Category Archives: invertebrates

Episode 508: The Night Parrot and Friends

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You can buy and download an ebook of Small Mysteries here!

Thanks to Murray and Nathan Andrew for their suggestions this week! Happy Halloween!

xeno-canto.org is an excellent resource for bird, insect, and other animal recordings by field scientists, naturalists, and citizen scientists!

Further reading:

Reconstruction of an extinct soundscape reveals ultrasonic communication in the Jurassic

John Young Rediscovered the Australian Night Parrot, but Did He Lie About His Later Findings?

A Naturalist With a Checkered Past Rediscovered a Long-lost Parrot . . . Then Things Got Interesting

Night Parrot man in jail after bush bolthole bid

‘Breakthrough discovery’: Indigenous Rangers in outback WA find up to 50 night parrots one of Australia’s most elusive birds

The Indo-Pacific leopard shark [photo by Felix Frost-Savage – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=150136016]:

A young Indo-Pacific leopard shark, so you can see why it’s also called the zebra shark:

One of John Young’s controversial night parrot photos, showing wire mesh in the upper right-hand corner that might be part of a cage or enclosure:

Show transcript:

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

This week is our Halloween episode, and a brand new one since I wasn’t going to skip Halloween! I thought about covering a really spooky topic, but decided to go with interesting instead. Thanks to Murray and Nathan Andrew for their suggestions this week.

First, though, a quick note that if you check the show notes, or go to the website at strangeanimalspodcast.blubrry.net, you’ll find a link to buy the Small Mysteries ebook! Unless I forgot to add it! It’s $3 and is available in epub, PDF, or whatever format file it is that Kindle uses. The ebook of Beyond Bigfoot & Nessie is there too for $5, which is cheaper than anywhere else.

We’ll start with Murray’s suggestion, the Indo-Pacific leopard shark! You might find this animal spooky if you’re afraid of sharks, but Murray isn’t, and in fact he was snorkeling off the coast of Australia where he lives when he saw a leopard shark not too long ago!

The Indo-Pacific leopard shark is also called the zebra shark, and it’s a different animal from the leopard shark that lives off the Pacific coast of North America. It’s bigger, for one thing. It can grow over 8 feet long, or 2.5 meters, and possibly larger. It’s covered with small dark brown spots on a lighter brown or yellowish background.

The reason it’s also called the zebra shark is because baby leopard sharks have stripes. The young shark is dark brown with a yellowish belly, and it has white or pale yellow stripes and spots. It looks so different from the adult leopard shark that scientists in the 18th century thought they were separate species.

The leopard shark lives in shallow water, often around coral reefs. It’s most active at night, and spends the day resting on the bottom of the ocean, doing nothing much. Murray pointed out that the leopard shark is the only shark that doesn’t have to keep swimming in order to push water through its gills, and I had to look this up to see if it was true. It turns out that a few sharks, including the leopard shark, have special organs called spiracles that pull water into the respiratory system without the shark needing to move. The spiracles are small openings just behind the eyes. It allows some bottom-dwelling sharks to rest on the sea floor. All other sharks really do have to keep swimming or they’ll suffocate. The leopard shark usually rests with its head pointing into a current, which helps bring oxygenated water to it so its spiracles are more effective.

The leopard shark mostly eats mollusks, along with small fish, crustaceans, and other small animals. It’s a slender, slow-moving shark that lives throughout the tropical Indo-Pacific. Its eyes are very small and so is its mouth, and it almost never bothers people. In other words, it’s not very spooky but it is very pretty.

Next, Nathan Andrew told me about an invertebrate that lived back in the Jurassic period, alongside dinosaurs. It’s an ancient katydid, an insect related to modern katydids, that lived about 165 million years ago.

We don’t know very much about what the world sounded like in those days. The sound-producing organs in most animals are made of soft tissue and don’t fossilize well. But katydids, crickets, and some related insects make their calls by stridulation, where the male has a serrated section of his wing or leg, depending on the species, and he rubs it over the opposite wing or leg to make a loud call. And the great thing is, the exoskeletons of these insects are made of chitin, which fossilizes well, as do their wings. The only problem is finding them, since they’re so small.

The research team worked with 20 well-preserved specimens of katydid ancestors called ensiferans, all of them found in the same part of China but including individuals from nine different species. Before they modeled the ensiferan wings, though, they used a microscanning laser, high-speed video, and motion detectors to measure the wings of living species of katydid and find out exactly how the wings moved. They used that information to build a digital model of the wings. Then they scanned the fossilized wings and applied them to their digital model, and examined how the ancient wings differed and didn’t differ from the modern wings.

The main reason they did all this was to get an idea of pitch and vibration in the ancient insects’ wings as they stridulated, and that gives us an idea of what they might have sounded like.

The different species of ensiferan communicated with different frequencies, including some that communicated in ultrasound, which is something that many modern katydids and their relatives still do.

But let’s listen to one of the recordings! First, though, here’s a modern katydid:

[katydid chirping]

Now, here’s a simulated call of an ancient katydid ancestor:

[ancient katydid chirping]

Finally, let’s talk about a spooky-sounding bird, the night parrot. It’s a small Australian parrot that’s yellowish-green with dark speckles and other markings. It’s closely related to the ground parrot, also found in Australia, which looks similar but is a brighter green.

Like the ground parrot, the night parrot can fly, but while the ground parrot prefers not to, the night parrot flies up to 25 miles a night, or 40 kilometers, to find food and water. It’s nocturnal and very shy, and spends almost all of its time in big clumps of spinifex and other grasses and shrubs, or in woodlands. Spinifex grows in dense banks, and the night parrot hides inside them during the day in tunnels it makes through the plants. It eats seeds and other plant material.

The night parrot used to be common throughout much of inland Australia, but is now critically endangered. For a long time scientists thought it was extinct, since there was not a single verified sighting of a night parrot between 1912 and 1979. Even now sightings are incredibly rare, leading to speculation that there may only be a few hundred or even just a few dozen of the birds left in the world.

In 1990 and 2006, two dead night parrots were found in different parts of western Queensland, so scientists knew the birds were still hanging on. Then in 2013, naturalist John Young discovered a small population of the birds.

You may remember that back in episode 474, which ran on March 2, 2026, we talked about the buff-breasted button quail. A naturalist named John Young featured in that episode, and I made sure to cite my sources very carefully, because accusing someone of scientific fraud is a serious matter. And yes, this is the same John Young.

In 2006, Young had learned of the dead night parrot discovered in western Queensland, and he camped out for weeks in the same area where it was found. He heard night parrot calls but couldn’t see them in the darkness. He searched for years until in 2013, he got photographs of a night parrot. But the presence of wire mesh in the photograph indicated Young might have trapped a night parrot to take its photo, which is illegal. The photos were also timestamped at 5pm, when a nocturnal bird wouldn’t have been active, and Young touched up the photos as well—he says to remove a spinifex twig from the bird’s feathers, but some people question whether he was erasing damage done to the feathers when he captured the bird.

The 2013 photos really do show a night parrot, but later photos that Young presented might not be real. He claimed to have found nests with eggs in them, but in the photos, some of the eggs look like they’re made of clay, while others are clearly eggs from a different parrot species. Even the nests are suspicious. Night parrots lay their eggs directly on the ground inside spinifex bushes, but Young’s photos show acacia leaves and other vegetation, not spinifex. There’s more, but you get the idea.

John Young was arrested in 2024 after evading the police for a year, by the way. His arrest didn’t have anything to do with birds so I won’t talk about it here, since this isn’t a true crime podcast. In 2025 he pleaded guilty and is still in prison as this episode goes live, which is where he belongs considering the crime in question.

