Category Archives: South America

Episode 416: The heaviest tarantula and the bitey-est ant

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Thanks to Siya, Sutton, Owen, and Aksel for suggesting this week’s topic, the Goliath birdeater tarantula and the fire ant!

Further listening:

The TEETH Podcast

Further reading:

Tropical fire ants traveled the world on 16th century ships

The Goliath birdeater tarantula, bigger than some kittens:

Fire ants:

Show transcript:

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

This week we’re going to talk about two invertebrates, a spider and an insect. Thanks to Siya, Sutton, Owen, and Aksel for suggesting them!

We’ll start with the spider, which Siya and Sutton both suggested. It’s the goliath tarantula, also called the goliath birdeater. You know it has to be a big spider if it’s called a birdeater. We’ve talked about it before, but not in a long time.

The goliath birdeater is the heaviest spider in the world. If you think of the usual spider, even a big one, it’s still pretty lightweight. Let’s use a wolf spider as an example, which is found just about everywhere in the world. It’s a hunting spider that doesn’t spin a web, and while different species vary in size, the biggest is the Carolina wolf spider found in many parts of North America. A big female can have a legspan of four inches across, or 10 cm, with a body up to an inch and a half long, or 35 mm—but it weighs less than an ounce. That’s barely 28 grams, or just a little heavier than five sheets of printer paper.

In comparison, the goliath birdeater tarantula can weigh over 6 ounces, or 175 grams. That’s heavier than a baseball, or two packs of cards. Its legspan can be as much as 12 inches across, or 30 cm with a body length of about 5 inches, or 13 cm. It’s brown or golden in color and lives in South America, especially in swampy parts of the Amazon rainforest. It’s nocturnal and mostly eats worms, large insects, other spiders, amphibians like frogs and toads, and occasionally other small animals like lizards or even snakes. And yes, every so often it will catch and eat a bird, but that’s rare. Birds are a lot harder to catch than worms, especially since the Goliath birdeater lives on the ground, not in trees.

Because it’s so large, the goliath looks like it would be incredibly dangerous to humans. It does have fangs and can inflict a venomous bite, but it’s not very strong venom. The danger comes from a very different source, because the goliath birdeater is famous for its urticating spines.

Many species of tarantula have special setae, hairlike structures called urticating spines, that can be dislodged from the body easily. If a tarantula feels threatened, it will rub a leg against its abdomen, dislodging the urticating spines. The spines are fine and light so they float upward away from the spider on the tiny air currents made by the tarantula’s legs, and right into the face of whatever animal is threatening it. The spines are covered with microscopic barbs that latch onto whatever they touch. If that’s your face or hands, they are going to make your skin itch painfully, and if it happens to be your eyeball you might end up having to go to the eye doctor for an injured cornea. Scientists who study tarantulas usually wear eye protection.

The goliath birdeater tarantula is considered a delicacy in northeastern South America. People eat it roasted. Apparently it tastes kind of like shrimp.

Next, Owen and Aksel wanted to learn about fire ants. I couldn’t believe that we’ve never talked about fire ants before!

Fire ant is the name for any of the more than 200 species in the genus Solenopsis, but it’s typically used to refer to the species Solenopsis invicta. It’s native to tropical South America but has been introduced to parts of North America, Australia, China, Taiwan, India, Africa, and many other places where the climate is tropical or sub-tropical.

The fire ant initially became so invasive due to Spanish galleons in the 16th century, which carried trade goods around the world. A ship that’s meant to carry a lot of cargo is built so that it needs to be weighted down to a certain degree to sail safely. A lot of times if a Spanish ship didn’t have enough goods in its hold to make it weigh enough, the captain would bring a few tons of soil onboard to make up the difference. Then, when the ship got to its next port where it was supposed to pick up new cargo, it would just dump the dirt wherever it was. It didn’t matter to the fire ant if the dirt was dumped into the water, because fire ants are prepared for their nests getting flooding. They cling together and form huge rafts that the wind pushes to shore. But more often, the dirt would get dumped on land for other ships to re-use.

A team of scientists figured out where the invasive fire ant populations came from by comparing the genetic signatures of 192 different populations. They hypothesized that the ants with the highest genetic diversity were the original population, and that as the ants were moved around the world by ship, genetic diversity would get lower and lower, since all the ants were descendants of the original colony or colonies transported accidentally in the dirt. They mapped out the genetics, then compared the results to Spanish trade routes in the mid-1600s, and it all matched up.

The fire ant made it to the United States in the late 1930s or early 1940s, the West Indies around 1980, and Australia around 2001. These days a lot of fire ants end up transported to new areas in golf course sod imported from Florida.

A fire ant colony consists of a queen, thousands of worker ants, and larger soldier ants that protect the workers and especially the queen. Some colonies have more than one queen. The ants eat anything, including seeds and insects, and even small animals, but also including dead animals they find. The colony can have as many as a quarter million ants. The nest is underground and entrances can be far from the nest itself, and nests can be so large that they can cause structures built over them to collapse.

Invasive animals of any kind aren’t good for the native animals, and the same is true for the fire ant. The fire ant specializes in colonizing areas where humans have disturbed the ground, whereas native ants often have trouble surviving in disturbed areas. The fire ants crowd out native ants and can destroy some native plants.

But the main reason why people don’t like fire ants is that they bite and they’re venomous. The bites cause a burning sensation and painful swelling, but some people are allergic to the venom and can actually die from ant bites. Luckily, that’s rare, but the bites are still painful.

Some countries have spent millions of dollars trying to eradicate the fire ant, including Australia and New Zealand. New Zealand seems to have succeeded, but Australia is still struggling to get the invasion under control. Fortunately, a lot of animals eat fire ants, which helps. One of the animals that especially loves to eat fire ants is the wolf spider, so now we’ve come full circle in this episode.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. 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!

If you are wishing that I’d gone into more detail about fire ant attacks, you might like the TEETH podcast. It’s the only podcast where you’ll hear wild animal attack stories directly from the survivors, hosted by a wilderness guide and attack survivor himself. I’ll put a link in the show notes so you can go listen. It’s appropriate for all ages. I don’t think they’ve actually covered a fire ant attack, but they’ve got lots of other fascinating accounts.

Episode 415: Animals with Names

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This week we’re going to learn about some animals that seem to have individual names!

Further reading:

Bottlenose dolphins can use learned vocal labels to address each other

How Do Dolphins Choose Their Name?

Vertical transmission of learned signatures in a wild parrot

Baby Parrots Learn Their Names from Their Parents

Study: African Elephants Address Each Other With Name-Like Calls

Marmoset Monkeys Use Names to Communicate with Each Other

The green-rumped parrotlet (photo by Rick Robinson, taken from this site):

Show transcript:

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

This week we’re going to learn about some animals that seem to be using names to refer to other individuals or themselves.

Let’s start with bottlenose dolphins, because they’re well-studied and scientists have known about this particular aspect of their society for over a decade. Every bottlenose dolphin has a signature whistle that identifies it to other dolphins. The signature whistles can be complex and the dolphin may add or change details to indicate its mood or other information. It’s not precisely a name in the way humans would think of it, but it is an identifier.

The dolphin creates its own signature whistle when it’s young. Some dolphins pattern their whistles on their mother’s signature whistle, while others mimic their siblings or friends. Some seem to pattern theirs on a distant acquaintance, which sounds to me like they just like something about an unusual whistle and decide to incorporate it into their own whistle. As dolphins grow up, females typically don’t change their whistles, but males often do. Male dolphins often pair up together and remain bonded, and a pair may change their signature whistles to be similar.

When a dolphin is trying to find a friend it can’t see, it will mimic that friend’s signature whistle. If a mother can’t see her calf and is worried, she’ll do the same, and her calf will answer by repeating its signature whistle. A lost calf will imitate its mother’s whistle. But it’s even more complicated than it sounds, because a group of dolphins who get together to forage may choose a shared whistle that the whole group uses. This helps them coordinate their behaviors to work together. Each member of the group uses a slightly different version of the group whistle, which means that each member can identify who’s speaking.

Other cetaceans seem to use a similar kind of name. Sperm whales, for instance, have a unique click sequence that they use to announce themselves when approaching other whales. The signature clicks always appear at the beginning of a sequence and don’t vary.

Bottlenose dolphins and many other cetaceans are extremely social animals. So are parrots. Studies of parrot calls indicate that parrots appear to have signature calls that they use the same way as dolphins do, to identify themselves to other parrots and as a way for other parrots to call for them. A study of wild green-rumped parrotlets in Venezuela discovered that the birds give a unique signature call to each baby while it’s still in the nest, and the baby continues to use its call its whole life, often with small changes.

The study set up video cameras to monitor 16 nests of a large wild population of the parrots. The population has been well studied and is used to using nesting tubes that scientists have set up for them. This makes it easier for the scientists to monitor nesting behaviors. In this case, to test whether the names had something to do with genetics or not, the scientists sneakily moved half of the eggs from one nest to another, so that half the parents unknowingly raised some chicks that weren’t actually related to them.

Despite the egg switcharoo, all the chicks were given names that were similar to the parents’ signature calls. The parents started using a specific signature call soon after the eggs hatched, and the babies started imitating it. Gradually each baby added its own specific flourish to the call that made it their own, so while you can say that the parents named their babies, it’s just as true to say that the babies named themselves. The parrots use the signature calls to announce themselves, but also to call for friends, siblings, and parents.

Elephants are also extremely social animals. Recent studies of African savanna elephant calls indicate that elephants also have an identifying rumble sound that acts as a name. In fact, it acts more like a name as humans use names than the signature sounds made by dolphins and parrots. An elephant will use a specific rumble when addressing another elephant, but the rumble isn’t the speaker’s name, it’s the recipient’s name. It’s the difference between me saying, “Hi, I’m Kate. How are you?” and me saying, “Hi, Kelly, how are you?” when I’m talking to my friend Kelly. Dolphins and parrots seem to be saying something like, “Kate here, I’m swimming this way.”

Marmosets seem to use names the same way that elephants do. Marmosets are a type of small monkey native to Central and South America, which live in treetops and eat fruit and other plant material, and the occasional insect. A 2024 study found that marmosets that know each other address individuals with specific sounds, whether or not they’re related.

All the animals we’ve talked about today are incredibly social, just like humans are. In the case of dolphins, parrots, and marmosets in particular, it’s easy for individuals to travel and forage together but be out of sight of one other. Having a way to track friends and family members when you can’t see them is important to keep a group together.

