Category Archives: South America

Episode 239: Mystery Crocodiles

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Thanks to Pranav and Max for their suggestions. Let’s learn about some mystery crocodiles (and crocodile mysteries) this week!

Further reading:

Huge prehistoric croc ‘river boss’ prowled waterways

Extinct “horned” crocodile’s ancestry revealed

New species of crocodile discovered in museum collections

Rediscovery of “Lost” Caiman Leads to New Crocodilian Mystery

The Orange Cave-Dwelling Crocodiles

The horned crocodile’s fossil skull:

A baby Apaporis River caiman, looking fierce but cute (picture from link above):

An orange crocodile (later released, picture from link above):

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. We’ve got a crocodile episode this week you can really sink your teeth into. Thanks to Pranav and Max for their suggestions! (Yes, I do have a cold but hopefully I don’t sound too bad. I got a covid test today to make sure it’s just a cold, and it’s just a cold.)

We talked about crododilians in episode 85, so if you want to learn more about the saltwater crocodile or how to tell the American crocodile from the American alligator and so forth, that’s the episode to listen to. This episode is going to talk about mystery crocodiles!

The partial skull of a massive extinct crocodilian discovered in Queensland, Australia over a century ago was finally described in June of 2021. All we have is the partial skull from an animal that lived between 2 and 5 million years ago, but researchers can estimate the size of the whole animal by comparing the dimensions of its skull with its closest living relation. That happens to be an animal called the false gharial that lives on a few islands in South Asia, including Java and Sumatra. It’s the only living member of the subfamily Tomistominae, which used to be common worldwide. The false gharial can grow as long as 16 feet, or 5 meters, but its extinct Australian cousin was much bigger. The new species, Gunggamarandu maunala, may have grown up to 23 feet long, or 7 meters.

A smaller extinct crocodile, called the horned crocodile, lived in Madagascar until only about 1,400 years ago. It grew a little over 16 feet long, or 5 meters. It had two projections at the back of its head that look like horns, although they weren’t actually horns and probably weren’t all that big or noticeable when the crocodile was alive.

Like Gunggamarandu, the horned crocodile’s fossils were discovered almost 150 years ago but only definitively described in 2021. In this case, though, the delay was because no one could decide where the horned crocodile belonged in the crocodilian family tree. The Nile crocodile lives on Madagascar now, and some researchers assumed that the horned crocodile was either a close relation of the Nile croc or its ancestor. Since new evidence points to the Nile crocodile being a fairly recent arrival to the island, that’s not likely, so researchers analyzed the fossil remains and reclassified the horned croc as a member of the dwarf crocodiles in 2007. Finally, though, a research team analyzed the horned croc’s DNA and determined that it belongs in its own genus and is most closely related to the ancestral species of all living crocodiles. This suggests that crocodiles evolved in Africa and spread throughout the world from there.

Researchers aren’t sure what caused the horned croc to go extinct, but it may have been a combination of factors, including a drying climate on Madagascar, the arrival of humans, and the arrival of the Nile crocodile.

Speaking of the Nile crocodile and DNA, a 2011 genetic study of the Nile crocodile resulted in a surprising discovery. The study tested not just DNA samples gathered from 123 living Nile crocodiles but from 57 crocodiles mummified in ancient Egypt. The goal was to see if there were differences between modern crocodiles and ones that lived several thousand years ago, and to determine whether maybe there was a subspecies of Nile crocodile that hadn’t been recognized by science. Instead, they discovered that what was previously known as the Nile crocodile is actually two completely different species!

The Nile croc lives in Africa and is a large, aggressive animal that can grow just over 19 feet long, or almost 6 meters. The West African croc also lives in Africa and is a smaller, less aggressive animal that can grow up to 13 feet long, or 4 meters. Since crocodiles of all species show a lot of variation in size and appearance, no one realized until 2011 that there were two species living near each other. They’re not even all that closely related.

After the finding was published, zoos across the world tested their crocodiles and discovered that a lot of their Nile crocs are actually West African crocs.

Something similar happened more recently, in 2019, when a team of scientists did a genetic study of the New Guinea crocodile. They gathered DNA from 51 museum specimens from 7 different museums, and compared them to living New Guinea crocodiles. They were hoping to determine if there are actually two species of crocodile living in different parts of New Guinea, which had been suspected for a while. It turns out that yes, there are two separate species! Knowing exactly what kinds of animals live in a particular environment helps conservationists protect them properly.

In 1952 a subspecies of the spectacled caiman was discovered by science, called the Apaporis River caiman. It lives in Colombia, South America and is relatively small as crocs go, maybe 8 feet long at most, or 2.5 meters. After that, though, it wasn’t seen again. This was partly due to how remote and hard to navigate its habitat is, and partly due to a dangerous political situation, with rebel forces occupying the jungle where the crocodiles live. A peace treaty signed in 2016 made it safe for scientists to travel to that area at last, and a Colombian biologist named Sergio Balaguera-Reina visited with various indigenous tribes of the area to ask about the Apaporis caiman and learn everything they knew about it.

At night, he and two local people paddled upriver in a canoe and searched for the caimans—and he found lots of them. He caught as many as he could to take DNA samples before releasing them again. When he got home, he tested the DNA and made a surprising discovery. Even though the Apaporis caimans look very different from another subspecies of spectacled caiman found in other parts of South America, their DNA is quite similar. That means the differences, especially the Apaporis caiman’s much narrower snout, are due to selective pressures in its environment. Balaguera-Reina is working on figuring out the causes of the Apaporis caiman’s physical differences.

The Siamese crocodile was once common throughout South Asia, but habitat loss has had a major impact on the species and for a long time it was thought to be extinct in the wild. It grows up to 13 feet long at most, or 4 meters, and is not very aggressive. It’s kept in captivity in crocodile farms, where it’s bred and killed for its meat and skin, but a lot of those farms have multiple species of closely related crocodiles and they can and do interbreed, meaning that the Siamese crocodiles in the farms are most likely hybrid animals.

In 2001 a team of conservationists traveled to Thailand to search for tigers, and one of their camera traps recorded a Siamese crocodile just walking along the river like it was no big deal. The photograph was especially lucky because it shouldn’t have even happened. The camera traps used actual film, not digital cameras which were still expensive and not very good back then. The rolls of film could capture 36 pictures before the film ran out, but the crocodile appeared on the 37th picture. Film is manufactured in long strips, then cut into pieces and rolled up and put in little canisters for a photographer to put in the camera, and the roll is a little longer than it needs to be because the ends have to be anchored in place. This particular strip of film just happened to be long enough to take 37 pictures instead of 36. If it hadn’t been, the conservationists wouldn’t have known the crocodile was still alive.

A follow-up expedition to look specifically for crocodiles discovered more of them. Since then a captive breeding program was set up, and in 2013 the first hatchlings were released into the wild.

Sometimes when a crocodile is killed, interesting things turn up in its stomach. This is what happened in 2019 when a crocodile farm in Queensland, Australia necropsied one of their saltwater crocs to see what he had died of. The croc was over 15 feet long, or 4.7 meters, and was about 60 years old. When they opened up his stomach, they found a piece of metal and six screws, the kind of metal called an orthopedic plate. It’s used to join two pieces of broken bone or strengthen an injured bone so it won’t break.

Medical devices like this are always etched with a serial number, but the metal was inside the croc’s belly for so long that the serial number was corroded off by stomach acid. This would have taken decades to happen, so the crocodile had to have eaten the metal decades ago, possibly as long as 40 years ago.

The farm contacted the police but so far they haven’t been able to trace what might have happened. The croc wasn’t bred on a farm but had been caught wild. The farm owner sent pictures of the plate to a surgeon, who determined that yes, it was probably from a human, not an animal, and that it looks like a type of plate used in Europe. The farm owner hopes the discovery will one day help solve a missing persons case.

Let’s finish with an interesting discovery in the rainforests of Gabon, a small country on the west coast of central Africa. The Abanda caves in the area are extensive, not very well explored, and full of bats and insects. A man named Olivier Testa, a professional explorer who often leads scientific expeditions into remote areas, heard a rumor about a population of orange [I read this as strange instead of orange and was too lazy to fix it] crocodiles living in the cave system. A lot of people would have just laughed, because everyone knows crocs and other reptiles like hot weather, sunshine, and warm water to hunt in. But when Testa got the opportunity to join an expedition into the cave system in 2010, he remembered the crocodiles.

Guess what they found in the cave. I bet you all guessed correctly. There really were crocodiles in the caves, specifically African dwarf crocodiles, and the biggest ones did look slightly orangey in color. Crocs don’t live in caves, but there they were. The following year the expedition returned, and this time they were there to find out more about the crocs.

A crocodile expert named Matthew Shirley came along, and he figured out why the crocodiles were in the cave. There are an estimated 50,000 bats living in the cave system, so many that the crocodiles could basically just reach up and snap bats off the walls to eat. There are lots of crickets in the cave too, and young crocs eat lots of insects.

As for the orange color of the older crocs, that comes from the water in the cave. Bats have to pee just like every other animal does, and where they roost over the water they pee into the water, naturally. So much bat urine actually has an effect on the water composition, turning it extremely alkaline. This affects the skin color of animals that stay in it for a long time, as the older crocs have.

The cave crocodiles appear to spend the dry season in the caves, eating bats and avoiding humans who hunt crocs. During the rainy season, they emerge from the caves to mate and lay their eggs in rotting vegetation outside.

This is the first population of crocodiles ever found that spends time in caves deliberately. Some researchers speculate that the crocodiles could eventually evolve into a new subspecies of dwarf crocodile that’s especially adapted to the cave system.

You know what we call those? We call them dragons.

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at if you’d like to support us that way.

Thanks for listening!

Episode 238: The Pink Fairy Armadillo and Two Adorable Friends

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This week we’ve got three adorable little animals to learn about! Thanks to Simon and Thia, Elaine, and Henry for their suggestions!