In much better news, also in 2024 a team of Indigenous rangers and scientists discovered a population of 50 night parrots in Western Australia’s Great Sandy Desert. One of the reason night parrots have become so rare is that feral cats eat them, but in this particular area, there are plenty of dingoes. Dingoes don’t eat night parrots, but they do eat cats. So the presence of dingoes has inadvertently helped save the night parrot. The area where the night parrots were found is being kept secret, except that it’s in the Ngururrpa Indigenous Protected Area in northern Western Australia. It’s a very remote area where livestock and most vehicles are not allowed, which has also helped the night parrots survive.

This is what the night parrot sounds like, first a short call recorded in 2015, and then clips of a male calling during a thunderstorm, recorded in 2017.

[night parrot calls]

Maybe the night parrot isn’t actually a spooky bird despite its name, but it’s pretty awesome anyway! Have a fun, safe, and happy Halloween!

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s.

Thanks for listening!

Episode 503: The Mystery of Typhloesus

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Further reading:

A possible home for a bizarre Carboniferous animal: is Typhloesus a pelagic gastropod?

Typhloesus

An artist’s rendition of what Typhloesus might have looked like [pic taken from the Nix Illustration link above]:

Show transcript:

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

I recently discovered the excellent Nix Illustration blog, which is about scientific illustration and palaeontology. I’m finding so many fun topics that I keep going back to it, so I hope you don’t mind another invertebrate mystery I learned about from the site. There are links in the show notes if you want to read the original blog posts.

This month’s mystery is Typhloesus wellsi, sometimes referred to as the “alien goldfish” because of its shape and its peculiar anatomy. It definitely wasn’t a fish. It lived around 324 million years ago and was first discovered in the early 1970s in Montana, in the middle of North America. It grew up to four inches long, or 10 cm, and was shaped not like a real goldfish but kind of like a goldfish cracker. Its body was roughly cylinder-shaped, and it had a vertical tail fin and a pair of fin-like lobes on its sides that are referred to as keels. But it didn’t have eyes or, as far as scientists can determine, an anus. It did have a mouth and gut cavity–but it also had something truly unexpected and mysterious in its body, a pair of disc-shaped organs that contained a lot of iron but whose function is completely unknown and unlike anything scientists have ever seen.

Those initial specimens also contained lots of conodont teeth, which led scientists to hope they’d finally discovered the conodont animal. We’ve talked about conodont teeth before, but it’s been quite a while ago. Conodont animals were incredibly common for around 300 million years, and their teeth are found throughout the world. Technically they’re not teeth but tooth-like structures called conodont elements, some of them microscopic, some of them almost an inch long, or 2 cm. Each animal had three types of conodont elements, and they interacted in a way that we don’t fully understand since they were completely different from modern animal mouthparts.

Until the 1980s, no one knew what the conodont animal looked like. The only fossils we had were the tiny teeth. Then some body impressions of the conodont animal were discovered. Now we know it was shaped like an eel and grew up to 20 inches long, or 50 cm. We also know it had large eyes, a notochord (or primitive spine), and fins on the tail end. It was probably related to hagfish and lampreys and may have looked similar, although not everyone agrees with this classification.

Whatever the conodont animal was related to, Typhloesus definitely wasn’t one. It turns out that the conodont teeth associated with Typhloesus fossils were actually in its gut, after the alien goldfish ate a conodont animal.

So scientists were back to square one. What was Typhloesus?

In 2022, a study of several specimens revealed a clue. Typhloesus had a radula. That’s a mouthpart that resembles a tooth-studded tongue. Snails, for instance, use tiny radulas to scrape algae and other food off of rocks. True radulas are a trait of mollusks, which means Typhloesus was most likely an early mollusk, maybe even a gastropod like snails and slugs.

That’s a start to classifying Typhloesus, but it doesn’t explain the pair of weird disc-shaped organs. It’s called a ferrodiscus and we still don’t know what it was for. Because of its placement just under the midgut and its high concentration of iron, which would have made it quite hard in comparison to most of the rest of its body, the ferrodiscus might have had something to do with digestion. Then again, it might have had something to do with chemoreception, which is probably how Typhloesus found its food. Some modern mollusks have a chemoreceptor organ under the radula, but it’s mainly a bundle of nerve cells and not any kind of weird iron discs. We just don’t know what the ferrodiscus was.

Typhloesus probably swam around until it encountered a small animal like a conodont, and then it would stick its radula out like a spiky tongue and use it to grab the animal. Typhloesus had no anus, so after it digested its meal it just spat out the indigestible parts. It might also have been a scavenger that used its radula to pull pieces off of a dead animal to eat.

Not every scientist agrees that Typhloesus was a mollusk. Only mollusks have true radulas, although not all mollusks have them, but other animals have evolved similar structures. Typhloesus is so different from known mollusks, living and extinct, that scientists can’t definitively determine what it was related to. It had no gills and no notochord, so we know it had to be an invertebrate. Some cnidarians, which include jellyfish and sea anemones, have no anus, but Typhloesus has even less in common with that phylum of animals than it has with mollusks. Some flatworms have no anus, but again, Typhloesus doesn’t seem to have a lot of other traits in common with flatworms.

Until we learn more about it from studying well-preserved fossils, we can only speculate about where Typhloesus fits in the tree of life and what the ferrodiscus actually was. Mysteries like this are part of the challenge of science, and part of the fun too.

Thanks for your support, and thanks for listening!

NEW Episode 500: Crikey, it’s 500 episodes!

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It’s our 500th episode! Wow!

Thanks to Rosie, Remy and Julien, and Dylan, Emily, and Michelle for their suggestions this week!

Further reading:

Crikey! Newly Discovered Snake Species Named After Steve Irwin

Steve Irwin’s Treesnail

A young Steve Irwin’s tree snail [photo taken from link above]:

A marbled lungfish:

A fennec, smallest and cutest of all foxes:

Show transcript:

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

This week we have a brand new episode, because it’s episode 500! Congratulations to me and to you too, listening to the 500th episode of a podcast! That doesn’t happen very often!

Despite the big 5-0-0, I’m going to treat this like a regular episode. Thanks to Dylan, Emily, and Michelle, Remy and Julien, and Rosie for their suggestions this week!

We’ll start with Dylan, Emily, and Michelle, who live in Australia. A while back now they got to visit the Australia Zoo, which is run by the Irwin family. Steve Irwin was a conservationist, science educator, and wildlife rehabilitator, also known as the Crocodile Hunter for his work relocating crocodiles who were endangering people, and vice versa. He died tragically young in 2006 but his wife and children continue his work.

Michelle pointed out that Irwin has been honored by scientists who have named newly discovered animals for him, so let’s learn about a few of them!

The most recent one is a type of wolf snake discovered on the Great Nicobar Island off the coast of India and described in 2025, Lycodon irwini. It’s mostly black in color with a slender body, and can grow as much as 47 inches long, or 119 cm. That’s almost four feet long! Luckily it’s non-venomous, plus it has only been found on that one island in evergreen forests, so you’re not likely to run across one by accident. It probably eats small animals like frogs, but we don’t know a whole lot about it yet.

Back in 1990, Steve Irwin caught a strange turtle while fishing with his father, Bob, who was also a conservationist. Between them, the two men knew a whole lot about Australian wildlife but they didn’t know what the turtle was. They sent pictures to a turtle expert, who determined that yes, it was a species new to science. It was described in 1997 and named Irwin’s turtle, Elseya irwini.

Irwin’s turtle has a black and yellow carapace and lives in the lower part of the Burdekin River in northern Queensland. The female also has a light-colored head and other pale spots on the body.

Like some other turtles, it can absorb oxygen from the water through its cloaca, which is often referred to as its butt. A chamber at the end of the cloaca contains structures that act like gills and absorb oxygen. This allows it to stay underwater longer, and in fact it can’t survive in water that doesn’t contain enough oxygen.

