Episode 235: Deep-Sea Squid



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This week we visit the weirdest squid in the deep sea!

I was a guest on Tim Mendees’s After Hours that’s now up on YouTube! It’s mostly about my writing but we talk about all kinds of stuff, including cephalopods! There is some bad language but it’s not all that bad and it’s mostly toward the end.

Further reading/watching:

Elusive Long-Tailed Squid Captured on Film for First time

See Strange Squid Filmed in the Wild for the First Time (ram’s horn squid)

Multiple observations of Bigfin Squid (Magnapinna sp.) in the Great Australian Bight reveal distribution patterns, morphological characteristics, and rarely seen behaviour

Untangling the Long-Armed Mystery of the Bigfin Squid

Drawing of a long-arm squid and an actual long-arm squid:

Asperoteuthis mangoldae, which really should be called the long-tailed squid:

 

Verany’s long-armed squid, with its tentacles mostly retracted (so not looking very long-armed):

Verany’s long-armed squid with tentacles extended:

Drawing of a paralarval Verany’s long-armed squid:

The ram’s horn squid, floating along doop doop doop:

Drawing of the coiled internal shell of the ram’s horn squid:

A clawed armhook squid mama with her egg cluster:

Bigfin squid!

Another bigfin squid! Good grief look at that!

Show transcript:

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

Before we get started, a quick announcement that I was a guest on a YouTube show called After Hours recently! I was there mostly to talk about my writing, but naturally animals came up too, especially cephalopods. There’s a link in the show notes if you want to watch the show. There is a little bad language, but not too bad and it’s more toward the end.

Anyway, in a not-exactly coincidence, this week we’re going to look at some of the weirdest deep-sea squids known. Yes, weirder than the flying squid we talked about in episode 101. We don’t know much about any of them, but they’re definitely not what you expect when you think about squid.

Let’s talk first about Asperoteuthis acanthoderma, the long-arm squid. It’s also sometimes called the thorny whiplash squid because it has little pointy tubercules in its skin and long, whiplike feeding tentacles. It lives in the deep sea and has been found in both the Pacific and the Atlantic Oceans, although very rarely. Despite its name, its feeding tentacles are much longer than its arms, although its arms are pretty long too. A squid’s body is generally more or less torpedo-shaped and is called a mantle. It has eight arms and two feeding tentacles that are usually longer than the arms. Many squid species have relatively short arms compared to mantle length.

The feeding tentacles in long-arm squid are very slender and delicate, and they’re easily broken off after the animal dies and has washed around in the water for a while. One intact specimen has been found and measured, though. It had a mantle length of almost a foot and a half long, or 45 cm, but its total length, including the tentacles, was 18 feet, or 5.5 meters. The tentacles were 12 times the mantle length.

Using that ratio, one large specimen found in 2007, which was 6 1/2 feet long, or 2 meters, including both mantle and arms, is estimated to have measured up to 24 feet long when it was alive, or over 7 meters. Most of its length is due to its incredibly long, thin feeding tentacles.

So what does the long-arm squid eat with those long, delicate tentacles? We don’t know. We don’t know most things about the long-arm squid.

Another species of Asperoteuthis is Asperoteuthis mangoldae. So little is known about it that it doesn’t even have an informal name. It was only described in 2007 and has only been found around the Hawaiian islands in the Pacific Ocean. It looks similar to the closely-related long-arm squid but without the incredibly long feeding tentacles. Instead, it has a sort of tail, so I nominate it to be called the long-tailed squid. It was caught on video for the first time in 2019 by a deep-sea rover. You’re going to hear a lot about deep-sea rovers in this episode. There are lots of links in the show notes to articles with embedded video of various squids, which is really interesting to watch.

Asperoteuthis mangoldae is a long, slender squid. I couldn’t find any measurements so it could be that’s just not known right now. The species in this genus have an extension of the mantle, on the side opposite of the arms, that looks like an extra fin but that doesn’t seem to be used as a fin. In the long-tailed squid, this extra fin is as long as its mantle and arms and feeding tentacles all measured together. Most of the time the thin flaps of skin on either side of the so-called tail are extended, making it look like a really long fin, but when the squid feels threatened and needs to flee, it collapses the fin part around the middle section so that it reduces drag in the water. That way the squid can move faster. Researchers speculate that the tail section may make the squid look much larger to potential predators, and possibly may imitate an organism called a siphonophore that has stinging cells.

Another squid called Verany’s long-armed squid is Chiroteuthis veranii. It’s related to the long-arm squid we talked about at the beginning of the episode, but they’re placed in different genera. It lives throughout the world’s oceans, often in the deep sea although not as deep as some of the species we’re talking about today. Unlike most squid, whose arms are all about the same length, two of its arms are much wider and longer than the others.

Like the other long-arm squid, its feeding tentacles are incredibly long and thin. The mantle is quite small, up to 8 inches long, or 20 cm, with the legs about the same length as or a little longer than the mantle, but the total length of this squid, including the feeding tentacles, is over four feet, or 130 centimeters. Most of the time the feeding tentacles are retracted, though, so they’re no longer than the arms, and they’re protected by the two largest arms. When the squid sees a tiny fish or crab or other small animal it wants to eat, it can shoot its retracted tentacles out at high speed to catch it. It’s probable that other species of long-armed squid hunt the same way.

A squid’s eggs hatch into an initial form called a paralarva. This is actually the case for other cephalopods too, including octopuses. The paralarvae usually just look like teeny-tiny miniature versions of the adult, but with stubby little arms. In the case of Verany’s long-armed squid, though, the larval squid looks sort of like a little rod. It’s long and thin, mostly transparent, and has a gladius, also called a pen, that sticks out the end of the mantle on the opposite side from the arms. The pen of a squid is named after an ink pen, although the other name, gladius, refers to the shape of a type of ancient Roman sword. It’s a vestigial shell but located inside the squid’s body. The tail of the long-tailed squid we just talked about is given structure by the gladius, so it’s possible that its paralarvae look rod-like, like those of Verany’s long-armed squid.

Speaking of internal shells, the ram’s horn squid has a coiled internal shell. This is unique among all the squid known to be alive today, so the ram’s horn squid is the only living member of its own order and its own family and its own genus. Technically it’s not really considered a squid although it is a closely related cephalopod. It’s small, with a mantle length only about an inch and a half long, or 4.5 centimeters. Its eight arms are quite short and it has two feeding tentacles that are about the same length as its mantle. Its mantle has an outer covering that extends down almost to the squid’s eyes, and it’s big enough that the squid can pull its eyes and legs and tentacles under this covering. The spiral shell resembles that of a nautilus, but it’s inside the squid instead of the nautilus living inside the shell. The shell contains gas that the squid uses to adjust its buoyancy.

For a long time researchers were confused as to how the ram’s horn squid oriented itself in the water. The empty shells from dead squid wash ashore pretty often, and experiments with them show that they want to float with the big end of the shell pointing downward. That confused the researchers, since that would mean the squid floats around with its arms downward too, which means that the photophore on the tail end of its mantle points upward. A photophore is a light-emitting organ, which is common in deep-sea animals. Usually an animal wants its light to point downwards, which means that larger animals looking up toward the surface see a little light sparkling amid the light shining down from the surface instead of seeing a squid-shaped shadow against the surface.

Then, in late 2020, a deep-sea rover exploring the northern section of the Great Barrier Reef off the coast of Australia got a video of a ram’s horn squid in the water. It was the first time a living one had ever been observed. In the video, the squid is floating with its arms pointing upward, flapping the fins on its mantle to move along in the water. Mystery solved! There’s still a lot we don’t know about the ram’s horn squid, but at least we know it doesn’t swim around upside-down.

Another squid that has only recently been seen alive in the wild from a deep-sea rover is the clawed armhook squid. My brother Richard alerted me to this one in a Twitter thread. The clawed armhook squid lives in the northern Pacific Ocean and has a mantle length of about seven inches, or 18 cm. Its arms are about the same length as its mantle. It gets its name from the female, which has small hooks on her arms to help her keep hold of her egg cluster. She lays about 3,000 eggs in a tube-like cluster that looks sort of like a gray cloth bag that’s open at both ends. Most squid lay their eggs on the sea floor and leave them, usually dying soon after, but the clawed armhook squid holds her egg cluster until the eggs hatch. She makes sure the eggs get enough oxygenated water by pumping water through the middle of the bag. She also swims away from anything that might want to eat her eggs or her, although she can’t swim very fast since she has to use her arms to hold onto the egg cluster. She usually stays in deep water far from shore while the eggs are developing, because there are fewer predators there than in her usual habitat nearer shore. In 2001 a rover spotted a mother squid with her egg cluster at 8,200 feet below the surface, or 2500 meters. That’s more than a mile and a half down, or two and a half kilometers.

Unfortunately for the mother squid, after she lays her eggs, she can’t use her arms for anything except holding and taking care of them, and that includes eating. She just doesn’t eat once she lays her eggs, and while we’re not sure how long it takes for them to hatch, it may be as much as nine months. It’s most likely that she dies after her babies hatch. All the female squids seen with egg clusters have been missing their feeding tentacles, and researchers think the squid may actually bite off her own tentacles so they don’t get in the way of her eggs.

Finally, the family Magnapinnidae, also called bigfin squids, were mysteries for over a century. For a long time they were only known from paralarval and juvenile individuals. Five species are known but there may be more, but no scientist has ever been able to study an adult except through photographs and videos made by deep-sea rovers.

All squid have fins of some kind on the mantle to help it move around. Different species, naturally, have varying sizes and shapes of fins. In the bigfin squid, as you may have guessed, the fins are very big. They look more like wings and can be almost as large as the entire mantle. But that’s not the really weird thing about these squid, although it was the most obvious thing when all we knew about them were young specimens. The arms and tentacles of squid don’t develop to their full length until the squid is an adult. The bigfin squid’s arms and tentacles are very long and they’re also very different from all other squids.

In 2001, a deep-sea rover used by an oil company in the Gulf of Mexico caught video of a large, unusual squid. Fortunately, one of the men operating the rover remotely asked for a copy of the squid video for his girlfriend, who was interested in deep-sea animals. His girlfriend asked around, trying to find out what kind of squid it was, and eventually contacted a squid expert at the Smithsonian National Museum of Natural History. The squid expert is named Mike Vecchione and when he saw the video, he freaked out. He’d never seen anything like this squid before. He says he jumped out of his chair and started yelling in excitement.

Then, once he calmed down, he contacted all his squid expert colleagues, who also freaked out, and eventually they found more footage of the weird squid taken by other oil rig rovers. The workers operating the rovers had no idea that the squid was a scientific mystery so hadn’t thought to contact any scientists. Finally the squid was identified as an adult bigfin.

In 2015, a deep-sea rover in a scientific expedition caught video of two bigfin squid near Australia, and in 2017 it saw three more. It also spotted some juvenile bigfin squid in the same area. Even better, the rover was able to use lasers to get a much more accurate estimate of the squid’s size than ever before. All five were different sizes, so they were probably five different individuals.

The bigfin squid has very thin arms and tentacles, referred to as vermiform. That means worm-shaped, which gives you an idea of how thin we’re talking. The largest bigfin squid measured by the rover in 2015 and 2017 had a mantle length of about 6 inches, or 15 cm, and a fin width of 5.5inches, or 14 cm, but the longest arm or tentacle length was 5.5 feet, or 1.68 meters. Measurements of other bigfin squid suggest it can grow up to 26 feet long, or 8 meters, and maybe even longer.

In the bigfin squid, the arms and tentacles are the same size. In other squids, the tentacles are usually longer and look different from the arms. The great length of the arms and tentacles of the bigfin squid comes from what’s called a distal filament that grows from the tip of the arm or tentacle. The filaments are sometimes missing, so it’s possible that they’re sometimes damaged and lost or maybe bitten off. The squid seems to use its arms and tentacles the same way instead of using its arms for some things and its tentacles for other things.

