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Episode 370: Animals Discovered in 2023

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Let’s look at some of the most interesting animals discovered last year!

Further reading:

Newly-discovered ‘margarita snails’ from the Florida Keys are bright lemon-yellow

Tiny spirits roam the corals of Japan—two new pygmy squids discovered

Strange New Species of Aquifer-Dwelling Catfish Discovered in India

Bizarre New Species of Catfish Discovered in South America

Unicorn-like blind fish discovered in dark waters deep in Chinese cave

New Species of Hornshark Discovered off Australia

Cryptic New Bird Species Identified in Panama

New Species of Forest Hedgehog Discovered in China

New species of voiceless frog discovered in Tanzania

The weird new spiny katydid:

Show transcript:

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

It’s time for our annual discoveries episode, where we learn about some animals discovered in the previous year! There are always lots more animals discovered than we have time to talk about, so I just choose the ones that interest me the most.

That includes the cheerfullest of springtime-looking marine snails discovered in the Florida Keys. The Florida Keys are a group of tropical islands along a coral reef off the coast of Florida, which is in North America. A related snail was also discovered off the coast of Belize in Central America that looks so similar that at first the scientists thought they were the same species with slightly different coloration. A genetic study of the snails revealed that they were separate species. The one found in the Keys is a lemony yellow color while the one from Belize is more of a lime green.

The snails have been placed into a new genus but belong to a group called worm snails. When a young worm snail finds a good spot to live, it sticks its shell to a rock or other surface and stays there for the rest of its life. Its shell isn’t shaped like an ordinary snail shell but instead grows long and sort of curved or curly. The snail spreads a thin layer of slime around it using two little tentacles, and the slime traps tiny pieces of food that float by.

The new snails are small and while the snail’s body is brightly colored, its shell is drab and helps it blend in with the background. Scientists think that the colorful body may be a warning to potential predators, since its mucus contains toxins. It mainly lives on pieces of dead coral.

Another invertebrate discovery last year came from Japan, where two new species of pygmy squid were found living in seagrass beds and coral reefs. Both are tiny, only 12 mm long, and are named after little forest spirits from folklore. Despite its small size, it can eat shrimp bigger than it is by grabbing it with its little bitty adorable arms. Both species have been seen before but never studied until now. The scientists teamed up with underwater photographers to find the squid and learn more about them in their natural habitats.

As for invertebrates that live on land, an insect called the blue-legged predatory katydid was discovered in the rainforests of Brazil. It’s a type of bush-cricket that’s dark brown in color except for the last section of its legs, which are greenish-blue. Those parts of its legs are also really spiny. That is literally all I know about it except for its scientific name, Listroscelis cyanotibiatus, but it’s awesome.

Let’s leave the world of invertebrates behind and look at some fish next. This was the year of the catfish, with new species discovered in both India and South America. Catfish can be really weird in general and both these new species are pretty strange.

The first is tiny, only 35 mm long at most, or a little over an inch, and it has four pairs of barbels growing from its face. It looks red because its blood shows through its skin, because its skin doesn’t have any pigment. The fish also doesn’t have any eyes. If this makes you think it’s a cave-dwelling fish, you’re exactly right, but instead of an ordinary cave it actually lives in an aquifer.

An aquifer is a source of water underground. It’s actually a layer of rock that’s broken up or otherwise permeable so that water can get through it, but with a non-permeable layer underneath. The water is trapped in the layer, sometimes far underground. If you’ve ever seen a spring, where water bubbles up from the ground, that water comes from an aquifer that has found its way to the surface. If you’ve ever drunk water pumped or dipped up from a well, the well-water also comes from an aquifer. The water gets into the aquifer in the first place when rain soaks into the ground, but it takes a long time to fill up.

There are really deep aquifers that are completely sealed off from the surface, created thousands or even millions of years ago. As far as we know, nothing lives in those, although we could be wrong. Aquifers that are closer to the surface with some surface openings develop unique ecosystems, including animals that are found nowhere else on earth. That’s the case with the tiny red catfish found in the state of Kerala in India.

Scientists asked people in the area to watch out for any unusual animals when they had a new well dug or cleaned, and before long people from four towns reported finding the little red fish. Three other related species had previously been found in the state.

On the other side of the world, in South America, a much different type of catfish was discovered in Bolivia and Brazil. This one is an armored catfish, and the male actually grows short dermal teeth on the sides of his head that he uses to fight other males. Dermal teeth are teeth that grow on the skin instead of in the mouth, and it’s surprisingly common in fish, especially armored catfish.