Studies about animals using names are becoming more common, with both the marmoset study and the elephant study published in 2024. It may not seem like a big deal, but using a specific vocal label for a specific individual is a huge indicator of linguistic intelligence. We haven’t known a lot about it before recently because the recordings of animals communicating was time-consuming and difficult to categorize. Now we have sophisticated computer programs that can compile the information for us, so that scientists can study it more easily. I wouldn’t be a bit surprised if more and more studies start finding animals that use names.

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 414: Two Marvelous Frogs

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Thanks to Eilee and Alexis for their suggestions this week, two amazing frogs!

Further reading:

Paradoxical frog: The giant tadpole that turns into a little frog

Fungus is wiping out frogs. These tiny saunas could save them.

How to build a frog sauna

The paradoxical frog [photo by Mauricio Rivera Correa – http://calphotos.berkeley.edu, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=6703905]:

The Vietnamese mossy frog [photo by H. Zell – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=81804225]:

Show transcript:

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

Let’s start 2025 off right with an episode about frogs! Thanks to Alexis and Eilee for their suggestions.

Let’s start with Eilee’s suggestion, the paradoxical frog. The paradoxical frog is a type of tree frog that lives in South America. Like other frogs, it likes ponds and shallow lakes. Some individuals are green and some are brown, and a frog may have darker stripes or splotches, or might just be plain. The tadpoles eat algae and other tiny food, while the adults eat insects.

As with most frogs, the paradoxical frog hatches into a larval stage called a tadpole or pollywog, which is fully aquatic. It later metamorphoses into its adult form as a frog. Most tadpoles start out very small and grow larger, then metamorphose into a juvenile frog which then grows to fully adult size. But while the paradoxical frog’s tadpole starts out small, it can grow to as much as 11 inches long, or 28 centimeters! It’s the largest tadpole in the world as far as we know.

So how big is the adult frog if the tadpole is so enormous? About 3 inches long, or 7.5 cm, from snout to vent. That’s why it’s called the paradoxical frog, because a paradox is something that seems contradictory to expectations. Instead of the ordinary way of things, where a small tadpole grows into a bigger frog, in this case a big tadpole grows into a smaller frog. It’s sometimes called the shrinking frog.

One interesting detail is that not all of the tadpoles are that big. If a female lays her eggs in a small body of water that’s likely to dry up, or that doesn’t have a lot of food available, or if there are a lot of predators in the water, the tadpole metamorphoses quickly and doesn’t grow very big. But if the tadpole is in a better location it matures much more slowly, which allows it to reach much larger size before metamorphosing.

I should also mention that the 11-inch-long tadpole that is the largest ever measured was actually raised in captivity. In the wild, the largest paradoxical frog tadpole ever measured was 6 ½ inches long, or almost 17 cm. That’s still really big, but not that ridiculously big. But the confusing thing is that the tadpole is big and bulky, up to four times the size of the adult frog. Where does all that mass go after it transforms?

Early scientists who learned about the paradoxical frog wondered the same thing. They were so confused that they suggested that the frog actually came first and later metamorphosed into the tadpole, which then metamorphosed into a fish. But the main reason the tadpole is so long is its tail. When it metamorphoses into a frog, it absorbs the tail and therefore appears to shrink. The bulkiness of the tadpole’s body matches the bulkiness of the frog’s body. And unlike most frogs, which metamorphose into juvenile frogs that still have some growing to do, the paradoxical frog metamorphoses into a completely adult frog. It’s as big as it will ever get and fully mature, ready to mate and lay eggs.

Next, Alexis wanted to learn about the Vietnamese mossy frog. It lives in parts of Vietnam, Laos, and other nearby areas. It prefers mountainous rainforests and the female often chooses to lay her eggs in a tree hollow or even a rock cavity where water has collected. Instead of laying her eggs in the actual water, though, she lays them on rocks or branches above the water. The eggs don’t dry out because of the high humidity in rainforests, and when they hatch, the tadpoles fall into the water.

The tadpoles take a long time to mature, anywhere from four to eight months depending on how warm it is while they’re developing. They grow quite large, although not anywhere near the size of the paradoxical frog tadpole.

A big female Vietnamese mossy frog can grow up to 3 ½ inches long, snout to vent, or 9 cm, and is chubby and round. It’s nocturnal and spends the day hiding on mossy rocks or among plants in the water, then comes out at night to hunt insects like crickets as well as other small animals like worms.

The reason it’s called the mossy frog is because it looks for all the world as though this frog is covered in moss, or maybe is just made out of moss. It’s green and brown in color and its skin is covered in little bumpy structures called tubercules. This helps it blend in incredibly well in the rainforest, where moss is pretty much everywhere. If it feels threatened and it can’t jump into the water to hide, it will play dead.

This is what a Vietnamese mossy frog sounds like:

[frog beeping]

As we’ve talked about in other frog episodes, frogs throughout the world are declining in numbers because of a fungus that infects their skin. The effects of this fungus are worse in cold weather, so a team of scientists speculated that helping the frogs stay warm might help them stay healthier in winter and even help them recover from the infection. They tested their hypothesis by offering infected frogs a variety of temperatures in their enclosure. The frogs could pick where they wanted to spend their time. The frogs liked the warm areas but didn’t spend all their time in them, but they all recovered from the infection. Frogs who were given an overall warm environment also recovered, but not as fast. Frogs who had an ordinary enclosure without warmer areas remained infected with the fungus. Even better, frogs who had recovered from infection with the warm environment also showed resistance to later infections.

The team worked to develop plans that allow people to easily build what they call frog saunas. They don’t require electricity or fuel, just sunshine. When the saunas are placed near ponds or other areas with frogs, the frogs find them quickly and use them. There’s a link in the show notes if you want to learn how to make a frog sauna for your own back yard.

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 413: The Great American Interchange

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Thanks to Pranav for suggesting this week’s massive topic!

Further reading:

When did the Isthmus of Panama form between North and South America?

Florida fossil porcupine solves a prickly dilemma 10-million years in the making

Evidence for butchery of giant armadillo-like mammals in Argentina 21,000 years ago

Glyptodonts were big armored mammals:

The porcupine, our big pointy friend:

Show transcript:

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

This week, at long last, we’re going to learn about the great American interchange, also called the great American biotic interchange. Pranav suggested this topic ages ago, and I’ve been wanting to cover it ever since but never have gotten around to it until now. While this episode finishes off 2024 for us, it’s the start of a new series I have planned for 2025, where every so often we’ll learn about the animals of a particular place, either a modern country or a particular time in history for a whole continent.

These days, North and South America are linked by a narrow landmass generally referred to as Central America. At its narrowest point, Central America is only about 51 miles wide, or 82 km. That’s where the Panama Canal was built so that ships could get from the Atlantic Ocean to the Pacific and vice versa without having to go all around South America.

It wasn’t all that long ago, geologically speaking, that North and South America were completely separated, and they had been separated for millions of years. South America was part of the supercontinent Gondwana, while North America was part of the supercontinent Laurasia.

We’ve talked about continental drift before, which basically means that the land we know and love on the earth today moves very, very slowly over the years. The earth’s crust, whether it’s underwater or above water, is separated into what are called continental plates, or tectonic plates. You can think of them as gigantic pieces of a broken slab of rock, all of the pieces resting on a big pile of really dense jelly. The jelly in this case is molten rock that’s moving because of its own heat and the rotation of the earth and lots of other forces. Sometimes two pieces of the slab meet and crunch together, which forms mountains as the land is forced upward, while sometimes two pieces tear apart, which forms deep rift lakes and eventually oceans. All this movement happens incredibly slowly from a human’s point of view–like, your fingernails grow faster than most continental plates move. But even if a plate only moves 5 millimeters a year, after a million years it’s traveled 5 kilometers.

Anyway, the supercontinent Gondwana was made up of plates that are now South America, Africa, Australia, Antarctica, and a few others. You can see how the east coast of South America fits up against the west coast of Africa like two puzzle pieces. Gondwana actually formed around 800 million years ago, then became part of the even bigger supercontinent Pangaea, and when Pangaea broke apart around 200 million years ago, Gondwana and Laurasia were completely separate. North America was part of Laurasia. But Gondwana continued to break apart. Africa and Australia traveled far away from South America as molten lava filled the rift areas and helped push the plates apart, forming the South Atlantic Ocean. Antarctica settled onto the south pole and India traveled past Africa until it crashed into Eurasia. By about 30 million years ago, South America was a gigantic island.

It’s easy to think that all this happened just like taking puzzle pieces apart, but it was an incredibly long, complicated process that we don’t fully understand. To explain just how complicated it is, let’s talk for a moment about marsupials.

Marsupials are mammals that are born very early and finish developing outside of the mother’s womb, usually in a special pouch. Kangaroos, wallabies, koalas, wombats, and Tasmanian devils are all marsupials, and all from Australia. But marsupials didn’t originate in Australia and are still present in other parts of the world.

The oldest known marsupial appears in North America about 65 million years ago, which was part of the other supercontinent on Earth at the same time as Gondwana, called Laurasia. About the time marsupials were spreading out across Laurasia, from North America all the way to China, Laurasia and Gondwana were connected for a while along the northern edge of South America. Animals were able to cross from Laurasia to Gondwana before the two supercontinents split apart again. Marsupials spread from Laurasia and across Gondwana before the continent of Australia separated about 50 million years ago. Marsupials did so well in Australia that researchers think that before Australia was fully separated from Gondwana, marsupials actually started spreading back out of Australia and into Gondwana again.

While marsupials were doing extremely well in Australia, in South America, birds were the dominant vertebrate for a long time. We talked about terror birds in episode 202. Phorusrhacidae is the name for a family of flightless birds that lived from about 62 million years ago to a little under 2 million years ago. They were carnivores and various species ranged in size from about 3 feet tall to 10 feet tall, or 1 to 3 meters, and had long, strong legs that made them fast runners. The terror bird also had a long, strong neck, a sharp hooked beak, and sharp talons on its toes.

Other birds in North America were likewise huge, but could fly. Those were the teratorns, which are related to modern New World vultures. Since they had huge wingspans and could fly long distances easily, they could just fly between North and South America if they wanted to, so teratorns were found on both continents starting around 25 million years ago. They only went extinct around 10,000 years ago. The largest species known, Argentavis magnificens, lived in South America around six million years ago. It’s estimated to have a wingspan of at least 20 feet, or 6 meters, and possibly as much as 26 feet, or 8 meters. That’s the size of a small aircraft.

In addition to giant predator birds, South America had crocodilians that could grow over 30 feet long, or 9 meters, and possibly as much as 40 feet long, or 12 meters. And, of course, it had ancestral forms of animals we’re familiar with today, like sloths, anteaters, armadillos, opossums, monkeys, capybaras, and lots more. Some of these were incredibly large too, like the giant ground sloth that was as big as an African elephant and the glyptodon that was related to modern armadillos. Glyptodon had a huge bony carapace and rings of bony plates on the end of its thick tail that made it into a club-like weapon, and it was the size of a car. Both the giant ground sloths and the glyptodonts were plant-eaters, as were the notoungulates.