The bigfin squid holds its arms and tentacles differently from any other squid, in what’s called a crane pose or elbow pose. It’s not clear from the articles I read, but it seems to be that if you don’t count the distal filaments, the arms and tentacles are not actually all that long in comparison to its mantle. When it’s hunting, the squid holds them out from its body with the extremely long filaments hanging down. It looks like the squid has elbows that way. Squid don’t have elbows because squid, like other cephalopods like octopuses, don’t have any bones. We talked about how octopuses move without bones in episode 142 if you’re interested, and it’s the same for squid.

The bigfin squid can retract the filaments by coiling them up. One researcher said the coiled-up filaments look sort of like an old-fashioned phone cord, which will mean nothing to my younger listeners but the rest of us just thought, “Oh yeah, that makes total sense.” The filaments are sticky and trap tiny animals and particles of food drifting in the water. If you remember way way way back in episode 11 where we talked about the vampire squid, it uses its feeding tentacles the same way, including being able to retract them, but the vampire squid and the bigfin squid are not very closely related at all.

A research sub investigating a WWII shipwreck spotted a bigfin squid 3.7 miles below the surface, or 6,000 meters, which made it the deepest squid ever recorded. Imagine looking out the window of a submarine, assuming they have windows, trying to see details of a shipwreck, and suddenly there’s a massive squid with incredibly long, thin arms looking back at you.

You can find Strange Animals Podcast 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!


Episode 234: Sun Bears, Water Bears



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Thanks to Enzo and Lux for their suggestions! Let’s learn about the sun bear and the water bear this week!

Sun bear just chillin:

Sun bears got long tongues:

The water bear, AKA tardigrade, is not actually a bear. For one thing, it has twice the number of legs as bears have:

Show transcript:

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

It’s summer in the northern hemisphere, which means hot weather and sunshine and, if you’re lucky, a trip to the lake or ocean. To celebrate summertime, let’s talk about two animals suggested by Enzo and his sister Lux. They wanted to hear about the sun bear and the water bear. Get it? Sun and water?

Enzo’s suggestion is the sun bear, which we talked about a little bit way back in episode 76, but which is a fascinating animal that deserves a lot more attention.

The sun bear lives in southeast Asia in tropical forests and is most closely related to the black bear. It has silky black fur, although some are gray or reddish, and a roughly U-shaped patch of fur on its chest that varies in color from gold to almost white to reddish-orange. Its muzzle is short and is lighter in color than the rest of its face, usually gray. It has small ears too. It’s the world’s smallest bear, only around three feet long from head to tail, or 150 cm, and four feet tall when standing on its hind legs, or 1.2 meters. Researchers think its chest spot acts as a threat display. When a sun bear stands on its hind legs, the chest spot is really obvious, which may warn potential predators away. Even so, tigers and leopards will attack and eat sun bears.

The sun bear spends a lot of time in trees, more than any other bear. It has long claws that it uses for climbing and to tear open logs to get at insect larvae. It eats a lot of termites and especially loves honey, which it licks from the hive with its long tongue–up to 10 inches long, or 25 cm. It also eats a lot of plant material, especially fruit and acorns. It will catch and eat birds and small animals, or sometimes larger animals like deer, but it mostly eats insects and fruit.

The female sun bear makes her den in a hollow tree to give birth. She has one or two cubs at a time, and like other bear cubs they’re born extremely small and with their eyes and ears sealed shut. This is the case with animals like dogs and cats too, but newborn bears are tiny compared to how big the mother bear is. The eyes and ears continue developing after the cub is born, but it’s a few months before it can see and hear properly. A cub remains with its mother for almost three years.

Other than mothers and babies, the sun bear is solitary. Adults don’t typically interact except to mate, although adult sun bears kept in captivity will play together. A 2019 study of sun bears came to a surprising conclusion that they communicate with each other by mimicking facial expressions. This is something humans do all the time, of course, and apes do too. Dogs also mimic facial expressions. Humans, apes, and dogs are all intensely social animals, so researchers have always assumed that the mimicking of facial expressions is important because of that sociability. I mean, that just makes sense. If you see a friend approaching and they have a big smile on their face, naturally you’re going to smile too. But here are these solitary bears with facial communication just as well-developed as in apes. Researchers think it may be a trait that’s so important to mammals as a whole that it develops even in species that don’t spend a lot of time interacting.

The sun bear is threatened by habitat loss and hunting, but it does well in captivity and is popular in zoos. Conservation efforts are in place to protect the sun bear in the wild as well as continue a healthy captive breeding program around the world.

Lux wanted to hear about the water bear, which is also called the tardigrade or the moss piglet. I can’t believe we haven’t covered the tardigrade before—we even have one in our new logo! Patrons may remember parts of this section from a Patreon bonus episode from 2017, but I’ve updated it a lot.

The water bear isn’t a bear at all but a tiny eight-legged animal that barely ever grows larger than 1.5 millimeters. Some species are microscopic. Pictures of the water bear are taken with an electron microscope because otherwise they just look like a teensy little dot.

There are about 1,300 known species of water bear and they all look pretty similar. It looks for all the world like a plump eight-legged stuffed animal made out of couch upholstery. It uses six of its fat little legs for walking and the hind two to cling to the moss and other plant material where it lives. Each leg has four to eight long hooked claws. It has a tubular mouth that looks a little like a pig’s snout or a bear’s snout.

An extremophile is an organism adapted to live in a particular environment that’s considered extreme, like undersea volcanic vents or inside rocks deep below the ocean floor. Tardigrades aren’t technically extremophiles, but they are incredibly tough. Researchers have found tardigrades in environments such as the gloppy ooze at the bottom of the ocean to the icy peaks of the Himalayas. It can survive massive amounts of radiation, dehydration for up to five years, pressures even more intense than at the bottom of the Mariana Trench, temperatures as low as -450 Fahrenheit, or -270 Celsius, heat up to 300 degrees Fahrenheit, or 150 Celsius, and even outer space. It’s survived on Earth for at least half a billion years. Mostly, though, it just lives in moss.

One thing to remember is that different species of tardigrade are good at withstanding different extreme environments. Not every tardigrade is able to do everything we just talked about. They’re tough, but they’re not invulnerable. Many species can withstand incredible heat, but only for half an hour or less. Long-term temperature increases, even if only a little warmer than it’s used to, can cause the tardigrade to die.

Most species of tardigrade eat plant material or bacteria, but a few eat smaller species of tardigrade. It has no lungs since it just absorbs air directly into its body by gas exchange. It has a teeny brain, teeny eyes, and teeny sensory bristles on its body. Its legs have no joints. Its tubular mouth contains tube-like structures called stylets that are secreted from glands on either side of the mouth. Every time the tardigrade molts its cuticle, or body covering, it loses the stylets too and has to regrow them. In some species, the only time the tardigrade poops is when it molts. The poop is left behind in the molted cuticle.

The tardigrade’s success is largely due to its ability to suspend its metabolism, during which time the water in its body is replaced with a type of protein that protects its cells from damage. It retracts its legs and rearranges its internal organs so it can curl up into a teeny barrel shape, at which point it’s called a tun. It needs a moist environment, and if its environment dries out too much, the water bear will automatically go into this suspended state, called cryptobiosis.

The tardigrade’s DNA gets fractured during dehydration but it’s incredibly successful at repairing its DNA upon rehydration, which explains a big part of its success. In 2016, Japanese researchers sequenced the genome of the species of tardigrade that best resists radiation. In the process, they discovered a new protein in the tardigrade’s genome, which they named DSUP, short for damage suppressor. Even more interesting, when cultured human cells were given the ability to create DSUP, after exposure to X-rays, they showed half the DNA damage that non-DSUP cells showed.

Tests in 2007 and 2011 that exposed tardigrades to outer space led to some speculation that tardigrades might actually be from outer space, and that they, or organisms that gave rise to them, might have hitched a ride on a comet or some other heavenly body and ended up on earth. But this isn’t actually the case, since genetic studies show that tardigrades fit neatly into what we know of animal development and evolution.

The tardigrade is probably most closely related to arthropods, like insects and spiders. Their closest relatives were probably lobopodians, extinct wormlike organisms with stubby legs. The famous Hallucigenia creature is a lobopodian, which we talked about in episode 69 about the Cambrian explosion. There’s still a lot we don’t know about the tardigrade’s ancestry, since we have so few fossilized water bears, but many researchers think their oldest ancestors were probably much bigger than the microscopic or nearly microscopic living animals. In other words, maybe once there were water bears you could pick up and hug. Well, they probably weren’t that big, but I like to imagine it. I think that if you hugged a water bear too hard, it would make this noise: [little prrrt sound]

You can find Strange Animals Podcast 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way, and don’t forget to join our mailing list. There’s a link in the show notes.

Thanks for listening!


Episode 233: The Astonishing Aye-Aye



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Thanks to Elaine, Molly, and Oliver for suggesting the aye-aye! I guess it’s an idea whose time has finally come.

Further reading:

Gimme six! Researchers discover aye-aye’s extra finger

Ah yes, I have many many many fingers:

S p i d e r h a n d s:

A baby aye-aye (blep):

Show transcript:

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

I can safely say that this week’s episode is brought to you by popular demand. It was suggested by not one, not two, but three different listeners, two of them very recently. Elaine wanted to know about the aye-aye, and then Molly wanted to know about the aye-aye, and then Oliver wanted to know about the aye-aye. I think it’s high time we all learned about the aye-aye, because it’s a weird and amazing animal.

The aye-aye is a primate, specifically a type of lemur, but it doesn’t look like other lemurs. It kind of looks like a weird possum at first glance. Its shaggy fur is brown or yellowish but the hairs are tipped with white, which gives it a frosty appearance. Its face is white or pale gray. Its eyes are large, very round, and orange or yellow, and it has really big ears sort of like a bat’s ears. It grows up to three feet long, or 90 cm, including its really long tail.

To picture what an aye-aye looks like, imagine a little monkey with brownish fur tipped with white, with a tail longer than its body that’s thickly furred like a squirrel’s tail. Its head looks like a squirrel or possum, but with big orangey staring eyes and big bat ears that are sort of stuck out to the sides of its head instead of on top. Its hind feet look like monkey feet with an opposing digit to help it grab onto branches, because it lives in trees. But its hands look like SPIDERS. The fingers of its hands are extremely long and thin like spider legs. That’s what it looks like.

The aye aye’s fingers are long for an interesting reason, and if you don’t already know, I bet you would never be able to guess. Go on, guess. Just shout it out. I won’t hear it but everyone around you will hear you shout, “THE AYE-AYE’S FINGERS LOOK LIKE SPIDER LEGS BECAUSE IT WANTS TO SCARE PREDATORS INTO THINKING IT’S TWO SPIDERS WITH A MONKEY FRIEND.” You would be wrong, sorry, but that’s a good guess.

No, the aye aye uses its fingers to find grubs and other insects hidden in rotting wood or under bark, just like a woodpecker. Here’s how that works, and you’re not going to believe it, but it’s true. The aye aye is a primate, which means it has five fingers just like monkeys and apes and humans, but again, they’re extremely long and thin. The middle finger is even thinner than the others. It looks like a jointed twig. If it really was a spider, other spiders would ask what happened to that leg because it’s so much thinner than the other legs.

The aye aye uses the thin finger to tap-tap-tap on tree branches and trunks at night, and it listens with its huge ears to the echoes of its tapping. That’s echolocation, just like bats and a few other animals use to navigate, but the aye aye uses it to listen for hollow places in the tree where insects are hiding. It can also hear the tiny movements of insects. Its ears are just that sensitive.

When the aye aye locates an insect, it chews a hole into the wood and then uses its long fingers to fish the insects out. It has claws at the end of its fingers that help it catch the insects, although the claws are actually just claw-like fingernails. Primates don’t have claws, we have nails, and that includes the aye-aye. It doesn’t just eat insects, though. It eats fruit, seeds, various kinds of fungus, honey, flowers, and flower nectar. It actually eats more plant material than insects. It may also eat frogs, since some frogs in Madagascar lay their eggs in small holes in trees that are filled with rainwater, but it’s also possible that the aye-aye doesn’t care about frogs or frog eggs or tadpoles. Frogs definitely use the little holes the aye-aye chews as perfect little nurseries for their eggs.