Further reading:

Turning the spotlight on the rusty-spotted cat (Wildlife SOS)

The cute and fuzzy pink fairy armadillo:

The cute and fuzzy rusty spotted cat:

The cute and fuzzy baby Arctic tern:

Adult Arctic terns:

Show transcript:

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

This week we’ve got three strange and adorable animals for you, all listener suggestions because I’m getting really behind on those. Thanks this week to Simon and Thia, Elaine, and Henry!

First, Simon and Thia suggested the pink fairy armadillo. That’s one we covered briefly in a Patreon episode back in 2018, but it deserves to be featured in the main feed because it’s so strange and cute. It lives in deserts and grasslands of central Argentina, South America, but since its range is so restricted and it spends most of its life underground and is rarely seen by humans, we don’t know much about it.

The pink fairy armadillo is the smallest armadillo species known. It only grows about 4.5 inches long, or 11.5 cm, small enough to sit in the palm of your hand. It’s protected by a leathery shell that runs from its nose along the top of its head and down its back to its bottom, and the shell is segmented like a regular armadillo’s shell except that it’s a delicate pink. The fluffy fur on the animal’s sides and tummy is white. It has a short spade-shaped tail, but the rear of its body is flattened, and it uses its flat bottom to compress dirt in the tunnels as it digs. It has a small head, short legs, and gigantic front claws. Its hind claws are big too.

It spends almost all of its life underground, digging shallow tunnels and eating small animals like worms, insect larvae, snails, and insects like ants, which it probably hunts by scent. It has a good sense of smell but its eyes are tiny and its ears don’t show at all, although it does have good hearing. It can dig extremely quickly. It loosens the soil with its huge front claws, kicks it back with its hind claws, and then does a quick reverse to tamp the new dirt heap into a firm column with its flat bottom. This keeps the floor of its burrow clear so the armadillo can breathe properly and helps keep the burrow from collapsing.

Almost the only time the pink fairy armadillo surfaces is when it reaches an obstacle it can’t dig through or around, and then its claws are so big it has trouble walking on hard surfaces. This is bad if it tries to cross a road. Most sightings of pink fairy armadillos are of roadkill animals. Sometimes it surfaces after heavy rain when its burrows are flooded.

The reason the pink fairy armadillo’s shell is pink is that blood vessels show through it. Researchers think it can regulate its temperature according to how much blood flows through the vessels beneath the shell. The shell is only attached to the body by a membrane along the spinal column and doesn’t protect it as well as other armadillo shells do, but then it’s almost always underground so the shell probably mostly protects it from rocks and roots.

The pink fairy armadillo doesn’t do well in captivity, usually dying from stress within a day or two of capture, and since it’s almost always underground it can be hard to find and study. It’s threatened by habitat loss, climate change, poaching, and the use of pesticides. It’s extremely sensitive to changes in temperature and soil.

The pink fairy armadillo has a similar-looking but slightly larger relative, the greater fairy armadillo, which can grow up to 7 inches long, or 17.5 cm. It’s also a burrowing armadillo that lives in South America, which has an additional conservation problem. It’s considered by locals to be the spirit of a dead baby, so if a local sees it they usually kill it.

Next, Elaine suggested the rusty spotted cat. It’s a tiny cat that lives in forests and grasslands in South Asia, especially in India and Sri Lanka, and although it resembles a tiny domestic cat, it’s not all that closely related to domestic cats or their wild cousins.

The rusty spotted cat is reddish-gray with darker stripes on the face and small rusty-red spots over most of its body. It’s about half the size of a domestic cat and grows up to 19 inches long at most, or 48 cm, not counting its tail, which adds another 12 inches or so to its length, or 30 cm. This is where I tried to measure my cats with the soft plastic tape measure I use for sewing, but they thought it was a toy so I never did figure out how long they are. Also, my tape measure has holes in it now from claws and teeth. The rusty spotted cat only weighs up to about 4 pounds, or 1.8 kg. Keep in mind that these numbers are for the biggest possible rusty spotted cats. Most are much smaller. They’re basically kitten-sized.

The rusty spotted cat is mostly nocturnal and eats small animals like mice and other rodents, birds, lizards, and insects. It mostly hunts on the ground and mostly only climbs trees to escape predators. It’s a fierce hunter and can be very aggressive despite its small size, so even though it’s really cute and some people want to keep it as a pet, it’s very wild and not friendly. You’re way better off adopting a small domestic cat. Besides, the rusty spotted cat is endangered in the wild due to habitat loss and hunting for its fur, so we shouldn’t be keeping it as pets.

Conservationists are working to protect the rusty spotted cat by educating people who live in the area about what the cat is. While a mother rusty spotted cat is out hunting, she leaves her kittens in a little nest in long grass. If she makes her nest in a cultivated field, like a tea plantation, sometimes a worker harvesting or caring for the plants will find the kittens. People are basically good at heart and want to help baby animals, so a lot of times the worker will take the kittens home thinking they’re abandoned. A conservation group called Wildlife SOS is working to teach people to leave the babies alone, and when they hear about someone who’s found a kitten, they send someone out to learn where the kitten was found and when, and will reunite the kittens with their mother. Wildlife SOS also helps other animals in India, including leopards and elephants. There’s a link in the show notes if you want to find out more and maybe donate to the program to help these adorable teeny-tiny wildcats.

Finally, Henry suggested the Arctic tern, a bird that lives…pretty much everywhere, in fact, not just the Arctic. It breeds along the coasts in the northern parts of the northern hemisphere, including parts of Canada, Greenland, northern Europe, and Siberia, but after its babies are grown and the short northern summer comes to an end, it takes off for the southern hemisphere and spends the winter—which is summer in the southern hemisphere—around South Africa and Australia and New Zealand, all the way down to the Antarctic. When that summer ends, it flies back north to breed again. That’s an astoundingly long migration.

The Arctic tern spends most of its life flying above the ocean, hunting for small animals like fish, krill, amphipods, and crabs. It’s not a picky eater, though. It will also eat worms, insects, and berries, although it mostly eats these land foods when it’s nesting. It’s a beautiful bird that looks a little like a seagull, but is more lightly built and slender than most gulls. It’s white and pale gray with a black cap that extends down the back of the neck, a red bill, and short red legs and webbed feet. Its tail is forked like a swallow’s tail and it has long wings, which allow it to catch even the smallest sea breeze and fly extremely fast. Its wingspan is about 2.5 feet across, or 75 cm.

The Arctic tern mates for life. Even though the male and female have traveled literally around the world separately for most of the year, they both return to the same nesting ground, find each other, and start their summer courtship. The pair will fly high together with the female chasing the male, and then they’ll fly lower where the male will catch a little fish and offer it to the female. On land, they’ll do a little courtship dance where they raise and lower their tail and wings while strutting around together. Finally the pair decides where they want to build a nest.

The nest isn’t fancy, just a little scooped out place in the ground with maybe some grass in it. Parents take turns keeping the eggs warm and defending the nest from potential predators. It’s an aggressive bird and will even attack polar bears and drive them away, even though it’s just a delicate little bird. It will dive at the predator’s face and peck with its strong, sharp bill. Once the babies hatch, both parents feed the chicks until they learn how to fly.

An Arctic tern chick is possibly the cutest bird you will ever see, at least today. It’s gray and white with short legs, and it’s super super fluffy. The coloration helps it blend in with the rocks around the nesting site.

The Arctic tern travels over 40,000 miles every single year, or more than 70,000 km, and still manages to find its way back to the same breeding colony. How does it know where it is and where it’s going? Like many birds, it can sense the earth’s magnetic field. It combines this sense with where the sun is in the sky and can pinpoint exactly where it is in the world and where it needs to go. It’s like having built-in Google Maps.

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at if you’d like to support us for as little as one dollar a month and get monthly bonus episodes. There are links in the show notes to join our mailing list and to our merch store.

Thanks for listening!

Episode 237: Geckos and Other Arboreal Reptiles

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Thanks to Riley, Richard, and Aiden and Aiden’s unnamed friend for suggestions this week! We’re going to learn about some geckos and other reptiles that live in trees. Thanks also to Llewelly for a small correction about lions. Also, I mispronounced Strophurus–it should be more like Stroff-YOUR-us but I’m too lazy to fix it.

Further reading:

Cancer Clues Found in Gene behind ‘Lemon Frost’ Gecko Color

A chameleon’s feets:

A rare healthy lemon frost domestic leopard gecko (photo taken from article linked above):

An ordinary leopard gecko:

I don’t remember what kind of gecko this is (golden spiny-tailed?) but I love it:

A crested gecko looking surprised:

The green iguana:

A black mamba. Watch out!

Flying snake alert!

The draco lizard with its “wings” extended (male) and the draco lizard with its “wings” folded (female):

A parachute gecko showing how it works:

Show transcript:

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

This week we’re going to learn about some reptiles, specifically reptiles that live in trees. This is a suggestion from Riley, who wanted to hear about arboreal reptiles in general and the crested gecko in particular. Thanks also to my brother Richard, who suggested the dragon-tailed gecko. An anonymous reviewer also suggested the leopard gecko so we’ll learn about that one too. Specifically, the anonymous reviewer said “me and my friend Aiden suggest either red foxes or leopard geckos.” We actually covered the red fox in episode 138, about city animals, and in episode 106, about domestication, but we’ve only mentioned the leopard gecko briefly way back in episode 20.

Arboreal animals have some traits in common, whether they’re reptiles or mammals or something else. In general, an animal that spends most of its time in trees is small and lightweight, either has long legs or very short legs, may have a long tail to help it balance, and may also have various adaptations to its feet to help it maneuver through branches.

This is the case with the chameleon, which is arboreal and has weird feet. Its feet look more like mittens. The feet are called zygodactylous, which means it has two toes pointing forward and two pointing backwards. A lot of birds have feet like this too. Chameleons have other adaptations for arboreal life, like prehensile tails that can twine around a twig to help it keep its balance. The chameleon really deserves its own episode some day, so let’s move on to learn about some geckos.

