Category Archives: amphibians

Episode 436: Red-Eyed Tree Frog

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Thanks to Trech for suggesting this week’s topic, the red-eyed tree frog!

Further reading:

Tadpoles hatch in seconds to escape predator

The colorful red-eyed tree frog [photo by Geoff Gallice]:

Show transcript:

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

This week we’re going to have a short little episode about a little frog, suggested by Trech.

The frog in question is the red-eyed tree frog, which is native to Central America, including parts of Mexico, and northwestern South America. It lives in forests, always around water. You might be thinking, “of course, frogs live in water,” but remember that this is a tree frog. It lives in trees. But it still needs water for its babies, just not quite in the way most frogs do.

Before we learn about that, let’s learn about the frog itself. A big female can grow about 3 inches long, or 7.5 cm, while males are smaller. It’s a cute frog, of course, because frogs are always cute, but it’s also brightly colored. It’s bright green with red eyes, blue and yellow stripes on its sides, and orange feet.

Ordinarily, a frog with such bright colors would warn potential predators that it’s toxic, but the red-eyed tree frog isn’t toxic at all. Its bright colors have a different purpose. When it’s sitting on a leaf, the bright colors are hidden and only the frog’s smooth green back is showing, which makes it look like just another leaf. Only its eyes are bright, but it closes its eyes when it’s resting. But if a predator approaches, the frog opens its eyes suddenly and jumps up, revealing all those bright colors. The predator is startled, and maybe even hesitates because it thinks the frog might be toxic, and by the time the predator decides it should try eating the frog after all, the frog is long gone.

Oh, and if you’re wondering, the red-eyed tree frog can see through its eyelids. They’re actually not eyelids like we have, but a membrane that it can move over its eyes. The frog is nocturnal and eats insects like mosquitoes, crickets, and moths. It has a good sense of smell, which helps it find insects in the dark.

The tree frog also has suction cups on its toes that help it stay put on smooth leaves. During the day it sticks itself to the underside of a leaf to sleep where it’s more hidden. The female also lays her eggs on the underside of a leaf. This protects them from heavy rain, since the frogs breed during the rainy season, and it also helps hide them from predators. The female chooses a leaf that’s growing above water, and if the leaf isn’t very big she’ll lay eggs on both sides of it and fold the leaf to help hide all the eggs. The eggs stick to the leaf with a type of jelly that also helps keep them from drying out.

The eggs hatch in about a week, but they can hatch a few days early if a predator approaches. The embryonic tadpoles in their eggs can sense vibrations, and if a predator like a snake shakes the leaf as it approaches the eggs, the tadpoles can hatch within seconds. They drop straight down into the water below the leaf.

Hatching early when in danger is called phenotypic plasticity, and it’s really rare. It’s especially unusual because the embryonic tadpoles can actually tell the difference between a typical predator of frog eggs and vibrations caused by other animals or the wind. They can hatch so quickly because the stress reaction causes the pre-tadpoles to secrete an enzyme from their little noses, which weakens the egg wall and allows them to push and wiggle their way out.

Tadpoles stay in the water for several weeks, or sometimes several months depending on conditions, during which time they eat algae and other tiny food in the water. As they grow bigger, the tadpoles can eat bigger food, including other tadpoles. They switch to tiny insects after they metamorphose into froglets.

At some point during its development, a red-eyed tree frog needs to eat enough food containing carotenoids in order to develop properly, and in order to develop brightly colored skin as an adult. The red-eyed tree frog is a popular pet, but captive-bred frogs sometimes aren’t as brightly colored because they didn’t get enough of the right foods as young frogs.

During breeding season, a male will claim a small branch and jump and bounce around on it, both to call attention to himself and to shake other males off the branch. He also croaks loudly to attract a mate. This is what he sounds like:

[frog call]

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

Thanks for listening!

Episode 432: The Fossa and Other Animals of Madagascar

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This week we learn about the fossa and a few other animals of Madagascar, a suggestion by Pranav!

Further reading:

The stories people tell, and how they can contribute to our understanding of megafaunal decline and extinction in Madagascar

The fossa!

The votsotsa is a rodent, not a rabbit! [photo by Andrey Giljov – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=113271739]:

The golden mantella frog is sometimes golden, but sometimes red:

The nano-chameleon may be the smallest reptile in the world:

Show transcript:

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

This week we have a very old Pranav suggestion, animals of Madagascar!

The island country of Madagascar is off the southeastern coast of Africa. About 88 million years ago, it broke off from every other landmass in the world, specifically the supercontinent Gondwana. The continent we now call Africa separated from Gondwana even earlier, around 165 million years ago. Madagascar is the fourth largest island in the world and even though it’s relatively close to Africa these days, many of its animals and plants are much different from those in Africa and other parts of the world because they’ve been evolving separately for 88 million years.