The aye-aye is native to the forests of Madagascar and mostly lives along the east coast. It spends the day sleeping in trees, in a nest it makes out of twigs and dead leaves. Since it may travel more than a mile at night while it forages, it doesn’t always sleep in the same nest. It can make a new one in less than an hour, and then it crawls inside and wraps its long tail around it and falls asleep, cozy and warm.

The aye-aye hardly ever comes down to the ground. It’s mostly solitary except during mating season, although sometimes a few aye ayes will forage together. When aye-ayes do forage together, it’s usually a male and female, or one female and more than one male, or just two or more males. Female aye-ayes are more aggressive than males and they don’t want anything to do with other females.

The aye aye has so many non-primate characteristics that I hardly know where to start. For one thing, it’s nocturnal. Very few primates are nocturnal. It echolocates to find its food, which is completely weird. Also, its incisors grow continuously like a rodent’s. Incisors are those squarish front teeth. Since it uses its incisors to chew holes in wood, they need to keep growing or they’d get worn down to nothing eventually. The aye-aye’s incisors are very similar to a squirrel’s, and in fact is skull and jaw are also very similar to those of a squirrel. You know what that means. Yes, convergent evolution! It’s everywhere! Its skull and teeth look so much like a big squirrel’s that when scientists first examined the aye-aye back in the 18th and early 19th centuries, they classified it as a rodent. It wasn’t until 1931 that it was recognized as a primate, and even today some researchers think it’s not as closely related to primates as is currently thought. Genetic studies do indicate that it’s most closely related to lemurs, though. The aye-aye also has fewer teeth than lemurs and other primates, only 18 in all.

If you shine a light at an aye-aye at night, its eyes will reflect some of the light just like a cat. This is due to a specialized layer in the eye called the tapetum lucidum, which reflects light toward the retina so the animal can see better in the dark. Very few primates have a tapetum lucidum because most primates are diurnal, or active during the day, instead of nocturnal like the aye-aye.

Most nocturnal animals don’t see colors very well or at all. Naturally, they don’t need to since colors are hard or impossible to see in low light. But when researchers studied aye-aye genetics to learn more about how color vision developed in primates, including humans, they were in for a big surprise. The aye aye is completely nocturnal, but it still has the gene to see colors related to green and blue. Researchers have no idea why this is the case, although naturally they have some theories.

One theory is that the aye-aye uses its color vision to find flowers, especially blue flowers. Another theory is that it can see ultraviolet, which allows it to see urine marks left by other aye-ayes, since urine glows in ultraviolet light. The most ultraviolet light is available at dusk, which is when an aye-aye first ventures out to see what’s going on in its territory.

But let’s go back to the aye-aye’s fingers again. I just can’t get over its fingers. Not only is the skeletal middle finger just plain weird-looking, it’s weird compared to all other animal fingers. That one middle finger has what’s called a ball and socket joint, which is just not a joint found in fingers. You may not be familiar with the term, but you know what a ball-and-socket joint is because you have some in your own body. Your leg bones fit into your hip bone with ball-and-socket joints and your upper arm bones fit into your shoulders the same way. This allows you to move your arms and legs all around, whereas your fingers mostly just bend down, and a little bit up and sideways. But the aye-aye’s thin middle finger is incredibly flexible because of its ball-and-socket joint. All its other fingers have ordinary finger joints.

But wait, there’s more about the aye-aye’s fingers. In 2019, results of a study of the aye-aye’s unusual hands were published, and I just want to point out that the lead author of that paper is quoted as saying, “When you watch [an aye-aye] move, it looks like a strange lemur walking on spiders.” I’m not the only one who thinks their hands look like spiders!

Anyway, the study intended to learn more about the tendons in an aye-aye’s hands. But the researchers found a little structure on the wrist that no one had ever noticed before. It’s a small pseudo-thumb, or false thumb, which acts as an extra digit and helps the aye-aye climb through trees.

The pseudo-thumb isn’t just a little nubbin that helps it balance. No, it’s basically a real digit. It has bone and cartilage inside, muscles that allow it to move just like a regular thumb, and it even has a little thumbprint. It’s also strong. Researchers think that the aye-aye’s other fingers are so specialized that they’re not much help in climbing, so it developed an extra thumb.

Strange and specialized as the aye-aye is, it’s not the only animal we know of that had long, thin fingers that it used to tap on trees to find insects. 55 million years ago an animal called Labidolemur kayi lived in Europe and North America and shared many characteristics with the aye-aye. It was a little smaller than the aye-aye but had the same rodent-like teeth and two long thin fingers. Labidolemur kayi shared an ancestor with both rodents and primates, although it wasn’t a direct ancestor of the aye-aye. The aye-aye developed its rodent-like teeth and long thin fingers independently. Say it with me again: convergent evolution!

The aye aye is not only the only member of its own genus, it’s the only member of its own family. There used to be another species called the giant aye-aye that was at least twice the size of the living aye-aye, but it went extinct an estimated 1,000 years ago. Yes, just one thousand years ago, that’s all. We don’t know much about the giant aye-aye because all we have are some subfossil remains.

The aye-aye is endangered due to habitat loss and persecution by locals, who think it’s bad luck due to its weird appearance. It was actually thought to be extinct in 1933, but in 1957 researchers stumbled across one and probably breathed a sigh of relief that we hadn’t lost the aye-aye after all. In 1966 nine aye-ayes were taken to a small forested island off the eastern coast of Madagascar. The island is a nature reserve, and the aye ayes settled right in and are doing well there. At least now, if deforestation continues on the mainland of Madagascar, the aye-aye will be safe from extinction. Since then aye-ayes have also been introduced to another island and several nature reserves and national parks. It’s also kept in some zoos, and the first aye-aye was born in captivity in 1992.

The female aye-aye has one baby every few years, and she takes care of it by herself. Baby aye-ayes have green eyes and floppy ears.

You can find Strange Animals Podcast 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes. There are links in the show notes to join our mailing list and to our merch store.

Thanks for listening!


Episode 232: Almost Domesticated



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Thanks to “dog freak Ruby,” we’re going to learn about some animals that aren’t exactly domesticated but aren’t really wild either.

Further reading:

Memories of Ángela Loij

Mongolian horse and its person:

Mongolian horses:

OH MY GOSH HEART HEART HEART (photo from this website):

Dingos!

An artist’s rendition of the Fuejian dog (left) and a picture of the cuelpo (right):

The cuelpo, happy fox-like canid:

A very fancy rat:

Show transcript:

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

Before we get started, and before I forget again to tell you about this, I’m planning a bonus Q&A episode for August. If you have any questions about the podcast, podcasting in general, me, or anything else, feel free to email me at strangeanimalspodcast@gmail.com, or otherwise contact me through social media!

A few episodes ago I mentioned in passing that the Australian dingo is a type of feral dog. It’s a more complicated situation than it sounds, so while I didn’t want to confuse the issue at the time, I kept thinking about it. Then I remembered that a listener emailed me a while back wanting to know more about how dogs were domesticated. We covered the topic pretty thoroughly back in episode 106, but I realized that there’s an aspect of domestication we didn’t cover in that episode. So thanks to “dog freak Ruby,” here’s an episode about a few animals that are only semi-domesticated.

Domestication, after all, isn’t a switch you can flip. It’s a process, and depending on the animal species and the circumstances, it can take a really long time. It’s not the same thing as taming an animal, either. An individual animal might become tame with the right treatment, but that doesn’t mean any individual of that species would react the same way. Domesticated animals show genetic changes that their wild counterparts don’t, changes that make them more likely to treat humans as friends instead of potential predators.

Generally, a fully domesticated animal requires some level of care from a human to survive, even if it’s just feral cats living near humans so they can find and kill rodents and avoid most predators. Feral domesticated cats don’t live the same way as their wild ancestors do. But sometimes it’s not as cut and dried as it sounds. While mustangs and other feral horse populations are considered domesticated animals, they live like wild animals and don’t need humans to survive. They mostly just need humans to leave them alone so they can thrive on their own. But if you capture a mustang that’s lived its whole life in the wild, with the right treatment it will eventually become tame, because its ancestors were bred for thousands of years to trust and depend on humans.

That brings us to our first semi-domesticated animal, the Mongolian horse. Yes, I’m still really into Mongolia and the Hu, and I’m excited to say I have tickets to see the Hu twice in concert this fall, if everything goes well. I’ve been listening to a program called the Voice of Mongolia in English, which is primarily a shortwave radio program but it’s also released as a podcast, and it talks about various aspects of Mongolian culture. Recently they had an episode about horses, so some of my information comes directly from that show.

Mongolia is a country in central Asia that’s mostly open steppes, which is a type of grassland. The soil isn’t right for most crops, but it’s great for horses. The people of Mongolia are traditionally nomadic, moving around from place to place to find grazing for their horses and other livestock, and about half of the current population still lives this way.

The Mongolian horse is a small, tough breed that probably hasn’t changed much in the last thousand years, possibly longer. It’s one of the oldest breeds of horse in the world and the ancestor of many other horse breeds. For a long time people assumed it was the domesticated descendant of the wild Przewalski’s horse, but genetic testing has determined that domestic horses developed from a different wild horse species that’s extinct now. Genetic testing also showed that the Mongolian horse has the highest genetic diversity of any horse breed tested. It’s incredibly strong for its size, can gallop for miles without tiring, has strong hooves that never need trimming or shoeing, and seldom needs or receives veterinary care.

The main reason for all these traits is that Mongolian horses live like wild horses in most ways. They live loose, grazing as they like, and if they get too far away from their humans, the owners will go out to find them. But they’re still domesticated. Mare’s milk is an important part of the Mongolian diet, so the mares are used to being milked, and people use their horses to ride, carry packs, and pull carts. The stallions are frequently raced. At the same time, though, they’re not really pets. Mongols don’t give their horses names, but instead refer to them with a detailed description. The Voice of Mongolia in English says the Mongolian language has over 300 words to describe horses, while Wikipedia says it’s over 500. Either way, the terminology is so precise that everyone knows exactly which horse someone’s talking about, which if you think about it is more useful than a name.

The Australian dingo is in a similar situation. It’s considered a feral dog breed, but it doesn’t need people to survive. Most feral dogs throughout the world barely scrape by, eating garbage and rats and often dying of starvation or disease. Dingos live like wild animals and do just fine. But at the same time, they’re happy to hang out with people from time to time, acting as hunting companions who are neither dependent on humans nor frightened of them.

The dingo is a strong, tough, lean dog that stands around 22 inches tall at the shoulder, or 56 cm. It has flexible joints like the Norwegian lundehund we talked about in episode 230, which allows it to climb cliffs and fences and otherwise navigate difficult terrain. It’s usually a yellowy or ginger color, sometimes with small white markings, although some dingoes are black and tan. It can survive on very little water. It often hunts in packs and will hunt animals larger than it is, like the red kangaroo.

The dingo was probably brought to Australia by humans, although we’re not sure when. Dingo fossils have been found dating to 3,500 years ago in western Australia, so it was at least that long ago. Genetic studies show that the modern dingo and the dingo of 3,500 years ago are pretty much identical. It also shows that it’s definitely a domestic dog, related to other dog breeds that were once common in Asia around 7,000 years ago, but which are rare now. It’s most closely related to the New Guinea singing dog, which makes sense since New Guinea is so close to Australia. Until somewhere between 6,500 and 8,000 years ago, New Guinea and Australia were connected when sea levels were low. Genetically the two dog breeds have been separated for about 8,300 years, which suggests that the dingo has been in Australia for at least that long.