The new catfish has been named Sturisoma reisi and it grows about 8 inches long, or 20 cm. It’s actually been known to scientists for a long time, but until recently no one realized it wasn’t one of five other catfish in the genus Sturisoma. They all look kind of similar. It’s a slender, active catfish with a long tail and a pointy rostrum that lives in swift-moving rivers. It was actually described in 2022, not 2023, but I only just realized I have the wrong year so let’s just move along quickly to another fish.

This one isn’t a catfish but it looks like one at first glance since it has barbels around its mouth. These are the whisker-like feelers that give the catfish its name. The newly discovered fish needs feelers because it doesn’t have working eyes, and it also doesn’t have scales or pigment in its skin. It was found in a cave in China, and in fact it’s only been found in a single pool of water in a single cave. The pool is only about 6 feet across, or 1.8 meters, and about two and a half feet deep, or 80 cm, but it’s home to a perfectly healthy population of fish. The fish grow about 5 inches long on average, or 13 cm.

The fish is a new member of the genus Sinocyclocheilus, and of the 76 known species in the genus, most live in caves. The new fish has been named S. longicornus because of a structure on its head that kind of looks like a unicorn horn, if the unicorn was a pink cave fish and its horn was shaped sort of like the tip of a ballpoint pen, also called a biro.

Some other species in this genus also have a so-called horn, although the new fish’s is larger than most. It juts forward and extends above what we can describe as the fish’s forehead. Scientists have absolutely no idea what it’s for. Since the fish can’t see, it can’t be to attract a mate. It’s also not likely to be a navigational aide since the fish has its barbels and a well-developed lateral line system to find its way around. Besides, it lives in a pool of water not much bigger than the desk I’m sitting at. It doesn’t exactly travel very far throughout its life.

Scientists have a lot of other questions about the fish, including how it survives in such a tiny pool of water.

Speaking of fish with horns, a new species of hornshark was discovered last year off the northern coast of Australia. Hornsharks live in shallow warm waters throughout much of the Pacific and Indian oceans, where they spend most of the time at the bottom looking for small invertebrates like crustaceans to crunch up, although sea urchins are their favorites. They’re also called bullhead sharks because they all have short snouts and broad heads with prominent brows. The name hornshark comes from the fins, some of which have spines.

One species of hornshark is the zebra hornshark, which lives in the Indo-Pacific, from southern Japan down to northern Australia. As you may guess from the name, it has stripes, which makes it popular in aquariums and zoos. It only grows to about 4 feet long, or 1.25 meters. Until last year, scientists thought that all the zebra hornsharks around Australia belonged to the same species. Then they noticed that one population that lives off of northwestern Australia has a different stripe pattern and only grows about two feet long, or 60 cm. After a genetic study, it turns out that it’s a totally different species.

A lot of animal discoveries are like this, where everyone thinks an animal is one species, but after close study and genetic testing they find out it’s two or more species that just look very similar. That’s one of the great things about DNA testing being so effective and quick these days, but it’s not always as cut and dried as it sounds. There’s no easy way to determine for sure if animals are different species, subspecies, or just the same species with population variants. Scientists can’t just rely on genetics, but they also can’t always rely on observations of the animal’s physical traits or its behavior in the wild. They have to look at all the data available, and then they still argue about the best interpretation of the data.

The notion of a separate species or subspecies is an artificial one that gives us a way to better understand a natural process. If a population of animals is separated from another population, eventually both will develop separately until they’re two related but very different animals. There’s no way to point at a specific generation and say, “well, NOW they’re different from the last generation” because the process is so slow and the changes are usually so small. It’s like looking at a rainbow and trying to determine exactly the point where red turns into orange and orange turns into yellow.

Take the slaty-backed nightingale-thrush as an example. It’s a dark gray songbird with a short tail and bright orange legs and beak, and it lives in the mountains of Central and northern South America. It spends most of its time in thickets where it’s hard to see but easy to hear, since it has a lovely song. This is an example of what it sounds like, although its song varies depending on where it lives.

[bird song]

It turns out that there’s a lot of variation in the bird’s song because the slaty-backed nightingale-thrush probably isn’t all one species. In late 2023 a team of researchers published a ten-year study of the bird, looking at everything from song variations to genetics. They determined that not only was it not a single species, it was most likely seven different species and four subspecies. Because the bird lives in the mountains and doesn’t fly very far during its lifetime, populations that are separated by steep mountains and valleys have developed into separate species.