But at various times in the past, some animals from Africa were able to reach Madagascar. We’re still not completely sure how this happened. Madagascar is 250 miles away from Africa, or 400 kilometers, and these days the prevailing ocean currents push floating debris away from the island. In the past, though, the currents might have been different and some animals could have arrived on floating debris washed out to sea during storms. During times when the ocean levels were overall lower, islands that are underwater now might have been above the surface and allowed animals to travel from island to island until they reached Madagascar.

We’re not sure when the first humans visited Madagascar, but it was at least 2,500 years ago and possibly as much as 9,500 years ago or even earlier. It’s likely that hunting parties would travel to Madagascar and stay there for a while, then return home with lots of food, but eventually people decided it would be a nice place to live. By 1,500 years ago people were definitely living on the island.

Let’s start with the fossa, an animal we’ve only talked about on the podcast once before, and then only in passing. It resembles a type of cat about the size of a cougar, although its legs are short in comparison to a similarly-sized cat. Its tail is almost as long as its body, and if you include its tail, it can grow around five feet long, or 1.5 meters. It’s reddish-brown with a paler belly. Its head is small with a short muzzle, rounded ears, and big eyes.

But the fossa isn’t a felid. It resembles a really big mustelid in many ways, especially a mongoose, and some studies suggest it’s most closely related to the mongoose. Really, though, it’s not closely related to anything living today. It spends a lot of time in trees, where it uses its long tail to help it balance. It even has semi-retractable claws. It eats lemurs and other mammals, birds, insects, crabs, lizards, and even fruit.

There used to be an even bigger fossa called the giant fossa, although we don’t know much about it. We only know about it from some subfossil remains found in caves. We’re not sure how big it was compared to the fossa living today, but it was definitely bigger and stronger and might have grown 7 feet long including its tail, or a little over 2 meters. There used to be much bigger lemurs living on Madagascar that have also gone extinct, so the giant fossa probably evolved to prey on them.

Most scientists estimate that the giant fossa went extinct at least 700 years ago, but some think it might have survived in remote areas of Madagascar until much more recently. There are even modern sightings of unusually large fossas, sometimes reported as twice the size of a regular fossa.

One interesting thing about the fossa is that its anus is hidden most of the time by a little fold of skin called an anal pouch, sort of like built-in underwear.

One animal most people outside of Madagascar have never heard of is the votsotsa, also called the Malagascar giant rat or the giant jumping rat since it’s a rodent that is especially known for its ability to jump. It actually looks a lot like a rabbit in size and shape, including its long ears, but it has a long tail. It’s gray or brown in color and grows about a foot long, or 30 cm, with a tail that can be up to 10 inches long, or 25 cm.

The votsotsa mates for life and both parents raise the single baby the mother gives birth to once or twice a year. It’s a nocturnal animal that spends the day in its burrow, which can be as much as 16 feet long, or 5 meters, with multiple exits. It eats nuts and seeds, fruit, leaves, and other plant material, along with insects and other small animals.

Lots of bats live on Madagascar, including the Madagascar flying fox. It’s a fruit-eating bat that’s brown or golden-brown in color with gray or black wings, and it’s the biggest bat native to the island. It has a wingspan of more than four feet across, or 125 cm. Like other species of flying fox, it lives in colonies of up to a thousand individuals that roost together in trees during the day. It mostly forages in the evenings, searching for fruit like figs. It eats flowers and sometimes leaves as well as fruit, and it may even be a pollinator for the kapok tree’s flowers.

Naturally, Madagascar also has a lot of reptiles, amphibians, and other non-mammalian animals. For instance, the golden mantella frog. It’s a little frog that’s only found in a few small areas, and measures around 20 millimeters long snout to vent. Some individuals are golden yellow while others are bright orange or red. As you may remember from our many previous episodes about frogs, such bright colors act as a warning to potential predators, to let them know that the frog is toxic. It absorbs toxins from some of the insects it eats. It’s active during the day in summertime, and in winter it spends most of the time hiding and doing nothing, which is the best way to spend the winter.

There are also lots of chameleons on Madagascar, including one called the nano-chameleon. It gets its name from its size, which is extremely small. It’s the smallest chameleon in the world, only 29 mm long at the very most, which is barely more than an inch long. Males are smaller than females, usually around 22 mm. It was described in 2021 and is brownish-grey with pale yellow or yellow-brown markings. Chameleons are famous for changing color, but the nano-chameleon doesn’t. It also mostly lives on the ground, where it hunts tiny insects and other invertebrates. Some scientists think it may be the smallest reptile in the world.