As a result, Irwin’s turtle is endangered due to habitat loss, especially from pollution and the damming of its river home. It used to be common but its numbers are in decline. The Australia Zoo started a captive breeding program to help conserve the species, and in 2023 they succeeded in hatching the very first Irwin’s turtle babies ever bred in captivity.

The last one is my favorite, a land snail named after Steve Irwin. It was described as a new species in 2009, only a few years after Irwin died, and was named Crikey steveirwini. It’s the only species in the genus Crikey. It only lives in high altitudes in the tropical rainforests of northeastern Queensland. It’s rare and not much is known about it, because it’s so hard to find and so small. It has a cone-shaped shell that’s striped with spiral bands of brown, yellow-brown, and white, and it only grows 15 mm long at most.

Next, brothers Remy and Julien wanted to learn about the African lungfish. Lungfish are fascinating fish, because as you can probably guess from the name, they have gills but they also have lungs, and the fish needs both to get enough oxygen.

Four species of lungfish live in Africa, all belonging to the family Protopteridae. They’re eel-like in shape although they’re not closely related to eels at all, with soft scales, and a dorsal fin that continues down the fish’s back and continues around the end of the tail, since the dorsal fin and tail fin are actually fused into one big fin. Its only other fins are the pectoral and pelvic, which are very thin and are more like flexible legs than actual fins. The lungfish can actually crawl along the bottom of the swamp or lake with its fins, although it can also swim like an eel.

While the African lungfish does have gills, they’re small and are mostly associated with eliminating carbon dioxide instead of absorbing oxygen. The lungs do most of the work. The fish surfaces periodically to gulp fresh air into its lungs. It’s one of the few fish that can drown if it can’t surface for air.

African lungfish eat insect larvae, especially of aquatic insects, crustaceans, mollusks, small fish, and frogs, but it can also sometimes eat seeds and other plant material. It usually lives in shallow water like swamps and small rivers, where there’s not a lot of oxygen in the water. In many cases, its waterways dry up periodically, but the fish can still survive. As its water gets lower and lower, the lungfish digs into the mud and curls up, then secretes a thick mucus that helps retain moisture and stops its body from drying out. Its metabolism slows way down so it doesn’t need to breathe very often, and it doesn’t need to eat. It can survive this way for up to four years, although it usually only has to stay in its cocoon for a few months, until the rains return and its waterways fill up again.

The smallest species of African lungfish is the East African lungfish, which only grows about 17 inches long, or 44 cm, while the largest is the marbled lungfish that can grow a whopping six and a half feet long, or two meters.

Lastly, Rosie suggested we learn about the fennec fox, which lives in northern Africa. It’s the smallest fox in the world, barely eight inches tall at the shoulder, or 20 cm, but it has incredibly large ears. Its ears can be as much as six inches long, or 15 cm.

Part of the reason its ears are so big is so it can hear insects and other small animals moving around underground, but they’re also big because they help dissipate heat from the fox’s body into the air. Since the fennec lives in deserts, that’s only one of many adaptations it has to the heat and lack of water.

For instance, the fennec gets most of its water through the food it eats. It’s also a nocturnal animal. The pads of its paws are protected by long, coarse hairs that grow between the pads, so hot sand won’t burn its toe beans. The hair also gives the fox better traction in loose sand.

The fennec’s fur is a pale sandy color with a black tip to the tail, and it has dark eyes. It eats rodents, birds and their eggs, insects, scorpions, and other small animals, as well as fruit and other plant material. It can jump really far, some four feet in one bound, or 120 cm. Not only can it run really fast, it can change directions really quickly too. This helps it escape predators and catch prey.

Fennecs can be social animals and like to play, even as adults. Pairs mate for life and both parents take care of the babies. A fennec’s burrow can be very large and may even link up to neighboring fennec family burrow, so neighbors can visit each other without going out into the heat of the day.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s.

Thanks for listening!

Thanks to those of you who backed my recent crowdfunding campaign! Right now the Small Mysteries book isn’t available yet, but in the Halloween episode in October, I’ll make sure to put a link where you can buy the ebook.

Episode 499: The Mystery of Amiskwia

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Further reading:

Cambrian Explosion Month #18: Stem-Gnathifera

Ambiguous Amiskwia

Amiskwia, possibly [picture taken from above link]:

Show transcript:

Welcome to the Patreon bonus episode of Strange Animals Podcast for May 2025!

We’ve talked about a lot of strange and mysterious animals from the Cambrian in past episodes, especially episode 69, but I don’t think we’ve learned about Amiskwia yet. For a long time it was another mystery animal from the Burgess Shale and a few other places, dating back as much as 518 million years ago, but as of only a few years ago the mystery seems to be solved, at least mostly.

Amiskwia grew about an inch long, or 2.5 cm, which actually made it one of the larger animals that lived in the Cambrian. It probably looked superficially like a slug, with a slightly flattened body and a pair of short tentacles on its head. It had a paddle-shaped tail and two flaps on its sides that probably acted as fins to help it swim. Its mouth was on the underside of its head and was surprisingly complicated, with two pairs of plates with little spikes on them. We even know about its internal anatomy, since some of the Amiskwia fossils are so well preserved that its insides can be studied too. It had a brain and a simple digestive tract.

Amiskwia was described in 1911 by Charles Walcott, who described a lot of the Burgess Shale fossils. Walcott classified it as a type of arrow worm. When scientists gave it a closer look later, not everyone agreed it was related to modern arrow worms. Some suggested it might be a type of ribbon worm, or maybe an early mollusk, while others argued that it was so different from known animals that it belonged in its own phylum.

A 2019 study suggested that Amiskwia’s weird mouth plates matched up with the mouth plates in a living animal, and a 2022 follow-up study confirmed the 2019 findings. Not everyone agrees, but as of now, Amiskwia is considered an ancestral gnathiferan.

There! Mystery solved! Wait, what do you mean you don’t know what a gnathiferan is?

As everyone knows, especially me, I definitely didn’t just learn about this type of animal myself just now, gnathiferans include a lot of different animals with complex jaws—not like your own jaws, but with little plates and spikes and moving parts made of chitin. Most gnathiferans are tiny, microscopic or barely a few millimeters long, so Amiskwia was a giant in comparison.

Arrow worms are also generally considered to be gnathiferans, so Wolcott wasn’t too far off in his description of Amiskwia. We don’t know what Amiskwia ate, but it could probably swim pretty well and most likely hunted other animals or scavenged already dead ones. Scientists think it probably spent most of its time swimming well above the sea floor, which is why it’s a relatively rare fossil.

Another Cambrian mystery animal that lived even earlier than Amiskwia, around 520 million years ago, and which is probably related to it, is Timorebestia. Its fossils were discovered in Greenland and only described in 2024. It had a pair of long tentacles or antennae, a rounded paddle-like tail, and fins on each side of its wide, flattened body. Its tentacles were around half the length of its body–and if Amiskwia was a giant compared to modern gnathiferans, Timorebestia was a colossus! It grew almost 8 inches long, or over 20 cm, not even counting its tentacles!

Some Timorebestia specimens are so well preserved that scientists can identify what they ate right before they died, and it looks like they mostly ate small arthropods. Timorebestia was probably the biggest and strongest predator in the area when it was alive, one of the earliest apex predators discovered.

Another similar animal was Nectocaris, which has been discovered in the Burgess Shale of Canada and other Cambrian fossil sites in China and Australia. It was flattened and had a pair of tentacles on its head, and a fin on both sides of its body–but it had a lot of features not found in Amiskwia and Timorebestia, including eyes. It also seems to have had a tube or funnel of some kind that emerged from the underside of the body near the head. It might have been a proboscis of some kind, but some scientists think it was a funnel like the ones found in modern squid, used to jet through the water quickly. Many scientists even think Nectocaris was a precursor to squid and other cephalopods, but other scientists disagree. Some specimens are about one inch long, or around 3 cm, while others are around 4 inches long, or about 10 cm. This might mean there were two species, or that the small ones were juveniles, or that males and females were different sizes. We just don’t know.