The biggest gecko known grows up to two feet long, or 60 cm, but most are much smaller. There are more than 1,800 species known and they’re all really interesting and honestly, adorable. They’re mostly nocturnal and eat small animals like insects. About 60% of all gecko species have toe pads that allow them to walk up walls and windows and even across ceilings.

Like many other lizards, most geckos species can drop their tail if a predator attacks. The tail thrashes around on its own for several minutes, distracting the predator so the gecko can escape. The gecko later regrows a little stumpy tail, but it can’t drop it a second time. Many species of gecko store fat in the tail, so it needs that tail. A genus of gecko called the fish-scaled gecko, which lives on Madagascar and nearby islands, has big scales that come loose easily if an animal tries to bite it or if a scientist tries to capture it. The predator gets a mouthful of scales while the gecko runs off. The scales grow back eventually and can be lost again.

Scientists are always interested in animals that can regenerate parts of the body, to learn how that works. A study published in 2017 identified the type of cells that allow the gecko to regrow the part of its spinal cord that’s lost with its tail. In 2018, the same team published their discovery that geckos renew brain cells. This is amazing, since humans and many other animals are born with all the brain cells they’ll ever have, and if something happens to injure the brain, the damage can’t be repaired. Maybe one day people will be able to heal their brains just like the gecko does.

Most species of gecko don’t have eyelids. Instead, the gecko has a protective scale over its eyeball. To remove dust and other debris from the scale, the gecko licks its eyes.

The leopard gecko grows about 11 inches long, or almost 28 cm, and is one of the species that doesn’t have toe pads. That makes it easier to keep in captivity, since it’s less likely to climb out of its terrarium. It’s a handsome lizard that’s yellowish or orangey in color with black spots, but baby leopard geckos actually have black stripes. It’s native to parts of the Middle East and south Asia where it’s mostly hot and dry, and in the wild it spends its day in a burrow and only comes out at night to hunt.

The leopard gecko has been kept as a pet for so long that some people consider it the first truly domesticated lizard. It’s easy to take care of and is usually comfortable around people. Breeders select for brighter colors than are found in wild geckos, including various color and pattern morphs.

One color variety of domestic leopard gecko is called the lemon frost morph, an especially attractive coloration. It’s a pastel yellow with white underneath and brown or black speckles that form broad bands over the lizard’s back. It’s really pretty and when the trait cropped up unexpectedly around 2015, its owner started breeding for the color. Lemon frost babies were rare and incredibly expensive, with people paying up to $2,000 for a single gecko.

Unfortunately, people soon learned that lemon frost geckos were prone to a type of rare skin cancer that affects the iridophores, which are pigment-producing cells. Up to 80% of all lemon frost morphs develop the cancer. Geneticists have discovered that the color morph is due to a single mutation in a single gene, but that the change in that gene also makes the gecko susceptible to cancer. Scientists are now trying to figure out more about how it works in hopes of learning how to prevent skin cancer in humans.

The dragon-tailed gecko is one name for the golden spiny-tailed gecko, one of twenty species in the genus Strophurus. All Strophurus geckos are from Australia and they all spend most of their lives in trees and shrubs. Unlike other geckos, Strophurus geckos don’t drop their tails when threatened. Instead, they have a unique way of deterring predators. A Strophurus gecko can squirt an incredibly smelly liquid from tiny pores in its tail. If it feels threatened, instead of dropping its tail, it will raise its tail up and wave it back and forth as a warning. It also opens its mouth to reveal a bright yellow or blue lining, which alerts the potential predator that this is not a lizard it wants to mess with. If that doesn’t scare the predator away, it will squirt liquid at its face. The liquid is sticky and smells horrible, and if it gets in an animal’s eyes it can cause eye irritation.

Strophurus geckos grow up to 5 inches long, or 13 cm, and species may look very different from each other. Some are drab and spiny, some are smooth and brighter in color. The dragon-tailed gecko has a broad reddish or golden stripe down the top of its tail.

The crested gecko is native to a collection of remote Pacific islands called New Caledonia. It can grow more than 10 inches long, or 25 cm. It has tiny spines above its eyes that look like eyelashes and more spines in two rows down its back, like a tiny dragon. It can be brown, reddish, orange, yellow, or gray, with various colored spots, which has made it a popular pet. These days all pet crested geckos were bred in captivity, since it’s now protected in the wild.

The crested gecko spends most of its time in trees, and not only does it have adhesive toe pads, it also has tiny claws. Most geckos don’t have claws. It can drop its tail like other geckos, but it doesn’t grow back. This doesn’t seem to bother the gecko, though.

The crested gecko was discovered by science in 1866, but wasn’t seen after that in so long that people thought it was extinct. Then it was rediscovered in 1994, so hurrah for the crested gecko!

Let’s move on from geckos to some other arboreal reptiles. A lot of reptiles live mostly in trees, and not all of them are small. The green iguana, for instance. It’s native to southern Mexico into parts of South America but has been introduced in many other places in the Americas, where it’s often considered an invasive species. In warm weather it lives in trees, although it will climb down to the ground in cool, rainy weather, and it can grow up to six and a half feet long, or 2m.

Although the iguana can be really long, most of its length is tail. It has an incredibly long tail for its size. It’s not that heavy, either, with the biggest green iguana ever weighed only a little more than 20 lbs, or 9.1 kg. Most are much lighter. It has long legs and long toes with claws, which makes it a good climber. It uses its tail to balance. It’s usually a drab olive-green or brown in color, although babies are brighter green with reddish spots and some adults are more orange in color. The tail is patterned with broad stripes. It has spines along its back and down its chin, and males develop a large dewlap that hangs down under the neck.

Although the iguana looks like a small dragon, it eats leaves, flowers, fruit, and other plant material, although it will also sometimes eat a grasshopper or snail and even bird eggs every so often. Many people keep green iguanas as pets, but they can be hard to keep healthy in captivity.

Another big reptile that lives in trees is the black mamba, a snake that lives in parts of Africa. It’s a slender snake that can be black in color, but that’s actually rare. The name black mamba comes from the inside of the snake’s mouth, which is black. When it feels threatened, it will raise its head high and open its mouth as a threat display. It can even flatten its neck to look like a hood like some cobras do. You really don’t want to see this threat display, because the black mamba’s venom is deadly and it’s an aggressive snake. Without treatment and antivenin, someone who is bitten can die within 45 minutes.

The mamba’s body can be gray, gray-green, brown, or brownish-yellow. It can grow nearly 15 feet long, or 4.5 meters, which makes it the second-longest venomous snake in the world, after the king cobra that we talked about in our Q&A episode last week.

The black mamba mostly lives in open forests and savannas, and it’s equally at home on the ground and in trees. It hides in termite mounds or in holes in trees at night, then comes out in the morning to warm up in the sunshine. Then it goes hunting, usually for small animals like rodents but also for larger ones like the rock hyrax. The rock hyrax can grow almost two feet long, or 50 cm, and looks kind of like a big rodent even though it’s not a rodent. It’s actually most closely related to the elephant. The black mamba will sneak up on a hyrax, bite it quickly, and then just wait until it dies to swallow it whole. The mamba also hunts birds and bats, which is why it spends so much time in the trees.

Some reptiles are so well adapted to living in trees that they can glide from tree to tree, like the flying snakes we talked about in episode 56. Flying snakes live in southeast Asia, and of course they can’t really fly. A flying snake has ridged scales on its belly that help it climb trees, and when it wants to move from one tree to another, it can flatten its body by flaring its ribs. This gives it more surface area to catch air, like a long skinny Frisbee. It’s been measured as gliding as far as 100 meters, or 109 yards, which is just a little longer than an American football field.

The largest species of flying snake, the golden tree snake, can grow over four feet long, or 1.3 meters. It’s striped black, gold, and yellow although some may be green and black. It eats small animals it finds in trees, including frogs, birds, bats, and lizards. It’s venomous, but its venom is weak and not dangerous to humans.

Many lizards can glide too, including the draco lizard. The draco lizard is common throughout much of southeast Asia and spends almost its whole life in trees, eating insects like ants and termites. It’s a small, slender lizard that only grows about 8 inches long at most, or 20 cm, and that includes its very long tail. Many gliding animals, like the flying squirrel, have gliding membranes called patagia that stretch from the front legs to the back legs, but the draco lizard is different. It has greatly elongated ribs that it can extend like wings, and the skin between the ribs acts as a patagium. This skin is usually yellow or brown so that the lizard looks like a falling leaf when it’s gliding.

The male draco also has a brightly colored dewlap under its chin that it can extend to attract a mate. When a female is ready to lay her eggs, she climbs down from her tree, finds some soil that’s soft enough for her to stick her head into to make a little hole, and then lays her eggs in the hole and covers them with dirt to hide them.

The draco lizard is beautiful and looks like a tiny dragon, and I want one to live in my garden and every time I go out to water my plants or pull weeds, I want it to fly down and ride around on my shoulder.

To bring us full circle, some geckos can also glide using thin membranes of skin around their body, legs, tail, and toes that act as patagia. They’re called parachute geckos, which is just perfect.

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at if you’d like to support us that way.

Thanks for listening!

Episode 232: Almost Domesticated

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

Further reading:

Memories of Ángela Loij

Mongolian horse and its person:

Mongolian horses:

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


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

The cuelpo, happy fox-like canid:

A very fancy rat:

Show transcript:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at if you’d like to support us for as little as one dollar a month and get monthly bonus episodes. There are links in the show notes to join our mailing list and to our merch store.

Thanks for listening!

Episode 213: More Honeybees, But Stingless

Thanks to Nicholas for this week’s suggestion! Let’s learn about the Australian stingless bee and its relatives!

Listen to BewilderBeasts if you want more fun, family-friendly animal facts!

Further reading/watching:

Australian Stingless Bees

Women Work to Save Native Bees of Mexico (I really recommend the short video embedded on this page! It’s utterly charming!)