Traditionally, Aboriginal Australians would take a dingo puppy from its den to keep as a pet, a hunting dog, or sometimes a herding animal. Sometimes the dingo would stick around when it was grown, but sometimes it would return to the wild. There’s a lot of controversy about breeding dingoes as pets, since it would be easy to breed the wild traits and behaviors out. Since the dingo has been killed as a livestock pest since white settlers arrived in Australia, in many places its numbers are in decline and there are worries that the wild dingo could go extinct. There are already problems with the dingo cross-breeding with other dog breeds. It’s a complicated topic, because while the dingo is a dog, it’s not precisely domesticated at this point but also not precisely a wild animal.

There used to be a domesticated canid in South America called the Fuegian dog, which was probably used as a hunting dog, especially to hunt otters. On cold nights, the dogs would wrap themselves around their people like living blankets so everyone stayed nice and warm.

The Fuegian dog wasn’t a dog, though. It was the domesticated form of the culpeo, also called the Andean fox. It’s actually not a fox although it looks a lot like one. It’s related to wolves and jackals, and it lives on the western slopes of the Andes Mountains all the way down to the southern tip of Patagonia. It eats small animals like rodents and introduced European rabbits. While the culpeo is sandy or tawny in color with gray on its back and a black tip to its tail, the Fuegian dog was sometimes brown and white or all white. Reportedly the Fuegian dog was not very tame in general and was an aggressive animal compared to actual dogs. It would hunt on its own and basically acted like a wild animal that just happened to hang out with humans a lot, like the dingo does today.

The culpeo is doing just fine, but the Fuegian dog is extinct. The Fuegian dog was tamed by a Patagonian people called the Selk’nam [shelknam], or ‘Ona, who were nomadic hunter-gatherers. They lived in such a remote part of South America that Europeans didn’t encounter them until the late 19th century when settlers showed up to raise sheep and rubber trees. We’ve talked about what happened to them in a previous episode, although I can’t remember which one. The Selk’nam didn’t understand the concept of livestock, so they figured those sheep were literally fair game. The sheep were living on their own hunting grounds, after all. The Selk’nam killed some of the sheep, and in retaliation, the European settlers murdered all the Selk’nam. I was going to tell you the name of the man who started the genocide, but I don’t think anyone should remember his name. It wasn’t just “oh, you killed my sheep, I’m going to shoot you because I’m mad,” either. There was a bounty on Selk’nam people, and that’s all I’m going to say because it’s just too awful and disturbing.

By 1930, only about 100 Selk’nam remained alive, and the very last member of the people, Ángela Loij, died in 1974. There’s a link in the show notes to a page with lots of information about her as a person.

In 1919 when Christian missionaries visited what was left of the Selk’nam, they discovered that all the dogs had been killed off by the people themselves because the dogs were too fierce and killed livestock. It sounds like a last, desperate attempt by the Selk’nam to stop the murder of their people by keeping their dogs from killing any sheep. But by then it was too late, and the genocide wasn’t really about the sheep in the end. It was racism and hatred. Remember that all people are equal, no matter what they look like or how they live. Don’t ever let anyone tell you otherwise.

Okay. Let’s finish with the story of another semi-domesticated animal, one that doesn’t involve people being terrible to each other. The kind of rat you can buy as a pet is considered semi-domesticated, and it hasn’t actually been domesticated for very long. The person mainly responsible for the pet rat is a man called Jack Black. Not the actor Jack Black; this was a different guy who lived in the mid-19th century.

Jack Black was a ratcatcher in London, England who said he was the Queen’s official rat-catcher even though he wasn’t. He was definitely an extravagant character who always wore what he called his uniform, which included a big leather sash over one shoulder decorated with rats made of iron, a crown, and the initials V.R. for Victoria Regina, or Queen Victoria. He told people the queen herself gave him the sash, but actually his wife made it for him. Black also carried a big domed cage with him to hold the rats he caught.

He mainly caught rats to sell to people who were training their dogs to kill rats, which was also a popular thing to watch. I mean, that doesn’t sound like any fun to me but this was before video games were invented. Occasionally, though, Black would catch a rat that had interesting markings or that was an unusual color. These rats he would keep, tame, and breed to produce more rats with different colors and patterns. He sold the tame, pretty young rats to people as pets. He especially liked white rats, which made popular pets then and are still popular today.

Pet rats, usually called fancy rats, are a subspecies of the brown rat, or Norway rat, which we talked about in episode 143. We also talked about Jack Black briefly in that episode, but at the time I didn’t realize he wasn’t really a royal rat catcher. By 1900 fancy rats were popular pets and remain so today, and are becoming more and more domesticated. If they’re not fully domesticated they’re well on their way, all thanks to a guy who thought rats were neat.

You can find Strange Animals Podcast 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes. There are links in the show notes to join our mailing list and to our merch store.

Thanks for listening!


Episode 231: Fish of the Twilight Zone



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Let’s learn about some strange fish of the mesopelagic, or the twilight zone deep in the ocean! Thanks to Page, Joel, Anonymous Animal Lover, Brigham, and Fireburster for suggestions this week!

Further reading:

In Defense of the Blobfish

Further viewing:

Pacific viperfish (video embedded)

The Pacific viperfish, head-on (or rather teeth-on), still from video linked above:

Sloane’s viperfish, rocking those teeth:

The blobfish as it’s usually seen on the internet:

The blobfish as it looks when it’s cozy in its deep-sea environment:

The barreleye, which I have helpfully labeled for you:

Look at the bristlemouth’s sharp thin teeth! Good thing it’s only a few inches long:

An indignant bristlemouth (someone should take MS Paint away from me):

The bristlemouth is the most abundant vertebrate in the WORLD (photo by Paul Caiger):

Show transcript:

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

Where on earth does the time go? Suddenly we’re halfway through 2021 and I’m still vaguely thinking we’re only a few months in. I’m getting seriously behind on listener suggestions, so let’s have an episode about some weird fish that’s all listener suggestions. Thanks to Page, Joel, an animal lover who wants to remain anonymous, Brigham (whose name I hope I’m pronouncing correctly), and someone who calls themself Fireburster. Fireburster and Anonymous Animal Lover also both left us really nice reviews, so thank you! I picked all these suggestions at random, just grabbing fish suggestions that sounded interesting, but the great thing is they all turned out to live in a specific part of the deep sea.

Brigham and Fireburster both suggested the same fish, so let’s start with that one: the dragon fish. Neither of them specified which kind of dragon fish they’re talking about, though. It’s a popular name for weird fish of various kinds. We’ve even talked about a few before, the Pacific blackdragon of episode 193, which was coincidentally suggested by Page, and the barbeled dragonfish in that same episode. That’s the episode about William Beebe’s mystery fish, which happens to be my current favorite.

We only talked about the barbeled dragonfish briefly before, so let’s learn more about them now.

The barbeled dragonfish gets its name from the filament that hangs down from its chin, called a barbel. If you’ve ever wondered what the proper name for a catfish’s whiskers is, they’re also barbels. The dragonfish’s barbel has a photophore at the end that produces blue-green bioluminescent light, and the fish flashes the light to attract prey. Its head is large and its jaws are full of sharp teeth, so when an animal comes close, CHOMP! The barbeled dragonfish grabs it.

The dragonfish isn’t very big, with the blackdragon that we talked about in episode 193 being the largest at only 16 inches long, or 40 cm. Most species are about half that. So what happens when an animal the same size as or even bigger than the dragonfish happens along?

The dragonfish eats it, that’s what happens. It has large jaws that it can unhinge to swallow prey that’s bigger than it is, and its stomach can expand considerably to hold whatever it swallows. Mostly it just eats tiny animals like krill and amphipods, though.

We don’t know a whole lot about dragonfish. Various species live throughout most of the world’s oceans, especially in tropical and subtropical areas, and they don’t live in the deepest parts of the ocean. Instead, they’re found in what’s called the twilight zone, or more properly the mesopelagic. Only 1% of all light shining down from the surface makes it down this far, which is why so many animals produce their own bioluminescent light. The dragonfish also has photophores along its sides that it can flash to help attract prey or attract mates. On nights when the moon isn’t too bright, the dragonfish will migrate closer to the surface to find more food, but it makes sure to go back to the twilight zone before the sun rises.

[twilight zone music]

One genus of dragonfish is called the viperfish, and they’re a little different from other dragonfish. Instead of a barbel on the chin, viperfish have a light at the end of a long spine that’s a modified dorsal fin. This is similar to the anglerfish we’ve talked about many times before, even though dragonfish and anglerfish aren’t related. Convergent evolution, at it again!

The viperfish has teeth so long they don’t fit in its mouth. Instead, they stick out, which gives it its other name of fangfish. Sloane’s viperfish has the largest teeth of all the viperfish species, so long that they form a cage across its mouth to stop prey from escaping before the fish can swallow it. Unlike most dragonfish, Sloane’s viperfish sometimes swims toward its prey very quickly, slamming into it and wounding it with its fangs. It even has a sort of built-in shock absorber in its spine right behind its head. The Pacific viperfish can also be aggressive when hunting.

This is probably a good place to learn a little more about the twilight zone, AKA the mesopelagic. It’s measured not by depth but by how much light is available from the surface, in this case only 1% of light. There’s also not as much oxygen in the water here as at the surface. Many, if not most, animals that live in the mesopelagic migrate closer to the surface at night to find food, then retreat to the darkness below to avoid being seen as the sun rises and fills the upper layers of water with more light.

Lots and lots of animals live in the mesopelagic, from giant squid to oarfish, although most of the animals here are small. Below this layer of water is the bathypelagic, and below that is the real depths, the abyssopelagic where conditions are extreme and life gets really weird and scarce. The uppermost layer of the ocean is called epipelagic, if you were wondering. No plants live in the mesopelagic or below, because there’s not enough light. Obviously, the ocean isn’t always deep enough to have a bathypelagic layer or below, and quite often the mesopelagic ends at the sea floor.

It’s hard to study mesopelagic animals because many of them can’t survive at the surface. They’re built to withstand the increased water pressure at depths up to 3,300 feet, or 1000 meters, below the surface, and when they’re dragged up in nets they often die within minutes. Many marine animals have an organ called a swim bladder that’s filled with gases, which helps the animal stay neutrally buoyant in the water so it doesn’t float upward or sink downward when it’s not moving. The animal can adjust the amount of gas in its bladder as it swims upward, but when it’s pulled upward quickly in a net it can’t expel enough gas fast enough and the swim bladder can burst or expand so much that it squishes the rest of its insides, killing the animal before it even reaches the surface. Animals that don’t migrate vertically often don’t have a swim bladder since they don’t need it, and they’re just adapted for water pressure that’s as much as 120 times greater than pressure at the surface. This pressure difference is why blobfish look so blobby, so let’s talk about the blobfish next, Anonymous’s suggestion.

The blobfish lives on the sea floor in deep water near Australia and New Zealand. It grows about a foot long at most, or 30 cm, and is grayish with little spikes all over it. It has a gelatinous body with weak muscles and a weak skeleton, but it doesn’t need either since the intense pressure of the water presses in around the fish all the time and keeps it just the way it should be. It looks like a fish. Its gelatinous flesh is slightly less dense than the water around it, which means it can float just above the sea floor without much effort, just drifting along, giving its tail and broad fins a little flap every so often. It eats whatever detritus floats down from far above, although it’s also mostly on the lookout for small crustaceans that live on the sea floor.

The problem comes when a fishing net catches a blobfish and brings it to the surface. Suddenly there’s no nice firm water around the fish. Instead of being slightly less dense than the water around it, the blobfish is suddenly way more dense than the water, and it expands as a result. Then someone looks at this horrible dead pinkish blob that was once a happy live fish and thinks, “Gross! I’ll take a picture of that for the internet,” and that’s why the blobfish gets its name. Poor blobfish!

Fortunately, scientists have developed a compression chamber for the animals they study. When a deep-sea animal is put in the compression chamber and brought to the surface, the compression chamber keeps the water pressure where the animal needs it. The animal doesn’t die horribly, and that allows researchers to observe a live animal instead of a dead blobby one.

