Africa was home to some of the world’s most amazing known animals.

In 1909, animal dealer Carl Hagenbeck published a book called Beasts and Men, where he shared a friend-of-a-friend story about a monster in Central Africa. It wasn’t a very satisfying story, frankly. Hagenbeck heard from one of his employees and also from a big-game hunter that “the natives” reported a “half-elephant, half-dragon” monster living in the swamps. No doubt with visions of million-dollar brontosaurus sales in his future, Hagenbeck sent an expedition to look for the monster. They didn’t find anything.

Nevertheless, the press took the story and ran with it. People were dinosaur-crazy then like nothing else, and headlines like “Brontosaurus Still Lives” whipped the public into a frenzy of excitement. The only papers that didn’t go over the top about live dinosaurs in Africa were those published in Africa, which were more skeptical.

Hagenbeck’s story placed the monster in Rhodesia, which is now Zambia and Zimbabwe. Europeans set off on expeditions to the area, found nothing, and assumed they just weren’t looking in the right place. Monsters from native folklore were cited as proof of dinosaurs just down the river or in the next lake. Bullheaded or over-enthusiastic Europeans cherry-picked information from the Africans they interviewed. They believed details about native monsters as though they were real sightings and ignored it whenever an interviewee said, “That’s an imaginary animal. It’s not real. We just tell that story to children.”

In 1919, London newspapers reported a couple of monster stories, one from a Mr. Lepage in the Belgian Congo, one from a Mr. Gapelle in “the interior of the Congo.” Both stories are about an improbable animal with a humped back, a horn on its nose, scales, and a kangaroo-like tail. But the stories fell apart very soon when people who knew David Le Page pointed out he was a known practical joker. Le Page was the source of both stories, the first under his own name, the second under an anagram of his last name. Gapelle is roughly Le Page backwards. He’d made them both up.

The stories were nonsense, but they kept being repeated. They also shifted focus from Rhodesia to the Congo. Expeditions started focusing on that area, still searching for the African brontosaurus. This went on for decades. It’s still going on, and no one has ever found anything.

At some point, the name mokele mbembe got attached to the rumors of brontosaurus-like dinosaurs living in Africa. The name is supposedly from the Lingala language and means “one who stops the flow of rivers.” Lingala is a Creole language based on Bantu, which is used as a lingua franca in the western part of the Democratic Republic of Congo.

Gradually the notion that the mokele-mbembe is an actual brontosaurus faded away. We know more about sauropods these days. We know they’re not going to be hiding in heavy swamps, lakes, or jungles. They were animals of open forests and scrubland where there was solid footing. So some people now think the mokele-mbembe is a smaller, sauropod-like creature that lives in or near water, maybe in underwater burrows, and is generally described as a plant-eater that is peaceful unless attacked, at which point it turns deadly.

Despite the lack of dead animals or skins, pictures, footprints, or any other proof whatsoever, it’s oddly plausible that a large unknown water reptile is living deep in the Congo. It’s such a big place! The animals we do know about are amazing! And in 2006 and 2007, researchers found a population of 100,000 previously unknown gorillas not that far from Lake Tele. What else might be hidden in the swamps and forests surrounding the lake?

But. People have been searching for the mokele-mbembe for so long that it’s actually become a revenue stream for villages around Lake Tele, where expeditions now focus although it’s 1200 miles from the site of Hagenbeck’s 1909 report. Cryptozoological expeditions hire the same paid guides and translators year after year, and the guides are like travel guides anywhere. They make sure the travelers go away with the remarkable stories they came to hear, and they make sure that the expedition leaves the villages richer. One Japanese expedition in 1981 got stranded by their guides after refusing to pay what the guides thought they should.

It’s nonsense for explorers to say breathlessly, “The natives couldn’t possibly have known what a diplodocus was but pointed to its picture!” when dozens of previous explorers have likely talked to the same individuals. And when explorers stray from Lake Tele and into areas where expeditions haven’t yet traveled, the villagers don’t report any sightings of dinosaur-like monsters.