House of the Royal Lady Bee: Maya revive native bees and ancient beekeeping

A Maya beekeeper’s hut and some Central/South American stingless bees (pictures from the last link, above):

Stingless bees build their combs in a spiral shape:

An Australian stingless bee collecting nectar and pollen:

Show transcript:

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

Last year Nicholas emailed me with a correction to episode 183 and a suggestion. In that episode I said that only honeybees make honey, but Nicholas pointed out that the Australian stingless bee also makes honey. In fact, he keeps some of these bees himself! So let’s learn about Tetragonula carbonaria and its close relations, as well as some other interesting bee information!

Stingless bees don’t just live in Australia. Different species live in parts of Australia, Africa, Asia, and Central and South America. Most produce honey, although not very much of it compared to the European honeybee. They don’t sting but some species will bite.

Stingless bees are much smaller than European honeybees. Some look more like a flying ant than a bee unless you look closely. A stingless bee worker only grows around 4 mm long, while a European honeybee worker grows about 15 mm long. Different species have different markings, but Tetragonula carbonaria, which is sometimes called the sugarbag bee, is black all over.

Stingless bees have a lot in common with honeybees, which makes sense because they’re closely related. The stingless bee lives in a social colony with a caste structure of the queen who stays home and lays eggs, male drones that mate with new queens, and infertile female workers. Young worker bees keep the hive clean and take care of the brood, or developing larvae, while older worker bees are the ones who fly out and forage for pollen and nectar. While stingless bees only have one queen laying eggs at any given time, some species will have a few backup queens in case of an emergency. These backup queens don’t produce eggs because they only mate with the drones if the reigning queen dies.

In a few species of stingless bee, there’s actually another caste in addition to the ordinary queen, drone, and worker. It’s the soldier caste. Soldier bee larvae get extra food, and they grow to be larger and stronger than other bees to help them guard the colony, especially the hive entrance. Before the stingless bee soldier castes were discovered, no one realized that any bees ever had soldiers, although some ant and termite species have them.

The stingless bee builds a nest in tree cavities, preferably in the tops of large trees because that keeps the hive warm and protected. It’s a tropical bee so it needs to stay warm. If any insect or other small animal gets into the hive, the bees can’t sting it because as their name implies, they don’t have working stingers. Instead, they swarm the intruder and attempt to smother it with anything they can find, including wax, resin, and mud.

The stingless bee builds honeycombs, but they’re spiral shaped. They’re made from beeswax mixed with resin that the worker bees collect from certain plants. The combs can be yellow like ordinary honeycombs, or they can be black, brown, or reddish. The word honeycomb isn’t actually accurate because it’s not where the bees store honey. The honey is stored in large chambers in the nest called honeypots. The combs are properly called brood combs because they’re used for baby bees. Worker bees fill the cells about three-quarters full of honey and pollen and the queen lays one egg in each cell. The workers then cap the cell. When the egg hatches, the bee larva has plenty of nutritious honey and pollen to eat. Once the larva has metamorphosed into an adult bee, it chews a hole through the cell’s cap and emerges.

If you’re wondering whether you can eat the honey of the sugarbag bee, yes! It’s runnier than ordinary honey but it smells wonderful and according to Nicholas, it has a tangy citrusy flavor. It sounds really good. Stingless bees don’t produce nearly as much honey as European honeybees, though, which makes sense since honeybees have been selectively bred over centuries to produce more honey than the hive could possibly need. The beekeeper takes the extra to eat, but naturally leaves plenty for the hive to live on.

People in Australia only started keeping stingless bees around the early 1980s, but it’s growing more and more popular. Since the bees are native to Australia, they’re much better for the environment than the European honeybee. They’re also incredibly good at pollinating crops, and if the weather’s warm enough, they’ll happily pollinate year round. A lot of people who keep stingless bees don’t even bother to harvest the honey, just use the bees as pollinators and as weird pets.

Before European honeybees became popular all over the world, many cultures kept stingless bees. This includes the ancient Maya, who kept stingless bees for their honey and wax. There was even a god associated with the bees, and the bees themselves were called “royal lady bees.” They look like tiny honeybees with striped abdomens, but their eyes are blue. It’s a forest bee that will pollinate flowers growing at the tops of tall trees as well as low-growing flowers, which is good for the environment and helps the native trees in particular.

Some modern Maya still keep stingless bees, but so few traditional beekeepers are left that the stingless bees in the Yucatan are endangered. Fortunately, a women’s collective in the area has started teaching local women how to keep the bees. The new beekeepers can sell honey on the gourmet market for extra money, and the bees have help competing with introduced European honeybees. It’s also a source of local pride to have royal lady bees around again.

When a stingless bee worker finds flowers producing a lot of nectar, she marks the area with pheromones. Other bees from her nest detect the pheromones and arrive to help harvest all the nectar and pollen. Pheromones are chemicals that correspond to scents, and although humans can’t detect them, bees have a really sensitive sense of smell. Their sense of smell is so good, in fact, that people in Croatia have trained European honeybees to find a particular scent for a surprising purpose.

Croatia is a country near Italy on the Adriatic Sea, and while it’s an independent country now, its independence only came after a whole lot of fighting. During the war, soldiers hid landmines all over the country and now, decades later, no one remembers where they are. There may be as many as 90,000 mines in the country, and they’re still deadly if a person or animal steps on one.

Obviously, Croatia needs to disarm the landmines—but finding them is the hard part. That’s where the bees come in.

The bees in question are ordinary European honeybees. Scientists train the bees by mixing nectar with tiny traces of the chemical signature of TNT. The bees quickly learn to associate TNT with food, and the scientists follow the bees with drones to see where they go.

I learned about these bomb-sniffing bees from a podcast called BewilderBeasts, which I highly recommend. There’s a promo for it at the end of this episode and I’ll put a link in the show notes. BewilderBeasts’s logo and their first episode both feature the bomb-sniffing bees.

Let’s finish with some interesting folklore associated with honeybees. Many bee-keeping cultures across the world have a superstition that you have to tell the bees about important events in the family. In English it’s literally called “telling the bees.” If you don’t, the bees may swarm and leave you. Some cultures especially stress that the bees must be told about the death of the beekeeper, and that they need to be invited to the funeral too or at least given cake or wine from the service afterwards.

This particular superstition ties into the association with bees and honey with the afterlife. In ancient Egypt and many other cultures across Asia and Europe, honey was a funerary gift for the dead, and tombs were sometimes decorated with images of bees and beehives. Honey isn’t just good to eat, it’s been used as a medicine for millennia and as an ingredient in skin cream and other cosmetics, so it has always been valuable. Every single bee-keeping culture in the world—literally every single one—gives religious significance to honey to some degree or another.

Humans all agree: honey is good, bees are good, and bee-keeping is worth the effort.

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at if you’d like to support us that way.

Thanks for listening!

Episode 212: The River of Giants

Thanks to Pranav for his suggestion! Let’s find out what the river of giants was and what lived there!

Further reading:

King of the River of Giants

Spinosaurus was a swimming dinosaur and it swam in the River of Giants:

A modern bichir, distant relation to the extinct giants that lived in the River of Giants:

Not actually a pancake crocodile:

A model of Aegisuchus and some modern humans:

Show transcript:

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

A while back, Pranav suggested we do an episode about the river of giants in the Sahara. I had no idea what that was, but it sounded interesting and I put it on the list. I noticed it recently and looked it up, and oh my gosh. It’s amazing! It’s also from a part of the world where it’s really hot, as a break for those of us in the northern hemisphere who are sick of all this cold weather. I hope everyone affected by the recent winter storms is warm and safe or can get that way soon.

The Sahara is a desert in northern Africa, famous for its harsh climate. Pictures of the Sahara show its huge sand dunes that stretch to the horizon. This wasn’t always the case, though. Only about 5,500 years ago, it was a savanna with at least one lake. Lots of animals lived there and some people too. Before that, around 11,000 years ago, it was full of forests, rivers, lakes, and grasslands. Before that, it was desert again. Before that, it was forests and grasslands again. Before that, desert.

The Sahara goes through periodic changes that last around 20,000 years where it’s sometimes wet, sometimes dry, caused by small differences in the Earth’s tilt which changes the direction of the yearly monsoon rains. When the rains reach the Sahara, it becomes green and welcoming. When it doesn’t, it’s a desert. Don’t worry, we only have 15,000 more years to wait until it’s nice to live in again.

This wet-dry-wet pattern has been repeated for somewhere between 7 and 11 million years, possibly longer. Some 100 million years ago, though, the continents were still in the process of breaking up from the supercontinent Gondwana. Africa and South America were still close together, having only separated around 150 million years ago. The northern part of Africa was only a little north of the equator and still mostly attached to what is now Eurasia.

Near the border of what is now Morocco and Algeria, a huge river flowed through lush countryside. The river was home to giant animals, including some dinosaurs. Their fossilized remains are preserved in a rock formation called the Kem Kem beds, which run for at least 155 miles, or 250 km. A team of paleontologists led by Nizar Ibrahim have been working for years to recover fossils there despite the intense heat. The temperature can reach 125 degrees Fahrenheit there, or 52 Celsius, and it’s remote and difficult to navigate.

For a long time researchers were confused that there were so many fossils of large carnivores associated with the river, more than would be present in an ordinary ecosystem. Now they’ve determined that while it looks like the fossils were deposited at roughly the same time from the same parts of the river, they’re actually from animals that lived sometimes millions of years apart and in much different habitats. Bones or even fossils from one area were sometimes exposed and washed into the river along with newly dead river animals. This gives the impression that the river was swarming with every kind of huge predator, but it was probably not quite so dramatic most of the time.

Then again, there were some really fearsome animals living in and around the river in the late Cretaceous. One of the biggest was spinosaurus, which we talked about in episode 170. Spinosaurus could grow more than 50 feet long, or 15 m, and possibly almost 60 feet long, or 18 m. It’s the only dinosaur known that was aquatic, and we only know it was aquatic because of the fossils found in the Kem Kem beds in the last few years.