Next, let’s learn about Page’s suggestion, the barreleye fish. It lives in the North Pacific in deep water, and it has upward-pointing eyes that are very sensitive to light. It’s a small fish, only about six inches long, or 15 cm, and is mostly dark in color, as you would expect from a deep-sea fish. It’s chonky in shape with large fins that help it stay motionless in the water while it looks for tiny fish and jellyfish silhouetted against the water’s surface far above. Then the barreleye will move quickly to grab its prey.

It seems like there’s something I’m forgetting to tell you. Hmm. There’s something unusual about the barreleye fish, I just know it.

Oh yeah. The domed top of its head is transparent and its eyeballs are inside the dome. You can see the internal eyeballs and its brain through its transparent head, which is otherwise filled with liquid. It is really weird-looking. Its eyes are tubular, which gives it its name, and they can rotate around to focus on things or look straight ahead when it wants to. The eyes also have bright green lenses, which helps filter out the faint sunlight from above so the fish can better see the bioluminescent glow of other deep-sea animals.

It wasn’t until 2004 that researchers realized the barreleye’s eyes were covered by the transparent dome, because it’s fragile and would end up destroyed when a fish was dragged up by nets. The first photographs and video of the barreleye in its natural environment, taken by deep-sea remote vehicles, must have freaked the researchers out completely.

If you’re wondering why the barreleye has its eyeballs hidden inside a transparent dome, researchers have wondered that too. The best guess is that the dome protects the large, sensitive eyes from jellyfish stings, since barreleyes love to eat jellyfish.

Finally, Joel suggested the bristlemouth fish. The bristlemouth is a small, slender fish that generally grows no longer than a person’s finger, although one species grows up to 14 inches long, or 36 cm. Males are smaller than females. It lives throughout the world’s oceans and is black or dark brown to hide it in the twilight zone where it lives. Like the barbeled dragonfish, which by the way really likes to eat it, it migrates closer to the surface at night to find food, then goes deeper again in the daytime to hide in the darkness.

The bristlemouth gets its name from its teeth, as you may have guessed. It has a large mouth lined with lots of short, thin teeth. It mostly eats small crustaceans, especially copepods, but will also grab tiny fish and other animals. Its lower jaw is longer than its upper jaw and can open wide to grab animals larger than it is. Unlike the other fish we’ve talked about today, its eyes are small and it doesn’t use them to find prey. Instead, it uses its lateral line system, which allows it to detect tiny movements in the water. The male bristlemouth also has a good sense of smell to help it find a female. All bristlemouths start out life as male, but some males metamorphose into females as they age.

The bristlemouth also has rows of light-emitting photophores on its underside to help hide it from predators. Its photophores glow to match the amount of light shining down from far above, which means its silhouette is much harder to see by fish or other animals below it.

There’s still a lot we don’t know about the bristlemouth, but we do know one thing. It’s the most abundant fish in the ocean. Literally there are more bristlemouths in the world than any other vertebrate, estimated at hundreds of trillions of them, possibly as many as a quadrillion, which is a million billion. That’s a lot of fish. There are so many that Navy sonar bounces off them and looks like a false bottom of the ocean. The United States Navy calls it the Deep Scattering Layer and wasn’t sure what was causing it, but the mystery was solved in 2010 when a research vessel with fine-mesh nets kept bringing up unbelievable numbers of the tiny fish. Specifically, the abundant ones are bristlemouth fish in the genus Cyclothone, which mostly lives in tropical areas.

The first person to see a bristlemouth in its natural habitat was William Beebe in the 1930s, during a bathysphere descent into the twilight zone, which brings us right back to where we started this episode.

You can find Strange Animals Podcast 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way, and don’t forget to join our mailing list. There’s a link in the show notes.

Thanks for listening!


Episode 230: Weird Dogs and Round Frogs



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Let’s learn about some strange dog breeds (including a mystery dog!) and what may be the cutest frog ever. Thanks to Brad and Dan for their suggestions this week, and a special thanks to Richard from NC for suggesting the Carolina dog at just the right time.

Check out Dan’s podcast, “Sure, Jan!

Further viewing:

World’s Cutest Frog – Desert Rain Frog

A talbot dog from the olden days:

The Xoloitzcuintli dog:

Norwegian lundehund hard at work:

The Norwegian lundehund has lots of toes:

DOUBLE NOSE DOGGO (Pachón Navarro):

ANOTHER DOUBLE NOSE DOGGO (Tarsus Catalburun):

The Carolina dog:

The desert rain frog, round boi:

Show transcript:

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

A few weeks ago I got to meet two listeners, Brad and Dan. We met for coffee and had a great time talking about animals and podcasting and lots of other things. Dan is a podcaster too, cohost of a great show called “Sure, Jan!” which discusses musical theater in detail with a lot of insight and humor. There’s some language not appropriate for kids, but honestly, any kid who’s so into musical theater that they’re listening to a three-part deep dive into “Everybody’s Talking About Jamie,” they can handle a few bad words. There’s a link in the show notes if you want to check it out.

Brad and Dan both gave me topic suggestions, so this is their episode!

We’ll start with Brad’s suggestion about strange dog breeds. We actually covered this topic a few years ago in a Patreon episode, so Patreon subscribers may recognize a lot of this information, but I’ve done some additional research and added to it.

There are a lot more dog breeds out there than most people know, many of them very rare and restricted to particular regions of the world. Often they were bred for specific purposes, sometimes purposes that no longer exist. This is the case for the turnspit dog. It was a short-legged dog that was bred to run on what was called a dog wheel. The dog wheel looked like a big hamster wheel and turned the spit, a metal rod suspended over the fire that a big piece of meat was stuck onto. The dog ran in the wheel, which turned it, which turned the cord attached to the spit, which turned the spit, which meant the meat cooked evenly instead of staying raw on one side and burning on the other. Usually a household had two turnspit dogs so one could rest while the other took a turn running in the wheel. Once better technology was invented to cook meat, the turnspit dogs were out of a job and eventually stopped being bred. They’re now an extinct breed.

Another extinct dog breed is the Talbot hound. It was a large, relatively slow and heavy hound with white or pale-colored fur, popular in Europe for hundreds of years as a hunting dog. It appears on many coats of arms. It was less of a breed than a type of dog, with many large hounds being referred to as talbots as far back as the 15th century and Talbot being a common name for a hound in the 14th century and possibly earlier. By the 17th century it was more of a standardized breed, resembling a white or light-colored bloodhound in appearance with a tail that curled upward. But by the 19th century it had gone extinct. It might have been the ancestor of the modern beagle.

Many dog breeds aren’t all that old, only dating back to roughly the early 19th century. In the Victorian era in Britain, people got really interested in recreating dog breeds from antiquity, so some breeds that people think date back to antiquity were actually developed just a few hundred years ago. But there are some breeds that genuinely have been around and more or less unchanged for a really long time.

The Xoloitzcuintli (sho-lo-eets-quint-lee) or Xolo is a rare breed of dog that was originally bred by the Aztecs and dates back more than 3,500 years. It’s a hairless dog, although many actually do have a full coat. The hairless variety has black or gray-blue skin that is susceptible to sunburn, while the coated variety has short, dense hair. Because hairlessness is genetically related to a condition where not all the teeth form, hairless Xolos usually have fewer teeth than coated Xolos. Hairless dogs need sunscreen and skin care to keep their skin healthy just like people do.

Another old dog breed is the Norwegian Lundehund. It’s a small, active dog bred specifically for hunting puffins. The breed nearly went extinct after a dog tax made it hard for people to afford keeping numerous dogs, and instead they started using nets to hunt puffins. After the puffin was declared a protected species, even the people who still kept lundehunds for hunting stopped breeding them.

By 1963 there were only six purebred lundehunds alive, five of them related to each other. As a result, despite careful breeding guidelines, modern lundehunds are extremely inbred and prone to genetic diseases. Currently a group of breeders and geneticists are working on crossbreeding the Lundehund with other Nordic breeds to retain the lundehund’s unique traits but make it healthier.

The lundehund definitely has unique traits. It has six toes on each foot, has incredibly flexible leg and neck joints, and can fold its ears shut to keep out water and dirt. All these traits helped it climb nearly vertical cliffs and caves where puffins nested. It also has a double coat to help keep it warm in cold weather. But there is good news for the lundehund: it has a job again! In 2013 the dogs started being used to find bird nests around Norwegian airports. Airports need to keep birds away from the flight paths of planes, since if they hit the plane’s windshield or get sucked into the engine’s air intake, they can cause a plane to crash. The lundehunds hunt down bird nests on the airport grounds so they can be removed before there’s a terrible accident.

While I was working on this episode, Richard from NC, who had no idea that I was researching weird dog breeds, asked if I’d heard about the Carolina dog, also known as the American dingo. I looked it up and it’s a real animal—specifically, a dog breed. But it has a strange history.

The Carolina dog is medium-sized, up to 20 inches tall at the shoulder, or 51 cm, but lightly built. Its short hair is often yellow, ginger, or pale brown in color, sometimes with white markings. It has long, slender, erect ears and a long tail. White settlers sometimes called it the Indian dog because Native Americans kept it as a pet or hunting dog, but there were also plenty of feral Carolina dogs living in the wild in the eastern United States.

Archaeological excavations done in the late 19th century found lots of dog remains buried with people. Several archaeologists noted that the dog’s jaw was slightly different from other dog breeds, lacking one pair of teeth. They suggested that the so-called Indian dogs were descended from the earliest domesticated dogs in Asia and migrated into North America when humans did in the Pleistocene.

This was the accepted theory until 2013, when genetic testing was finally done on the breed. Later genetic studies have also been carried out. The studies all conclude that although the Carolina dog has interbred with modern dog breeds, it does have genetic markers that indicate some of its ancestors are from East Asia. It’s more complicated than it sounds, though. A 2018 genetic study compared fossils from ancient North American dogs with the living Carolina dogs and didn’t find much of a match. The fossil dogs migrated from Siberia and were isolated in North America for 9,000 years. Then their unique genetic signature vanished, with the exception of some Arctic dog breeds, as Eurasian dogs brought to North America from Europe took over. Some Carolina dogs do contain that unique genetic signature, but there’s no way to tell if it’s from ancient ancestors or more recent cross-breeding with Arctic breeds.

What is definitely true is that the Carolina dog shares a lot of physical traits with other feral dog populations from around the world. Basically, if dogs are allowed to live and breed without human help or interference, the result is a dog that looks a lot like the Carolina dog of North America, or the pariah dog of Asia, or the dingo of Australia.

But let’s talk now about dogs with double noses, such as the Pachón Navarro, a Spanish hunting dog that sometimes has a double nose, also called a split nose. That doesn’t mean it has two snouts or four nostrils, but that each nostril has its own nose pad separated by a strip of skin and fur, with a groove running down the middle of the snout.

The Pachón Navarro almost went extinct as a breed. A breeding program got underway in the 1970s but it’s still a rare breed. It’s a pointer hound bred since at least the 15th century in the Pyrenees Mountains, and it has short hair that’s white with brown or orange markings, especially on the ears and over the eyes. Not all dogs of this breed have the double nose, and some modern breeders try not to breed for it since the double nose trait is linked to a cleft palate that can cause other health issues.

The double-nosed trait is only seen in one other dog population. The Tarsus Catalburun [chatal-burrun], or Turkish pointer, may be a descendant of Spanish dogs favored by Turkish nobility, or it may be the dog that gave rise to the Pachón Navarro breed. Most historians think the breed was probably developed in the 19th century from European dogs since there has never been a tradition of hunting with pointers in the area. It’s really rare outside of Turkey and rare inside of Turkey, with a population of only a few hundred dogs that are somewhat inbred. They’re mostly kept by partridge hunters.

There is a mystery associated with double-nosed dogs. The Andean tiger hound is a third variety of double-nosed dog that’s supposed to live in Bolivia, South America. It’s supposedly descended from dogs brought to the Americas by Spanish Conquistadors in the 16th century.