Small animals, especially ones with mostly soft bodies, don’t fossilize as often as larger and more robust animals. We’re very lucky that we have so many beautifully detailed Cambrian fossils, since so many modern gnathiferans and their close relations aren’t otherwise found in the fossil record at all.

Thanks for your support, and thanks for listening!

Episode 498: Octopolis

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Further reading:

https://sharonahill.substack.com/

https://metazoan.net/54-octlantis/

https://metazoan.net/109-octopolis-and-octlantis/

Scientists discover an underwater city full of gloomy octopuses

The gloomy octopus [photo by Niki Hubbard – https://www.inaturalist.org/photos/118664956, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=123044473]:

Show transcript:

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

As I’ve mentioned before, I really don’t like April Fools Day, which is April first. I especially don’t like it when someone makes an April fools day post online and just leaves it there afterwards. It’s too easy for other people to stumble across it and think it’s real. This goes double for strange animal and cryptid reports.

I subscribe to geologist Sharon Hill’s Pop Goes the Cryptid articles, and on March 31 she talked about a hoax called the North American Pine Squid. It got popular around Halloween of 2024. It’s said to be a black squid or octopus that lives in pine trees in remote, heavily forested places like the Pacific northwest and the Appalachian mountains. Most of the time it eats small animals like birds and squirrels, along with pine cones, but if someone walks underneath its tree, the pine squid grabs the person, pulls them up into the tree, and they’re never seen again.

But you don’t have to worry, because the pine squid isn’t a real animal. It’s also not even a new story. It’s based on another hoax called the Pacific Northwest tree octopus, which dates back to 1998. In the case of the tree octopus, it wasn’t created as a hoax or an April fool’s joke but as a study about whether children can tell if a website is reliable or not. The researchers made a page with information about a type of octopus that lived in the ocean but that also climbed trees. Then they asked several classrooms of children around age 11, from different schools in different countries, to read the page, look at the pictures provided, and answer some questions.

The study found that most of the children thought the page contained reliable information. Only a few figured out that the tree octopus wasn’t real. The study has been used repeatedly to argue that children need more lessons in how to evaluate a website to know if it contains reliable information, and of course that’s always a good thing. But it makes me a little angry too, because how were the kids supposed to know that octopuses can’t climb trees? There are so many amazing and strange animals out there, a tree octopus sounds perfectly normal if you don’t know very much about octopuses. So I argue that kids should be taught about everything, and taught in as interesting a way as possible so that they remember it better. The same goes for adults.

But this episode isn’t actually about April fools day, tree octopuses, or pine squids. It is about a type of octopus, and what I’m going to tell you is so weird that I have to reassure you that it’s actually true. It’s not a hoax or an April fools joke or anything like that. It’s about the gloomy octopus and the underwater cities some populations have created, referred to as Octopolis and Octlantis. I swear I’m not making this up!

The gloomy octopus lives off the eastern coast of Australia and the northern coast of New Zealand. It’s mainly brown and gray, but it has orange on the undersides of its arms, and it’s covered in little bumps that help camouflage it. Its eyes are white. On average, it has an armspan of about 6 ½ feet, or 2 meters, with females generally larger than males. Like many other octopuses, when the female lays her eggs, she stops eating completely and protects the eggs until they hatch. After they hatch, she dies.

The gloomy octopus lives in shallow warm water and especially likes places with lots of rocks, seagrass, reefs, and other places where it can hide. It spends a lot of time in a den it digs into the sea floor, only coming out at night to hunt. It especially likes scallops, but it will eat pretty much anything it can catch, including sea snails, crabs, seahorses, and even other gloomy octopuses. It usually brings its food back to its den to eat.

The gloomy octopus was thought to be a solitary animal until 2009. That’s when a biologist named Matt Lawrence was exploring Jervis Bay in New South Wales. In this particular part of the bay, the sand is silty and there are a lot of predators, so it’s not great for the gloomy octopus. But not only did Lawrence find a gloomy octopus there, he found 16 of them living in close proximity.

The octopuses’ dens were very close to each other, surrounding a human-made object that’s so encrusted with sea life that it can’t be identified. Scientists think it was a piece that fell off a boat at some point. Even more interesting, there are so many shells around, especially scallop shells, that instead of making dens in the sand, the octopuses are basically making dens in huge piles of scallop shells. The octopuses spend time moving the shells to improve their dens.

In other words, Lawrence had found an octopus city. Admittedly, it’s a very small city by human standards, with only 16 residents identified at any given time, but for a supposedly solitary animal, that’s pretty amazing.

The site was nicknamed Octopolis, and scientists think the presence of the piece of boat actually started the site. When it fell into the sand, it provided a great place for a gloomy octopus to hide. Since gloomy octopuses bring mollusks back to the den to eat, naturally they discard the shells near their dens. Once enough discarded shells had piled up, it provided better building material for another den. Another octopus moved in as the first one’s neighbor, which meant twice as many shells being discarded. Pretty soon another octopus joined the first ones, and eventually there were 16 separate dens in a little community.

Then, in 2017, another octopus city was discovered not far from Octopolis. Instead of a human-made object at its center, it has a few rocks sticking up in the middle of the city, which has been nicknamed Octlantis.

Observations of the octopuses living in these communities are surprising. The octopuses come out during the day even though ordinarily the gloomy octopus is most active at night, especially around dawn and dusk. They interact with each other in various ways, sometimes fighting, sometimes pairing off to mate, sometimes sneaking into another octopus’s den and trying to take it over. It might not be full of underwater skyscrapers and underwater scallop vendors on busy corners, but there’s a lot of hustle and bustle in these cities.

When biologists revisited Octopolis in 2023, they only found three octopuses. Octlantis had a little more activity and a few more octopuses, but nothing like its busy 2017 numbers. But this doesn’t mean that the cities are deserted. Low Octopolis populations were also discovered in 2010 and 2013, but a high population in between. The biologists also noted that the presence of sharks caused the octopuses to move, and in 2023 a shark was hanging around Octopolis.

Another reason for the changing population sizes at the sites is that gloomy octopuses don’t live very long. A three-year-old gloomy octopus is really old, since most die before they reach their first birthday. The octopuses spotted in Octopolis and Octlantis in 2023 might be as much as 14 generations removed from the ones seen in 2009. Young octopuses have to continually repopulate the cities as the older ones die off, and that might take longer some years than others.

Just because we know about Octopolis and Octlantis doesn’t mean those are the only two octopus cities in existence. There are probably a lot more. Scientists just haven’t noticed them yet. In years where sharks are spending too much time in Octopolis, the octopuses might just move to a city we don’t know about. Octopolis and Octlantis might even be really small in comparison to some cities. If you’re a diver around Australia or New Zealand, keep a sharp eye out for an octopus city. You might be the first human to visit New Octleans.

Thanks for your support, and thanks for listening!

Episode 497 Megarachne

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Megarachne as we know it now:

Show transcript:

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

Megarachne is only known from two specimens, neither of which is complete, which adds to the confusion. It lived around 300 million years ago in what is now South America. It was described in 1980 from the first specimen discovered and was named Megarachne, which means big spider. The scientist who described it thought it was a type of primitive spider related to modern tarantulas, but much bigger. He estimated its legspan was 20 inches, or 50 cm, with a body length of just over 13 inches, or 34 cm. That made it the largest spider ever known by a lot.