Another dinosaur that lived around the river is Deltadromeus, with one incomplete specimen found so far. We don’t have its skull, but we know it had long, slender hind legs that suggests it could run fast. It grew an estimated 26 feet long, or 8 meters, including a really long tail. At the moment, scientists aren’t sure what kind of dinosaur Deltadromeus was and what it was related to. Some paleontologists think it was closely related to a theropod dinosaur called Gualicho, which lived in what is now northern Patagonia in South America. Remember that when these dinosaurs were still alive, the land masses we now call Africa and South America had been right in the middle of a supercontinent for hundreds of millions of years, and only started separating around 150 million years ago. Gualicho looked a lot like a pocket-sized Tyrannosaurus rex. It grew up to 23 feet long, or 7 meters, and had teeny arms. Deltadromeus’s arms are more in proportion to the rest of its body, though.

Some of the biggest dinosaurs found in the Kem Kem beds are the shark-toothed dinosaurs, Carcharodontosaurus, nearly as big as Spinosaurus and probably much heavier. It grew up to 40 or 45 feet long, or 12 to almost 14 meters, and probably stood about 12 feet tall, or 3 ½ meters. It had massive teeth that were flattened with serrations along the edges like steak knives. The teeth were some eight inches long, or 20 cm.

Researchers think that Carcharodontosaurus used it massive teeth to inflict huge wounds on its prey, possibly by ambushing it. The prey would run away but Carcharodontosaurus could take its time catching up, following the blood trail and waiting until its prey was too weak from blood loss to fight back. This is different from other big theropod carnivores like T. rex, which had conical teeth to crush bone.

Dinosaurs weren’t the only big animals that lived in and around the River of Giants, of course. Lots of pterosaur fossils have been found around the river, including one species with an estimated wingspan of as much as 23 feet, or 7 meters. There were turtles large and small, a few lizards, early snakes, frogs and salamanders, and of course fish. Oh my goodness, were there fish.

The river was a large one, possibly similar to the Amazon River. In the rainy season, the Amazon can be 30 miles wide, or 48 km, and even in the dry season it’s still two to six miles wide, or 3 to 9 km. The Amazon is home to enormous fish like the arapaima, which can grow up to 10 feet long, or 3 m. Spinosaurus lived in the River of Giants, and that 50-foot swimming dinosaur was eating something. You better bet there were big fish.

The problem is that most of the fish fossils are incomplete, so paleontologists have to estimate how big the fish was. There were lungfish that might have been six and a half feet long, or 2 meters, a type of freshwater coelacanth that could grow 13 feet long, or 4 meters, and a type of primitive polypterid fish that might have been as big as the modern arapaima. Polypterids are still around today, although they only grow a little over three feet long these days, or 100 cm. It’s a long, thin fish with a pair of lungs as well as gills, and like the lungfish it uses its lungs to breathe air when the water where it lives is low in oxygen. It also has a row of small dorsal fins that make its back look like it has little spikes all the way down. It’s a pretty neat-looking fish, in fact. They’re called bichirs and reedfish and still live in parts of Africa, including the Nile River.

There were even sharks in the river of giants, including a type of mackerel shark although we don’t know how big it grew since all we have of it are some teeth. Another was a type of hybodont shark with no modern descendants, although again, we don’t know how big it was.

The biggest fish that lived in the River of Giants, at least that we know of so far, is a type of ray that looked like a sawfish. It’s called Onchopristis numidus and it could probably grow over 26 feet long, or 8 meters. Its snout, or rostrum, was elongated and spiked on both sides with sharp denticles. It was probably also packed with electroreceptors that allowed it to detect prey even in murky water. When it sensed prey, it would whip its head back and forth, hacking the animal to death with the sharp denticles and possibly even cutting it into pieces. Modern sawfish hunt this way, and although Onchopristis isn’t very closely related to sawfish, it looked so similar due to convergent evolution that it probably had very similar habits.

The modern sawfish mostly swallows its prey whole after injuring or killing it with its rostrum, although it will sometimes eat surprisingly large fish for its size, up to a quarter of its own length. A 26-foot long Onchopristis could probably eat fish over five feet long, or 1.5 meters. It wouldn’t have attacked animals much larger than that, though. It wasn’t eating fully grown Spinosauruses, let’s put it that way, although it might have eaten a baby spinosaurus from time to time. Spinosaurus might have eaten Onchopristis, though, although it would have to be pretty fast to avoid getting injured.

But there was one other type of animal in the River of Giants that could have tangled with a fully grown spinosaurus and come out on top. The river was full of various types of crocodylomorphs, some small, some large, some lightly built, some robust. Kemkemia, for instance, might have grown up to 16 feet long, or 5 meters, but it was lightly built. Laganosuchus might have grown 20 feet long, or 6 meters, but while it was robust, it wasn’t very strong or fast. It’s sometimes called the pancake crocodile because its jaws were long, wide, and flattened like long pancakes. Unlike most pancakes, though, its jaws were lined with lots and lots of small teeth that fit together so closely that when it closed its mouth, the teeth formed a cage that not even the tiniest fish could escape. Researchers think it lay on the bottom of the river with its jaws open, and when a fish swam too close, it snapped it jaws closed and gulped down the fish. But obviously, the pancake crocodile did not worry spinosaurus in the least.

Aegisuchus, on the other hand, was simply enormous. We don’t know exactly how big it is and estimates vary widely, but it probably grew nearly 50 feet long, or 15 meters. It might have been much longer, possibly up to 72 feet long, or 22 meters. It’s sometimes called the shield crocodile because of the shape of its skull.

We don’t have a complete specimen of the shield crocodile, just part of one skull, but that skull is weird. It has a circular raised portion called a boss made of rough bone, and the bone around it shows channels for a number of blood vessels. This is unique among all the crocodilians known, living and extinct, and researchers aren’t sure what it means. One suggestion is that the boss was covered with a sheath that was brightly colored during the mating season, or maybe its shape alone attracted a mate. Modern crocodilians raise their heads up out of the water during mating displays.

The shield crocodile had a flattened head other than this boss, and its eyes may have pointed upward instead of forward. If so, it might have rested on the bottom of the river, looking upward to spot anything that passed overhead. Then again, it might have floated just under the surface of the water near shore, looking up to spot any dinosaurs or other land animals that came down to drink. Watch out, dinosaur! There’s a crocodilian!

Could the shield crocodile really have taken down a fully grown spinosaurus, though? If it was built like modern crocodiles, yes. Spinosaurus was a dinosaur, and dinosaurs had to breathe air. If the shield crocodile hunted like modern crocs, it was some form of ambush predator that could kill large animals by drowning them. You’ve probably seen nature shows where a croc bursts up out of the water, grabs a zebra or something by the nose, and drags it into the water, quick as a blink. The croc can hold its breath for up to an hour, while most land animals have to breathe within a few minutes or die. The shield crocodile and spinosaurus also lived at the same time so undoubtedly would have encountered each other.

Then again, there’s a possibility that the shield crocodile wasn’t actually very fearsome, no matter how big it was. It might have been more lightly built with lots of short teeth like the pancake crocodile’s to trap fish in its broad, flattened snout. Until we have more fossils of Aegisuchus, we can only guess.

Fortunately, palaeontologists are still exploring the Kem Kem beds for more fossils from the river of giants. Hopefully one day soon they’ll find more shield crocodile bones and can answer that all-important question of who would win in a fight, a giant crocodile or a giant swimming dinosaur?

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at if you’d like to support us that way and get twice-monthly bonus episodes as well as stickers and things.

Thanks for listening!

Episode 210: The Mysterious Lightbulb Lizard

Does the Shreve’s lightbulb lizard really emit light? (Hint: sort of.) Let’s find out!

Further reading:

The Lightbulb Lizard of Benjamin Shreve

Shreve’s lightbulb lizard, looking pretty ordinary really:

A web-footed gecko in moonlight:

A Jamaican gray anole showing off his dewlap:

Show Transcript:

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

This week let’s learn about an interesting reptile with a mystery that’s mostly solved, but still really weird. It’s called Shreve’s lightbulb lizard.

The story of this little lizard starts in 1937, when zoologist Ivan Sanderson was collecting freshwater crabs on a mountaintop in Trinidad. They were probably mountain crabs, also called the manicou crab, which is actually a pretty astonishing animal on its own. It’s a freshwater crab that doesn’t need to migrate to the ocean to release its eggs into the water. Instead, the female carries her eggs in a pouch in her abdomen. The eggs hatch into miniature crabs instead of larvae, and they stay in her pouch until they’re old enough to strike out on their own.

The mountains of Trinidad are made of limestone, which means they’re full of caves, and Sanderson was reportedly catching crabs in an underground pool or stream. He noticed a flash of light in the darkness and naturally went to find what had made it. All he found was a little lizard hiding under a ledge. It looked kind of like a brown skink and was pretty boring, but when the lizard turned its head, Sanderson saw a flash of dotted light down both its sides. When he caught the lizard and examined it while it was sitting in his hand, it flashed its lights again.

Sanderson knew he’d found something extraordinary, because lizards don’t bioluminesce. We still don’t know of any terrestrial vertebrate that emits light. Lots and lots of marine animals do, and some terrestrial invertebrates like lightning bugs and glow-worms, but no terrestrial vertebrates.

Sanderson took the lizard back to his camp, where he and his team observed it in different situations to see if it would light up again. They moved it to warmer areas and colder ones, made loud noises nearby, even tickled it, and they did indeed see it light up a few times. The light came from a row of tiny eyespots along its sides, from its neck to its hips. It had one row of these spots on each side, and each spot looked like a tiny white bead. The greenish-yellow flashes of light seemed to shine through the spots, as Sanderson said, like “the portals on a ship.”