Naturally, not everyone agrees with these findings, but it’s always good when a little-studied animal gets some attention. Until last year, no one knew much about this shy little bird, and the controversy of whether it’s one species or lots of closely related species will hopefully lead us to learn even more about it. One population of the bird discovered in Panama had never been documented before, too.

This episode is getting pretty long for someone who just got over a cold, so let’s cover one newly discovered mammal and a newly discovered frog. A new species of forest hedgehog was discovered in China last year and it’s adorable! It’s related to the hedgehogs found in Europe and other areas, but is most closely related to four known species of forest hedgehog that live mostly in central Asia. The new species was discovered in eastern China, over 1,000 km away from the nearest population of other forest hedgehogs. Another species was only discovered in 2007 from southwestern China.

Unlike most hedgehogs, the new species is sexually dimorphic, meaning that males and females don’t look identical. Males are mostly gray while females are more reddish-brown in color.

Let’s finish with another adorable animal, a little frog from Tanzania, a country in east Africa. It’s a type of spiny-throated reed frog, which are all rare and increasingly threatened. They’re also very small, not much bigger than an inch long, or about 30 mm. The male has tiny little spines on his throat that researchers think might be a way that females recognize the males of their own species during mating season instead of by a distinctive croaking sound. That’s because spiny-throated reed frogs can’t make sounds, leading to their other common name of the voiceless frog.

In 2019, researchers were in the Ukaguru Mountains in Tanzania looking for a completely different frog, the beautiful tree toad, which may be extinct. While they didn’t find any of the toads, they did find a little greenish-brown frog with copper-colored eyes that turned out to be completely new to science. It was found in a nature reserve and appears to be common locally, which is good, but the nature reserve is also very small, which is not so good. Hopefully now that we know the little frog exists, it will lead to further protections of the area that will help all the other animals and plants where it lives, including the beautiful tree toad.

This is what the voiceless frog sounds like:

[silence]

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. 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.

Thanks for listening!

Episode 342: Giant Snails and Giant Crabs

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Thanks to Tobey and Anbo for their suggestions this week! We’re going to learn about some giant invertebrates!

Further reading:

The Invasive Giant African Land Snail Has Been Spotted in Florida

A very big shell:

The giant African snail is pretty darn giant [photo from article linked above]:

The largest giant spider crab ever measured, and a person:

Show transcript:

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

This week we’re going to learn about some giant invertebrates, suggested by Tobey and Anbo. Maybe they’re not as big as dinosaurs or whales, but they’re surprisingly big compared to most invertebrates.

Let’s start with Tobey’s suggestion, about a big gastropod. Gastropods include slugs and snails, and while Tobey suggested the African trumpet snail specifically, I couldn’t figure out which species of snail it is. But it did lead me to learning a lot about some really big snails.

The very biggest snail known to be alive today is called the Australian trumpet snail, Syrinx aruanus. This isn’t the kind of snail you’d find in your garden, though. It’s a sea snail that lives in shallow water off the coast of northern Australia, around Papua New Guinea, and other nearby areas. It has a coiled shell that’s referred to as spindle-shaped, because the coils form a point like the spindle of a tower. It’s a pretty common shape for sea snails and you’ve undoubtedly seen this kind of seashell before if you’ve spent any time on the beach. But unless you live in the places where the Australian trumpet lives, you probably haven’t seen a seashell this size. The Australian trumpet’s shell can grow up to three feet long, or 91 cm. Not only is this a huge shell, the snail itself is really heavy. It can weigh as much as 31 lbs, or 14 kg, which is as heavy as a good-sized dog.

The snail eats worms, but not just any old worms. If you remember episode 289, you might remember that Australia is home to the giant beach worm, a polychaete worm that burrows in the sand between high and low tide marks. It can grow as much as 8 feet long, or 2.4 meters, and probably longer. Well, that’s the type of worm the Australian trumpet likes to eat, along with other worms. The snail extends a proboscis into the worm’s burrow to reach the worm, but although I’ve tried to find out how it actually captures the worm in order to eat it, this seems to be a mystery. Like other gastropods, the Australian trumpet eats by scraping pieces of food into its mouth using a radula. That’s a tongue-like structure studded with tiny sharp teeth, and the Australian trumpet has a formidable radula. Some other sea snails, especially cone snails, are able to paralyze or outright kill prey by injecting it with venom via a proboscis, so it’s possible the Australian trumpet does too. The Australian trumpet is related to cone snails, although not very closely.