The female Darwin’s bark spider is about the same size as the female nano-chameleon, if you don’t count the spider’s legs. Males are much smaller. Darwin’s bark spider is a type of orb-weaver, which is the kind of spider that spins large webs that look like Halloween decorations. It was described in 2010 after first being discovered by scientists in 2009, which is surprising because it builds the largest orb webs known. Some webs can be over 30 square feet in size, or 2.8 square meters.

The silk is the strongest biological material ever studied, twice as strong as any other spider silk studied. The spider builds its web over water, because it eats a lot of mayflies and other insects that are attracted to water. It also eats a lot of dragonflies, and dragonflies are quite large and strong insects that don’t usually get caught in spiderwebs.

The people of Madagascar are considered very poor compared to other countries, after almost a century of French colonization and the resulting instability after it regained independence in 1960. A lot of animals that were once considered to be forbidden to bother, for religious and cultural reasons, now end up killed so people can eat them instead of starving. Mining and slash-and-burn agriculture has also contributed to pollution, habitat loss, and other factors that aren’t good for the animals of Madagascar or its people. Luckily, eco-tourism, where people visit the island to experience its beauty and see animals and plants found nowhere else on earth, is becoming more common. Hopefully that will help improve conditions for the people who live there and for the animals too.

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

Thanks for listening!

Episode 421: Australian Animals

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Thanks to Nora, Holly, Stephen, and Aila for their suggestions this week!

Further reading:

How ‘bin chickens’ learnt to wash poisonous cane toads

Monkeys in Australia? Revisiting a Forgotten Furry Mystery Down Under

The Australian white ibis:

The greater glider looks like a toy:

The thorny devil is very pointy:

Show transcript:

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

This week we’re going to talk about some animals native to Australia, which is Nora’s suggestion. We’ll learn about animals suggested by Holly, Stephen, and Aila, along with a mystery animal reported in the 1930s in northern Australia.

Australia isn’t currently connected to any other landmass and hasn’t been for about 50 million years. That means that most animals on the continent have been evolving separately for a very long time. While in other parts of the world placental mammals took over many ecological niches, marsupials are still the dominant mammal type in Australia. Most marsupial females give birth to tiny, helpless babies that then continue their development outside of her body, usually in a pouch.

But let’s start the episode not with a marsupial but with a bird. Stephen suggested the Australian white ibis, a beautiful bird that doesn’t deserve its nickname of bin chicken.

The white ibis is related to ibises from other parts of the world, but it’s native to Australia, and is especially common in eastern, northern, and southwestern Australia. It’s a large, social bird that likes to gather in flocks. Its body is mostly white with a short tail, long black legs, and a black head. Like other ibises, the adult bird’s head is bare of feathers. It also has a long, down-curved black bill that it uses to dig in the mud for crayfish and other small animals. When the bird spreads its magnificent black-tipped wings, it displays a stripe of featherless skin that’s bright red.

The Australian white ibis prefers marshy areas where it can eat as many frogs, crayfish, mussels, and other animals as it can catch. But at some point around 50 years ago, the birds started moving into more urban areas. They discovered that humans throw out a lot of perfectly good food, and before long they started to become a nuisance to people who had never encountered raccoons and didn’t know they should clamp those trash barrels closed really securely.

But no matter how annoying the Australian white ibis can be to people, it’s been really helpful in another way. In the 1930s, sugarcane plantation owners wanted to control beetles and other pests that eat sugarcane plants, so they released a bunch of cane toads in some of their fields in Queensland. But the cane toads didn’t do any good eating the beetles. Instead, they ate native animals and spread like wildfire. Since the toads are toxic, nothing could stop them, and there are now an estimated two billion cane toads living in Australia. But the Australian white ibis eventually figured out how to deal with cane toads.

The ibis will grab a cane toad, then whip it around and throw it into the air so that the toad secretes its toxins in hopes that the bird will leave it alone. Then the ibis will wash the toad in water or wipe it in wet grass, which washes away the toxins. Then the ibis eats the toad. Goodbye, toad!

Our next Australian animal is one suggested by Holly, the greater glider. When I saw the picture Holly sent, I was convinced it wasn’t a real animal but a toy plushie, but that’s just what the greater glider looks like. It’s incredibly cute!

The greater glider lives in eastern Australia, and as you might guess from its name, it is the largest of the three glider species found in Australia, and it can glide from tree to tree on flaps of skin between its front and back legs. Until 2020 scientists thought there was only one species of glider with local variations in size and coat color, but it turns out those differences are significant enough that it’s been split into three separate but closely related species.