Other palaeontologists, especially arachnologists who specialize in spiders and their relations, weren’t convinced Megarachne was a spider. But it wasn’t until 2005 when a more complete specimen was discovered that anyone could say for sure what it was. The second specimen made it clear that it wasn’t a spider at all but a sea scorpion, or eurypterid, and not an especially large one compared to some. It probably grew to 21 inches long, or 54 cm.

But by then, Megarachne had gotten really popular as a giant spider. It was in the BBC documentary Walking with Monsters, although the producers changed its name to Mesothelae right before it aired, which was just after the new findings about Megarachne came out. Mesothelae is a suborder of big spiders from parts of Asia that retain many traits of ancestral spiders. It was a valiant attempt by the BBC to make the documentary less incorrect, but of course the spider they were talking about still wasn’t a spider and no spider known has ever grown that large.

But while Megarachne isn’t a giant spider, and isn’t even a very big eurypterid, it is important since not very many eurypterids are known from South America. It also appears to be closely related to Mycterops and Woodwardopterus, similar-looking euripterids from North America and Europe. But some researchers think it’s not as cut and dried as it sounds. Instead of three similar creatures living in different areas, they think there’s something else going on.

Eurypterids were arthropods, the phylum that includes insects, arachnids, and crustaceans, among others. Arthropods have an exoskeleton that they molt periodically as they grow, and many arthropods have complicated life stages compared to other animals. When a shark hatches, it looks like a miniature adult and just grows larger as it gets older, but when an arthropod hatches, it usually doesn’t look anything like its adult form. Some arthropods go through many stages of life before reaching the adult body plan. Crustaceans have numerous larval stages, for instance, that often look very different from the adult. Some researchers think that Megarachne, Mycterops, and Woodwardopterus were all the same animal, and that the differences are due to it being in three different stages of development when it died and was preserved.

We don’t have any way to know if this was correct, of course, not until we hopefully find more fossil remains. Other eurypterids did appear to go through some physical changes during maturation, as far as researchers can tell with the remains we have, but Megarachne, Mycterops, and Woodwardopterus belonged to a different family from other eurypterids and are much rarer. They might have been quite different developmentally.

We can also look at the living relations to see how likely it is that eurypterids had different larval stages where they looked different from the adult form. Eurypterids were probably most closely related to horseshoe crabs, although not everyone agrees. Horseshoe crabs have been around for 445 million years and are really neat animals that we’re lucky to still have in the world. The horseshoe crab hatches into a larva that looks a lot like a trilobite. It does indeed go through physical changes as it grows and molts over the course of three years, so it’s reasonable to assume that eurypterids did too.

On the other hand, some researchers think eurypterids were more closely related to modern scorpions. Scorpions actually give birth to live babies instead of laying eggs, and the female carries the babies on her back for several days up to several weeks, depending on the species. Once the babies have their first molt they look a lot more like miniature adults and pretty soon are able to leave their mother and hunt on their own. So again, it’s possible that eurypterids had a system more like this instead of like the horseshoe crab’s.

While we’re talking about scorpions, did you know that scorpions glow blue-green in ultraviolet light? The scorpion’s exoskeleton contains fluorescent chemicals, but we’re not sure why. Scorpions do have incredibly light sensitive eyes, and can navigate at night using only starlight. Their eyes can’t form sharp images like ours can, though. And scorpions have a lot of eyes. Spiders have four pairs of eyes, but some scorpions have more than that. All species have a pair on top of the cephalothorax, which corresponds to the head, and more on the sides of the cephalothorax. Some species have up to five pairs of eyes in addition to the ones on top of the head. Twelve eyes seems like overkill but it works for the scorpion. Eurypterids had both compound eyes and simple eyes.

That’s all we know about Megarachne right now, at least until we find more fossilized specimens. Let’s hope we do, and while we’re at it, let’s hope we find some more fossilized giant spiders because that would be cool.

Thanks for your support, and thanks for listening!

Episode 496 Two Mystery Invertebrates

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Further reading:

How did a tiny bee get to French Polynesia? Eight new species help solve a scientific mystery

Secrets in the canopy: Scientists discover 8 striking new bee species in the Pacific

Canopy specialist Hylaeus bees highlight sampling biases and resolve Michener’s mystery

Scientists discover endoparasitic marine tapeworm trapped in Cretaceous amber

Show transcript:

Welcome to the Patreon bonus episode of Strange Animals Podcast for August 2024!

It’s the start of Invertebrate August, so we have two invertebrate mysteries to discuss today, one mostly solved and one not.

Let’s start with the solved mystery, about a tiny bee. In 1934, three tiny bee specimens were collected in French Polynesia, specifically on a particular type of flower in the Tuamotu Archipelago. The bees really were tiny, only 4 mm long. They weren’t described until 1965, when they were placed in the genus Hylaeus. This is a really big genus with over 500 species that live throughout the world, but the species most closely related to the newly described Tuamotu’s masked bee lives in Australia, New Guinea, and New Zealand.

In case you’re kind of hazy on geography, like me, Australia, New Guinea, and New Zealand are part of what’s called Oceania, a giant chunk of the Pacific Ocean where there’s not a whole lot of land. I mean, except for Australia, which is big. The Tuamotu Archipelago is also part of Oceania, and part of French Polynesia, but it’s really remote. It consists of a spread-out collection of 78 low islands, many of them too tiny to support humans, none of them with a source of fresh water except for rain. They’re tropical and quite beautiful, with many unique animals and plants living on and around them. They’re also almost 2,500 miles, or 4,000 km away from the places where the tiny bee’s closest relatives live.

Even in 1965, scientists had questions about the tiny bee. How did 4mm bees get to such remote islands, and were they even still around? The bees hadn’t been seen in the wild since 1934. Since the Tuamotu Archipelago has suffered from European explorers and missionaries bringing invasive species to some islands, colonization by France, and nuclear weapons testing, scientists worried the bee had gone extinct and that they would never solve the mystery of how it got there in the first place.

Bees are attracted to flowers, and the three 1934 specimens were discovered on flowers, so naturally scientists had been looking for the bees on flowers. But it turns out that in the Polynesian islands, bees mostly hang out in the treetops. Once scientists figured this out, they began discovering new species of bee—eight of them in fact, collected between 2014 and 2019 from various islands in Fiji, Micronesia, and French Polynesia.

All eight species are closely related to Tuamotu’s masked bee, so scientists now have a pretty good idea of how it traveled thousands of miles to get to its French Polynesian home. Its ancestors island-hopped. There are more than 1,700 islands in the Pacific Ocean, many of them barely known to humans.

Researchers think there are probably a lot more species of bee to be discovered in the treetops of Pacific islands, now that they know where to look. With luck, they’ll be able to find Tuamotu’s masked bee too, quietly living out its bee life above the scientists’ heads.

Next, let’s discuss our unsolved mystery. Amber, which is fossilized tree resin, is the gift that just keeps on giving to the scientific world, and our mystery involves a flatworm found in amber.

The amber comes from Myanmar and dates to about 99 million years ago. In addition to bits of inorganic matter like tiny pebbles and sand grains, most organisms found in amber from this site are insects and roundworms, animals you’d expect to find on and around trees. The team examining this particular piece of amber found lots of interesting things, but then they discovered this one.

The flatworm is about 10mm long and it’s beautifully preserved, which means the scientists were able to compare it to modern flatworms to see what it might be most closely related to. It’s most similar to a parasitic flatworm found in shark intestines. You know, an animal not typically found in trees. (I stole that joke from paleontologist Kenneth De Baets, by the way. Credit where credit’s due.) It isn’t a complete worm but a partial one, basically a tentacle with little hooks to keep it in place in the host animal’s digestive system.