Obviously, we know very little about the Australian trumpet, even though it’s not hard to find. The trouble is that its an edible snail to humans and humans also really like those big shells and will pay a lot for them. In some areas people have hunted the snail to extinction, but we don’t even know how common it is overall to know if it’s endangered or not.

Tobey may have been referring to the giant African snail, which is probably the largest living land snail known. There are several snails that share the name “giant African snail,” and they’re all big, but the biggest is Lissachatina fulica. It can grow more than 8 inches long, or 20 cm, and its conical shell is usually brown and white with pretty banding in some of the whorls. It looks more like the shell of a sea snail than a land snail, but the shell is incredibly tough.

The giant African snail is an invasive species in many areas. Not only will it eat plants down to nothing, it will also eat stucco and concrete for the minerals they contain. It even eats sand, cardboard, certain rocks, bones, and sometimes other African giant snails, presumably when it runs out of trees and houses to eat. It can spread diseases to plants, animals, and humans, which is a problem since it’s also edible.

Like many snails, the African giant snail is a simultaneous hermaphrodite, meaning it can produce both sperm and eggs. It can’t self-fertilize its own eggs, but after mating a snail can keep any unused sperm alive in its body for up to two years, using it to fertilize eggs during that whole time, and it can lay up to 200 eggs five or six times a year. In other words, it only takes a single snail to produce a wasteland of invasive snails in a very short amount of time.

In June 2023, some African giant snails were found near Miami, Florida and officials placed the whole area under agricultural quarantine. That means no one can move any soil or plants out of the area without permission, since that could cause the snails to spread to other places. Meanwhile, officials are working to eradicate the snails. Other parts of Florida are also under the same quarantine after the snails were found the year before. Sometimes when people go on vacation in the Caribbean they bring back garden plants, without realizing that the soil in the pot contains giant African snail eggs, because the giant African snail is also an invasive species throughout the Caribbean.

Next, Anbo wanted to learn about the giant spider crab, also called the Japanese spider crab because it lives in the Pacific Ocean around Japan. It is indeed a type of crab, which is a crustacean, which is an arthropod, and it has the largest legspan of any arthropod known. Its body can grow 16 inches across, or 40 cm, and it can weigh as much as 42 pounds, or 19 kg, which is almost as big as the biggest lobster. But its legs are really really really long. Really long! It can have a legspan of 12 feet across, or 3.7 meters! That includes the claws at the end of its front legs. Most individual crabs are much smaller, but since crustaceans continue to grow throughout their lives, and the giant spider crab can probably live to be 100 years old, there’s no reason why some crabs couldn’t be even bigger than 12 feet across. Its long legs are delicate, though, and it’s rare to find an old crab that hasn’t had an injury to at least one leg.

The giant spider crab is orange with white spots, sort of like a koi fish but in crab form. Its carapace is also bumpy and spiky. You wouldn’t think a crab this size would need to worry about predators, but it’s actually eaten by large octopuses. The crab sticks small organisms like sponges and kelp to its carapace to help camouflage it.

The giant spider crab is considered a delicacy in some places, which has led to overfishing. It’s now protected in Japan, where people are only allowed to catch the crabs during part of the year. This allows the crabs to safely mate and lay eggs.

There’s another species called the European spider crab that has long legs, but it’s nowhere near the size of the giant spider crab. Its carapace width is barely 8 ½ inches across, or 22 cm, and its legs are about the same length. Remember that the giant spider crab’s legs can be up to six feet long each, or 1.8 meters. While the European spider crab does resemble the giant spider crab in many ways, it’s actually not closely related to it. They two species belong to separate families.

The giant spider crab spends most of its time in deep water, although in mating season it will come into shallower water. It uses its long legs to walk around on the sea floor, searching for food. It’s an omnivore that eats pretty much anything it can find, including plants, dead animals, and algae, but it will also use its claws to open mollusk shells and eat the animals inside. It prefers rocky areas of the sea floor, since its bumpy carapace blends in well among rocks.

Scientists report that the giant spider crab is mostly good-natured, even though it looks scary. Some big aquariums keep giant spider crabs, and the aquarium workers say the same thing. But it does have strong claws, and if it feels threatened it can seriously injure divers. I shouldn’t need to remind you not to pester a crab with a 12-foot legspan.

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. 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.

Thanks for listening!

Episode 259: Indestructible Animals

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Thanks to Nicholas and Emma for their suggestions this week as we learn about some (nearly) indestructible animals!