Sanderson sent the lizard to The British Museum in London where another zoologist studied it and discovered that it was actually a known species, but apparently very rare. Only two specimens had ever been caught, one a juvenile and one an adult female. The lizard Sanderson caught was male, and it turns out that only adult males have these little eyespots. Sanderson later caught seven more of the lizards.

Let’s jump forward a bit and get a better idea of what these lizards look like. Shreve’s lightbulb lizard grows around 5 inches long at most, or 13 cm, not counting its long tail. It has short legs, a pointy nose, and broad, flat scales on its back and sides. It’s mostly brown in color. It lives in high elevations in the Caribbean island of Trinidad and Tobago, which is just off the coast of Venezuela in South America. It prefers cool climates, unlike most reptiles, and while it turns out that it’s not actually very rare, it’s also hard to study because it lives in such remote areas, so we don’t know much about it. It may be nocturnal and it may be semi-aquatic. It certainly lives along mountain streams, where it eats insects and other small animals.

Now, we have mentioned Ivan Sanderson a number of times in past episodes, and you may remember me sounding pretty skeptical about some of his cryptozoological claims. But Sanderson was a zoologist with a good reputation as a field scientist, and more importantly, he wasn’t the only one who saw the lizard light up.

The British Museum zoologist, H.W. Parker, who studied the first lizard Sanderson found, was actually the scientist who had originally discovered the lizard a few years before. He was very interested in the little portholes along the male lizard’s sides and studied them carefully. But he couldn’t find anything about them that indicated how they lit up. Each tiny eyespot consisted of a transparent center spot with a ring of black skin around it. The eyespots did not contain glowing bacteria, specialized nerve endings, ducts, reflecting structures, or anything else that he could think of that might cause a flash of light.

Other zoologists examined the so-called lightbulb lizard over the next few decades and none of them saw it emit light either. By 1960 no one believed it was bioluminescent.

I’m taking most of my information from a blog post by Dr Karl Shuker, a zoologist who writes a lot about cryptozoological mysteries. If you want to read his article, there’s a link in the show notes. Shuker was the one who got some modern scientists interested in the lightbulb lizard again, and there’ve been some recent studies. The lizard has been reclassified several times recently and its current name is Oreosaurus shrevei. Oreosaurus is spelled Oreo-saurus and it may be pronounced that way, and while I would like to think that the name comes from the white-appearing center of the eyespot with black pigment around it like an Oreo cookie, the name Oreosaurus is older than the cookie and as far as I can tell it means mountain lizard.

Some experiments conducted in the early 2000s finally figured out just what is going on with the lightbulb lizard. Sanderson was right: he and his colleagues really did see light coming from the eyespots. But it’s reflected light, not light emitted by the lizard itself. The white dots in the middle of the eyespots are reflective at some angles. Not only that, but when the lizard feels threatened, the skin around the white dots becomes even darker, which makes the reflection seem brighter. It’s partly optical illusion, partly just optics.

The big question now is why the lightbulb lizard has these reflective spots at all. The female doesn’t have them. That suggests that the male uses them in some way to attract a mate, but we don’t know.

While I was researching this episode, I kept coming across mentions of other lizards named lightbulb lizards. They’re all related to Shreve’s lightbulb lizard and I suspect the name got popular after Sanderson’s findings, which he published in a book of his nature travels called Caribbean Treasure. As far as I can find, none of the other lightbulb lizards have these reflective eyespots. Many are burrowing reptiles and they all have short legs and look a lot like skinks.

Meanwhile, in glowing lizard news, scientists discovered in 2018 that chameleons glow fluorescent under ultraviolet light. Even their bones are fluorescent. A lizard called the web-footed gecko, which lives in the desert in Namibia, Africa, has translucent markings on its sides and around its eyes. In daylight the markings don’t show, but in moonlight they glow neon green due to special pigment cells called iridophores. Iridophores are found in cephalopods and other marine animals, but they’ve never been seen before in land animals. Male Jamaican gray anoles have a colorful throat decoration called a dewlap that they extend to attract a mate, and the skin is translucent so that when sunlight passes through it, the colors glow brightly.

All these findings are only a few years old, so obviously we’re only just learning about all the different ways that lizards use light to their advantage. I wouldn’t be a bit surprised if a genuinely bioluminescent lizard was discovered eventually. So when you’re outside at night, don’t assume that every little flash of light is a firefly.

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at if you’d like to support us that way.

Thanks for listening!

Episode 204: Frogs of Many Cheery Colors

Let’s finish off a very weird year and welcome in the new year with a basket of colorful frogs!

The northern leopard frog comes in many color morphs, all of them pretty:

The starry dwarf frog is also pretty and has an orange tummy:

The astonishing turtle frog:


Poison dart frogs are colorful and deadly (blue poison dart frog, golden poison dart frog):

The tomato frog looks like a tomato that is also a frog:

Show transcript:

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

It’s the very last week of 2020, and good riddance. Let’s kick the old year out the back door and welcome in the new year with a basket of pretty frogs. That’s right, we’ve got a frog episode this week!

Let’s start with the northern leopard frog, with thanks to an anonymous reviewer who gave the podcast a really nice five-star review and only signed the review “norhern lepord frong.” I looked that frog up online to see what it looked like, and it’s so pretty, honestly, it’s just the prettiest frog! If you had a basket of northern leopard frogs, they might just look like friendly flowers, because while most are green or brown with darker spots, some are much brighter green with yellow markings, some are dark brown, and some are even pinkish white because of a rare albino trait. Its spots are outlined with yellow or light green and it has two folds of skin that run the length of the body and are sometimes yellow. These folds of skin are called dorsolateral folds and many frogs have them, although they’re not always as easy to spot as in the northern leopard frog.

The northern leopard frog is native to the northern part of North America, especially southern Canada and the northern and western United States. It grows up to 4.5 inches long, or 11.5 cm, measured from snout to vent. As you may recall from previous frog episodes, that’s how frogs are always measured. It basically just means nose to butt. Females are larger than males, which is also the case for most frogs.

It lives anywhere that it can find fresh water, including rivers, streams, creeks, ponds, marshes, even drainage ditches, but it prefers slow-moving or quiet water. As a result, it’s threatened by loss of habitat, pollution, and climate change, all of which affect the water it needs to live, and it’s also threatened by non-native animals and diseases. But while it doesn’t live in as many places as it used to, right now it’s doing fine overall and isn’t considered endangered.

Like most frogs, the northern leopard frog eats insects and any other small animal it can swallow. It has a long sticky tongue that it can shoot out so quickly that even an insect can’t outfly it, but it doesn’t just eat insects. It’s a big frog with a big mouth, and it’s been recorded eating other species of frog, small snakes, small birds, and even a bat. But mostly it eats insects, slugs, snails, and worms. Probably the frog that was documented as catching and eating a bat is famous in the northern leopard frog world, or at least it would be if real life was like the inside of my head and frogs had their own tiny newspapers.

The northern leopard frog was once considered a delicacy, with most frogs’ legs coming from this particular species. It’s also sometimes kept as a pet. It’s mostly nocturnal and semi-aquatic, sometimes called the meadow frog because it will leave the water to hunt for food in grassy areas. It hibernates in winter but is better adapted to cold weather than a lot of frogs are.

There’s also a southern leopard frog that looks very similar to the northern leopard frog but lives farther south, which you probably guessed from the name. It’s also slightly larger than the northern leopard frog, up to five inches long, or 13 cm.

Male leopard frogs, like many other frogs, have special vocal sacs in the throat that allow a male to make a loud call in spring to attract females. Different species of frog have different calls, naturally, and the vocal sacs are shaped differently in every species. The male leopard frog, northern and southern, has two vocal sacs that he fills with air like balloons, which amplifies the sound of his voice and makes it much louder.

This is what a northern leopard frog sounds like:

[frog sound]

Another colorful frog is from India and was only discovered in 2010. A team of scientists surveying the mountains for reptiles and amphibians noticed a teensy frog in the leaf litter one night. Its back was brown with light blue dots that looked like stars in a night sky, but its belly was orange like a sunset. It’s a very pretty frog.

The researchers caught several of the frogs and thought they were pretty but not especially unusual. There are at least 400 known frogs in India and new species are found pretty frequently. The team named it the starry dwarf frog because of the blue dots and its size, less than 20 mm long, or around half an inch. That’s about the size of an adult’s thumbnail.

After the expedition, though, when the team examined the frogs more closely, they realized they had something different from other frogs. It didn’t seem to be related to any other frog species in India or anywhere else. A genetic analysis indicated that the starry dwarf frog is literally not closely related to any frog alive today. For millions of years India was a big island after it separated from Madagascar and Africa but before it collided with mainland Asia, so many species evolved independently from species in other parts of the world. Scientists hope to learn more about the starry dwarf frog to learn more about how other frogs evolved.

Let’s move on to another colorful frog, and a very weird one, the turtle frog. Simon brought this one to my attention, so thank you, Simon! This frog gets its name because it sort of looks like a tiny turtle without a shell.

The turtle frog lives in western Australia in areas that are much dryer than most frog habitats. Its body is bulbous with strong, stubby legs that allow it to burrow into the sand. Generally, when a frog burrows into sand or mud it does so by moving backwards, digging itself deeper with its strong hind legs. But the turtle frog digs forward, using its front legs to dig. Turtles are also forward diggers. Unlike most other frogs, the turtle frog doesn’t have long hind legs that it uses for jumping. It just has short legs in front and back.

It ranges in color from brown to reddish-brown to pink and it grows up to 2 inches long, or 5 cm. Its head is small, rounded, and distinct from the body, like a baby turtle’s head sticking out from its shell–but without a shell, without a beak, and with small black-dot eyes.

Obviously the turtle frog isn’t related to the turtle at all. Turtles are reptiles while frogs are amphibians. The turtle frog has adapted to a semi-arid climate and a diet of termites by evolving the ability to dig deep burrows, some of them almost four feet deep, or 1.2 meters, and the ability to break into termite nests. As a result, its body plan is different from most other frogs.