The greater glider is nocturnal and only eats plant material, mostly from eucalyptus trees. It has a long fluffy tail, longer than the rest of its body is. Its tail can be as much as 21 inches long, or 53 cm, while its body and head together can measure as much as 17 inches long, or 43 cm. It has dense, plush fur, a small head with big round ears, black eyes, and a little pinkish nose, and it superficially looks like a big flying squirrel. But the greater glider isn’t a rodent. It’s a marsupial, closely related to the ringtail possum. Some individuals have dark gray or black fur and some have lighter gray or brown fur, but all greater gliders have cream-colored fur on their tummies.

The greater glider’s gliding membranes, also called patagia, are connected at what we can refer to as their elbows and ankles. It uses its long tail as a rudder and it’s very good at gliding from tree to tree. It almost never comes down to the ground if it can avoid it. When it glides, it folds its front legs so its little fists are under its chin and its elbows are stuck out, which stretches the membranes taut.

Aila suggested we learn more about the thorny devil, an Australian reptile we talked about way back in episode 97. It’s a spiky lizard that grows to around 8 inches long, or 20 cm. In warm weather its blotchy brown and yellow coloring is paler than in colder weather, when it turns darker. It can also turn orangey, reddish, or gray to blend in to the background soil. Its color changes slowly over the course of the day as the temperature changes. It also tends to turn darker if something threatens it.

It has a thick spiny tail that it usually holds curved upward, which makes it look kind of like a stick. It moves slowly and jerkily, rocking back and forth on its legs, then surging forward a couple of steps. Researchers think this may confuse predators. It certainly looks confusing.

As if that wasn’t enough, the thorny devil has a false head on the back of its neck. It’s basically a big bump with two spikes sticking out of its sides. When something threatens the lizard, it ducks its head between its forelegs, which makes the bump on its neck look like a little head. But all its spines make it a painful mouthful for a predator. If something does try to swallow it, the thorny devil can puff itself up to make it even harder to swallow, like many toads do. It does this by inflating its chest with air.

The thorny devil eats ants, specifically various species of tiny black ants found only in Australia. It has a sticky tongue to lick them up. This is very similar to the horned lizard of North America, also called the horny toad even though it’s not a toad, which we talked about most recently in episode 376. But despite their similarities in looks, behavior, and diet, the horned lizard and the thorny devil aren’t closely related. It’s just yet another example of convergent evolution.

Now, let’s finish with a strange report from the 1930s about a colony of hundreds, if not thousands, of monkeys in Australia. Australia doesn’t have very many native placental mammals, and no monkeys. But several Australian newspapers reported in 1932 that a party of gold prospectors encountered the monkeys in northern Australia, specifically Cape York Peninsula. The monkeys were reportedly gathered in one area to eat a huge crop of red nuts, and they appeared to be large monkeys that weighed up to 30 lbs, or 13 kg. Another gold prospector said in follow-up articles that he too had seen the monkeys and even shot a few of them, although he hadn’t saved any part of the bodies.

Newspaper hoaxes were pretty common back in the day, but by the 1930s things had mostly settled down and papers were more interested in imparting actual news instead of making it up. Cape York Peninsula was quite remote at the time, with rivers, rainforests, and savannas where a lot of animals unknown to science probably still live. But not monkeys!

One thing to remember is that at the end of the 19th century, it was a fad to release animals from one area into another. That’s how the European starling was introduced to North America, where it has become incredibly invasive. In the early 1890s, a group of people released a hundred starlings into New York City’s Central Park, because they wanted all the birds mentioned in Shakespeare’s writings to be present in the United States. This fad included Australia, where colonizers tried to release all sorts of animals. Most of the animals didn’t survive long, and we don’t have any records of monkeys being released, but it’s possible that someone just did it for fun and didn’t tell anyone.

Another suggestion is that the prospectors saw tree kangaroos and thought they were monkeys, even though tree kangaroos don’t actually look like monkeys. They look like little kangaroos that live in trees, not to mention they’re mostly nocturnal. Besides, the local Aboriginal people reportedly told the prospectors about the monkeys, and they would have identified tree kangaroos easily if that’s what they were. No other native Australian animal known to live in the area resembles a monkey either.

Zoologist Karl Shuker suggests the monkeys might have been macaques native to New Guinea. New Guinea isn’t all that far away from Australia, and macaques were often kept as pets too. It would have been pretty easy for someone to buy a bunch of macaques, import them on a ship, and release them into the wilderness. Or the macaques might have gotten there on their own, rafting to Australia on fallen trees washed out to sea during storms.

If there really were monkeys in Australia 90 years ago, of course, the big question is: are they still there?

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

Thanks for listening!

Episode 414: Two Marvelous Frogs

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

Further reading:

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

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

How to build a frog sauna

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

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

Show transcript:

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

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

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

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

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

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

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

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

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

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

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

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

This is what a Vietnamese mossy frog sounds like:

[frog beeping]

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

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

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

Thanks for listening!