Further listening:

Patreon episode about Metal Animals (unlocked, no login required)

Further reading:

Even a car can’t kill this beetle. Here’s why

The scaly-foot snail’s shell is made of actual iron – and it’s magnetic

The scaly-foot gastropod (pictures from article linked above):

The diabolical ironclad beetle is virtually unsquishable:

Limpet shells:

The business side of a limpet:

Highly magnified limpet teeth:

Show transcript:

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

This week we’re going to learn about some indestructible animals, or at least animals that are incredibly tough. You may be surprised to learn that they’re all invertebrates. It’s a suggestion by Nicholas, and one of the animals Nicholas suggested was also suggested by Emma.

We’ll start with that one, the scaly-foot gastropod, a deep-sea snail. We actually covered this one a few years ago but only in a Patreon episode. I went ahead and unlocked that episode so that anyone can listen to it, since I haven’t done that in a while, so the first part of this episode will sound familiar if you just listened to that one.

The scaly-foot gastropod lives around three hydrothermal vents in the Indian Ocean, about 1 ¾ miles below the surface, or about 2,800 meters. The water around these vents, referred to as black smokers, can be more than 350 degrees Celsius. That’s 660 degrees F, if you even need to know that that’s too hot to live.

The scaly-foot gastropod was discovered in 2001 but not formally described until 2015. The color of its shell varies from almost black to golden to white, depending on which population it’s from, and it grows to almost 2 inches long, or nearly 5 cm. It doesn’t have eyes, and while it does have a small mouth, it doesn’t use it for eating. Instead, the snail contains symbiotic bacteria in a gland in its esophagus. The bacteria convert toxic hydrogen sulfide from the water around the hydrothermal vents into energy the snail uses to live. It’s a process called chemosynthesis. In return, the bacteria get a safe place to live.

The snail’s shell contains an outer layer made of iron sulfides. Not only that, the bottom of the snail’s foot is covered with sclerites, or spiky scales, that are also mineralized with iron sulfides. While the snail can’t pull itself entirely into its shell, if something attacks it, the bottom of its foot is heavily armored and its shell is similarly tough.

Researchers are studying the scaly-foot gastropod’s shell to possibly make a similar composite material for protective gear and other items. The inner layer of the shell is made of a type of calcium carbonate, common in mollusk shells and some corals. The middle layer of the shell is regular snail shell material, organic periostracum, [perry-OSS-trickum] which helps dissipate heat as well as pressure from squeezing attacks, like from crab claws. And the outer layer, of course, is iron sulfides like pyrite and greigite. Oh, and since greigite is magnetic, the snails stick to magnets.

Unfortunately, the scaly-foot gastropod is endangered due to deep-sea mining around its small, fragile habitat. Hopefully conservationists can get laws passed to protect the thermal vents and all the animals that live around them.

The scaly-foot gastropod is the only animal known that incorporates iron sulfide into its skeleton or exoskeleton, although our next indestructible animal, the diabolical ironclad beetle, has iron in its name.

The diabolical ironclad beetle lives in western North America, especially in dry areas. It grows up to an inch long, or 25 mm, and is a dull black or dark gray in color with bumps and ridges that make it look like a piece of tree bark. Since it lives on trees, that’s not a coincidence. It spends most of its time eating fungus that grows on and under tree bark.

Like a lot of beetles, it’s flattened in shape. This helps it slide under tree bark and helps it keep a low profile to avoid predators like birds and lizards. But if a predator does grab it and try to crunch it up to eat, the diabolical ironclad beetle is un-crunchable. Its exoskeleton is so tough that it can withstand being run over by a car. When researchers want to mount a dead beetle to display, they can’t just stick a pin through the exoskeleton. It bends pins, even strong steel ones. They have to get a tiny drill to make a hole in the exoskeleton first.

The beetle’s exoskeleton is so strong because of the way it’s constructed. In a late 2020 article in Nature, a team studying the beetle discovered that the exoskeleton is made up of multiple layers that fit together like a jigsaw puzzle. Each layer contains twisted fibers made of proteins that help distribute weight evenly across the beetle’s body and stop potential cracking. At the same time, the arrangement of the exoskeleton’s sections allows for enough give to make it just flexible enough to keep from cracking under extreme pressure. Of course, this means the beetle can’t fly because its wing covers can’t move, but if it falls from a tree it doesn’t need to worry about hurting itself.

Engineers are studying the beetle to see if they can adapt the same type of structures to make airplanes and cars safer.