The notoungulates are an extinct order of hoofed animals that lived throughout South America. They were probably most closely related to rhinoceroses, horses, and other odd-toed ungulates, but they’re completely extinct with no living descendants. Some were tiny and actually looked and probably acted more like rabbits than horses, while others were massive. We talked about trigodon in episode 387, and it and many of its close relations in the family Toxodontidae were the size and build of a modern rhinoceros. Trigodon even had a small horn on its forehead. A closely related group, Litopterna, is also a completely extinct order of ungulates, which were mostly smaller and more deer-like than the notoungulates.

The Pleistocene is also called the ice age, but it’s more accurate to say that it was a series of ice ages with long periods of warmer weather in between–tens of thousands of years of warmer climate, then a colder cycle that lasted tens of thousands more years. When the glaciers were at their maximum, with ice sheets covering some parts of the world over a mile thick, or a kilometer and a half, sea levels were considerably lower because so much of the world’s water was frozen solid. That exposed more land that would ordinarily be partially or completely underwater, and it also led to a dryer climate overall. At the same time, volcanic activity in the ocean separating what is now North and South America had been building up volcanic islands for millions of years. All these factors and more combined to form the Isthmus of Panama, also called Central America, that is basically a land bridge connecting the two continents.

This started around 5 million years ago and the isthmus was fully formed by about 3 million years ago, or at least that’s the most accepted theory right now. A 2016 study suggested that the land bridge started forming far earlier than that, possibly as early as 23 million years ago, possibly 6 to 15 million years. Studies are ongoing to learn more about the timeline.

What we do know is that once the land bridge opened up, animals started migrating into this new area. Animals from North America migrated south, and animals from South America migrated north. It didn’t happen all at once, of course. It was a slow process as various animal populations expanded into Central America over generations. Some animals had trouble with the climate or couldn’t find the right foods, while others did really well and expanded rapidly.

The ancestors of some animals that made it to North America and are still around include the Virginia opossum, the armadillo, and the porcupine. Meanwhile, the ancestors of llamas, horses, tapirs, deer, canids, felids, coatis, and bears traveled to South America and are still there, along with many smaller animals like rodents. Many other animals migrated, survived for a while, but later went extinct. This included a type of elephant called the gomphothere and saber-toothed cats that migrated south, while ground sloths, terror birds, glyptodonts, capybaras, and even a type of notoungulate migrated north.

You may notice that more animals that migrated south survived into modern times. South America was much warmer overall than North America, and most animals that traveled north had trouble adapting to a colder climate and competing with animals that were already well-adapted to the cold. Animals traveling south encountered warmer climates early, and if they were able to tolerate hot weather they didn’t have to worry about any climactic shocks on the rest of their journey south. As a result, North American animals were able to establish themselves in larger numbers, which helped them adapt even faster since more babies were being born and surviving.

One South America to North America success story is the porcupine. Porcupines are rodents, and there are two groups, referred to as old world and new world porcupines. Those are not great terms but that’s what we have right now. The old world porcupines are found in parts of Africa, Asia, and Italy, although they were once more widespread in Europe, while new world porcupines are found in parts of North and South America. Old world porcupines live exclusively on the ground and are larger overall than new world ones, which spend a lot of time in trees. Surprisingly, the two groups are only distantly related. They evolved spines separately. They’re also only very distantly related to hedgehogs.

The one thing everyone knows about the porcupine is that it has quills, long sharp spines that make hedgehog spines look positively modest. Porcupine quills are dangerous. They’re modified hairs, and actual hair grows in between the quills, but they’re covered in strong keratin plates and are extremely sharp. They also come out easily and regrow all the time. A porcupine can hold its spines down flat so it won’t hurt another porcupine, which is what they do when they mate.

Only one species of porcupine lives in North America, called the North American porcupine. It lives throughout much of the northern and western part of the continent, from way up in the far north of Canada down to central Mexico, although it doesn’t live in most of the southeast. We don’t know if the North American porcupine developed after South American porcupines migrated north, or if it developed much earlier, around 10 million years ago. Porcupine experts have been arguing about this for years, because there aren’t very many porcupine fossils to study.

Then a nearly complete fossil porcupine was discovered in Florida. It was such a big deal that the scientific team that discovered it decided to create an entire college course for paleontology students to help study the specimen. The resulting study was published in May of 2024, and the results suggest that the North American porcupine evolved a lot longer ago than the Isthmus of Panama formed.

The North American porcupine had to change a lot to withstand the intense cold when its ancestors were tropical animals. The North American porcupine is very different from its South American cousins. It spends less time in trees and doesn’t have a prehensile tail, it eats a lot of bark instead of mostly leaves, and it has thick insulating fur between its quills. The fossilized specimen discovered in Florida still had a prehensile tail and didn’t have the strong jaw it needed to gnaw bark off trees, but it already showed a lot of adaptations that are seen in the North American porcupine but not in South American species.

Ultimately, of course, a lot of large animals went extinct around 12,000 to 10,000 years ago, the end of the Pleistocene. Animals like mammoths that were well-adapted to cold died out as the climate warmed, and so did their predators, like dire wolves and the American lion. The notoungulates and other megaherbivores in South America went extinct too.

One animal that I haven’t mentioned yet that migrated south successfully was Homo sapiens. Maybe you’ve heard of them. Until very recently, the accepted time frame for humans migrating into South America was about 16,000 years ago, although not everyone agreed. But in July of 2024, a new study pushed that date back to 21,000 years ago.

The study examined glyptodont fossils found in what is now Argentina. The fossils were found on the banks of a river and were determined to show butchering marks from stone tools. The bones were dated to almost 21,000 years ago, which means that humans probably moved into South America a lot earlier than that. It takes time to travel from Central America down to Argentina.

One detail most people don’t know about when it comes to the Great American Interchange is how marine animals were affected. It was exactly opposite for them. Instead of a new land to explore, which caused very different animals to encounter each other for the first time, the Isthmus of Panama cut populations of marine animals from each other. They’ve been evolving separately ever since. So I guess whether a land bridge is bad or good depends on your point of view.

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 409: Guinea Pigs and Capybaras

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Thanks to Mary, Mila, and Riley for their suggestions this week!

Further reading:

Comfortable and dermatological effects of hot spring bathing provide demonstrative insight into improvement in the rough skin of Capybaras

Comfort of capybaras determined by SCIENCE:

An especially attractive guinea pig:

Guinea pigs come in lots of colors, patterns, and fur types [picture taken from this excellent site]:

Show transcript:

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

This week we’re going to learn about two rodents, one small and one big. Thanks to Mary and Mila who both suggested the guinea pig, and thanks to Riley who suggested the capybara.

This episode is a bit unusual because part of it comes from a Patreon episode from 2023. Like, literally a big chunk of this episode is the original audio from that one, and you’ll be able to tell the difference in audio and know just how lazy I was this week. The episode actually came together in an unusual way too. Riley’s parent emailed me last week with some new suggestions, including capybaras, but wasn’t sure if we had already covered the topic. I thought we had, but of course there’s always more to learn about an animal. Well, since this is the beginning of a new month I was on the Patreon page to upload the December episode, and while I was there I did a quick search for capybaras and discovered the episode I was thinking of. I decided to add some more information about guinea pigs to it since I already mention guinea pigs a lot in that episode, and here is the result!

The capybara is a rodent, and a very big one. It is, in fact, the biggest rodent alive today. To figure out just how big the capybara is, picture a guinea pig. The guinea pig is also a rodent, native to the Andes Mountains in South America. No one’s sure why the guinea pig is called that in English, since it doesn’t come from Guinea and doesn’t have anything to do with anything else called guinea, but as someone who had two pet guinea pigs when I was a kid, I know exactly why they’re called guinea pigs. This is what an actual pig sounds like:

[pig squealing]

And this is what a guinea pig sounds like:

[guinea pig squealing]

Also, it’s sort of shaped like a pig. The guinea pig is a chonky little animal with short legs, only a little stub of a tail, and little round ears. Its face is sort of blocky in shape and it has a big rounded rump, similar to that of a capybara. The guinea pig is actually closely related to the capybara, and is a pretty good-sized rodent in its own right. It grows about 10 inches long, or 25 cm, on average, and roughly half that size tall.

The guinea pig has been domesticated for at least 7000 years, but it wasn’t domesticated for people to keep it as a pet. In South America and many other places now, it’s a very small farm animal raised for its meat. Guinea pig has been an important source of protein for all that time, so important that it was considered sacred in many cultures.

In the early 16th century when Europeans started arriving in South America, sailors took guinea pigs with them on ships so they’d have fresh meat on the voyage. But when the cute little animals arrived in Europe, people started buying them as pets.

Guinea pigs eat plants, mostly grass, and are social animals. If you want a pet guinea pig, make sure to get at least two. Like rabbits and some other animals, including the capybara, the guinea pig excretes special pellets that aren’t poop, but are semi-digested pellets of food. The guinea pig eats the pellets so they can pass through the digestive system again and the body can extract as many nutrients as possible from it. What’s left is then excreted as a regular poop pellet.

Even in places where the guinea pig is routinely kept as livestock and eaten, people breed guinea pigs as pets too. The pet variety is smaller than the meat variety and has different markings and different colors. Guinea pigs naturally have short, smooth hair and are usually reddish-brown in color, but different colors, fur length and texture, and white markings have been bred into different varieties. There are even mostly hairless varieties.

Most people these days are familiar with what a guinea pig looks like, but most people are not familiar with what a capybara looks like.

So, picture a guinea pig. Now, imagine it growing and growing and growing until it’s the size of a large dog. Instead of orange and white, or black and white, or any of the other colors and patterns of a pet guinea pig, imagine its fur as being a solid rusty-brown color. The capybara can grow almost 4.5 feet long, or 134 cm, and can stand up to two feet tall, or 62 cm. That is a big rodent!

The capybara lives throughout most of South America, although it doesn’t live in the Andes or in Patagonia. It’s semi-aquatic and spends a lot of time in the water, sometimes even sleeping in the water with just its nose poking up so it can breathe. It can hold its breath for up to five minutes, and of course it swims extremely well. It even has webbed toes. It eats a lot of water plants and also eats grass, fruit, and other plants and plant parts.