The modern worm is classified as a type of tapeworm, and tapeworms are distressingly common parasites. If you’ve ever adopted a rescue cat or dog, you’ve probably had to have it treated for a tapeworm infestation. Luckily, tapeworms are also very specific about which species they parasitize, so you can’t get tapeworms from a pet. (It’s still icky.) Fish get tapeworms too, after eating marine invertebrates carrying various kinds of tapeworm larvae.

The question is, how did a parasitic worm found in fish end up in amber? Occasionally there is rare amber found that fell into water and trapped water organisms, but this particular amber wasn’t associated with water. Other items found in the same piece of amber included sand grains, tiny hairlike structures found on some ferns, and the nymph of a scale insect. The team suggests that the tree where the amber came from grew near a beach and that a dead shark washed ashore. While scavengers were picking through the carcass, a piece of worm somehow got separated from the body and ended up in a tree. Possibly a scavenger grabbed a big yummy mouthful of rotting shark guts and either climbed or flew up into a tree to eat it, and part of the worm fell out and landed in a blob of amber.

Because tapeworms are endoparasites, meaning they live inside their hosts, and because they’re soft-bodied and fragile, it’s very rare that one is preserved. Pretty much the only other preserved tapeworm specimen we have isn’t a tapeworm itself but some eggs found in fossilized shark dung, dated to 270 million year ago. Scientists aren’t even completely sure the eggs are from a flatworm since they’re not that well preserved. So it’s fantastic that this particular specimen was so well preserved, and that it made its way into the hands of scientists!

Thanks for your support, and thanks for listening!

Episode 493: NEW The Mystery of Esconichthys and Friends

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Yes, this is a NEW episode! Thanks to Eesa, Grace, and Viki for their suggestions this week. (Actual episode starts at 3 minutes 28 seconds.)

Find the Backerkit campaign here!

Further reading:

Nix Illlustration: Esconichthys

The southern hognose snake [picture by Caudatejake – Own work, CC BY-SA 4.0]:

A beach wolf spider [photo by Memer15151 – Own work, CC BY-SA 4.0]:

Oviraptor may have looked kind of like this when alive [art by PaleoNeolitic – Own work, CC BY 4.0]:

Two halves of an esconichthys fossil:

Show transcript:

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

Oh, hi! This is a brand new episode, earlier than I expected! I noticed recently that one of the Patreon episodes I’d scheduled for September is one that I’d already run in the main feed a few years ago. I decided to just make a new episode for this week and move the episode that would have run this week to that September slot, because I have an announcement!

For our five-year anniversary I published the book Beyond Bigfoot & Nessie: Lesser-Known Mystery Animals from Around the World, with a lot of the entries taken from episodes but also some new topics added. I always intended to do a follow-up for our ten-year anniversary, and have even done a lot of work on it. It’s called Small Mysteries, focusing on smaller mystery animals that don’t get a lot of attention. It’s about half the length of Beyond Bigfoot, all or almost all chapters taken from the podcast. But at this point, I don’t think I have time to finish it. I’m staying very busy and happy, with a part-time job taking care of people’s pets while they’re on vacation, and I’m also writing fiction again.

But since that book is half-done, and a lot of people might want a copy even if I don’t add much more to it, I’m going to make it available as an ebook only. Do you remember last time I made a crowdfunding campaign, and the people who backed the campaign got a copy of the book as soon as it was published? I’m doing that again, but NOT for Small Mysteries. It’s for a different book, called The Moonhound, a cozy fantasy set in an alternate reality Smoky Mountains. The main character is a rabbit who moves to the mountains and meets a possum, and they have adventures. Even if this doesn’t interest you, there’s a $1 backer tier and if you click that, you have the option to add the Small Mysteries ebook for $2. That means the book is $3. Does that make sense? I feel like it’s confusing.

The campaign starts on July 15, 2026 and runs through August 15, 2026. If you’re listening to the episode before July 15, 2026, you can click through the link in the show notes and follow the campaign, so that you get an email when it goes live. If it’s between July 15 and August 15, 2026, click the link in the show notes and there’s the campaign! If it’s after August 15, 2026, see if there’s a link in the show notes that will take you to a place where you can buy the ebook.

Okay, that took way too long, so let’s get to this week’s episode! We have some suggestions that have come in recently, so we’ll cover a few of those animals, and we’ll finish up with a small fossil mystery in honor of the book. Thanks to Eesa, Grace, and Viki for their suggestions! A quick shout-out to Remy and Julien, and Dylan, Emily, and Michelle for their suggestions too. I’ll get to those in the 500th episode that will run at the end of August.

We’ll start with Viki’s suggestion, the hognose snake. The name hognose is used for various species of snake, most of them in North and South America, but some in Madagascar. It’s a common snake in many parts of North America, so since we talked about the eastern hognose back in episode 81, let’s talk about the southern hognose in this episode. It’s found along the coastal plain of the southeastern United States, including parts of North and South Carolina, Georgia, and northern Florida, and because it has a restricted range where people like to live too, it’s vulnerable to habitat loss. It used to live in other states too but its range has shrunk considerably since it was first described in 1766.

The southern hognose grows about two feet long, or 61 cm, and like other hognose snakes, its nose turns up like a little pig’s snout. The shape of its nose actually may help it dig into leaf litter and dirt to hide. Some individuals are brown or gray, some are red or yellowish. It has darker blotches on its upper side and adults have white bellies. It has a big head that makes some people believe it’s venomous, but it’s actually harmless to humans and most animals.

The only animals that really need to worry about the hognose are amphibians, like toads, frogs, and salamanders, although it will also eat lizards, small mammals like mice, and even large insects. It especially likes to eat toads, and while some toads are toxic, the hognose snake is resistant to toad toxins. A toad will frequently puff itself up to make it appear larger and make it hard for a snake to swallow, but the hognose has a solution for that too. It has big teeth at the rear of its upper jaws, like fangs in the back of its mouth. It uses those teeth to puncture puffed-up toads so they deflate, just like a horrible balloon.

But the most memorable thing about the hognose is what it does when it feels threatened. Phase one is aggression. The snake will flatten its neck to look more threatening, raise its head like a cobra, and hiss and strike—but without biting. It’s just trying to scare you away. If that doesn’t work, the snake puts phase two into effect. It will flop down and roll onto its back like it’s dead, its tongue hanging out of its mouth. It even emits a foul musky smell from its cloaca. If you call its bluff and roll drama queen snake onto its belly, it will turn onto its back again, because it’s really insistent that it’s dead.

Since we’ve already scared away a lot of people who don’t like snakes, let’s learn about a spider next. Grace suggested we talk about the wolf spider, and also wonders if wolf spiders live in northern California.

Wolf spiders are common throughout the world, and while they look scary, they bite people very rarely and their venom is weak, no worse than a bee sting. The wolf spider with the biggest legspan is Hogna ingens, with a legspan less than 5 inches across, or 12 cm. It lives on one island in the Maderia archipelago, and is a beautiful soft gray with white stripes on the legs. The Carolina wolf spider is the most common one found in North America. A big female can have a legspan of four inches, or 10 cm, but its body is not much more than an inch long, or 35 mm, and the spider actually weighs less than an ounce. That’s barely 28 grams, or just a little heavier than five sheets of printer paper.

The wolf spider is a hunting spider, mostly solitary, and most species don’t spin webs. When a female lays her eggs, she attaches the egg case to the underside of her abdomen so she can take them with her while she hunts insects. When the eggs hatch, the teensy babies ride around on the top of her abdomen for a few weeks until they’re big enough to not need their mother’s protection.

Some species of wolf spider will dig a burrow to rest in, and will jump out and grab any insect that happens by, while other species of wolf spider rest in rock crevices and other small spaces. Males are smaller than females and often have flashier patterns. The Carolina wolf spider is mainly gray or brown with darker and lighter longitudinal stripes down the head and body.