Nicholas also suggested the limpet, another mollusk. It’s a type of snail but it doesn’t look like the scaly-foot gastropod or like most other snails. Its shell is shaped like a little cone with ridges that run from the cone’s tip to the bottom, sort of like a tiny ice-cream cone that you don’t want to eat. There are lots of species and while a few live in fresh water, most live in the ocean. The limpets we’re talking about today are those in the family Patellidae.

If you think about a typical snail, whose body is mostly protected by a shell and who moves around on a wide flat part of its body called a foot, you’ll understand how the limpet is a snail even though it looks so different superficially. The conical shell protects the body, and the limpet does indeed move around on a so-called foot, gliding along very slowly on a thin layer of mucus.

The limpet lives on rocks in the intertidal zone and is famous for being able to stick to a rock incredibly tightly. It has to be able to do so because otherwise it would get washed off its rock by waves, plus it needs to be safe when the tide is out and its rock is above water. The limpet makes a little dimple in the rock that exactly matches its shell, called a home scar, and as the tide goes out the limpet returns to its home scar, seals the edges of its shell tight to the rock, and waits for the water to return. It traps water inside its shell so its gills won’t dry out while it waits. If the rock is too hard for it to grind down to match its shell, it grinds the edges of its shell to match the rock. It makes its home scar by rubbing its shell against one spot in the rock until both are perfectly matched.

The limpet mostly eats algae. It has a tiny mouth above its foot and in the mouth is a teensy tongue-like structure called a radula, which is studded with very hard teeth. It uses the radula to rasp algae off of the rocks. Other snails do this too, but the limpet has much harder teeth than other snails. Much, much harder teeth. In fact, the teeth of some limpet species may be the hardest natural material ever studied.

The teeth are mostly chitin, a hard material that’s common in invertebrates, but the surface is coated with goethite [GO-thite] nanofibers. Goethite is a type of of iron, so while the limpet does have iron teeth, it still doesn’t topple the scaly-foot gastropod as the only animal known with iron in its skeleton. Not only does the goethite help make the teeth incredibly strong, which is good for an animal that is scraping those teeth over rocks constantly, the dense chitin fibers in the teeth make them resistant to cracking.

The limpet replaces its teeth all the time. They grow on a sort of conveyer belt and move forward until the teeth in front, at the business end of the radula, are ready to use. It takes about two days for a new tooth to fully form and move to the end of the radula, where it’s quickly worn down and drops off.

Meanwhile, even though the limpet’s shell doesn’t contain any iron, its shape and the limpet’s strong foot muscles mean that once a limpet is stuck to its rock, it’s incredibly hard to remove it. It just sits there being more or less impervious to predation. Humans eat them, although they have to be cooked thoroughly because they’re tough otherwise, naturally.

Finally, one animal that Nicholas suggested is probably the royalty of indestructible animals, the water bear or tardigrade. Because we talked about it recently, in episode 234, I won’t go over it again. I’ll just leave you with an interesting note that I missed when researching that episode.

In April of 2019, an Israeli spacecraft was launched that had dormant tardigrades onboard as part of an experiment about tardigrades in space. There were no people onboard, fortunately, because the craft actually crashed on the moon instead of landing properly. The ship was destroyed but the case where the tardigrades were stored appears to be intact.

It’s not exactly easy to run up to the moon and check on the tardigrades, so we don’t know if they survived the crash landing. Studies since then suggest they probably didn’t, but until we can actually land on the moon and send a rover or an astronaut out to check, we don’t know for sure. Tardigrades can survive incredibly cold, dry conditions while dormant. It’s not exactly the experiment researchers intended, but it’s definitely an interesting one.

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 147: Snails and the Gooseneck Barnacle

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Thanks to Kim and Richard E. this week for two awesome suggestions! We’re going to learn about land snails and about the gooseneck barnacle!

Some baby snails and a mama snail, or at least an adult snail that is probably ignoring all those babies:

A giant African snail:

Unlocked Patreon episode about giant African snails (and other stuff)

A rare Polynesian tree snail, white-shelled variety:

A grove snail:

Gooseneck barnacles:

A barnacle goose. Not actually related to the gooseneck barnacle:

Show transcript:

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

We’re getting to some more excellent listener suggestions this week, this time about some interesting invertebrates. Thanks to Kim who suggested snails, and to Richard E for suggesting the gooseneck barnacle.

We’ve talked about various snails before, in episodes 27, 57, 81, and 136, but let’s dig in and really learn about them.