Episode 386: The Greater Siren and the Anhinga

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Thanks to Kai and Emily for their suggestions this week!

The greater siren [photo by Kevin Stohlgren, taken from this site]:

The anhinga [photo by Tim from Ithaca – Anhinga, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=15526948]:

An anhinga swimming [photo by Wknight94, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons]:

Show transcript:

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

This week we’re going to learn about two animals, one suggested by Kai and the other suggested by Kai’s mom Emily. It’s so awesome to hear when families like to listen to the podcast together. This episode even includes a mystery animal I bet you’ve never heard of.

Let’s start with Kai’s suggestion, the greater siren. The greater siren is an amphibian, specifically a salamander, but it’s probably not the kind of salamander you’re thinking of. For one thing, it can grow over three feet long, or about a meter, which is pretty darn big for a salamander. It’s dark green or gray in color with tiny yellow or green speckles, and while it has short front legs, those are the only legs it has or needs. It also has external gills which it keeps throughout its life, unlike most salamanders who lose their external gills when they metamorphose into adults.

The greater siren lives primarily in Florida, but it’s also found in coastal wetlands throughout much of the southeastern United States. It’s mostly nocturnal and during the day it hides among water plants or under rocks, and will even burrow into the mud. At night it comes out to find food, which includes crayfish and other crustaceans, insects and spiders, little fish, other amphibians, snails, and even algae. It swallows its food whole, even snails and other mollusks. It poops out the shells and other undigestible pieces.

The grater siren’s body is long but thin, sort of like an eel, with a rounded tail that’s slightly flattened to help it swim. While it does spend its whole life in the water, it has small lungs that allow it to breathe air if it needs to. It can wriggle above ground for short distances if it needs to find a new pond or river, and sometimes it will sun itself on shore. In drought conditions when its water dries up, the greater siren will burrow into the mud and secrete mucus that mixes with dead skin cells to form a sort of cocoon. The cocoon covers everything but the siren’s mouth, so it can still breathe. Then it enters a state of torpor called aestivation, and it can stay in its mud cocoon for a long time, possibly as much as five years, and still be fine once the water returns. It does lose a lot of its body fat and its gills wither away, but it regenerates them quickly once it has water, and will gain weight quickly too once it has food.

In early spring, the female siren lays her eggs in shallow water. The male fertilizes them and takes care of them for the next two months, when they hatch into little bitty sirens that go off on their own right away.

The greater siren has tiny eyes and probably doesn’t see very well. It has a good sense of smell instead, and it can also sense movement and vibrations around it with its lateral line system. This is an organ found in many fish and a lot of larval amphibians, although the greater siren retains it throughout its life. It allows the animal to sense the movement of water in extremely fine detail. The greater siren can probably also sense electrical impulses, which is something that all animals generate when they use their muscles.

If there’s a greater siren, you may be thinking, there must be a lesser siren too. There is, and it’s very similar to the greater siren, just not as big. It only grows about two feet long at most, or 61 cm.

Kai mentioned that the greater siren looks a lot like the axolotl, a critically endangered salamander found only in Mexico. I checked to see if the two salamanders were closely related and was actually surprised to find that they’re not. They’re both salamanders and therefore share the same order, but that’s all. The greater siren and its close relations do share one important trait with the axolotl, though, which is neotony. Neotony is when an adult organism retains juvenile traits, which in the case of the salamander means it retains gills and lives underwater as an adult.

Next, Emily wanted to learn more about a bird called the anhinga. It’s sometimes called the snakebird because it has a long, serpentine neck. But before we learn about the anhinga, let’s learn about a mystery animal from Kentucky. I promise this will make sense in a minute.

In 1993 a man named Barton Nunnelly and his wife were sitting in their back yard in Stanley County, Kentucky. It was a nice day and their house was close to the Ohio River, so as they often did they just relaxed and watched the river. On this particular day, they both noticed a strange animal in the water. It was snake-like with a bill similar to a duck’s, but it obviously wasn’t a duck. It swam with its head and neck above the water, but its body was never visible. It frequently sank into the water, then surfaced elsewhere. The couple watched the animal for half an hour before it disappeared downstream.

For most people, that sighting would just be an interesting story to tell at parties, but Barton Nunnelly was a cryptozoologist. That’s someone who likes to investigate mystery animals, and while it’s a great word, it’s not an official branch of science. Zoologists, biologists, and other scientists study mystery animals all the time as part of their jobs. Nunnelly investigated—and in fact still does investigate, since he’s alive and well—mystery animals that are a lot more mystery than animal, like Bigfoot. He wrote about his sighting of what he thought might be a young freshwater sea serpent in his book Mysterious Kentucky.