The capybara has some features that are typical of rodents, like its teeth. Rodent teeth grow continuously since they’re easily worn down by chewing, especially chewing tough plants like grass. It also has some features that are uncommon in rodents. For instance, it can’t synthesize vitamin C, a trait it shares with the guinea pig and with humans. If a capybara kept in captivity isn’t given fruit and other foods that contain vitamin C, eventually it will develop scurvy.

But the capybara doesn’t otherwise have any resemblance to a pirate. It’s a sociable animal and famously chill. In the wild it lives in groups that can number up to 100 individuals, although up to 20 is more common.

The capybara has a scent gland on its nose called a morillo. The female has a morillo but the male’s is bigger since he scent marks more often by rubbing the gland on plants, trees, rocks, other capybaras, and so on. During mating season, the female capybara attracts a male by whistling through her nose, because who doesn’t like a lady who can whistle through her nose? The capybara will only mate in water, so if a female decides she doesn’t like a male, she just gets out of the water and walks away from him.

The female usually gives birth to four or five babies in one litter. Females with babies, called pups, help care for the babies of their friends. Most often, the pups who are too young to wander around without someone to watch them carefully, stay in a group. One or two females remain close to the pups to watch them while the other mothers find food, and the babysitters trade out every so often. When a capybara pup gets hungry, if its mother isn’t nearby, another lactating female will allow the pup to drink some of her milk. This is rare in most animals, since producing milk takes a lot of energy and a mother animal naturally wants to expend her energy on her own babies. But it’s beneficial for the whole group for capybara pups to be cared for by all the mothers.

Capybaras are big enough that adults have a certain amount of protection from predators, but they do have to worry about animals like jaguars, caimans, and anacondas. Smaller predators like eagles will eat capybara pups if they can catch them. Fortunately the capybara can swim fast and run fast, and with everyone in its group watching out for danger, it’s a lot safer than it is by itself.

The capybara does well in captivity and is a popular animal in zoos, and in some zoos you might even be able to pet one. You’ve probably seen pictures of capybaras relaxing in what looks like a big outdoor tub with tangerines floating in it, or if you’re from Japan or just familiar with Japanese customs, relaxing in a yuzu bath. Hot springs baths, called onsen, are popular in Japan, and in winter when the days are short and chilly, adding a citrus fruit called yuzu to the bath is supposed to help prevent colds and help moisturize the skin. Some zoos in Japan now extend this custom to capybaras, because it’s adorable.

As an added bonus, it turns out that the yuzu bath is really good for the capybara. The capybara is a warm-weather animal, and winters in Japan can be very cold and dry. As a result, the capybara’s skin becomes dry too. Soaking in natural hot springs, with or without yuzu, restores the capybara’s skin to its normal condition, which is a lot more comfortable for the capybara and helps it stay healthy. We know this is the case because of a study published in December 2021 in the journal Nature.

Before we go, here’s one last interesting fact about the guinea pig, to bring us back to the beginning of this episode. The guinea pig is a fully domesticated animal and its wild ancestor appears to have gone extinct. There are related species that resemble a guinea pig, but there are no wild guinea pigs in the world today.

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 405: Anteaters and the Capelobo

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Thanks to Molly and Mila for suggesting the anteater and its relations this week!

Further reading:

How anteaters lost their teeth

The giant anteater has a long tongue and a little mouth, and adorable babies:

The giant anteater has a weird skull [photos by Museum of Veterinary Anatomy FMVZ USP CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=72183871]:

The tamandua is like a mini giant anteater that can climb trees:

The silky anteater looks like a weird teddy bear [photo by Quinten Questel – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=30287945]:

Show transcript:

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

This week we’re going to talk about some unusual mammals, suggested by Molly and Mila. It’s a topic I’ve been meaning to cover for almost two years and now we’re finally going to learn about it! It’s the anteater and its close relations, including a creepy anteater cryptid that would have fit in just fine during monster month.

A lot of animals are called anteaters because they eat ants, but the anteaters we’re talking about today belong to the suborder Vermilingua, meaning “worm tongue.” That’s because they all have long, sticky tongues that they use to lick up ants, termites, and other insects. Anteaters are native to Central and South America and are closely related to sloths, and more distantly related to armadillos.

The sloth and anteater share a common ancestor who lived around 60 million years ago, a little animal that mainly ate worms and insect larvae and probably lived in burrows. Because its food was soft and didn’t need a lot of chewing, when a mutation cropped up that caused its teeth to be weak, it didn’t matter. It wasn’t using its teeth anyway. When the first anteaters evolved from this ancestral species, they didn’t need teeth either, and gradually they lost their teeth entirely. Modern anteaters have no teeth at all.

Sloths also evolved from this weak-toothed ancestor, and sloths eat plants. Plants need a lot of chewing, and most animals that eat plants have really strong teeth, but sloths retained the genetics for weak teeth. They don’t even have an enamel coating on their teeth, and instead of grinding molars, their teeth are basically soft little pegs. Luckily for the sloth, the little peg teeth do continue to grow throughout its life, so it never wears its teeth down so far it can’t chew.

Anteaters, sloths, and their distant relation the armadillo all share the same type of vision from their shared ancestor too. They can’t see colors at all but have good vision in low light, which is why scientists think they all evolved from an animal that spent most of its time underground hunting for worms. Anteaters have strong claws that allow them to dig into termite and ant nests, and armadillos spend a lot of time in burrows they dig. We don’t actually know what the common ancestor of these related animals looked like because we haven’t found any fossils of it yet.

In the past, scientists thought that pangolins and aardvarks were related to anteaters because they all have similar adaptations to a similar diet, but that’s just another example of convergent evolution. We talked about pangolins and aardvarks back in episode 65, as well as the giant anteater.

The giant anteater is the one most people know about. It earns the name giant because it can grow almost eight feet long, or 2 1/2 meters, if you include the tail. Its fur is brown and cream with a distinctive black stripe from its chest to its back that scientists used to think acted as camouflage. Because the black fur is outlined with white, making it stand out, scientists now think it’s used as a warning to potential predators, because the giant anteater can be dangerous. If it feels threatened, it will rear up on its hind legs, using its long tail as a prop, to slash at a predator. Its claws are so big that it knuckle-walks on its forepaws.

The female anteater has one baby at a time and while it’s small, it rides on her back. Its black stripe matches hers exactly so that potential predators don’t notice it. The giant anteater’s tail has especially long, thick fur, and it will wrap the tail over its head like a blanket in cold weather.

You know how a cartoon character can cram its head into a bottle and its head stays bottle-shaped? It kind of looks like the giant anteater did that. Its head is small and its snout is shaped like a tube, with nostrils and a tiny mouth at the end. It can’t open its jaws very far.

Anteaters eat ants, although they also love termites and will eat other small insects and insect larvae. The giant anteater uses its massive front claws to dig into anthills. Then it flicks its tongue really fast, catching insects with a combination of tiny hooklets on the tongue and sticky saliva. An anteater’s tongue is over two feet long, or 60 cm, so long that when the anteater isn’t actually eating, the tongue rolls up at the back of its skull. The base of its tongue is attached not to its throat but to its sternum, also called the breastbone.

A feeding anteater eats as many insects as it can catch in a minute or two, then moves on to find a new anthill. It does this to avoid as many stings and bites as possible. Because the anteater doesn’t have teeth, it crushes insects against the top of its mouth before swallowing them, and its stomach acts like a bird’s crop. The anteater may deliberately eat sand or grit the way birds do to help pulverize the insects it’s eaten. Its eyesight isn’t very good so it hunts mostly by scent.

To conserve energy, the anteater’s body temperature is low to start with and drops when the animal is asleep. This is another trait it shares with its relations, the sloth and the armadillo.

There are three other species of anteater alive today, the silky anteater, and the northern and southern tamanduas. The tamandua, both northern and southern, looks like a miniature giant anteater but is typically less than half its size. The southern tamandua lives throughout much of South America while the northern tamandua lives throughout Central America, and both species look very similar. They don’t have the black warning stripe that the giant anteater has, though, and because they’re smaller and lighter, they can climb trees to find insects, which allows them to live in the same areas as giant anteaters without competing with them for food. They eat ants, termites, and the larvae of lots of other insects, and will also eat fruit. The tamandua has a partially prehensile tail that helps it climb trees.

The silky anteater is also called the pygmy anteater, because it’s the smallest species, only growing about 18 inches long, or 45 cm. That includes its partially prehensile tail. It lives in Central America and much of northern South America, and unlike the giant anteater that prefers savannas and open forests, the silky anteater lives in lowland rainforests because it spends its life in trees.

The silky anteater also doesn’t look much like the giant anteater. It kind of looks like a weird teddy bear with a long tail, and kind of looks like a weird sloth with a long tail. Its fur is short but fluffy, light brown or cream-colored, and some scientists think this makes it look like the seed pod of the silk cotton tree that’s common throughout its range and which it prefers. It sleeps curled up in a ball that also helps it look more like a seed pod.

The silky anteater has two long, sharp claws on its front feet, which it uses to climb trees, break open wasp nests, and defend itself from predators. Its hind feet have four claws that aren’t as long. It eats lots of wasps and wasp larvae, but it also eats other insects and even fruit. It has a tiny head and a long snout, but its snout is nowhere near as long as the giant anteater’s, or even the tamandua’s.

You might not think of any of these anteaters as scary, and in fact the silky anteater is so cute I want to pet it even though that would be a bad idea, but they can definitely be dangerous. The giant anteater in particular can kill jaguars and has even killed humans who try to capture or hurt it. Maybe that’s why one of the forms of the cryptid called the capelobo is a hairy man with a giant anteater’s head and claws.

The capelobo is a legend from Brazil that’s sort of like a Brazilian werewolf. In its animal form it looks like a tapir but with a dog-like head, but it can transform into its humanoid form where it looks like a monstrous giant anteater. It’s supposed to scream in the woods like someone in danger, and when people come to help, it catches them and squeezes them to death. Then it drinks their blood and eats their brains like some sort of terrible anteater zombie-vampire, which is not a phrase I ever thought I’d utter.

One suggestion about the capelobo squeezing people to death is that this is a story to help children stay away from giant anteaters. Remember that they stand up on their hind legs with their arms outstretched when they’re ready to fight. To a little kid, that looks an awful lot like a person with their arms out for a big hug. Don’t hug the capelobo, and don’t hug the giant anteater either.

The capelobo’s body is supposed to be heavily armored or even made of stone, except for its belly button. That’s the only place where it’s vulnerable, so to kill the capelobo, someone has to shoot it right in the naval. That sounds really hard, especially if it’s chasing you. Fortunately, it’s not a real animal—although to be on the safe side, maybe don’t go wandering into the Brazilian forest at night.