So far, we don’t have any good reports of the mokele-mbembe. No physical proof of any kind, no genuine local stories. It’s not looking good for our living dinosaur.

And here’s where the whole legend of the mokele-mbembe veers off the rails of maybe and crashes into the chasm of what the heck. The most fervent believers in this animal, the ones who mount repeated expeditions, have a massive and bizarre axe to grind.

Young Earth creationists believe the Earth was only created about 6,000 years ago. Not only do they think that it’s perfectly plausible to have dinosaurs still around after so little time, they firmly believe that if they can find proof of a living dinosaur and present it to science, probably going “AHA! What do you think of THAT?”, somehow the entire theory of evolution will crumble. Scientists will weep and realize how wrong they all were, and probably the creationists can teach the dinosaur tricks and walk it on a leash. I don’t know.

It just proves they don’t have the slightest idea of what evolution actually is, but instead of spending fifteen minutes with a high school biology textbook and an open mind, they keep spending thousands upon thousands of dollars to look for the mokele-mbembe. To SHOW THEM ALL.

That’s not to say that everyone who hunts for the mokele-mbembe is a creationist. Heck, if anyone wants to bring me along on their non-missionary expedition, I’ll jump at the chance. I’d love to visit a beautiful part of the world and meet people whose culture is very different from my own. But I wouldn’t expect to see a dinosaur.

The coelacanth is another animal that creationists believe disproves evolution. It’s also another one that’s been called a living fossil in the media. In December 1938, a museum curator in South Africa named Marjorie Courtenay Lattimer got a message from a friend of hers, a fisherman named Hendrick Goosen, who had just arrived with a new catch. Lattimer was on the lookout for specimens for her tiny museum, and Goosen was happy to let her have anything interesting. Lattimer went down to the dock, partly to look at the catch, but mostly to wish Goosen and his crew a merry Christmas. Then she noticed THE FISH.

It was five feet long, or 1.5 meters, blueish with shimmery silvery markings, with strange lobed fins and scales like armored plates. She described it as the most beautiful fish she had ever seen. She didn’t know what it was, but she wanted it. I’m like that too, but usually with craft supplies, not dead fish.

She took the fish back to the museum in a taxi—after an argument with the taxi driver. The fish did not smell very good and it was the size of a human being, after all. Once at the museum, Lattimer went through her reference books to identify the fish.

Imagine it. She’s flipped through a couple of books but nothing looks even remotely like her fish, the beautiful weird smelly one. Then she turns a page and there’s a picture of the fish like the one the taxi driver objected to…but that fish is extinct. It’s been extinct for some 66 million years. But it’s also a very recently alive fish resting on ice in the back of her museum.

Lattimer sketched the fish and sent the drawing and a description to a professor at Rhodes University, J.L.B. Smith. But Smith was on Christmas break and didn’t get her message until January 3. In the meantime, Lattimer’s museum director told her the fish was a grouper and not worth the ice it was lying on.

But Marjorie, she loved that fish. She wasn’t going to cut it up for bait. But December is the middle of summer in South Africa, so to keep it from rotting away, she had it mounted.

Then Smith sent her a near-hysterical cable that read, “MOST IMPORTANT PRESERVE SKELETON AND GILLS.” Oops.

This is perhaps a lesson for all of us. Once I missed the opportunity to see a rare snow goose that had stopped on our campus pond over winter break. If only I’d checked my work email while I was off, I could have seen that life bird. The agony I felt at missing it was probably only a shadow of what Professor Smith felt at losing the important innards of a living fossil, though. Also, I saw a whole bunch of snow geese in December of 2018.

On February 16, 1939, Smith showed up at the museum and immediately identified the fish as a coelacanth. The story made international news. When the museum put the fish on display for one day only, 20,000 people showed up to see it.

Smith got a little obsessed about finding another coelacanth. He offered huge rewards for a specimen. But it wasn’t until December of 1952 that a pair of local fishermen on the island of Anjuan, about halfway being Tanzania and Madagascar, turned up with a fish they called the gombessa. It was a second coelacanth.