That’s not all that’s different, though. Most frogs lay eggs in water, which hatch into tadpoles that live in the water until they metamorphose into small frogs. The turtle frog doesn’t have that kind of luxury. It doesn’t have a lot of water most of the time, so it hatches into a tiny froglet instead of a tadpole.

The most colorful frogs in the world live in the tropics, especially the poison dart frogs of Central and South America. Poison dart frogs are diurnal, meaning they’re most active during the daytime, and they’re fairly small, with the biggest species growing to no more than about two and a half inches long, or 6 cm. Different species of poison dart frogs are different colors and patterns, ranging from a lovely bright blue to red or yellow. These little frogs need to be brightly colored so that predators know to leave them alone, and the reason they should leave them alone is that poison dart frogs are incredibly toxic.

You may have heard the story that natives of South America would rub the tips of their darts or arrows on these frogs to transfer the frogs’ toxic secretions to the weapons. That’s where the name poison dart frog comes from. That’s sort of true, but not completely true. Not all poison dart frogs were used in this way, just four of the largest species that are especially toxic.

One of these four species is the golden poison dart frog, which lives in the rainforests of Colombia. It’s usually bright yellow with black eyes, although some individuals are a minty green or orange. It looks cheery, but a single frog has enough poison to kill two African elephants, not that it would because it lives in South America and not Africa and the elephants would not try to eat the frog. One frog has enough poison to kill 10 to 20 humans, though, so don’t try to eat one. In fact, don’t even touch it, because poison dart frogs store their poison in skin glands and if a frog feels threatened, it will secrete a tiny amount of the poison. If that poison gets into your body, you will die.

So why do people keep golden poison dart frogs as pets? That would be like having a pet stick of dynamite, right? Actually, it turns out that frogs born in captivity don’t develop the toxins that wild frogs have. Frogs that are captured in the wild and kept in captivity will eventually lose the toxins, although it may take several years. This is because the frog doesn’t manufacture the toxins itself but retains toxins found in some insects it eats, although researchers aren’t sure yet which insect or insects.

The golden poison dart frog lays its eggs on the ground. This sounds weird until you remember that it lives in a rainforest and the ground is covered with dead leaves that are constantly wet from rain. When the eggs hatch into tadpoles, though, they need more than just wet leaves, so the parent frogs squat down and the tadpoles wriggle onto the parents’ backs. They stick there and the parents carry them not to a pond but up into the trees. Water collects in the middle of large leaves of some rainforest tree species, and of course there are always little hollows and holes in tree trunks that can fill with rainwater. The frogs deposit the tadpoles into these little puddles, where the tadpoles eat mosquito larvae and algae. But even then, the parents don’t abandon their babies. Golden poison dart frogs are social animals, not generally a trait you associate with frogs, and they live in little groups of around half a dozen individuals. When the tadpoles finish developing and metamorphose into adult frogs, the parents lead their babies to other golden poison dart frogs so they can join a group.

Finally, our last colorful frog of the episode and the very last animal we’ll cover for 2020 is the tomato frog. As you might have guessed, the tomato frog is red-orange in color. It lives in Madagascar and a big female can grow up to 4 inches long, or 10.5 cm. Males are much smaller and are more yellow than red. But the tomato frog doesn’t use its coloring to hide among tomato plants. Its coloring advertises that it’s toxic, although its toxin is much different from those found in poison dart frogs and not deadly.

The tomato frog mostly eats worms and termites, which it finds by digging around in the leaf litter. It also catches insects with its sticky tongue. It’s not a very good swimmer, surprisingly, and spends most of its time on land or in swampy areas. It’s a mostly nocturnal frog.

If a tomato frog feels threatened, it will puff itself up to appear larger, which also incidentally makes it look even more like a tomato. It will also secrete a sticky white toxin that irritates a predator’s mucus membranes and can cause serious allergic reactions in humans. The toxin is so sticky that it will remain in the predator’s mouth for days. So if you live in Madagascar and have a tomato garden, carefully examine every tomato before you take a bite.

This is what a tomato frog sounds like:

[tomato frog croaking]

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at if you’d like to support us that way.

Thanks for listening!

Episode 202: Terror Birds and Pseudotooth Birds

Let’s find out about some gigantic birds this week! Thanks to Pranav and Richard for the suggestions!

Further reading:

Exceptionally preserved fossil gives voice to ancient terror bird

Antarctica yields oldest fossils of giant birds with 21-foot wingspans

Look at that beak! Llallawavis scagliai:

Big birdie!

A red-legged seriema and an unfortunate snake:

Another big birdie!

Toothy birdie!

Show transcript:

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

This week we’re going to learn about some gigantic extinct birds! Pranav wants to hear about Phorusrhacidae, also known as the terror bird. Something called a terror bird is definitely going to be interesting. My brother Richard also tweeted me about some huge extinct birds called pelagornithids, so we’ll talk about them too. Both birds were huge and successful, but extremely different from each other.

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. Flightless birds may make you think of ostriches and penguins and dodos, but remember that Phorusrhacids were called terror birds. They were carnivores and many of them were enormous.

Most terror birds lived in South America, with one species known from southern North America. A few newly discovered bird fossils from Africa and Europe may have been close relations of terror birds, but palaeontologists are still studying them.

Various species of terror bird 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. The beak was strong but the jaw muscles were relatively weak. Researchers think that it ambushed prey and chased it down, then either kicked it to death with its sharp talons or held it down with its feet and stabbed it to death with its beak. Smaller species may have grabbed its prey and thrown it back down with enough force to injure, stun, or outright kill the animal. It may have swallowed small prey whole and regurgitated pellets made up of compressed fur and bones, the way many modern carnivorous birds do today.

Although the beak was strong, it was also hollow. This would have made it weigh less, which meant that the bird could move its head more quickly. Some researchers think that it might also have acted as a resonant chamber, and that the bird could clap its beak closed to make a loud noise to communicate with other terror birds. It had excellent hearing and vision, but a poor sense of smell.

Many details of what we know about terror birds come from a single specimen discovered in 2010 in Argentina. The bird lived around 3 million years ago and stood four feet tall, or 1.2 meters. It was described in 2015 and is named Scaglia’s magnificent bird. I am not going to attempt to pronounce its scientific name [Llallawavis scagliai], but I’ll put it in the show notes along with a picture. Almost the entire skeleton is preserved in stunning detail, including details that hardly ever preserve, like the tiny bones that help the eye focus. Studies of the tiny ear bones and other details of the ear indicate that its hearing was most acute at low frequencies, which meant it would have been good at hearing footsteps. It also probably had a deep voice.

The terror bird had wings, but they were small and probably only used for display. The wings did have claws, though, and may have been used to fight other terror birds over mates or territory. Young terror birds of some species might have been able to fly, although adults certainly couldn’t.

The earliest known terror bird, Paleopsilopterus, lived about 60 million years ago in what is now Brazil. It was relatively small, only about three feet high, or 1 meter. It evolved only a few million years after the non-avian dinosaurs went extinct, and its descendants became larger and more fearsome until they were apex predators throughout South America.

Kelenken, for instance, grew up to ten feet tall, or three meters, and had an enormous beak, 18 inches long or almost 46 cm. It lived in what is now Argentina around 15 mya. It’s the tallest terror bird known but it was more slenderly built than others so was probably a faster runner. It was only discovered in 1999.

Brontornis, however, was the one that puts the terror into terror bird. It grew over 9 feet tall, or 2.8 meters, but it was massively built. It probably wasn’t a very fast runner and would have definitely been an ambush predator. Most likely it hid among trees or other tall vegetation, and when an animal came too close, BOOM! THERE’S A TERROR BIRD! RUN! TOO LATE, ARGH!

Titanis lived in parts of North America, with fossils found in Texas and Florida. It probably stood a little over eight feet tall, or 2.5 meters, although we don’t have any complete skeletons so can only estimate its actual size compared to other species of terror bird. You may find information online that says Titanis lived as recently as 10,000 years ago in Florida, and that it used the claws on its wings like hands to help catch prey. Both these things are wrong, unfortunately. The fossil bones found in the Santa Fe River in Florida had washed out of their original location and were mixed in with much more recent bones, and there’s no evidence that any terror bird used its wings like hands. Terror birds were descended from birds that could fly, not descended directly from dinosaurs, so its wings were still highly modified for flight.

Titanis lived in North America about five million years ago. But how did it get to North America from South America before the Isthmus of Panama formed around three million years ago? Before then, a big stretch of ocean separated the two continents. Researchers think it island-hopped, as the tops of mountains and hills in what is now Central America first emerged from the ocean as sea levels dropped, forming islands. Volcanoes also formed islands in the area. Titanis may have traveled to these islands by swimming or rafting during storms.

Terror birds went extinct after the Isthmus of Panama opened up when sea levels lowered. This connected North and South America, which allowed animals from North America to cross into South America and vice versa. The Andes Mountains also formed about this time and changed the climate of much of South America. Forests became open savanna where terror birds wouldn’t have been able to hide to ambush prey. Climate change combined with increased competition from saber-toothed cats and other North American predators probably led to the terror birds’ extinction.

There are no descendants of terror birds living today, but its closest living relations are probably the seriema birds, the red-legged and the black-legged seriema. Both live in South America and both are carnivorous birds that eat small animals like rodents, lizards, snakes, and even other birds. When it catches an animal, it beats it against the ground until it dies. It will also sometimes eat fruit and eggs.

The red-legged seriema stands a little over three feet tall, or a meter, with long legs, long neck, and long tail. It’s mostly brown and gray and it has a fan-shaped crest low down on its forehead, just above the bill. The gray-legged seriema looks very similar but is mostly gray. The seriema also has a sickle claw on each foot that it uses to cut pieces off its dead prey so it can swallow them more easily.