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 402: The Hoop Snake and Friends

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Thanks to Nora and Richard from NC this week as we learn about some scary-sounding reptiles, including the hoop snake!

Further reading:

The Story of How the Giant “Terror Skink” Was Presumed Extinct, Then Rediscovered

San Diego’s Rattlesnakes and What To Do When They’re on Your Property

Snake that cartwheels away from predators described for the first time

Giant new snake species identified in the Amazon

The terror skink, AKA Bocourt’s terrific skink [photo by DECOURT Théo – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=116258516]:

The hoop snake according to folklore:

The sidewinder rattlesnake [photo taken from this article]:

The dwarf reed snake [photo by Evan Quah, from page linked above]:

The green anaconda [photo by MKAMPIS – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=62039578]:

Show transcript:

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

As monster month continues, we’re going to look at some weird and kind of scary, or at least scary-sounding, snakes and lizards. Thanks to Nora and Richard from NC for their suggestions this week!

We’ll start with the terror skink, whose name should inspire terror, but it’s also called Bocourt’s terrific skink, which is a name that should inspire joy. Which is it, terror or joy? I suppose it depends on your mood and how you feel about lizards in general. All skinks are lizards but not all lizards are skinks, by the way.

The terror or possibly terrific skink lives on two tiny islets, which are miniature islands. These islets are themselves off the coast of an island called the Isle of Pines, but in French, which I cannot pronounce. The Isle of Pines is only 8 miles wide and 9 miles long, or 13 by 15 km, and is itself off the coast of the bigger island of New Caledonia. All these islands lie east of Australia. Technically the islets where the skink lives are off the coast of another islet that is itself off the coast of the Isle of Pines, which is off the coast of New Caledonia, but where exactly it lives is kept a secret by the scientists studying it.

The skink was described in 1876 but only known from a single specimen captured on New Caledonia around 1870, and after that it wasn’t seen again and was presumed extinct. Colonists and explorers brought rats and other invasive animals to the New Caledonian islands, which together with habitat loss have caused many other native species to go extinct.

But in December 2003, a scientific expedition studying sea snakes around the New Caledonian islands caught a big lizard no one recognized. Once the expedition members realized it was a terror skink, alive and well, they took lots of pictures and videos of it and then released it back into the wild. Since then, more specimens have been discovered during four different expeditions, but only on the islets, not on any of the bigger islands. It’s so critically endangered that its location has to be kept secret, because if someone captures some of the lizards to sell on the illegal pet market, the species could easily be driven to extinction.

The terror skink is gray-brown with darker stripes, a long tail, and a slightly downturned mouth that makes it look grumpy. It grows about 20 inches long, or 50 cm, including its tail. This is really big for a skink, so technically it’s a giant skink.

It gets the name terror skink from its size and from its teeth, which are large and curved like fangs. It mainly eats one particular species of land crab, which is why its jaws are so strong and its teeth are so sharp, so it can bite through the crab’s exoskeleton.

Another lizard with a spooky name that has been presumed extinct is the gray ghost lizard, suggested by Richard from NC. It’s more properly called the giant Tongan ground skink, and it’s native to some more South Pacific islands—specifically, the Tongan Islands. These islands are even farther east from Australia than the New Caledonian islands, and are actually closer to New Zealand than to Australia, although they’re not really very close to either.

The giant Tongan ground skink was described in 1839 from two specimens collected in the late 1820s on Tongatapu Island. They’re the only two specimens known and the lizard is considered extinct, especially considering that these days, the island is almost completed deforested and rats, dogs, and cats have been introduced to it, which has driven many species to extinction.

But after the terror skink was rediscovered, scientists started to wonder if the gray ghost might still be around. It was called the gray ghost because it was so hard to see, since it was dark gray in color. The native Tongan people considered it a good omen if someone saw one, since it was so rare.

A paper published in early 2024 suggests that the gray ghost might be living on some smaller islands where forests still remain, and also suggested that it might be nocturnal and a burrowing skink. That would explain why it was so rarely seen by the people who lived on its island when it was still alive.

We know basically nothing about the gray ghost. Hopefully an expedition to the smaller Tongan islands will rediscover it so we can learn more about it and protect it.

Richard from NC also suggested we talk about the hoop snake, an animal of folklore. I remember reading about it as a kid in a book about American folklore animals, most of which were clearly jokey and not meant to seem real. The hoop snake sounded more realistic.

The hoop snake was supposed to be a long, slender snake that slithered around normally most of the time, but when it needed to move faster, it would grab the end of its tail in its mouth and roll like a wheel, or a hoop. Some versions of the story had the snake rolling along with the tip of its tail pointed forward, and since the tail was supposed to be sharp and venomous, it would roll after you so fast that when its tail stabbed you, you’d drop dead. The only way to escape would be to jump behind a tree. The tail would stab the tree instead and you could run away while the hoop snake was trying to unstick its tail. The venom in its tail was supposed to be so deadly that the tree would turn black and die. Other versions of the story said you had to jump through the snake’s hoop to confuse it, which would allow you to get away safely.

All this is weird, to say the least, but some snakes do have ways of traveling that are unusual. The sidewinder, for instance, is a real species of rattlesnake from the southwestern United States and northwestern Mexico. It grows around 2 ½ feet long, or 80 cm, and has pointy scales, called keeled scales, including a pair above its eyes that make it look like it has little horns. Since it’s a type of rattlesnake, it has a rattle that it can shake to make a loud warning noise. It’s mostly brown in color, or sometimes pinkish, yellowish, or even whitish, with darker stripes or blotches down its back. Its coloration helps camouflage it against the ground, and it will actually change color slightly depending on the temperature. This is something other rattlesnakes can do too.

The sidewinder lives in desert conditions where it has to travel through loose sand, and the sand is also extremely hot. While the snake can travel normally when it wants to, it sidewinds to move quickly over loose sand or very hot sand that might burn it. It lifts most of its body up so that it’s only touching the ground in two places, then undulates its body so that the sections touching the ground constantly move. That way no part of its body has to stay in contact with hot sand for more than a split second. It travels in a path that runs diagonal to the direction its body is pointing. That sounds complicated, but it’s easy for the snake. It’s not even the only snake that can travel by sidewinding. Other desert-living snakes travel across hot sand by sidewinding, including several species from Africa, but just about any snake can do it if they need to. It allows a snake to travel over surfaces that are too slippery for its belly scales to get a grip.

The story of the hoop snake might be based on garbled reports of sidewinders, but it might just be a completely invented animal. The hoop snake story is found in other parts of the world too, especially Australia, although it dates back to at least the late 18th century in the United States.

No snake in the world has the anatomy to allow it to roll like a hoop without hurting itself. But there is one other snake that does something very similar, called cartwheeling. It’s the dwarf reed snake that lives in Malaysia and other parts of southeast Asia. Reed snakes aren’t very well known to science, so this cartwheeling activity wasn’t documented scientifically until recently, with the study published in 2023. Reed snakes are nocturnal and spend most of the daytime hiding under rocks or logs, or buried in dead leaves or sand, so they’re not seen very often by people. The dwarf reed snake is slender and only grows about 10 inches long, or 25 cm.

Some small snakes can jump short distances by pushing their tails against the ground. The dwarf reed snake does something similar, but more complicated. It pushes off with its tail, with its body curved in a sort of S shape. It lands on its head and rolls over completely, head to tail, and then pushes off the ground again with its tail. It can move extremely fast in this way to get away from predators, but it takes a whole lot of energy. But when it’s moving downhill, with gravity on its side, it can continue to cartwheel longer.

Cartwheeling isn’t something the snake does often, and it’s rare that a human would ever observe it. But just like sidewinding, some scientists think cartwheeling might be a motion that more snakes can do if they really need to. Maybe that’s where the hoop snake legend started.

Let’s finish with a suggestion from Nora, who wanted to learn more about the green anaconda. That’s a scary snake for sure, because it happens to be the biggest snake alive today, and almost the longest, as far as we know.

The green anaconda lives throughout much of South America, although not in Patagonia because like most reptiles, it needs warm weather to function. It’s a beautiful olive green with black blotches, and it’s a big, bulky snake. It spends a lot of time in the water, which helps it stay cool in hot weather and helps support its weight comfortably, and its eyes are near the top of its head so it can watch for prey while it’s mostly submerged.

The anaconda is a member of the boa family and is a constrictor. It’s not venomous, but you really don’t want a hug from a hungry anaconda. Its body is bulky because it’s incredibly strong, and once it starts to contract its muscles, whatever it’s constricting has only minutes left to live. It can kill animals as large as caimans, which are a type of crocodile, tapirs, capybaras, deer, and even jaguars. For the most part, though, an anaconda doesn’t want to bother with prey that could potentially hurt it, so it will stick with smaller animals that are still big enough to make it worth the effort. And yes, it is possible that an anaconda in the wild could kill and eat a human, but there’s no reliable evidence that it’s ever happened.

It’s hard to know exactly how long and how heavy an anaconda can get. There are lots of stories of 30-foot, or 9-meter snakes, but that seems to be a wild exaggeration. Snakes are stretchy, and a healthy live snake doesn’t really want to stretch out straight to be measured. A dead snake is even stretchier than a live snake. A shed snakeskin is the stretchiest of all, and usually has stretched out quite a bit when the snake was shedding. A good estimate is that a big female anaconda can grow about 20 feet long, or 6 meters, and can weigh around 250 lbs, or 114 kg. Males are smaller on average, and a wild snake will weigh less than one kept in captivity.

There are definitely larger individual anacondas, especially considering that reptiles continue to grow throughout their lives, but they’re probably not that much longer. This is only a little shorter than the reticulated python, which can definitely grow up to 23 feet long, or 7 meters.

One important detail about the size of the green anaconda is that the biggest snakes live in the Amazon rainforest–but the Amazon rainforest is really hard for humans to navigate safely and most anacondas killed or kept in captivity lived in other parts of South America. So there might easily be anacondas in the rainforest that are much bigger than the ones scientists have been able to measure so far.

In February of 2024, a journal article was published about a 2022 National Geographic nature documentary and scientific expedition to the Amazon basin to find a rumored population of extra-large anacondas. The expedition was led by hunters from the Waorani people, who consider the snakes sacred, and the hunters and their chief were credited as co-authors of the paper, as they should be since they provided so much information.

The scientists were able to examine several fully grown anacondas and take tiny tissue and blood samples to test later. They were astounded at the size of the snakes they found, including one that measured 20 and a half feet long, or 6.3 meters. The hunters reported seeing snakes that they estimated as over 24 feet long, or 7.5 meters, that might have weighed as much as 500 pounds, or 226 kg.