Now, with Nunnelly’s sighting in mind, let’s return to the anhinga and learn a little more about this unusual bird. It can grow almost three feet in length, or about 90 cm, with a nearly four-foot wingspan, or 115 cm. A lot of its body length is due to the long neck. The male is black all over with a white tail-tip, while the female looks similar but has a brown head and neck. It looks similar to the double-crested cormorant, a close relation, but it has a longer, sharper bill. It lives throughout much of South and Central America, and is also common around the Gulf of Mexico and parts of the southeastern United States. In North America it usually stays near the coast or around wetlands, but sometimes it’s found farther inland, especially along rivers.

The most interesting feature of the anhinga is the way it hunts. It has big webbed feet and swims extremely well, and it hunts fish, frogs, and other small animals underwater. Unlike other water birds, which have water-repellent oils coating their feathers, as soon as the anhinga gets in the water, its feathers get all wet. This causes it to lose buoyancy and sink, but that’s just fine with the anhinga. It also has dense bones compared to most birds, which helps it stay underwater. The bird swims underwater until it gets close to a fish or other prey animal. Then it stabs the animal with its sharp bill, before bringing it above water to swallow. Often it will swim with its body completely submerged but its head and neck sticking up out of the water.

One interesting fact about the anhinga is that it has no nostrils. It can only breathe through its mouth. It can hold its breath underwater for about four minutes and during that time can travel quite a distance, up to about 100 yards, or 90 meters, completely underwater. In addition to fish and frogs, it will eat crayfish, crabs, insects, water snakes, and lots of other small animals. After it’s done hunting, or if it wants a rest, it will stand in the sun with its wings spread in order to dry its feathers. Cormorants do this too for the same reason.

Now, think back to Barton Nunnelly’s sighting of a duck-billed water serpent. It sounds to me an awful lot like Nunnelly saw an anhinga hunting in the river. It’s a rare visitor that far inland, but not unheard of. Naturally, not everyone knows every single bird in the world, but I feel like if you’re going to write a book about mystery animals, you should do a little research first. But maybe that’s just me.

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

Thanks for listening!

Episode 370: Animals Discovered in 2023

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

Further reading:

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

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

Strange New Species of Aquifer-Dwelling Catfish Discovered in India

Bizarre New Species of Catfish Discovered in South America

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

New Species of Hornshark Discovered off Australia

Cryptic New Bird Species Identified in Panama

New Species of Forest Hedgehog Discovered in China

New species of voiceless frog discovered in Tanzania

The weird new spiny katydid:

Show transcript:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[bird song]

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

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

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

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

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

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

This is what the voiceless frog sounds like:

[silence]

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

Thanks for listening!

Episode 369: Animals and Ultraviolet Light

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Sorry to my Patreon subscribers, since this is mostly a rerun episode from April 2019. It’s a fun one, though!

The teensy pumpkin toadlet [photo by Diogo B. Provete – http://calphotos.berkeley.edu, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=6271494]:

The electromagnetic spectrum. Look how tiny the visible light spectrum is on this scale! [By NASA – https://science.nasa.gov/ems/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=97302056]:

Show transcript:

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

This was supposed to be the 2023 discoveries episode, but not only have I had a really busy week that’s kept me from finishing the research, I’m also coming down with a cold. My voice still sounds okay right now but considering how I feel, it’s not going to sound good for long, and I need to finish the March Patreon episode too! I decided to rerun a very old Patreon episode this week to allow me time to finish the March Patreon episode before my voice turns into an unintelligible croak. I did drop in some fresh audio to correct a mistake I made in the original episode and add some new information.

This is one of my favorite Patreon episodes and I hope you like it too. It’s about animals that can see ultraviolet light.

I was going to make this a frog news episode, but I started writing about a tiny frog from

Brazil called the pumpkin toadlet and the episode veered off in a very interesting direction. But let’s start with that frog.

It’s called the pumpkin toadlet because it’s an orangey-yellow color that is just about the same color as pureed pumpkin. It’s poisonous and lives in the forests of Brazil. During mating season, the pumpkin toadlet comes out during the day, walking around making little buzzing noises. Researchers assumed those were mating calls until they started studying how the pumpkin toadlet and its relations process sounds. It turns out that the pumpkin toadlet probably can’t even hear its own buzzing noise. But they did discover that the pumpkin toadlet fluoresces brightly under UV light.

We’ve talked about this phenomenon before, back in the Patreon episode about animals that glow. Quite a lot of frogs turn out to fluoresce in ultraviolet light, which is a component of daylight. That explains why the pumpkin toadlet comes out during the day in mating season. It wants to be seen by potential mates. It’s actually the frog’s bones that fluoresce, but since it has very thin skin without dark pigment cells, the ultraviolet light can light up the bones.