Snails are in the class gastropoda, which includes slugs, whether terrestrial, freshwater, or saltwater. Gastropods appear in the fossil record way back in the late Cambrian, almost 500 million years ago. Snails and slugs are so common that no matter where you live, you can probably find one within seconds, if you know where to look.

Snails have shells while slugs don’t, but there’s a third type of gastropod called a semi-slug. It has a shell, but one that’s too small for it to live inside. It’s more of a little armor plate than a snail shell. Slugs also have shells, but they’re vestigial and are actually inside the slug so you can’t see them.

Scientists have long tried to figure out if mollusks developed shells early or if they started out as a wormlike creature that later evolved a shell. A discovery of a 400 million year old mollusk fossil in Wales shows a wormlike body but also a shell—actually seven plate-like shells—which suggests that the shells developed early and that shell-less mollusks later lost them.

The snail has a spiraled shell that it can retract its body into, although not all snails can retract all the way into their shells. Snails that live on land are called terrestrial snails, or just land snails, and those are the ones we’ll talk about today. Land snails have lungs, or rather a single lung, although some land snails have gills instead and live in wet areas, although they’re not technically water snails.

Most land snails eat plant material, which they scrape up using a radula. You may remember from other episodes that the radula is a tongue-like structure studded with tiny chitinous teeth, microscopic ones in this case. Snails are sometimes so numerous that they can cause damage to gardens, so often people buy poison to kill the snails in their yard. But a 2014 study shows that killing snails isn’t very effective. The best way to get rid of snails, or at least minimize the damage they do to gardens, is to pick the snails up and transport them at least 30 yards away, or about 20 meters. Snails have a homing instinct, but distances more than about 20 meters are hard for them to navigate. The snails will probably just make a home where they end up. Also, no throwing them into your neighbor’s garden. That’s cheating.

Most land snails are hermaphrodites, which means the snail fertilizes the eggs of other snails and also produces eggs for other snails to fertilize. Some snails bury their eggs in soil while some hide them in damp leaf litter. The eggs hatch into teeny snails with teeny shells, and as the snail grows, its shell grows too by adding layers at the opening.

Snails need moisture to survive, so a snail secretes mucous that helps it retain moisture. The mucus is also thick enough to protect the snail from sharp objects as it travels around on the flat underside of its body, called a foot. Until recently researchers thought that the mucous also helped the snail move, but it turns out that gastropods move entirely due to muscular motions of the body, which start at the tail and travel in a sort of wave motion to the head. This isn’t the most rapid way to move—a typical snail can only advance about one millimeter per second—but it works for the snail. It can also climb walls and other vertical surfaces since the mucous helps it stick, even if it’s upside-down. The mucus a snail leaves behind in its track is visible until it dries after a few hours, usually called a snail trail or a slime trail.

If a snail’s environment becomes too dry, it will retract itself into its shell and secrete a layer of mucous that hardens, protecting its body from drying out. Later, when the environment is wetter, it softens the mucous and goes about its normal snail activities.

Scientists of all kinds study snails. One recently published study investigated the properties of snail mucous to try to develop an adhesive that can be turned from sticky to non-sticky and back to sticky. Another study from 2011 examined the way snails move to see if that can be adapted to various technologies.

Because snail shells are so common in the fossil record, scientists can measure the oxygen isotopes in shells to learn how dry or wet the environment was during the snail’s life. A recent study of snail shells from the Canary Islands indicates that 50,000 years ago the islands were much wetter than they are now. Also, there were more snails then than now.

The largest living snail known is the giant African snail, which can grow almost a foot long, or 30 cm. It’s native to East Africa but it’s an invasive species in many parts of the world. I actually covered this species of snail in a Patreon episode a few months ago, so I’ll unlock that episode and put a link to it in the show notes if you want to learn more about it. It’s kind of a weird episode and I spend entirely too much time at the end talking about my recent eye surgery, but you’ll learn about the giant African snail and a marine snail called the periwinkle.

New species of snail are discovered all the time, since snails are usually small, often hard to find, and many snails look sort of alike except to the trained eye. In 2012, two species of tiny snails were discovered in a cave in northern Spain. They’re called thorn snails and are less than 2 mm in size. Since they live in caves, like many cave animals they’ve lost pigment and are essentially transparent. More thorn snails new to science were discovered in Panama a few years ago. A snail specimen collected in South America in the 19th century was finally examined a few years ago and described as a new species in 2015. Those are just a few examples; so many snails have been described in the last few decades that it would get boring if I talked about all of them.