Beyond mere size, though, is something very interesting, which the scientists learned when they got home and ran genetic tests. The anacondas are actually quite different genetically from other anacondas known to science, that live farther south. They described the snake as a new species, which they refer to as the northern green anaconda, but it has actually resulted in a lot of controversy. Some scientists agree that the northern green anaconda is a separate species, others think it’s only a subspecies of the green anaconda, while others think the genetic differences are minor and separating the northern green anaconda from other anacondas isn’t justified by the evidence.

Obviously scientists need to follow up and learn more about the anacondas, but one thing is clear. There are some really, really big snakes out there in the Amazon.

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 398: Repeating Scientific Names

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Thanks to Alexandra, Pranav, Eilee, Conner, and Joel for their suggestions this week!

Velella velella, or by-the-wind-sailor [photo from this page]:

Porpita porpita, or the blue button [photo from this page]:

Cricetus cricetus, or the European hamster, next to a golden hamster:

Nasua nasua, or the South American coati [photo from this page]:

Mola mola, or the ocean sunfish:

Quelea quelea, or the red-billed quelea [photo from this page]:

Show transcript:

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

This week we’re going to learn a little bit about scientific names, and along the way we’re going to learn about several animals. Thanks to Alexandra, Eilee, Conner, Joel, and Pranav for their suggestions!

Alexandra inspired this episode by suggesting two animals, the by-the-wind-sailor and the blue button. Both are marine invertebrates that look superficially like jellyfish, but they’re actually colonial organisms. That means that although they look like a single animal, they’re actually made up of lots of tiny animals that live together and function as one organism.

The blue button is closely related to the by-the-wind-sailor and both are related to siphonophores. Both the blue button and the by-the-wind-sailor spend most of the time near or on the ocean’s surface and have a gas-filled chamber that helps keep them afloat, with stinging tentacles that hang down into the water, but both are made up of a colony of tiny animals called hydroids. Different hydroids have different functions, and all work together to find tiny food that will benefit the entire colony.

The blue button gets its name because its float is round and flat like a button, and often blue or teal in color. It’s quite small, only a little over an inch across, or about 3 cm, and its tentacles are not much longer. The by-the-wind-sailor is a little larger than the blue button, with a blue sail-shaped float that’s only a few inches across, or maybe 7 cm, with stinging tentacles of about the same size. The stings of both organisms aren’t very strong and aren’t dangerous to humans, but they do hurt, so it’s a good idea not to touch one. Since both can be very common in warm ocean waters and they sometimes get blown ashore by the wind in large numbers, it can be hard to avoid them if you’re visiting the beach at the wrong time. They can still sting you if they’re dead, too.

The by-the-wind sailor has the scientific name of Velella velella while the blue button’s scientific name is Porpita porpita. The term for a scientific name that contains the same words is a repeating scientific name, also called a tautonym or tautonymous name, and that’s the subject of this episode.

A scientific name is something we mention a lot but if you’re not sure what it means, it can sound confusing. Every organism with a scientific name has been described by a scientist, meaning it’s been studied and placed somewhere in the great interconnected web of life. The system of giving organisms scientific names is called binomial nomenclature. The first word of the name indicates which genus the organism belongs to, while the second word indicates what species it is. These are called generic and specific names. Some organisms also have a third word in their scientific name which indicates its subspecies.

The reason scientists use a complicated naming system is to make it easier for other scientists to know exactly what organism is being discussed. For example, let’s say a scientist has been studying hamsters in the wild to learn more about them, and publishes a paper about her observations. If she just calls the animal a hamster, someone reading it might assume she was talking about the hamster found in their part of the world, when the paper is actually about a totally different, although closely related, hamster that lives somewhere else. And that brings us to Pranav’s suggestion, the European hamster, whose scientific name is Cricetus cricetus [cry-SEE-tus].

The hamster most of us are familiar with is actually the golden hamster, also called the Syrian hamster, more properly called Mesocricetus auratus. That’s the most common species kept as a pet. We can learn from the different scientific names that the European hamster is in a different genus from the golden hamster, which usually means it’s pretty different in some significant ways.

The European hamster lives throughout parts of Eurasia, especially eastern Europe through central Asia, and used to be extremely common. It’s also called the black-bellied hamster because the fur on its underside is black, while the fur on its upper side is tan or brown with white markings. These days it’s critically endangered due to habitat loss and being killed by farmers who think it hurts their crops. It does eat seeds, vegetables, and some roots, but it also eats grass and many other plants that are considered weeds, as well as insects, including insects that farmers also don’t want in their gardens.

In many respects, the European hamster is a lot like the golden hamster. It carries food home to its burrow in its cheek pouches and stores food in a larder. It hibernates in cold weather but wakes up around once a week to have a snack from its larder, which honestly sounds like the best way to spend the winter. But the European hamster is larger than the golden hamster. Like, a lot larger. The golden hamster is maybe 5 inches long, or 13 cm, which is small enough that you can easily hold it in your hand. The European hamster grows up to 14 inches long, or 35 cm. That’s the size of a small domestic cat, but with a short little hamster tail and short little hamster legs.

Even though an organism’s scientific name only designates genus and species, and subspecies when applicable, it allows scientists to look up a more detailed family tree. Every genus is classified in a family and every family is classified in an order, and every order in a class, and every class in a phylum, and every phylum in a kingdom, and every kingdom in a domain. Almost all of the organisms we talk about in this podcast belong to the kingdom Animalia. The more of these categories an organism shares with another organism, the more closely related they are.

Conner suggested we learn more about the coati, which we talked about in episode 302. The South American coati’s scientific name is Nasua nasua [NAH-sue-uh]. It grows almost four feet long, or 113 cm, which makes it sound enormous, but half of its length is its long ringed tail. It lives in much of South America, especially the northern part of the continent.

The coati is related to the raccoon of North America, and the two animals’ scientific names can help us determine how closely they’re related. The common raccoon’s scientific name is Procyon [PROSE-eon] lotor, so we already know it belongs to a different genus than the coati. But both the genus Procyon and the genus Nasua are classified in the family Procyonidae. So we know they’re closely related, because they belong to the same family, but not as closely related as they’d be if they belonged to the same genus, so we can expect to see some fairly significant differences between the two animals.

The South American coati is diurnal, unlike the nocturnal raccoon. While female raccoons often live in small groups of a few animals that share the same territory, female coatis live in groups of up to 30 animals who forage for food together and are very social. The coati also doesn’t have a set territory. The male coati is completely solitary, while the male raccoon will also live in small groups of three or four animals. Both are omnivorous but the coati eats more fruit and insects than the raccoon does, and the coati doesn’t dunk its food in water the way the raccoon famously does.

The system of binomial nomenclature that we use today was developed by the Swedish botanist Carolus Linnaeus in 1735. We talked about some of his mistakes in episode 123. Linnaeus built on a system developed by a zoologist almost a century before him, but streamlined it and made it easier to use. In the 300 years since Linnaeus came up with his system, many other scientists have made changes to reflect increased knowledge about the natural world and how best to denote it.

I keep saying “organism” instead of “animal,” and that’s because all living organisms may be given a scientific name as they are described. This includes everything from humans to maple trees, from earthworms to harpy eagles, from bumblebees to mushrooms. Linnaeus originally included minerals in his classification system, but minerals don’t evolve the way living organisms do. One group that wasn’t given scientific names until 2021 are viruses. There’s still a lot of controversy as to whether viruses are technically alive or not, but giving them scientific names helps organize what we know about them.

Eilee suggested the ocean sunfish, which has the scientific name Mola mola. Because its scientific name is easy to say, and because there’s also a freshwater sunfish that isn’t related to the ocean sunfish, a lot of people just call it the mola-mola, or just the mola. We talked about it way back in episode 96, so we’re definitely due to revisit it.

The ocean sunfish doesn’t look like a regular fish. It looks like the head of a fish that had something humongous bite off its tail end. It has one tall dorsal fin and one long anal fin, and a little short rounded tail fin that’s not much more than a fringe along its back end. This isn’t even a real tail but part of the dorsal and anal fins. The sunfish uses the tail fin as a rudder and progresses through the water by waving its dorsal and anal fins the same way manta rays swim with their pectoral fins. Pectoral fins are the ones on the sides, while the dorsal fin is the fin on a fish’s back and an anal fin is a fin right in front of a fish’s tail. Usually dorsal and anal fins are only used for stability in the water, not propulsion. The ocean sunfish does have pectoral fins, but they’re tiny.

The ocean sunfish lives mostly in warm oceans around the world, and it eats jellies, small fish, squid, crustaceans, plankton, and even some plants. It has a small round mouth that it can’t close and four teeth that are fused to form a sort of beak. It also has teeth in its throat, called pharyngeal teeth. Its skin is thick and rough like sandpaper with a covering of mucus, and its bones are mostly cartilaginous. It likes to sun itself at the water’s surface, and it will float on its side like a massive fish pancake and let sea birds stand on it and pick parasites from its skin. This also helps it absorb heat from sunlight after it’s been hunting in deeper water.

The female ocean sunfish can lay up to 300 million eggs at a time. That is the most eggs known to be laid by any vertebrate. When the eggs hatch, the larval sunfish are only 2 ½ mm long. Once they develop into their juvenile form, they have little spines all around their thin end, which kind of make them look like tiny stars. If that seems weird, consider that the ocean sunfish is actually related to the pufferfish, although not very closely. The largest adult ocean sunfish ever reliably measured was 14 feet tall, or 4.3 meters, including the long fins, which is a whole lot bigger than 2 ½ mm.

Sometimes after an organism is initially described and named, later scientists learn more about it and determine that it doesn’t actually belong in the genus or family where it was initially placed. If it gets moved to a different genus, its scientific name also needs to change. Some organisms get moved a lot and their scientific names change a lot. But typically, the species name doesn’t change. That’s the case for a little bird from Africa.

Joel suggested a bird called the red-billed quelea [QUEE-lee-ya], whose scientific name is Quelea quelea. When Linnaeus described it in 1758, he thought it was a type of bunting, so he named it Emberiza quelea. Another scientist moved it into a new genus, Quelea, in 1850.

I’d never heard of the red-billed quelea, which is native to sub-Sarahan Africa, but it may actually be the world’s most numerous non-domesticated bird, with an estimated 1.5 billion birds alive at any given moment.

The red-billed quelea mainly eats grass seeds, and unlike the European hamster, it is actually a problem to farmers. The bird doesn’t know the difference between yummy grass seeds and yummy wheat, barley, milt, oats, sunflowers, and other food that humans eat. In fact, some researchers suggest that the bird has become incredibly numerous because it has all this great food to eat that was planted by people.