But does the Andean tiger hound really even exist? In 1913, explorer Lt.-Col Percy Fawcett reported seeing double-nosed dogs in the Amazon jungle. In a book Fawcett’s son compiled from his field notes and published in 1953, he reports,

“Here we saw for the first and only time a breed of dog known as the double-nosed Andean tiger hound. The two noses are as cleanly divided as though cut with a knife. About the size of a pointer, it is highly valued for its acute sense of smell and ingenuity in hunting jaguars. It is found only on these plains.”

But no one else who visited Bolivia ever reported seeing any of these dogs—until 2005 when another explorer, Colonel John Blashford-Snell, saw a double-nosed dog in a remote village. The dog was named Bella and her owner reported that she was a member of an extremely rare breed found only in Bolivia.

The following year Blashford-Snell returned to the village. Unfortunately Bella had died in the meantime, but she had had a puppy, named Xingu, who also had a double nose. While Blashford-Snell was in the area with a team of scientists investigating a 30,000 year old meteor crater, Xingu had a litter of puppies with a single-nosed dog and two of the four puppies had double noses.

It’s possible that the Andean tiger hound is a rare dog breed still hanging on in remote areas of Bolivia, a descendant of Spanish dogs. Then again, it might just be a trait that crops up occasionally in the local dogs, either due to Spanish double-nosed dogs in the ancestry or a similar genetic anomaly that developed independently. The trait occurs in other breeds occasionally, especially in wolfhounds and bullmastiffs.

All the dogs we’ve talked about are good. They’re good dogs, Brad.

Next, Dan wanted to hear about the desert rain frog. I know we’ve talked about it before at some point, but only briefly and I can’t even find which episode. So all this information is new to me too.

The desert rain frog only grows about two and a half inches long, or 6 cm. It’s not your average hopping frog that sits on a lily pad and goes ribbit and maybe plays a tiny banjo. Instead, it’s a round boi with short little thin legs that it uses to dig burrows in the sand where it lives. Which is a desert. It’s a rain frog that lives in a desert. Also, it makes this sound:

[desert rain frog sound]

The desert in question is a 6-mile-wide strip of land, or 10 km, along the southwestern coast of Africa, right at the border of Namibia and South Africa. Yes, it’s a desert along the ocean. It’s actually a specific habitat called a coastal desert. The frog lives in a small part of the Namib coastal desert, which is probably the world’s oldest desert—possibly as much as 80 million years old. Parts of it have stupendously huge sand dunes, up to 980 feet tall, or 300 meters, and 20 miles long, or 32 km.

Because it’s an amphibian, the desert rain frog has to keep its skin moist. This can be difficult to do in a desert. It digs its burrow deep enough to find moist sand to rest on, and it absorbs the moisture through its skin. Coastal deserts also receive some moisture in the form of sea fog. This helps plants to grow on the dunes, which means animals like antelopes come to eat the plants, which is important because their dung attracts the insects the frogs eat.

The female desert rain frog lays her eggs in her burrow on damp sand. The eggs hatch into tiny froglets instead of tadpoles.

The frog’s legs are too short to allow it to hop, but it has webbed toes that help it walk on loose sand. It’s nocturnal and spends the day in its burrow, but at night it comes out to walk around and catch insects. It will also emerge during the day when there’s a lot of fog. It mostly eats beetles and moths that are attracted to animal dung and it probably also eats the eggs those insects lay in the dung and the larvae that hatch out of the eggs. Because its skin is moist, sand sticks to it and helps camouflage the frog while it’s aboveground.

I need to stress how round this frog is, because I don’t think I have made it clear. It’s very round, generally described as spherical. It’s a little bigger than a ping-pong ball but it resembles a ping-pong ball that’s stuck all over with sand and has round golden eyes and a frowny little mouth and absurdly short legs. It may actually be the cutest frog, and that is a ferociously competitive title.

Unfortunately, because the desert rain frog lives in such a small, specific habitat, it’s endangered due to habitat loss and pollution. Strip mining for diamonds is common in the area and people have also started building roads and grazing livestock along parts of the coastal desert. Hopefully the desert rain frog and its habitat can be protected before it’s too late.

Let’s listen to this little frog again. This is the sound a desert rain frog makes when it feels threatened, actually. There’s a link in the show notes to the iconic video taken by wildlife photographer Dean Boshoff, which is where I got the audio, and when you watch it you can see that the frog is actually backing away. It’s okay, little frog. Everyone loves you.

[frog buzzy sound]

You can find Strange Animals Podcast 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way, and don’t forget to join our mailing list. There’s a link in the show notes.

Thanks for listening!


Episode 229: Blue Ghosts and Vanishing Sharks



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I got to meet some listeners this week to see the synchronous fireflies, so thanks to Shannon, Diana, Derek, and Autumn for hanging out with me! This week we’ll learn about a different kind of lightning bug as well as a shark mystery!

Derek’s photography, Enchanting Ectotherms

Further reading:

A shark mystery millions of years in the making

I suspect this is a doctored image but it’s gorgeous so here it is anyway, supposedly some blue ghost fireflies:

This is a real photo, no photoshop, taken by Derek Wheaton during our trip. The long line of light in the middle is a blue ghost moving with its light on during a long exposure:

A synchronous firefly on Derek’s hand (photo by Derek Wheaton):

A tiny blue ghost firefly on Derek’s hand (photo by Derek Wheaton):

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. It’s been an amazing week for me because I got to take some people to see our local synchronous fireflies! The fireflies put on a brilliant show for us and the weather was perfect, and it was so much fun to meet Shannon and Diana! Then, two nights later, I also took Derek and Autumn out to see the fireflies. In between, I started research on the blue ghost firefly, since I had originally thought it was just another name for the synchronous firefly, but it’s not. So this week we’re going to learn about the blue ghost firefly, along with some interesting breaking news about a shark mystery.

The blue ghost firefly only lives in parts of the eastern and central United States. In most places it’s rare, but like the synchronous fireflies that all flash together, the blue ghost fireflies are actually pretty common in the southern Appalachian Mountains. The reason why people don’t see them more often is that these days, most people don’t spend much time in the woods at night.

Like other fireflies, the blue ghost lives in forests with deep leaf litter where there’s a lot of moisture in the ground. The female lays her eggs in the leaf litter and when the eggs hatch, the larval fireflies eat tiny insects and other invertebrates like snails.

The blue ghost firefly is different from other firefly species in several ways. First, it doesn’t flash. The male stays lighted up for around a minute at a time while he flies low over the ground watching for a female to light up too. Its glow also appears bluish-white to human eyes, at least in the distance and when it’s really dark out. Up close, it looks yellow-green like other firefly lights. Researchers think it only looks blue because of the way human eyes perceive color in low light.

In the daytime, blue ghost fireflies don’t look like much. They’re small, around 7 mm long, and males are all brown. The females don’t have wings, and in fact they never metamorphose into the adult form and still look like larvae as adults. The female crawls to the end of a twig or blade of grass and glows to attract a mate.

When I was doing my research to learn about blue ghost fireflies, I kept seeing articles comparing its size to a grain of rice. I looked up the average size of a grain of rice, and that’s where I got 7 mm. I didn’t think too much about it.

When Shannon, Diana, and I were watching the synchronous fireflies, we noticed some fireflies that didn’t flash, just stayed glowing while they drifted along low over the forest floor. After I started researching blue ghost fireflies, I realized that was what had seen! So I was especially excited to go back out with Derek and Autumn and confirm it.

Derek works for a nonprofit that breeds endangered fish for conservation projects, which is awesome, but he’s also a photographer, so he brought his camera to try and get pictures and video of the fireflies. His photographs are amazing so if you want to see them I’ve linked to his Facebook page, EnchantingEctotherms, in the show notes. He does a lot of snorkeling so a lot of the animals he photographs are fish or other water animals like turtles and snakes, and he gives information about them in his posts.

Anyway, he wanted to get close-up pictures of a synchronous firefly and a blue ghost firefly, so we all spent some time trying to catch one of each—gently, of course, and without leaving the trail. We didn’t want to hurt ourselves in the dark or disturb the fireflies’ habitat. Derek caught a synchronous firefly first, and it looks like an ordinary firefly that I’m used to, the common eastern firefly, which grows to about 14 mm long. That’s half an inch long. Then, eventually, he also caught a blue ghost. It was so small that at first we thought he might have caught some other beetle by accident, until we looked more closely and saw the telltale head shape of a lightning bug. I took a photo myself and put it in the show notes so you can see just how small it is.

From my own observation, the blue ghosts are much dimmer than other fireflies, which makes sense since they’re so much smaller. The light does look faintly blue-white in the distance, but when it’s closer to you it looks like an ordinary firefly’s light. They do indeed fly very low to the ground while lit up, but they’re also cautious. We had trouble catching one because when we got too close, the firefly would fly down to the ground and put his light out.

Naturally, after photographing our lightning bugs we let them go again. I’m happy to report that the synchronous fireflies have expanded their range a lot since I first stumbled across them about ten years ago, and the blue ghosts seem reasonably common too. They live in a protected area of our local watershed so they’ll be safe and sound forever, hopefully.

This is good, because blue ghosts in particular are vulnerable to habitat loss. Since the female can’t fly, she can’t travel far to lay her eggs. During mating season, some state and national parks in the southern Appalachians close some trails to protect the blue ghost and other fireflies, especially from light pollution from flashlights.

The synchronous fireflies and blue ghosts are only active for a few weeks in June, which is their mating season. We’ll probably be just about at the end of this year’s display by the time you hear this, but if you’re going to be in East Tennessee and want to go out and see them with me next summer, just let me know. As we talked about in episode 180, they only live a few minutes’ walk away from a small parking lot but no one but me seems to know about them.

Next, let’s learn about a shark mystery that’s 19 million years old but that scientists only learned about recently. This month, June of 2021, a team of researchers published results of a shark study in the journal Science. The team had decided to graph the number and diversity of shark species known from the fossil record so they’d have a baseline to compare modern shark diversity to. But they discovered something really surprising.

Nineteen million years ago, there were over ten times as many sharks in the oceans as there are today. They were an important part of the ocean’s ecosystems, especially in the open ocean. And then…they disappear from the fossil record. Over 90% of the world’s sharks died, with shark diversity decreasing by more than 70%. Not only that, sharks never fully recovered from whatever happened.

So what did happen? We don’t know yet. There was a small extinction event called the Middle Miocene extinction peak five million years after the sharks vanished, which researchers think was due to global cooling leading to climate change. The cooling period was caused by a lot of factors, but a big cause was changes in ocean currents and air currents as the continents moved into new positions. Before that, though, the world was comfortably warm for millions of years and the shark population was overall quite stable. Researchers have found no reason why sharks suddenly started dying in such huge numbers, especially in the open ocean instead of in coastal waters.

The leader of the study, Elizabeth Sibert, says that there might have been a climate event of some kind that was disastrous to sharks but that was over relatively quickly, leaving very little evidence behind except for the fossil remains of way more sharks than usual and a lack of sharks afterwards.

Other scientific teams have already started studying the open ocean ecosystem from 19 million years ago and earlier for clues as to what happened, whether other animals were affected, and why sharks never regained their supremacy in the world’s oceans afterwards. That’s how science works: someone makes a discovery and that inspires lots of new studies, which lead to more discoveries. When we do learn more about the great shark die-off of the Miocene, I will keep you posted.

You can find Strange Animals Podcast 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way, and don’t forget to join our mailing list. There’s a link in the show notes.

Thanks for listening!

 


Episode 228: Monkey Lizards and Weird Turtle…Things



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Thanks to Ethan for this week’s topic, two weird animals that developed after the Great Dying we talked about last week!

Further reading:

Monkey Lizards of the Triassic

Placodonts: The Bizarre ‘Walrus-Turtles’ of the Triassic

Drepanosaurus (without a head since we haven’t found a skull yet, but with that massive front claw):

Drepanosaurus’s tail claw:

Hypuronector had a leaf-like tail:

Placodus was a big round-bodied swimmer:

Some placodonts [art by Darren Naish, found at the second article linked above]:

Henodus was the oddball placodont that probably ate plant material:

Show transcript:

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

 

Last week we talked about the end-Permian mass extinction, also called the Great Dying. This week let’s follow up with a couple of weird and interesting animals that evolved once things got back to normal on Earth. Thanks to Ethan who suggested both animals.