Everyone was happy. The fishermen got a huge reward—a hundred British pounds—and Smith had an intact coelacanth. He actually cried when he saw it. I didn’t cry when I saw those snow geese but I did make a horrible excited squeaking noise.

Most people have heard of the coelacanth because its discovery is such a great story. But why is the fish such a big deal?

The coelacanth isn’t just a fish that was supposed to be extinct and was discovered alive and well, although that’s pretty awesome. It’s a strange fish, more closely related to mammals reptiles than it is to ordinary ray-finned fish. The only living fish even slightly like it is the lungfish, and the lungfish is such a weird animal in its own right that it’s going to get its own episode one of these days. That episode is #55.

While the coelacanth is unique in a lot of ways, it’s those lobed fins that are really exciting. It’s not a stretch to say their paired fins look like nubby legs with frills instead of digits. Until DNA sequencing in 2013, many researchers thought the coelacanth was a sort of missing link between water-dwelling animals and those that first developed the ability to walk on land. As it happens, the lungfish turns out to be closer to that stage than the coelacanth, and both the lungfish and the coelacanth had already split off from the shared ancestor of marine and terrestrial organisms when they evolved around 400 million years ago. But for scientists in the mid-20th century, studying a fish that looked like it had little legs must have been electrifying.

But this fish story isn’t over yet. In 1997, a marine biologist on honeymoon in Indonesia found a coelacanth in a local market. And it was a different species of coelacanth. Can you imagine a better wedding gift?

Coelacanths are placid fish who do a lot of drifting, although their eight marvelous fins make them very maneuverable. They stay close to the coast and prefer rocky areas. They especially love underwater caves. They hunt for smaller fish and cephalopods like squid at night and rest in caves or hidden among rocks during the day. Sometimes sharks eat them, but for the most part coelacanths lead comfortable lives, floating around eating stuff. Sometimes they float around tail up or even upside down because they just don’t care.

Since the discovery of living coelacanths, more fossil coelacanths have been found. A 2015 paper in the Zoological Paper of the Linnaean Society describes over 30 complete specimens of 360 million years old coelacanths. The fossils were discovered about 60 miles from the mouth of the Chalumna River in South Africa, where Marjorie Lattimer found the first living coelacanth known to science. All the fossils are of juveniles, which were apparently living in a shallow, weedy bay that acted as a nursery. Living coelacanths give birth to live young, which is rare in fish, but researchers don’t know yet if young coelacanths grow up in similarly protected nurseries.

Another fossil species of coelacanth was described in a 2012 paper in the Journal of Vertebrate Paleontology, and this one was a surprise to researchers. All the coelacanths discovered up till then, living or extinct, looked pretty much alike. Scientists have made a not unreasonable assumption that the extinct coelacanths lived much like modern coelacanths do—you know, drifting around, eating stuff, and not worrying about anything much except sharks. Then several coelacanth fossils were discovered in British Colombia, Canada, and this new species shows every sign of being a swift, vicious predator. It’s so different from other coelacanths that it’s been given its own family. It’s called Rebellatrix, which is just so awesome I can’t stand it. Rebellatrix was about three feet long, or 91 cm, and had a fork-like tail similar to a tuna’s, which allowed it to swim fast. It lived 240 million years ago, only ten million years after an extinction event at the end of the Permian. Researchers think Rebellatrix may have evolved to fill a niche left by extinct predatory fishes.

But coelacanths these days are happy enough doing the drifting thing. Sometimes they get caught by accident by night fishermen, who either throw the fish back or sell them to museums. Because here’s the best thing of all about the coelacanth: they taste horrible. Not only that, their flesh is slimy. It’s full of oil and urea. If you eat a coelacanth, you won’t die, but you’ll end up with terrible diarrhea.

So far, living coelacanths have mostly been found off the coast of Africa, but they’re much more widely spread in the fossil record. Rumors of coelacanths in other places, like the Gulf of Mexico or around Easter Island, keep popping up. Maybe one day another population of these awesome fish will be discovered.

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

Thanks for listening!