A flock of red-billed quelea birds can number in the millions. The flock flies until they find grassland or fields with food they like. The first birds land, the birds behind them land a little bit farther along, and so on until all the birds have landed and are eating. But by the time the last birds of the flock land, the first ones have eaten everything they can find, so they fly up and over the rest of the birds until they find fresh grass to land in again. This is happening constantly with the entire flock of millions of birds, so that from a distance the flock’s movement looks like a cloud of smoke rolling across a field.

The red-billed quelea also eats insects, mostly during nesting season. Insects and other small invertebrates like spiders are especially nutritious for nestlings.

The quelea is about the size of a sparrow, which it resembles in many ways, although it’s actually a member of the weaver bird family, Ploceidae. It grows less than five inches long, or about 12 cm, including its tail, and it’s mostly brown and gray. Its beak and legs are orangey-red, and during breeding season the male has a rusty-red head with a black mask on his face.

One subspecies of red-billed quelea is native to western and central Africa. Since it’s a subspecies, it has three words in its scientific name: Quelea quelea quelea.

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 393: Little Spiders

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Thanks to Siya, Zachary, Khalil, and Eilee for their suggestions this week!

The enamel pin Kickstarter goes live on Wednesday, August 14, 2024!!

Further reading:

How spiders breathe under water: Spider’s diving bell performs like gill extracting oxygen from water

Aggressive spiders are quick at making accurate decisions, better at hunting unpredictable preys

Into the Spider-Verse: A young biologist shares her love for eight-legged creatures

A New Genus of Prodidominae Cave Spider from a Paleoburrow and Ferruginous Caves in Brazil

The diving bell spider [photo from this paper]:

Jumping spiders are incredibly cute, even the ones that eat other spiders [photo taken from this excellent site]:

The spoor spider’s web looks like a cloven hoofprint in the sand [photo by JMK – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=39988887]:

Show transcript:

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

I’m excited this week, because on Wednesday my little Kickstarter to fund getting more enamel pins made goes live, and also we’re talking about some weird and fascinating spiders! Thanks to Siya, Zachary, Khalil, and Eilee for their spider suggestions!

A lot of people are afraid of spiders, but don’t worry. All the spiders in this episode are small and completely harmless unless you are a bug. Also, they probably live very far away from you. Personally, I think most spiders are cute.

Let’s start with a spider suggested by Siya, who pointed out that we don’t actually have very many episodes about spiders. Siya suggested we learn about the diving bell spider, a tiny, remarkable animal that lives in parts of Europe and Asia.

The diving bell spider gets its name because it mostly lives underwater but still needs to breathe air, so it brings air with it into the water. A diving bell made by humans is a structure shaped sort of like a big bell that can be lowered straight down into the water on a cable. If the diving bell doesn’t tip to one side or another, the air inside it stays inside and allows a human diver to take breaths without coming to the surface. A diving bell made by spiders is made of silk but is shaped sort of the same, with an entrance at the bottom. The spider builds its bell among water plants to anchor it and keep it hidden. The spider brings air from the surface to replenish the supply of air inside the bell.

The spider does this by surfacing briefly. Its belly and legs are covered with tiny water-repellent hairs, and after surfacing the hairs trap air, so that when it dives back into the water it’s covered with little silvery bubbles. It swims down to its diving bell and rubs the bubbles off its body, which rise into the bell and are trapped there by the closely woven silk. Then it goes back to the surface for more air.

Once the bell is full of air, the spider only needs to replenish the air supply about once a day under normal circumstances. That’s because the bell itself acts as a sort of external gill. It’s able to absorb oxygen from the water quite efficiently, but it still loses volume slowly because nitrogen from the air diffuses into the water. If not for that, the spider probably wouldn’t need to come to the surface at all.

The diving bell is the spider’s home, especially for the female. Unlike most spiders, the female diving bell spider is much smaller than the male and she hunts differently. The male is an active hunter, swimming quickly to catch tiny animals like mosquito larvae, so he’s large and strong but only has a small diving bell. The female spends most of her time in her diving bell and only swims out to catch animals that come too close, or occasionally to replenish the air in her bell.

When the spider leaves its diving bell to hunt, air bubbles remain trapped on its abdomen, which allows it to breathe while it’s hunting too. Then it can dart back to its bell to get more air or hide if it needs to.

When a male finds a female, he will build his diving bell near hers. If she doesn’t object, he’ll build a little tunnel between the two bells so he can visit her more easily. The pair will mate in the female’s bell and she either attaches her egg sac to the inside wall of her bell or will build a little addition onto her bell that acts as a nursery.

The diving bell spider is gray or black in color and even a big male only grows about 15 mm long, head and body size together. His legs are longer. In the water the spiders appear silver because of the bubbles attached to their bodies.

The spider used to be common throughout much of Asia and Europe, but its numbers are in decline due to pollution and habitat loss, since it needs slow-moving streams, ponds, marshes, and other clean freshwater with aquatic plants to survive. It will bite if it feels threatened and some people claim that its bite is painful and leads to symptoms like fever, but there’s not a lot of evidence for the bite being dangerous or even all that painful to humans.

Next, Zachary suggested the Portia spider, and pointed out that it demonstrates “uniquely intelligent hunting.” If it weren’t such a tiny spider, it might be scary because it’s so smart. Fortunately for humans, not only is it even smaller than the diving bell spider, with even a big female no more than 10 mm long counting her head and body together, it’s a spider that eats other spiders.

There are 17 species of portia spider currently known, living in parts of Africa, Asia, Australia, and a lot of islands in southeast Asia. It’s a type of jumping spider and can jump as much as 6 inches, or 15 cm, from a complete standstill. It’s mostly brown with mottled darker and lighter markings that make it look like a bit of dead leaf when it’s standing still. It also has flaps on its legs that help it look less like a spider too.

Looking like a bit of dead leaf helps the Portia spider keep from being eaten by birds and frogs, but it also helps it when hunting prey spiders. Unlike almost all other spiders, the portia spider can travel on the webs of pretty much any species of spider without getting stuck. It will creep into another spider’s web and sneak up on it very slowly, or pretend to be a stuck insect to lure it closer. Most spiders don’t see very well, so they don’t identify the portia as a predatory spider. They either think it’s just a leaf stuck in its web or an insect, until it’s too late.

The portia spider will try many different ways to catch a spider. If one doesn’t work it will use another method, and will continue to try new methods and combinations of methods until it outsmarts the prey spider and can jump on it. The methods it uses can be incredibly complex and often require the portia spider to move away from the prey spider or even out of view of it, but it can remember exactly where the prey spider is and what it wants to do to approach it. Remember, this is an animal about the size of one of your fingernails. It has a teeny brain!

In captive studies, portia spiders are observed to be more or less aggressive depending on the individual. The more aggressive spiders tend to do a better job hunting prey with unpredictable behaviors, while the less aggressive spiders are more patient.

When the portia spider walks, it does so arrhythmically, which helps it imitate a dead leaf being moved by the wind. Some spiders are so nervous of portia spiders that if they sense an arrhythmic movement on their web, even if it’s not a portia spider, they’ll run and hide. For that matter, the portia spider will take advantage of wind and other natural occurrences to get closer to their prey.

In addition to active hunting, female portia spiders will also build funnel webs to catch insects. You know, kind of a side hustle. Any portia spider will spin a simple web to hide behind to rest. Portia spiders are also social, sharing food and even living together.

When the male portia spider wants to find a mate, he spins a little web near a female’s web and shakes his legs to attract the female. If she likes him, she’ll drum on his web to let him know. However, in most species, mating is a death sentence for the male. Remember how last week we talked about the praying mantis and how sometimes the female will actually eat the male after or even during mating? Well, that’s true for most species of portia spider too. In some species the female almost always eats the male. He gets to pass his genes along to the next generation, and she gets a good meal to help her grow healthy eggs.

Next, Leo’s friend Khalil suggested the wandering spider. This is the name given to a big family of spiders that live throughout much of the world. Most of them are quite large and look like tarantulas, especially the Brazilian wandering spider, also called the banana spider. It can have a head and body length of two inches, or about 5 cm, but a legspan of up to 7 inches, or 18 cm. That’s a lot of spider, and this week we’re talking about small spiders, but let’s take a quick detour and find out if the banana spider really is sometimes found in bunches of bananas sold in stores.

The banana spider lives in Brazil and other parts of northern South America and Central America, and that’s where a lot of the world’s bananas are grown. I couldn’t find any good estimates of how many bananas are exported every year, but the United States is the biggest importer of bananas. I’m going to switch completely to imperial measurements for a moment because the amounts I’m about to talk about make no logical sense anyway. About four bananas add up to one pound of weight, and 2000 pounds make up one ton. That means one ton of bananas is approximately 8,000 bananas. In 2023, over 5 million tons of bananas were imported to the United States. That is at least 40 billion bananas!

In comparison, no one seems to be tracking how many spiders are found hiding in banana bunches, but one paper from 2014 documented that of 135 spiders submitted to the scientists for study as having been found in all international shipments, of bananas and everything else, only seven were actually banana spiders. The rest were other kinds of spider, most of them completely harmless. When one is found it gets into the news because it’s so rare.

Spiders don’t live inside the banana peel anyway, and they don’t eat bananas. It’s just that bunches of bananas make good hiding places, and the spiders don’t know that people are going to chop the whole bunch down without even noticing a hidden spider. By the time the bananas get to the store, the big bunches have been cut up into little bunches of a few bananas each, which isn’t a great hiding space for a big spider. So your bananas are safe.

Anyway, the smallest wandering spider is probably in the genus Acanthonoctenus, which are native to Central and South America. A big female only grows about 15 mm long, head and body measured together, although her legspan is much larger. There are other wandering spiders with about the same body size in various genera. The problem is, there are hundreds of known species of wandering spider and probably a lot more that haven’t been discovered yet, but not a lot of people are studying them. We don’t know a whole lot about the smallest species because they’re harder to find and therefore harder to study. Many species have only ever had a single specimen collected. So if you want to become an arachnologist, you might look into wandering spiders for your specialization. Many of them are absolutely gorgeous, with striped legs and bright colors.

Like some other spiders, many Acanthonoctenus spiders will hide on a leaf or tree trunk by lying flat and stretching four of its legs out in front of it and the other four legs behind it. This makes it less spider shaped when a bird or lizard is looking around trying to find a snack.

Next, Eilee suggested the spoor spider, the name for Seothyra, a genus of spiders that live in sandy areas in southern Africa. Females grow up to 15 mm long, head and body together, while males grow up to 12 mm long and are usually considerably smaller than the females. The female can be brown, gray, or tan and may have stripes on her abdomen, while the male is more brightly colored. He can be yellow and black with a rusty-red head, sometimes with white spots on his abdomen.