 

The great dying marks the end of the Permian and the beginning of the Triassic period, which lasted from about 251 million years ago to 201 million years ago. In those 50 million years, life rebounded rapidly and many animals evolved that we’re familiar with today. But some animals from the Triassic are ones you’ve probably never heard of.

 

We’ll start with a reptile called the drepanosaur. Drepranosaurs are also sometimes called monkey lizards for reasons that will soon become clear. Paleontologists only discovered the first drepanosaur in 1980, Drepanosaurus, and within a few years they recognized a whole new family, Drepanosauridae, to fit that first discovery and subsequent closely related specimens. Drepanosaurs were weird little reptiles that probably looked like lizards in many ways, although they weren’t lizards.

 

How weird was Drepanosaurus? Very weird. Very, very weird.

 

It was obviously a climbing animal that probably spent all of its life in the treetops. It had lots of adaptations to life in trees, such as hind feet where all the toes pointed in the same direction and were somewhat curved, sort of like a spider monkey’s hand. That would help it get a good grip on branches. But those hind feet aren’t why it’s called the monkey lizard.

 

Drepanosaurus and its relatives are called monkey lizards because of their tails. Many monkeys have prehensile tails, which act as a fifth limb and help keep the monkey stable in a tree by curling around branches and hanging on. Drepanosaurus had something similar. Instead of being mobile from side to side like most reptile tails, Drepanosaurus’s tail could mostly only curve downward. Modern chameleons have an even more pronounced downward-curving tail that helps them climb. But the chameleon’s tail is still just a tail. The end of Drepanosaurus’s tail had several modified caudal bones that were probably exposed through the skin. Those modified bones acted as a claw to help the animal grab onto tree trunks and branches. So Drepanosaurus had claws on its front feet, claws on its hind feet, and a claw on its tail. It’s sort of like having five feet.

 

As if that wasn’t weird enough, let’s talk about those claws on the front feet. It had five toes on each foot, and four of them had ordinary claws. They were sharp but fairly small, about what you’d expect from an animal that grew about 19 inches long at most, or 50 cm. But the second toe on each foot, which corresponds to the pointer finger on a human hand, had a much bigger claw. MUCH BIGGER CLAW. It was as big as its whole hand! Most researchers think it used the claw to dig into rotting wood, insect nests, and bark to find insects and other small animals to eat.

 

But that’s not all. Drepanosaurus also had a structure called a supraneural bone at the base of its neck, made up of fused vertebrae, that would have made it look like it had a little hunch on its shoulders. While we don’t have a skull of Drepanosaurus, since we only have three specimens so far, this structure is also present in other drepanosaur species where we do have the neck and head, and they all have fairly long, slender necks and birdlike skulls with large eyes. It’s possible that the supraneural bone was the attachment site for special muscles that helped Drepanosaurus extend its neck very quickly to grab insects and other small animals.

 

Drepanosaurs in general shared many of the traits seen in Drepanosaurus, although with some differences. Many drepanosaurs had opposing toes on the feet that would help them grasp branches and twigs more securely. Most don’t have the giant claw on the front feet although most do have the tail claw. But one monkey lizard doesn’t live up to its name at all.

 

A little drepanosaur called Hypuronector limnaios, which only grew about five inches long, or 12 cm, had a much different tail from its relations. Its tail didn’t curve downward at all—in fact, it stuck up behind it and was probably not very flexible. Not only was the tail longer than the body and head together, it had long points growing down from the vertebrae, called haemal arches, which made the tail extremely large top to bottom but flattened from side to side.

 

In other words, its tail looked like a leaf. The drepanosaur could cling to a branch with its tail sticking up, and any nearby predators would probably think it was just another leaf growing from the branch, especially if the tail was covered in green skin. Some researchers speculate that it could have used its tail as a sail to glide from branch to branch too, or it might have acted as a parachute if it had to jump from a branch to escape a predator. Hypuronector’s front legs were longer than its hind legs, unlike other drepanosaurs, which suggests it might have had a flap of skin that helped it glide.

 

Drepanosaur fossils have been found in parts of the United States and western Europe, but were probably more widespread than that. We still don’t know a whole lot about them, so every new specimen that’s found can give paleontologists lots of new information. Most drepanosaurs resembled weird chameleons with birdlike heads, but they weren’t related to birds or chameleons. We don’t actually know what they were closely related to.

 

Ethan also suggested placodonts, another reptile that evolved in the Triassic. Don’t confuse them with placoderms, the armored fish that went extinct in the great dying. The “placo” part of both words means tablet or plate. Therefore, placoderms have skin—that’s the “derm” part—covered in plates, while placodonts have flattened teeth, because the “dont” part refers to teeth. That’s why you get braces on your teeth at the orthodontist but you go to the dermatologist for skin problems.

 

What did placodonts do with their flattened teeth? They used them to crush the shells of shellfish and crustaceans. From that you can infer that they were marine reptiles, and you would be right. The earlier species had big round bodies with heavy bones, which helped them dive to the ocean floor to find food. They lived in shallow coastal waters and had large flattened ribs that helped protect them from injury if currents pushed them into rocks. While the teeth in the back of the mouth were flattened to crush shells, the teeth in the very front of the mouth were sharp and pointed forward to grab prey.

 

One of the most common early placodonts was Placodus [PLAK-oh-dus], which grew nearly six and a half feet long, or 2 meters. Its long tail was flattened laterally to help it swim and it probably had webbed toes. Since its legs were small and relatively weak considering how heavy its body was, it probably couldn’t get around very well on land, so it would have stayed close to the water. It probably looked kind of like the modern marine iguana, which we talked about in episode 92, but with longer jaws. On the other hand, unlike the marine iguana, placodus had a third eye.

 

THIRD EYE ALERT! If you remember way back in episode 3, where we talked about the tuatara, we learned a little bit about the parietal eye, or third eye. Parietal eyes are found on the top of a few animals’ heads, including the tuatara, but they aren’t the same as ordinary eyes. They’re very small photoreceptive eyes that can only sense light and dark. In Placodus’s case, researchers think that ability helped it figure out which way was up more easily when it was underwater. If you’ve ever been knocked down by a wave you’ll understand how easy it is to get disoriented underwater.

 

Placodus and other early placodonts had a ridge of bony scutes on the back to help protect it from predators. In later placodonts those scutes were bigger and bigger until they were more like armor, which added weight to the body and meant that the bones didn’t have to be so dense. This meant that instead of having barrel-like bodies, later placodonts were a little more streamlined. Their bodies were more flattened than round, but still broad across with big plates protecting the back. Their legs were more like flippers.

 

Does this make you think of something? Something like a sea turtle?

 

Later placodonts looked a lot like turtles, a classic case of convergent evolution because they weren’t related to turtles at all. If you saw Placochelys, for instance, you’d probably just think it was a weird sea turtle, unless you got a really close look at it. It grew about three feet long, or 90 cm, with a triangular head, a knobby shell, and flippers with clawed toes at the ends. It had a beak like a turtle’s instead of Placodus’s forward-pointing teeth, but unlike a turtle it also had teeth in the back of the mouth. These were still big flat teeth used for crushing shellfish, but like other placodonts the upper teeth grew from the palate, or the roof of the mouth.

 

Other placodonts would have looked strange to us, like Psephoderma. It grew up to six feet long, or 180 cm, and instead of a single turtle shell, it had two shells. One covered its body from the back of the head down to the pelvis. The other covered its pelvis and was smaller. It had a long tail and a pointy nose.

 

At least one placodont didn’t live in the ocean and didn’t eat shellfish and crustaceans. Henodus grew about three feet long, or one meter, and lived in brackish water or possibly freshwater. Its shell was twice as broad as it was long. It also had a lower shell, or plastron, on its belly. Its nose was short and squared-off and it had a turtle-like beak, and instead of teeth it had denticles on the sides of its jaws. Some researchers think it was a filter feeder, filtering tiny animals from the water through the denticles, while other researchers think it may have eaten water plants. It might have done both.

 

There’s a lot we don’t know about placodonts. We don’t know if they laid eggs or gave birth to live young, and we don’t know what exactly they ate. Obviously their teeth were best suited to crushing shells, but we don’t actually know what kind of shellfish they preferred or if they only ate crustaceans or something else. Placodont remains have been found in Europe, the Middle East, and China, but they were probably more widespread than that. During the Triassic, as the supercontinent Pangaea broke up, it created lots of shallow oceans and island chains that would have been ideal for placodonts.

 

Unfortunately for the placodonts, as the landmasses moved farther apart over millions of years, the shallow seas became deeper. Populations would have become isolated from each other. Eventually placodonts went extinct, probably by a combination of habitat loss and competition from other animals as dinosaurs and their relatives spread throughout the world.

 

You can find Strange Animals Podcast 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way, and don’t forget to join our mailing list. There’s a link in the show notes.

 

Thanks for listening!


Episode 227: The Great Dying



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It’s another extinction event episode! This one’s about the end-Permian AKA the Permian-Triassic AKA the GREAT DYING.

Further Reading:

Ancient mini-sharks lived longer than thought

Lystrosaurus’s fossilized skeleton:

Lystrosaurus may have looked something like this but I hope not:

This artist’s rendition of lystrosaurus looks a little less horrific but it might not be any more accurate:

Show transcript:

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

It’s time for our next extinction event episode, and this week it’s the big one. Not the extinction event that killed the dinosaurs, but one you may not have heard of, one that almost destroyed all life on earth. I mean, obviously it didn’t and things are fine now, but it was touch and go there for a while. It’s the Permian-Triassic extinction event, or end-Permian, which took place just over 250 million years ago. It was so bad that scientists who aren’t given to hyperbole refer to it as the Great Dying.

Don’t worry, we won’t talk about extinction the whole time. We’ll also learn about some interesting animals that survived the extinction event and did just fine afterwards.

We have a better idea of what happened at the end of the Permian than we have about the earlier extinction events we talked about in episodes 205 and 214. Right about 252 million years ago, something caused a massive volcanic eruptive event in what is now Siberia. Some researchers speculate that the cause of the volcanic eruptions may have been a huge asteroid impact on the other side of the Earth, which was so powerful that it caused magma to move away from the impact like water sloshing in a jostled glass. The magma rose up toward the earth’s crust and eventually through it onto the surface.

The result was probably the largest volcanic event in the last half-billion years and it continued for an estimated two million years. Most of the eruptions were probably pretty low-key, just runny lava pouring out of vents in the ground, but there was just so much of it. Lava covered almost a million square miles of land, or 2.6 million square km. Ash and toxic gases from some eruptions also ended up high in the atmosphere, but one big problem was that the lava poured through sediments full of organic material in the process of turning into coal. Lava, of course, is molten rock and it’s incredibly hot. It’s certainly hot enough to burn a bunch of young coal beds, which added more ash and toxic gases to the air—so much ash that shallow water throughout the entire world became choked with ash.

The carbon dioxide released by all that burning coal caused severe ocean acidification and ocean anoxia—a lack of oxygen in the water. But it gets worse! A lot of lava erupted into the ocean right at the continental shelf, where the shallow coastal water becomes much deeper. This is exactly the place where you find methane deposits in the sediments on the ocean floor. When those deposits were suddenly disturbed by lava flowing into them, all the methane in the formerly tranquil depths was released and bubbled to the surface. Methane is a powerful greenhouse gas, meaning that if a whole lot of it ends up in the atmosphere in a short amount of time, it can cause rapid global warming—much faster than that caused by carbon dioxide. This global warming would have happened after a period of global cooling due to reduced sunlight reaching the earth through ash clouds, which lasted long enough and was severe enough that sea levels dropped as glaciers formed. Then everything heated way, way up. The ice caps melted, which may have led to a stagnation of ocean currents. This in turn would have contributed to the water’s anoxicity and toxicity. The average temperature of the ocean would have increased by almost 15 degrees Fahrenheit, or 8 degrees Celsius. Atmospheric warming may have been as much as 68 degrees Fahrenheit in places, or 20 degrees Celsius. That’s not the average temperature of the world, that’s the temperature increase.