Not all snails are brown, of course. Some have lovely shells in different colors, patterns, and shapes. A colorful snail called the Polynesian tree snail, found in Tahiti and a few nearby islands, has been a puzzle to researchers for over a century, since they couldn’t figure out how the snail came to be on the islands. Not only that, but a few of the islands have a variety of the snail with a white shell, which isn’t found on Tahiti. It turns out that the people of the area just liked the white shells, which they used to make jewelry, so they introduced the snails to their islands for a better supply of the shells. The Polynesian tree snail is critically endangered now, but some zoos have started a captive breeding program.

People have eaten snails for thousands of years, and certain species of snail are considered delicacies today. A type of grove snail that lives in Ireland and southern France but not anywhere in between may be evidence that humans brought the snails with them when they first colonized Ireland. Researchers suggest humans arrived in Ireland by boat from southern Europe around 8,000 years ago and brought the snails with them, possibly to farm. They’re actually really pretty snails with a yellow or yellowy-white shell striped with brown.

Another invertebrate humans like to eat is the gooseneck barnacle, also called the goose barnacle. It’s actually a crustacean, and I’m glad I checked because I was honestly certain that it was another mollusk. I think I had it mixed up with certain types of clams with long siphons. But the gooseneck barnacle is a crustacean like last week’s roly poly, but unlike the roly poly, it actually tastes really good—if you can get it.

The gooseneck barnacle attaches itself to rocks and other hard objects in intertidal areas of the Atlantic and Pacific, and it prefers rough water. It can be dangerous to gather. Richard E., who suggested the topic, specifically mentioned the variety known as percebes, which is a delicacy popular around the Iberian peninsula, especially in Portugal and Spain. He mentions that people have died trying to get them, and that his own grandparents have a saying about them, “If you want to get, you have to get your backside wet.”

The gooseneck barnacle attaches itself to an object by its stalk, called a peduncle, which is strong and tough enough to withstand rough waves. At the end of the stalk is the capitulum, which contains the body and is protected with five plates. It extends its legs, which are called cirri and resemble feathers, from an opening in the capitulum, and uses them to filter tiny organisms out of the water that it eats.

Like the land snail and many other invertebrates, the gooseneck barnacle is a hermaphrodite. It mates with the nearest other gooseneck barnacle, and since it literally cements itself to its rock and can’t move afterwards, it’s a good thing that barnacles live in clusters or there wouldn’t be any new ones, since the gooseneck barnacle can’t fertilize its own eggs. The barnacle keeps its fertilized eggs inside its body until they hatch into tiny larvae, which it releases into the water. The larvae live in the sea as plankton for a few months, moulting six times before they metamorphose into cyprid larvae. You may remember that term from the horrifying zombie animals episode last month, but these cyprid larvae are just looking for a nice rock to cement themselves to.

The gooseneck barnacle gets its name from its long stalk, which resembles a goose’s neck, and the protective plates on the capitulum do kinda-sorta look like a goose’s beak from the right angle. Now, back in the olden days people didn’t know that birds migrate. People knew that some birds lived in their area in the winter or summer, but they didn’t know what happened to the birds the rest of the year. Some people believed some birds hibernated, others actually believed they flew to the moon during the winter. In the case of a goose called the barnacle goose, which mostly breeds on remote Arctic islands and then spends the rest of the year in various parts of Europe, in the early medieval days people actually thought it didn’t actually lay eggs or have babies. They thought it and the gooseneck barnacle were the SAME ANIMAL, but that the gooseneck barnacle was a young barnacle goose that was still developing. Therefore, people rationalized, they weren’t actually geese but some sort of fish so could be eaten during Christian fast days when meat wasn’t allowed. This lasted until 1215 when the pope said no, actually, wherever they come from, those things are birds and you can’t eat them on fast days.

The gooseneck barnacle is still causing consternation these days. In 2016, some pieces of driftwood washed up on a few New Zealand beaches, covered with gooseneck barnacles. No one knew what in the heck those things were. A species of gooseneck barnacle is native to the area, but they aren’t usually seen on sandy beaches where people like to swim. A picture of the barnacles caused a lot of speculation as to what they were until scientists and naturalists identified them. Fortunately, though, no one suggested they were baby geese.

You can find Strange Animals Podcast online at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. You can also support the show and get two bonus episodes a month by signing up as a patron at Patreon.com/strangeanimalspodcast.

Thanks for listening!