Most species of wolf spider won’t come into your house, but if you do have a wolf spider in your house, you should actually consider yourself lucky. They love to eat cockroaches and ants, which are house pests. The wolf spider hunts mostly by sight and has good vision, and its eyes will even demonstrate eyeshine of various colors, depending on species, if you shine a flashlight around in the dark. Maybe don’t do that if you’re afraid of spiders.

And yes, there are wolf spiders in northern California, because there are wolf spiders in just about every part of the world except for Antarctica! Northern California actually has at least six species of wolf spider. One species does actually build a web, and there’s even a species that lives on the beach. That’s the beach wolf spider, which is a pale sandy color with darker and lighter stripes to help it blend in with sand and pebbles. It’s quite small but it moves really fast, and it’s mostly nocturnal. It lives not just in northern California but throughout beaches in North and Central America.

Next, Eesa sent a list of suggested animals, including oviraptor. I could have sworn we already covered oviraptor, but we haven’t! It’s a really interesting dinosaur, so let’s take a look now.

Oviraptor is a name that means “egg thief,” and it got this name because it was found near fossilized eggs. It lived in what is now Asia about 75 million years ago, and the first specimen was found in Mongolia (still my favorite country) back in 1923. The partial specimen was found lying across a nest of dinosaur eggs. When the dinosaur was described in 1924, it was given the name egg thief because the paleontologist Henry Fairfield Osborn assumed it died while robbing a nest to eat the eggs.

But even Osborn wrote that he might be wrong about the dinosaur, and in the 1990s new discoveries of oviraptor nesting sites proved this was the case. Oviraptor wasn’t stealing eggs, it was protecting them, because they were its own eggs. It probably actually ate fruit, seeds, and other plant material, along with small animals like lizards.

Oviraptor was a small dinosaur that was a little more than six feet long, or about 2 meters, and was the height of a medium to large dog. It walked on its hind legs. It had feathers on its arms and tail, and probably also had feathers over much of its body. It didn’t have teeth but it did have a beak that would have probablylooked a lot like a parrot’s beak. Its arms had three small claws but probably looked a lot like a wing in many ways, although scientists don’t think oviraptor could fly.

In other words, oviraptor probably looked a lot like a big, weird chicken, and like a chicken and many other birds, scientists think it sat on its eggs to keep them warm.

When a bird incubates its eggs, it’s not like you dropping down to sit on a chair. The bird’s feet are typically on either side of the eggs, and the bird squats down carefully so that its underside makes gentle contact with the eggs without crushing them. Female chickens and many other birds have a spot on the lower breast that doesn’t have any feathers, called a brood patch, which contains extra blood vessels just under the skin. This helps keep the eggs warm and is a soft part of the hen’s body, which helps cushion the eggs. We don’t know, but it’s possible oviraptor had something similar to a brood patch, and its feathered arms and tail also helped protect the eggs from cold air and rain. We now have numerous specimens that died while sitting on nests, probably buried in sandstorms, so we know that oviraptor basically brooded its nest the way modern birds do.

Finally, let’s finish with our small mystery fossil. It’s called Esconichthys apopyris and it lived about 308 million years ago in what is now the state of Illinois in North America. 308 million years ago, Illinois was a tropical area and partly covered by a warm, shallow sea. In a particular place known as the Mazon Creek formation, for a few million years conditions were just right to preserve dead animals and plants in astounding detail. A river carried dead plant materials and mud into an estuary along the ocean’s edge, where it sank and settled to the bottom of the sea floor. When an animal died, if it wasn’t eaten by something else, its body sank into this soft muddy mess. The bacteria in the mud produced carbon dioxide that combined with iron also present in the mud, which formed a mineral called siderite. This mineral encased the dead animal and slowed decay long enough for a detailed impression of the body to form in the mud. As the centuries passed and the mud became stone, the fossilized body impression was surrounded by a protective ironstone nodule. That’s why we know about the soft-bodied animals from the area, even though soft-bodied animals rarely leave fossil evidence.

Mazon Creek is where the Tully monster lived, which we talked about in episode 339, but the Tully monster isn’t the only mystery animal discovered there. Another one was Esconichthys.

We have lots of Esconichthys fossils, partly because it seems to have been extremely common, but also because it was a vertebrate. That means it had a notochord, a type of backbone. Most of the fossils we have are body impressions, so we do know a lot about what Esconichthys looked like when it was alive. What we don’t know is what it actually was.

Esconichthys was named for the Earth Science Club of Northern Illinois, ESCONI, and the latter half of its name means fish. But it doesn’t actually seem to have been a fish, even a larval fish. It grew up to about 3 inches long, or 8 cm, and had a pair of very obvious eyes, two pairs of feathery external gills, and a single fin on the underside of its tail. It didn’t have legs or any other fins. Some individuals had wide-set eyes, others had eyes that are close together, which may indicate two separate species, but we don’t know.

Esconichthys fossils are sometimes referred to as ghosts, because the limbless body with two dots for eyes does kind of look like a cartoon ghost. Other people call Esconichthys fossils grasshoppers or blades. This is because the animal’s gills were quite long and are often preserved pointing away from the rest of the body, or sometimes the rear of the body is folded upward. This can make it look roughly like a grasshopper or a pocket knife with one blade unfolded.

Esconichthys has been proposed as a larval lungfish or a larval amphibian, but it doesn’t really match either animal group. It’s the most common fossil found at the Mazon Creek formation by far, preserved in amazing detail, but scientists still have no idea what it is or what it might be related to.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s.

Thanks for listening!

Episode 487: Animals and the Sense of Taste

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Further reading:

What gives bees their sweet tooth?

Show transcript:

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

Right before I left on my trip to Belize a few months ago, my aunt Janice gave me a magazine to read on the plane, the Autumn 2021 copy of LivingBird. It’s about birds and birdwatching. I actually forgot to take it with me and it was in my car the whole time I was gone, but when I got home I took it in to read.

One article caught my eye, titled “Investigating the Sweet Tooth of Songbirds.” Literally the same day that I read that article, I stumbled across another article on ScienceDaily titled “What gives bees their sweet tooth?” And a podcast episode idea was born!

You may have heard that domestic cats can’t taste sweetness, and that’s true. When your pet cat wants to drink the milk in a bowl of sugary cereal, it’s not the sugar they care about because they can’t taste it. Also, milk isn’t good for cats and even if they can’t taste the sugar, it can end up giving them cavities.

The question is, why don’t cats taste sweetness? And what other animals can’t taste it either?

Carnivores like cats don’t need to taste sweet flavors because it’s just not present in meat, which is what carnivores eat. You can test this easily if you put two saucers on the floor for your cat, one with a small amount of unseasoned chicken and a sugar cube in the other. I guarantee you the cat will eat the chicken and play with the sugar cube, which will get sugar all over the floor so maybe don’t do that after all. This is where I share with you, for no reason, that when I was in elementary school I used to eat sugar cubes while pretending I was a horse.

Horses can taste sweet flavors like sugar because they’re herbivores. Herbivores eat plants, and in fact herbivores have a whole lot of taste buds so that they can easily tell what kind of plants they’re eating. Bitter tasting plants might be toxic while sweet ones provide lots of energy. Herbivores are also keenly attuned to the taste of salt since their diet is typically low in salt and they need to seek it out.

Humans are omnivores, and omnivores eat pretty much anything. Like our great ape cousins, we also evolved to eat a lot of fruit. Ripe fruit tastes sweet so we really like our sweet foods. Omnivores like dogs, pigs, and bears also like sweet foods because they’re high in calories and therefore provide a lot of energy.

But how does an animal lose an entire sense of taste? It’s not like all tigers woke up one day and boom, the ability to taste sweetness was gone. It happens gradually as the genes responsible for an animal’s sense of taste mutate over many generations.