So, basically, everything was terrible and it happened very quickly in geologic terms. A 2018 study found that everything looked pretty much fine for the 30,000 years leading up to the great dying. Some researchers even think the initial extinction event might have taken place over just a few centuries.

Marine animals were affected the most, especially marine invertebrates. Trilobites and placoderms went extinct, eurypterids went extinct, and corals went extinct until about 14 million years later when modern corals developed. Some researchers estimate that 95% of all marine species went extinct.

Things were better on land, but not that much better. At the end of the Permian, life was good on land and it was especially good for insects because of the high percentage of oxygen in the air and the variety of plant life in huge swamps around the supercontinent Pangaea. The largest insects that ever lived were buzzing around in the Permian. This included an order of insects called Meganisoptera, or griffinflies. Griffinflies looked like dragonflies and may be related to them. Some species had a wingspan 28 inches across, or 71 cm. The arthropod Anthopleura, sometimes called the giant millipede, lived in the Permian too. Some species grew six feet long, or 2.5 meters, and were about 18 inches wide, or 45 cm. It looked like a millipede but had even more legs. It probably looked scary, but it only ate plants as far as we know.

Instead of actively breathing the way most vertebrates do, most invertebrates use a passive system to absorb oxygen from the air. This is great when there’s a lot of oxygen. When the level of oxygen drops, though, the largest species can’t absorb enough oxygen to function and die out rapidly. That’s one reason why you don’t have to worry about spiders the size of bears. So all the large invertebrates and a lot of the smaller ones went extinct as oxygen was replaced with carbon dioxide, methane, and other toxic gases in the atmosphere.

The acid rain caused by toxic gases and the reduced sunlight caused by ash in the atmosphere also killed off plants. Forests died, so that the fossil record during and after the extinction event contains massive amounts of fungal spores from fungi that decompose trees. Some researchers think all of the world’s trees died. Forests disappeared for some four million years. Since trees absorb carbon dioxide from the atmosphere and release oxygen, the lack of trees made oxygen levels drop even more.

Animals that depended on forests to survive also went extinct, including about two-thirds of all amphibians, reptiles, and therapsids. Therapsids were proto-mammals and it’s a good thing they didn’t all die out because they eventually gave rise to mammals.

Everything I’ve described sounds so incredibly bad, you may be wondering how anything survived. One stroke of luck was probably the size of Pangaea. That was the supercontinent made up of most of the world’s landmasses all smushed together. Before the extinction event, the middle of Pangaea was probably pretty dry with swampier climates around the edges. After the extinction event, the interior of the supercontinent was the safest place to be.

One of the most common land animals after the extinction event was a herbivore called Lystrosaurus. Lystrosaurus was a therapsid, and it was nothing exciting to look at unless you were also a lystrosaurus. Some species were the size of a cat while some were much larger, up to 8 feet long, or 2.5 m. It had a short snout, a short tail, and a semi-sprawling gait. A lizard walks with its legs stuck out to the sides, while a dog or cat or pig walks with its legs underneath its body. Lystrosaurus was somewhere between the two.

It probably lived in burrows that it dug with its strong front legs. While it had a pair of tusks that grew down from the upper jaw, those were its only teeth. Instead it probably had a turtle-like beak that helped it bite off pieces of vegetation.

Lystrosaurus lived in the central part of Pangaea, in what is now Asia, Antarctica, South Africa, and eastern Europe back when all those areas were all scrunched up close together. It survived the extinction event and expanded its range, and for millions of years it was almost the only big land animal in the world. It had almost no predators because they’d all gone extinct, and it had very few competitors for food because they’d all gone extinct. Lystrosaurus made up 90% of all land vertebrates for millions of years.

How did it survive when so many other animals died out? There are several theories, but the most important factor was probably its lack of specialization. It could survive on any kind of plant instead of needing to feed on specific species of plant. There’s also evidence that it could enter a torpor similar to hibernation where its metabolism slowed way down. This would have been a literal lifesaver during the time when the air and water were toxic and very little plant life survived. Lystrosaurus could hunker down in its burrow for long stretches of time, then come out and find enough food and water to keep it going for another stretch of torpor.

Just imagine the world back then, after the initial extinction event but before the world had recovered—say, a million years after the volcanic activity stopped. Picture a series of gentle rolling hills dotted with grazing animals. It’s peaceful and very open because there are no trees. Grass hasn’t evolved yet so the ground is covered in fern-like plants from the genus Dicroidium, which lives in dry conditions. As you look closer with your mind’s eye, you realize that every single one of those grazing animals—thousands of them visible in every direction—are the same kind of animal that looks sort of like a fuzzy pig with a stumpy lizard tail, clawed feet, and a turtle’s beak. Lystrosaurus, living the good life.

In the ocean, the situation was similar. The shallows were toxic waste dumps of ash where the water had so little oxygen that nothing could survive. But the deeper ocean was still livable for some animals.

For a long time, scientists thought a group of early sharks called cladodontomorphs had gone extinct during the great dying. Their distinctive teeth had been common in the fossil record, but after the extinction event they disappeared. Cladodontomorphs only grew about a foot long at most, or 30 cm, and may have had a weird-shaped dorsal fin that pointed forward. They lived in shallow coastal waters. You know, the worst possible place to be 252 million years ago.

Then palaeontologists found some of those teeth in rocks that were in much deeper water 135 million years ago. It turns out the little sharks had survived the extinction event by moving into the open ocean where conditions were better. And they didn’t just survive, they lasted for another 120 million years.

So let’s break it down. It was probably four million years before trees developed again from different plants. It was some 14 million years before coral reefs could rebuild as modern corals developed after their cousins went extinct. It took 30 million years for terrestrial vertebrates to recover from the great dying and 50 million years for all the ocean’s ecosystems to fully recover. That’s a colossally long time. But it did recover.

So what animals arose once the recovery was well underway? Icthyosaurs. Archosaurs, which eventually evolved into pterosaurs, crocodilians, dinosaurs, and birds. And therapsids that eventually gave rise to modern mammals.

I don’t usually tease the following week’s show, but next week we’re going to learn about some weird and interesting animals that developed in the early to mid Triassic, after the extinction event was over and life started evolving in new directions. As I’ve said in the previous extinction event episodes: no matter how bad things get, there’s always going to be some little animal stumping along out of the carnage to get on with the business of surviving and thriving.

You can find Strange Animals Podcast 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!


Episode 226: Brood X Cicadas



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It’s the 2021 brood of 17-year cicadas! Thanks to Enzo (and several others) who suggested it!

Further listening:

Varmints! Podcast – “Cicadas”

Our local Brood X cicada (photo by me!):

The holes that cicadas emerged from (photo also by me):

Discarded cicada shells. My work keys and Homestar Runner keychain for scale:

Show transcript:

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

This week we’re going to talk about cicadas, specifically the 17-year cicadas that you may have heard about in the news or in your own back yard, depending on where you live. Thanks to the several people who suggested the topic on Twitter, with special thanks to Enzo who emailed me about it.

I actually wasn’t going to do a cicadas episode because we already talked about cicadas way back in episode 28. We didn’t go into too much detail in that one, but Varmints! podcast did a great in-depth show about cicadas recently so I’ve been referring people to them, and check the show notes for a link if you don’t already listen to Varmints. Besides, I hadn’t heard any of the cicadas myself so I didn’t see what the big deal was.

Then I returned to work after taking some time off to take care of my cat Poe, who by the way is doing really well now and thanks for all the well wishes! The second I got out of my car, I heard them. The cicadas. Now, we get cicadas every year where I live in East Tennessee, so the sound is familiar to me and I actually like it. I find it soothing and the quintessential sound of summer. But this was something else. At only 8am the trees along the edge of campus were filled with what I can only describe as a high-pitched roar.

I went out at lunch and the sound was even louder. I got some audio, so here’s what a whole bunch of cicadas sound like when they’re calling at once.

[cicada sounds]

I also got pictures, which you can see in the show notes.

The cicadas emerging in such numbers this year are 17-year cicadas. They spend almost all of those 17 years as nymphs underground, where they eat sap from the roots of trees and other plants. At the end of the 17 years, when the soil is warm enough, they emerge from the ground and molt into their final form, the full-grown adult cicada!

The adult cicadas have wings but aren’t very good fliers. I can definitely attest to that because when I was taking pictures of them, I kept having to dodge as cicadas flew from bush to tree and either didn’t see me standing there or thought I was a weird tree or maybe just couldn’t maneuver well enough to avoid me. They’re pretty big insects, up to two inches long, or five cm, with gray or black bodies and orangey-red legs and eyes. The wings have pale orange veins.

The first cicadas to emerge are mostly males, in such numbers that predators get too full to care when the females emerge a few days later. That way more females survive to lay eggs. At first the cicadas that emerge still look like nymphs, but within about an hour they molt their exoskeleton and emerge as full adults with wings. They’re pale in color until the new exoskeleton hardens and the wings expand to full size, which takes a few days.

This, of course, leaves behind a cicada shell, which is the shed exoskeleton. When I was very small, I was terrified of cicada shells even though they’re just empty and perfectly harmless. They look scary because of those big pointy legs and big round eyes. You can frequently find cicada shells still stuck to tree bark, and it’s okay to pick them up and collect them if you like. The cicada doesn’t need it anymore. You can see the slit along the back of the shell where the cicada climbed out.

The emerged cicadas climb or fly into trees where the males start singing. Males produce their loud songs with a structure called a tymbal organ in their abdomen. The abdomen is mostly hollow, which helps amplify the rapid clicking of a pair of circular membranes. The clicking is so fast, up to 480 times a second, that humans hear it as a continuous buzzing noise and not individual clicks. Some cicada songs are louder than 120 decibels, which is the same decibel level as a chainsaw.

A reminder: this is what they sound like:

[more cicada sounds]

A female finds a male by listening to his song. After a pair mates, the female makes little cuts in twigs at the end of a tree branch, usually new-growth twigs because they’re softer. She lays her eggs in the cuts, then soon dies and falls to the ground.

Within a few weeks, all the adult cicadas have died. But around eight weeks later, the eggs hatch. The new nymphs are teensy, only a few millimeters long. They drop to the ground and burrow into the soil up to a foot deep, or 30 cm. There they stay for the next 17 years, growing larger very slowly until it’s time to emerge.

The current big group of cicadas consists of three species that look very similar. It’s called brood ten although I agree with Varmints who think it should be brood X because the Roman numeral ten is an X and every time I see it, I read it as Brood X. There are plenty of other cicadas, though, including some that emerge every 13 years instead of 17 years, and some that emerge every year or every few years.

Cicadas have been around for some 4 million years and most species live in tropical areas. Brood X is only found in the middle to northern areas of the eastern United States. It used to be even more widespread, but habitat loss has reduced its range considerably. Every time a forest is bulldozed to build a lot of houses, the nymphs underground either die outright or emerge later to find no trees to protect them and their eggs. Brood eleven went extinct in the 1950s, so even though there are millions of cicadas now, there may come a summer when no Brood X nymphs survive to emerge 17 years later.

The sudden emergence of thousands upon thousands of big loud insects in a short amount of time can be alarming, but cicadas are completely harmless to people, pets and other animals, and plants. They don’t eat as adults and they only make noise for a few weeks. They also don’t live everywhere. Even on the college campus where I work, the cicadas are only present in certain places. On the edge of the parking lot they’re everywhere. If I walk down to the far end of the duck pond, nothing. So if you happen to have Brood X cicadas in your yard or on your street, just remind yourself that that makes your home special and they’ll all shut up soon.

Of course, depending on where you live, in three years the enormous brood 19, called the great southern brood, will emerge throughout the southeastern United States, along with the smaller but just as loud brood 8, called the Northern Illinois Brood. But that gives you three years to buy a good pair of earplugs.

You can find Strange Animals Podcast 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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!