The male spends most of his time running around finding food, and since he looks a lot like a type of wasp called the velvet ant, he’s in less danger than you’d think considering he’s active during the day. The female spends almost all of her life in an elaborate web that she builds into the sand.

The female excavates a burrow in the sand that can be as much as 6 inches deep, or 15 cm, lined with silk to keep it from collapsing. She gets sand out of the burrow as she constructs it by spinning little silk bags around the sand to carry it out. She leaves the bags of sand around the entrance, and once the burrow is finished, she incorporates the sandbags into the web itself. She spins web sheets and mixes them with sand to make mats around the burrow’s opening, which is hidden, and the spider can lift the web sheets to go in and out. Ideally she stays in the same burrow her whole life, repairing it as needed, because while it’s not an especially big web, it takes her a lot of energy to make.

The female puts sticky strands of silk around the edges of the web, then retreats to the underside of the web sheet or into the burrow if it’s too hot. When an insect gets stuck on the silk, she darts out and kills it, then takes it into her burrow to eat. Mostly she eats ants.

The name spoor spider, also called buck spoor spider, comes from the shape of the female’s web. In most species, the web sheet has two sides in a shallow depression in the sand. Since the web is also covered with and incorporates sand to hide it, the little depression with a rounded double shape at the bottom looks an awful lot like the footprint of an animal with a cloven hoof. The word “spoor” is a term indicating an animal’s track.

The spoor spider female only produces one egg sac in her life, and takes care of it in her burrow until the babies hatch. Then she takes care of the babies by gradually liquefying her own internal organs and regurgitating the liquid so the babies can eat it. When all her organs are gone she dies, naturally, and the babies eat the remainder of her body before venturing out into the world on their own.

Fossilized web sheets very similar to the modern spoor spider’s web have been found dating back 16 million years. Most spiderwebs can’t fossilize, but most spiderwebs aren’t built partly out of sand.

Finally, let’s finish up with a newly discovered spider from South America. I learned about it from Zeke Darwin, a science teacher who makes really interesting videos on TikTok. The spider has been described as a new species, named Paleotoca, and was discovered in Brazil. We know very little about it so far so I don’t have much information to share, but it’s so interesting that I just had to include it.

Paleotoca is pale yellow, although its abdomen has very little pigmentation, and its head and body together measure barely 2 mm. It doesn’t have eyes. You might be able to guess where it lives from its lack of eyes and lack of pigment in its body, but I bet I’m going to surprise you anyway. Paleotoca does live in caves, but technically these caves are burrows. It’s just that the burrows where it lives are extremely large, dug into the sides of hills thousands of years ago by giant ground sloths before they went extinct.

Luckily for the spider, there are also some natural caves in the area and at least one of the spiders has been found living in one. So little Paleotoca isn’t in danger of going extinct just because the burrow-builders are gone.

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 391: Welcome to Snake Island

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Follow the enamel pin Kickstarter here!

Let’s learn about some snakes this week! Thanks to Eilee, BlueTheChickenWing, and Richard from NC for their suggestions.

Further Reading:

Snake Island’s Venomous Vipers Find a New Home in Sao Paulo

‘Rarest Snake’ in the U.S. Hatches at Tennessee Zoo

The golden lancehead [picture from first article linked above]:

The Martinique lancehead/fer-de-lance:

The Louisiana pine snake, and a pine cone:

Show Transcript:

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

After today, the next four weeks will be all about invertebrates, or animals without a backbone, because it’s almost Invertebrate August! But this week let’s learn about some animals that are basically nothing but backbones, snakes! Thanks to Eilee, BlueTheChickenWing, and Richard from NC for their suggestions!

Also, if you like enamel pins even slightly as much as I do, I’m starting a Kickstarter in a few weeks to make some more. These will be bigger than the ones I made a few years ago and will include an aye-aye. Where else are you going to get an aye-aye enamel pin? There’s a link in the show notes if you want to sign up for an email reminder when the campaign goes live in mid-August. https://www.kickstarter.com/projects/kateshaw/familiar-friends-enamel-pins

Anyway, let’s start with Snake Island, suggested by Eilee. Snake Island is off the coast of Brazil in South America, and it’s quite small, only about 106 acres total, or 43 hectares. It’s hilly and a little over half of it is covered with a temperate rainforest, while the rest is grassy or just bare rocks. No one lives there these days and it’s a protected area that only scientists are allowed to visit, with the exception of members of the Brazilian navy who occasionally stop by to maintain the lighthouse that keeps ships from smashing into the rocky coast. Lots of birds live on the island or visit there, but other than that it’s mostly just snakes.

Specifically, the critically endangered golden lancehead pit viper lives on Snake Island and nowhere else in the world. It can grow nearly four feet long, or 118 cm, and is pale gold or golden-brown in color with darker splotches. It’s also incredibly venomous—but no one has ever been bitten by one as far as we know. If somehow you were bitten by one, it probably wouldn’t be a pleasant situation but you also probably wouldn’t die. That’s mainly because the golden lancehead’s venom is adapted to kill birds and reptiles, not mammals. And that’s because there are no mammals living on Snake Island.

The golden lancehead spends most of its time in trees or bushes, hunting for birds. It mainly eats two particular species of small bird that live on the island, although it will also eat other birds, lizards, and invertebrates like insects. Some reports say it will even eat smaller golden lanceheads. There’s another snake that lives on the island, Sauvage’s snail-eater, and the golden lancehead might occasionally snack on one of those. The snail-eater is also present on mainland Brazil and isn’t venomous. You can probably guess that it mainly eats snails. It’s small and thin, lives in trees, and is brownish-yellow with darker stripes and splotches.

The issue with Snake Island and its snakes is that there isn’t that much land available for the snakes to live on, and the forest has been damaged by human activity. Big chunks of forest were cleared by fire when people decided to try growing bananas on the island, which didn’t work very well. No one lives there now, but poachers do occasionally visit the island to catch snakes for the illegal wildlife trade. The golden lancehead is starting to show signs of inbreeding and disease as a result. As if that wasn’t bad enough, because the island is so close to the coast of Brazil, and mainland Brazil has its own problems with deforestation, fewer birds are migrating through the area every year. That means fewer birds stop at Snake Island and the snakes have less to eat.

Some reports claim that the island is so overrun by snakes that you’d encounter one with every step if you visited, but that’s not actually true. The snakes don’t live everywhere, and they spend almost all their time in trees. Recent studies estimate that around 2,000 to 4,000 snakes live on the island, which sounds like a lot until you remember that these are the only golden lanceheads in the whole world! Fortunately, rumors that anyone who sets foot on the island is at risk of being bitten and dying horribly from the golden lancehead’s venom keep a lot of people away. A captive breeding program in São Paulo, Brazil is also working to help the snakes.

The golden lancehead is a type of pit viper, closely related to other pit vipers found in Brazil. Its ancestors were trapped on the island when ocean levels rose at the end of the Pleistocene, around 11,000 years ago, and it’s been evolving separately ever since. Species in the genus Bothrops are also called fer-de-lance snakes, and that brings us to our next suggestion from BlueTheChickenWing.

BlueThe ChickenWing left us a nice review a while back and made two suggestions, one of which is the fer-de-lance. Fer-de-lance is a French term meaning spearhead, or lancehead, as in golden lancehead. The golden lancehead belongs to the genus Bothrops, pit vipers that are found throughout much of Central and South America as well as some Caribbean islands. We’re only going to talk about one other species of fer-de-lance this week, though, Bothrops lanceolatus, also called the Martinique lancehead. It too lives on an island, in this case the Caribbean island of Martinique.

The Martinique lancehead can grow up to 5 feet long, or 1.5 meters, with unverified reports of individuals twice that length. It’s light brown with darker speckles and a paler belly. It lives in forested areas and spends most of its time hidden, waiting for an animal to happen by. Then it strikes! It eats pretty much anything it can catch, including frogs and rats, bats and birds, rabbits, lizards, other snakes, and even large insects. Its venom isn’t as potent as the golden lancehead’s but it’s still dangerous to humans, and unlike the golden lancehead, it can and does occasionally bite people.

The Martinique lancehead is endangered due to habitat loss and poaching. People are naturally afraid of the snake and will kill it when they can, when all it wants is to be left alone to eat animals like rats and other snakes that people don’t want around either. Hospitals in Martinique keep antivenin in stock to treat the 20 or 30 people who are bitten by a fer-de-lance every year. Most people are fine after receiving treatment, but those who can’t get to the hospital in time or who try to treat the bite at home sometimes die.

The Martinique lancehead gives birth to live young, as is the case for other fer-de-lance snakes. The eggs remain inside the mother until the babies hatch, at which point the mother delivers them and they slither away to live on their own.

Speaking of snakes having babies, let’s finish with a suggestion by Richard from NC, who sent me an article that was only published literally two days ago as this episode goes live. This is not about a snake that lives on an island, but it’s so interesting I wanted to include it. It’s about the Louisiana pine snake, which is not venomous, but which is one of the rarest snakes in North America.

The pine snake is a type of constrictor, and like other constrictors it can grow quite large. The largest individual ever reliably measured was over 5 and a half feet long, or 1.8 meters. It’s tan or yellowish in color with a darker brown pattern.

It lives in open pine forests and grasslands in parts of western Louisiana and east Texas, but even when it wasn’t so rare, hardly anyone ever saw one because it spends most of its time underground. It’s specialized to eat a little rodent called Baird’s pocket gopher, and when it’s not actually hunting the gopher, it hangs out in the gopher’s old burrows to stay cool and safe. In winter it hibernates in a gopher burrow, and there’s nothing the gopher can do about that.

Baird’s pocket gopher looks a little bit like a small guinea pig because of its large head, tiny ears and eyes, chunky body, and short legs. It has long claws that help it dig rapidly in the sandy ground it prefers. While the Louisiana pine snake mostly eats the gophers, it will also eat other small animals like frogs, rabbits, and bird eggs when it finds them. The snake is threatened by habitat loss, especially the problem of roads being built through its habitat. A lot of snakes are killed by cars while trying to cross the road. Since the snake usually only lays a few eggs a year, rarely more than five, it’s hard for populations to grow.

Fortunately, the Memphis Zoo in Tennessee is headquarters for a careful captive breeding program of the pine snake. And a few days ago, a baby snake hatched and is doing great! Hopefully more will hatch soon. The babies will be cared for until they’re big enough to be safe from most predators, and then they’ll be released into the wild. So far around 300 captive-born snakes have been released into the wild, increasing the Louisiana pine snake’s chance for long-term survival.

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!