Let’s take as our example the bottlenose dolphin. The ancestors of the dolphin and other cetaceans were terrestrial animals related to the ancestors of modern even-toed ungulates like hippos, camels, deer, and pigs, and were probably either herbivores or omnivores. But as the dolphin’s ancestors evolved over millions of years, they shifted to a fully marine lifestyle and a fully carnivorous diet. Over the thousands and thousands of generations, the genes that control the ability to taste sweetness mutated so much that they’re now useless, but since the dolphin doesn’t need to taste sweetness the mutations don’t matter.

In the case of the bottlenose dolphin and other cetaceans, in fact, they also can’t taste bitterness or umami. Umami is what helps you taste the difference between chicken and turkey, steak and pork, tuna and trout. Basically it’s the flavor of meat or savory foods, including cheeses. You can taste the difference between cheddar and Swiss because of the umami receptors in your taste buds, which are determined by genes.

But the dolphin eats nothing but meat! Why would it lose the ability to taste meat? Researchers think it’s because the dolphin swallows fish and other animals whole, without chewing. Cetaceans and other marine carnivores like sea lions that swallow their food whole actually have almost no taste buds at all.

If you’re wondering what happens when an animal that can’t taste sweetness has to adapt to a diet where tasting sweet foods is important, that’s exactly what happened with songbirds. The ancestors of birds lost the ability to taste sweetness millions of years ago when they were dinosaurs. Then, well, you know what happened to the non-avian dinosaurs. Suddenly the ancestors of modern birds had a lot of available ecological niches to take advantage of and they evolved rapidly to fill them. This included small birds who eat berries and nectar.

Genetic studies suggest that the ancestors of songbirds regained the ability to taste sweetness around 30 million years ago in Australia. The same thing happened in hummingbirds at about the same time. In both cases, the genes that control the ability to taste umami evolved to taste sweetness instead—but songbirds and hummingbirds adapted different umami genes. That’s what you call a subtle case of convergent evolution.

Songbirds and hummingbirds adapted to a diet high in sugar because it’s a good source of energy and easily found in flowers. In turn, flowers needed to be pollinated and have their seeds spread around, so they evolved to provide even more sugars in nectar and berries. But birds aren’t the only animals that pollinate flowers and are attracted to nectar. Insects can all detect sweetness. However, bees are exceptionally attuned to sweetness and have two taste neurons instead of one per taste bud.

Insects don’t have taste buds the same way we do, of course. In mammals, reptiles, and birds, taste buds are located on the tongue, in a few parts of the mouth, and at the top of the throat. In insects, taste receptors can be in any number of places. They’re on an insect’s mouthparts but often also on their feet, legs, and antennae.

Some amphibians have taste receptors on the body as well as concentrated in the mouth, and many fish have taste receptors all over their body. Catfish in particular have the most taste buds known, up to 175,000. Humans have about 10,000. Cats only have about 500.

Before you start feeling sorry for your cat for not being able to taste sweet foods and not having a great sense of taste in general, cats have a taste receptor we don’t. It’s the water sense. To us, a nice cold glass of water tastes refreshing but doesn’t really have a flavor. A cat or dog, and many other animals whose diet is mostly meat even if they aren’t specifically carnivores, have the ability to taste water in a way we can’t even imagine. Because meat is high in salt content, having taste buds attuned to water helps the animal drink enough water to process all that salt.

If you gave me the choice, I’d choose sweetness over the ability to taste water. But my cats would probably disagree.

Thanks for your support, and thanks for listening!

Episode 484: The Sewellel and the Superflea

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The sewellel is a little rodent:

The superflea is a big flea (left, compared to a regular flea, right):

Show transcript:

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

Let’s learn about a rodent you may never have heard of, unless you live where it does, and a parasite that makes that rodent its host. It’s not an ordinary parasite, but don’t worry, it’s not icky. You can continue to snack.

The rodent is called the sewellel, Aplodontia rufa. It’s also called the mountain beaver even though it doesn’t always live in the mountains and it isn’t a beaver. It doesn’t even look like a beaver. For one thing, it only has a little nub of a tail and it only grows around 20 inches long, or 50 cm. It has small eyes and ears, short legs, a chunky body, and long claws. This body shape should give you a hint about its lifestyle: the sewellel is a digger, although it can also swim just fine and can even climb small trees to eat young twigs and leaves.

The sewellel is an aplodont, a large group of rodents that have been common in Europe, Asia, and North America for 40 million years. But it’s the only one left. All the other aplodonts went extinct several million years ago at least. We’ve actually talked before about one of the sewellel’s extinct relations, the horned gopher (which was not a gopher), in the Patreon episode about animals with nose horns.

The sewellel itself hasn’t been around all that long, only appearing in the fossil record a few million years ago. It lives in a small area of northwestern North America, in parts of British Columbia, Washington state, Oregon, and a few parts of California. It lives in forests where it doesn’t get too cold in the winter, since it doesn’t hibernate and isn’t as good at keeping itself warm as other rodents are. It also needs to drink more water than other rodents and prefers to live in wet climates as a result.

In fact, the sewellel is sometimes referred to as a living fossil since it lacks many features that all other living rodents have. Its teeth resemble a simpler version of squirrel teeth, so some researchers think it may be most closely related to squirrels, but even if that’s the case, it isn’t very closely related. The sewellel’s ancestors were more adapted to live in trees and a study published in 2018 determined that it had a larger brain than the sewellel. Since the sewellel is nocturnal and spends most of its life underground, it doesn’t need to see very well, and the part of the brain that processes vision is much smaller than in its ancestors.

The sewellel mostly eats ferns, although it also eats other plants, and some of its favorite plants are toxic to other animals. It’s a solitary, mostly nocturnal animal that digs deep, complex burrows, and it stays as close as possible to the burrow entrance so it can hide easily if it needs to. Everything eats the sewellel, from owls to coyotes to bobcats to eagles.

And that brings us to the parasite associated with the sewellel. Many animals have parasites that are specific to that particular species. The Patreon episode about whale lice has some information about how specific this can get. The male sperm whale has a different species of louse than the species that lives on female sperm whales, for instance. Also, the whale louse isn’t a louse, it’s a type of crustacean.

The sewellel’s parasite is a type of flea. Big deal, you say, fleas are all about the same.

Are they, though? Because the sewellel’s flea is actually kind of a big deal. It is, in fact, the largest flea known, called the superflea. It can grow up to 8 mm long (and possibly longer, reports vary). I just measured, and that’s the length of my little fingernail, from the base to the quick. Most species of flea are 3 mm long at most.

The superflea is only found on the sewellel. It looks like an ordinary flea except for its size, meaning it’s laterally flattened with legs that allow it to jump long distances. So why is it so big compared to other fleas, especially considering that it lives on an animal that’s about the size of a chonky cat? No one knows. No one has even the slightest idea why this flea is so big.

There used to be even bigger fleas, some up to two cm long. That’s 20 mm, or just a little more than twice the length of the superflea. Of course, those 20 mm fleas lived 165 million years ago and probably lived on dinosaurs. Also, they couldn’t jump and instead of being flattened laterally, or side to side, like modern fleas, they were flattened dorsoventrally, or top to bottom. So they weren’t very much like modern fleas.

That’s all we know about the superflea, but let’s have one last sewellel fact before we go. With all this talk of the sewellel being a primitive rodent whose closest relations are all extinct, you might think there’s nothing really special about it beyond its giant fleas. You would be wrong, though, because the sewellel’s front paws have opposable thumbs. It’s not as mobile as our opposable thumbs, but it allows the sewellel to manipulate food more easily. It will sometimes sit up on its big round bottom to eat, just like a really weird squirrel.

Thanks for your support, and thanks for listening!