I wanted to make sure I gave everyone the correct information about ultraviolet light, so I started researching it…and that led me down this rabbit hole. What animals can see in ultraviolet light? Can any humans see ultraviolet light? What does it look like?

Light is made up of waves of varying lengths. The retina at the back of your eyeball contains two types of cells, rods and cones, which are named for their shapes. Rods are for low-light vision and cones are for detail and color vision.

Humans have more cones than rods because we’re diurnal animals, meaning we’re most active during the day. Animals that are mostly nocturnal have more rods than cones, which help them see in low light although they don’t see color as well or sometimes at all as a result.

Most humans can see any color that’s a mixture of red, green, and blue, since we have three types of cone cells that react to wavelengths roughly equivalent to those three colors. Some people have what’s called red-green color blindness, which means either the person doesn’t have cones that sense the color red or cones that sense the color green. Various shades of green and red look alike for these people. Red-green color blindness is much more common in men than in women, with as many as 8% of men having the condition. A lot of times they don’t even know it. When I did my student teaching in a first grade class, one day I prepared a math lesson for the students that involved them sorting a little cup of candy into colors, and after they did the math problems associated with the different colors, they got to eat the candy. One little boy kept sorting certain colors of Skittles into the same column, and when I asked him, he didn’t realize they were different colors. They looked the same to him. So that day I learned to be careful about what kind of candy I used for sorting lessons, and he learned that he had red-green color blindness. My own dad was color blind too. It’s pretty common. Occasionally a person is born without the ability to see colors at all, but that’s extremely rare.

The visible light spectrum, also sometimes called the color spectrum, runs from violet to red. Just below violet is the wavelength referred to as ultraviolet. Many insects and birds can see ultraviolet, but typically an animal that can see ultraviolet can’t see infrared, which is the wavelength of light just past red. Birds that can see ultraviolet can usually see red, but not infrared.

In the original Patreon episode, this is where I said that humans can see ultraviolet light a little, but I was actually wrong. I thought blacklights worked by allowing us to see ultraviolet light, but that’s not the case. Blacklights are lamps that emit mostly ultraviolet light, but we only see a dark purple or blue that the blacklight’s filter allows through. While very few humans can see anything but the purple or blue, insects can see ultraviolet light and are attracted to it. That’s why bug zappers include blacklights. People also like blacklights because the ultraviolet light makes some things glow, which is fun to play with. It can also be useful in surprising ways. A lot of countries print paper money and other important documents with ink patterns that only show up under ultraviolet light. It’s easy to tell if the money or document is a fake if those hidden patterns don’t glow under a blacklight. Some diseases cause the sick person’s urine to glow specific colors under ultraviolet light, which helps a doctor determine what’s wrong with the person so they can be treated. If you have access to a blacklight, remember that even though you can’t see most of the light it emits, it can still hurt your eyes, so don’t stare into it.

Sometimes a person’s eye is diseased or damaged so they have to have the lens replaced with an artificial lens. Very rarely when that happens, the person wakes up after surgery and discovers they’re seeing ultraviolet way more than the rest of us. They report that the color is a pale purplish shade. This sounds cool, except that they have to wear special glasses that block ultraviolet light when they’re outside, since ultraviolet light can damage the eyes. It’s also the spectrum of light that causes sunburns. That’s what the UV means in products that say they block UV light; UV just means ultraviolet.

Many birds have a special cone cell that reacts specially to ultraviolet wavelengths. Urine reflects ultraviolet light, which allows predatory birds to track their prey by following urine trails. Some rodents and marsupials also have this cone cell. Researchers think having four types of cone cells, the three humans have plus the ultraviolet one, used to be the default in all animals, but some have evolved to not have the ultraviolet cone cell since they don’t need it. Some animals only have two types of cone cells, like mice, who can’t see as many colors as humans.

Researchers are just learning that many mammals are able to see ultraviolet much more than the typical human can. Reindeer, for instance, and some common animals like dogs, cats, and ferrets. Since power lines give off ultraviolet light, sometimes in bursts called coronal discharges, researchers now realize animals are affected by the light even though humans can’t see it. Reindeer have always avoided power lines, and now we know why. To them, the coronal discharges are a blaze of bright color that probably hurts their eyes, especially when it reflects off snow. Conservationists are calling for better shielding on power lines to cut down on the light they give out.

Some humans are born with ultraviolet-sensing cone cells, a condition called tetrachromacy. Since the lens of the human eye naturally filters out most ultraviolet light, people can have this extra cone cell and not even know it. They just tend to be better at differentiating colors than people without it. Some studies suggest that as many as 50% of women and 8% of men may be tetrachromatic—and that tetrachromatic women are also carriers of the trait of red-green color blindness. Since my dad was colorblind, that means I carry that trait from the genetic material I inherited from him, but I see colors really well…so maybe I have those extra cone cells! That’s exciting! Maybe you have it too!