The seriema can fly, but it prefers to walk or run. It can run up to 15 mph, or 25 km/h. It builds its nest in low bushes so it can just hop up onto the nest instead of having to fly. It’s also aggressive and will attack animals much larger than it is, driving them away from its nest or chicks. Farmers sometimes catch young seriemas and tame them, then allow them to patrol the farmyard to catch rats and snakes and drive away larger predators.

Next, let’s learn about a different giant extinct bird, Richard’s suggestion. Unlike the terror bird, pelagornithids could fly. They’re sometimes called pseudotooth birds because they had teeth, but they weren’t real teeth. They were pointy projections of the jaw bones that grew along the edges of its beak and were covered with keratin. Pelagornithids evolved around the same time as the terror bird, around 62 million years ago, and didn’t die out until about the same time as the terror bird, around 2.5 million years ago.

And like the terror bird, pelagornithids were huge, but in a different way than terror birds. They were sea birds that may have superficially resembled modern albatrosses, but they were much larger. The largest living albatross has a wingspan of about 11 1/2 feet, or 3.5 meters, but the largest known pelagornithid had a wingspan estimated at up to 21 feet, or almost 6.5 meters. Its wings were narrow and pointed like albatross wings are.

Researchers think that the pelagornithid probably mostly ate soft-bodied animals like squid and other cephalopods, because its teeth were not very strong. It probably scooped its prey up from the water while flying, like many modern seabirds do, although it could probably also sit on the water and dip its long, strong beak down to catch anything that swam too close. Its bones were too delicate for diving. It may have had a throat sac like a pelican too. It was probably white or gray in color and its wings and tail were probably black, which is the most common coloration for sea birds of any kind.

It had short legs but enormously long wings, so long that it probably couldn’t flap them. Its strongest muscles were the ones that held the wings out straight. It was definitely a bird, of course, but it was proportioned more like a flying reptile, Pteranodon, even though they weren’t related. You know what that means, of course. Convergent evolution! Researchers think the pelagornithid spent almost all its time soaring on ocean breezes, scooping up cephalopods and fish to swallow whole, and that Pteranodon probably did the same. These days, modern albatrosses fill that particular ecological niche, and the albatross has many similarities to the pelagornithid too.

Pelagornithids of various species were found throughout the world, from the Arctic and Antarctic to the tropics. It was extremely successful and unlike the terror bird, which was restricted to land, it could travel as far as it liked as long as it had a breeze to keep it aloft. It evolved soon after the non-avian dinosaurs went extinct and didn’t die out until the beginning of the Pleistocene. What happened then? Why aren’t these enormous birds still flying around?

The Pleistocene, of course, was the ice age, or more properly the ice ages. Its onset resulted from a lot of factors, including the movement of continents that changed ocean currents radically. Once the changes started, they accelerated quickly. As more water froze and became massive glaciers that weighted down entire continents, sea levels dropped and more land was exposed, including the Isthmus of Panama that connected North and South America. This would have radically changed the air currents that pelagornithids used to travel around the world, from nesting sites to feeding sites and back. It also drove many sea animals to extinction as their environments became too cold or too warm for them to adapt to, or the water where they lived just dried up completely.

The one place where pelagornithids couldn’t go was across continents. They needed constant sea breezes and lots of water where they could catch prey, and steep cliffs near water to nest on. As the ecological changes of the Pleistocene became more pronounced, pelagornithids had more and more trouble surviving, and finally they went extinct. Modern albatrosses, gulls, and cormorants expanded at the same time to fill the ecological niche left open by the pelagornithid.

While there are no living descendants of pelagornithids, researchers tentatively think they’re most closely related to living ducks, geese, and swans. Since most pelagornithid fossils are badly damaged and fragmented, so that we only have one or two bones preserved from any given animal, it’s hard for scientists to make conclusions as to what they were most closely related to. Hopefully more and better fossils will be found soon so we can learn more about these gigantic birds!

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at We also have a Patreon at if you’d like to support us and get twice-monthly bonus episodes for as little as one dollar a month.

Thanks for listening!

Episode 197: Titanoboa!

Thanks to Pranav for this week’s suggestion, Titanoboa, the biggest snake that ever lived!

Parts of this episode come from an old Patreon episode about super-gigantic snakes, which is unlocked and you can listen to it here.

A modern anaconda vertebra next to a Titanoboa vertebra. Guess which one is which:

Carlos Jaramillo, one of the scientists who found Titanoboa and Acherontisuchus (taken from a Smithsonian Channel video):

Show transcript:

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

This has been a really busy week for me and I wasn’t able to finish researching the episode I had planned. Instead, we’ll have a short episode on a topic Pranav suggested ages ago, TITANOBOA! In September 2017 I released a Patreon episode about giant snakes, including Titanoboa, but this episode is all new. Ha ha, I thought it would take me less time to research it than finishing the research for what will be next week’s episode, ha ha I was wrong. Anyway, I’m going to unlock the giant snakes Patreon episode so anyone can listen. There’s a link in the show notes if you want to click through and listen on your browser.

Oh, a big congratulations to the winner of my book giveaway, Arthina! Thanks to everyone who entered.

In 1994, a geologist named Henry Garcia found an unusual-looking fossil in northeastern Colombia in South America. Specifically, it was an area that had been strip-mined for coal. Fifty-eight million years ago the region was a hot, swampy, tropical forest along the edge of a shallow sea. The Andes Mountains hadn’t yet formed. The environment was probably most similar to the Everglades and the Mississippi River delta in North America, but the climate was much warmer than it is now. These days what was once swamp is a field of rock uncovered by coal mining, which is not good for the environment but is unbelievably good for palaeontology.

Garcia thought he’d found a piece of fossilized tree. The coal company in charge of the mine displayed it in their office along with other fossils. And there it sat until 2003, when palaeontologists arranged an expedition to the mine to look for fossil plants. A researcher named Scott Wing was invited to join the team, and while he was there he poked around among the fossils displayed by the mining company. The second he saw the so-called petrified branch he knew it wasn’t a plant. He sent photos to a colleague who said it looked like the jawbone of a land animal, probably something new to science.

In 2007, the fossil was sent for study, labeled as a crocodile bone. But the palaeontologists who examined the fossil in person immediately realized it wasn’t from a crocodile. It was a snake vertebra—but so enormous that they couldn’t believe their eyes. They immediately arranged an expedition to search for more of them, and they found them! Comparisons to living anacondas and boas, the snake’s closest living relatives, helped researchers estimate the snake’s size. They named it Titanoboa cerrejonensis and described it in an article published in 2009 in Nature.

In 2012, a partial Titanoboa skull was found. Snake skulls are fragile and don’t fossilize nearly as often as the more robust vertebrae and ribs. It turned out that Titanoboa had lots and lots of teeth, more teeth than modern boids have.

Palaeontologists have found fossilized remains from around 30 individual snakes, including young ones. The adult size is estimated to be 42 feet, or 13 meters. The largest living snakes are anacondas, which may grow up to 29 feet, or 8.8 meters, but which are usually less than half that length. Reticulated pythons grow up to about 26 feet, or almost 8 meters, and possibly longer, but are also usually less than half that.

Titanoboa might have grown up to 50 feet long, or 15 meters, and could weigh more than 2,500 pounds. That’s one and a quarter tons, or more than 1100 kg. The thickest part of its body would have been waist-high compared to an average human male. Of course, these are all estimations since we don’t have a complete skeleton or a living specimen to examine, and most estimates these days put the maximum length at around 42 feet, or 13 meters. Still humongous. Females were probably larger than males, as is the case with most snakes.

Once the skull was found containing all those little teeth, researchers determined that Titanoboa probably ate a lot of fish. That’s unusual for constrictors, but it makes sense to think that a snake that large, living in a hot, tropical area, would spend most of its time in the water.

Even though snakes are cold-blooded, which means their internal temperature fluctuates with the temperature of their environment, a snake that size would retain a lot of heat and even generate heat from metabolic processes. Metabolic processes are related to digestion, chemical reactions that break down food into nutrients that can be used by the body. This releases heat, and in an animal with a bulky body that heat is retained more than in an animal with a slender body. Titanoboa was so big that some researchers think it would have overheated from its own metabolic processes if it didn’t stay cool somehow. Therefore, it might have lived in deep water where it could stay cool. Modern anacondas spend most of its time in the water, although usually in the shallows where it can hide in wait for prey.

Titanoboa undoubtedly ate a type of lungfish that grew nearly ten feet long, or 3 meters, but it probably also ate anything else it could catch, including crocodilians. A gigantic crocodilian found in the same area as Titanoboa, Acherontisuchus, grew up to 21 feet long, or almost 6.5 meters. It lived in the water too and probably mostly ate fish, but it didn’t so much compete with Titanoboa as avoid it as much as possible. After all, a full-grown Titanoboa was more than twice the size of a full-grown Acherontisuchus and could have swallowed it whole after suffocating it.

Several gigantic freshwater turtles also lived alongside Titanoboa. One had a shell that measured 5 feet 8 inches long, or 1.72 meters. Another grew five feet long, or 1.5 meters, but had a shell that was almost perfectly round. Researchers think its shape kept it safe from Titanoboa, since it would have been too big for Titanoboa to swallow. Snakes have bones and jaws that can dislocate to allow them to swallow large prey whole, and stretchy skin, but they have limits. Another turtle had a shell that was described as being as thick as a dictionary. Since other crocodilians have since been found in the area too, the thick shell was probably a defense against crocodilian jaws and teeth. Basically, this was a dangerous place to live no matter how big you were, unless, of course, you were a gigantic snake.

Titanoboa and the other animals of the swampy rainforest lived only about ten million years after the extinction event that killed off the non-avian dinosaurs. Obviously they’d been evolving to fill ecological niches left empty by the dinosaurs. Little did they know, though, that continental drift would lead to a cooling climate that would drive many reptiles to extinction and give rise to the age of mammals!

You can find Strange Animals Podcast at That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or just tell a friend. We also have a Patreon at if you’d like to support us that way.

Thanks for listening!