But before we all get too excited, think about the mantis shrimp. Instead of four types of cone cells, it has up to 16 types.

Ultraviolet lightwaves are short. Shorter than that are X-rays, and shorter than those are gamma rays, which are ridiculously teeny. If your eyes could see X-rays, it basically just means you’d see a lot of skeletons walking around and it would feel bright all the time even if you closed your eyes, since X-rays penetrate less dense material like skin. If you could see gamma rays, all it would mean is that you could see stuff that was radioactive. Useful, yes, but not everyday useful.

Infrared is a different case, since infrared wavelengths are extremely long. Some animals can see infrared, but mostly they actually sense heat signatures given off by other animals. Night vision goggles work like this, basically allowing whoever wears them to see in infrared. Wavelengths longer than infrared are microwaves and radio waves, which nothing can see because it would pretty much just overwhelm the vision and you could see nothing but light, much of it the afterglow of the Big Bang, when the universe came into being.

A few years ago, a team of scientists working with an infrared laser started reporting occasionally seeing flashes of light where there shouldn’t be visible light. They were scientists, so of course they investigated with a scientific study of the infrared laser on human vision. This was a powerful laser that only emitted infrared light, and emitted it in quick pulses that released a set number of photons at a time. A photon is one particle of light, something along the lines of an atom. I’m not a physicist and don’t really understand it. The study revealed that sometimes, when the laser’s pulses were extremely close together, two photons would be absorbed by a single photopigment in the eye, which was enough to activate the pigment and allow the person to see a flash of light. But because the eye combined the photons, the eye reacted as though the wavelength of the light was half its length, which made it look green.

By the way, rod cells, the ones that help us see in low light, take a few minutes to achieve full sensitivity. That’s why it takes a few minutes for your eyes to adjust after you turn the light out at night.

It’s mind-blowing to think that light is an actual physical thing that actually physically goes into your eyeballs to let you see. There’s more to it than that, of course—nerves and the brain have a lot to do with how we are able to make sense of visual images. If something goes wrong with the eyeball, the nerves that connect it to the brain, or the part of the brain that deals with vision, it can lead to blindness of one kind or another. But at the very basic level, when you see, for instance, a hedgehog, it’s because light photons bounced off that hedgehog and into your eyeball. And that also means that when you look up at the night sky and see stars, you’re seeing the actual physical lightwaves given off by stars millions of light years away that physically go into your eyeball and bounce off the cone and rod cells, activating them and allowing your brain to form an image. That’s amazing, no matter if you can see ultraviolet or if you get the colors of candy mixed up because they look alike to you.

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

Episode 365: A New Temnospondyl

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Let’s take a look at some new findings about the temnospondyls this week!

Further reading:

Ancient giant amphibians swam like crocodiles 250 million years ago

Fossil of Giant Triassic Amphibian Unearthed in Brazil

Kwatisuchus rosai was an early amphibian [picture taken from article linked above]:

Koolasuchus was a weird big-headed boi:

Show transcript:

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

This week we’re going to revisit an animal we talked about way back in episode 172, the temnospondyl. That’s because a new species of temnospondyl has been named that lived about 250 million years ago, and some other new information has been published about temnospondyls in general.

In case you haven’t listened to episode 172 in a while, let’s brush up on some history. The temnospondyls arose about 330 million years ago during the Carboniferous period. Ocean levels were high, the continents were coming together slowly to form the supercontinent Pangaea, and much of the land was flooded with warm, shallow water that created enormous swampy areas full of plants. Naturally, a whole lot of animals evolved to live in the swamps, and the temnospondyls were especially successful.

Temnospondyls were semi-aquatic animals that probably looked a lot like really big, really weird salamanders. This was before modern amphibians evolved, and scientists still aren’t sure if the temnospondyls are the direct ancestors of modern amphibians or just cousins that died out with no living descendants. Temnospondyls do share many traits with modern amphibians, but they still had a lot in common with their fish ancestors.

Most temnospondyls had large heads that were broad and flattened in shape, often with a skull that was roughly triangular. Some had smooth skin but many had scales, including some species with scales that grew into armor-like plates. The earliest species had relatively small, weak legs and probably spent most of their time in the water, but it wasn’t long before species with stronger legs developed that probably lived mostly on land.

Many temnospondyls were small, but some grew really big. The biggest found so far is Prionosuchus, which is only known from fragmentary specimens discovered in Brazil in South America. It had an elongated snout something like a ghavial’s, which is a type of crocodilian that mostly eats fish, and a similar body shape. That’s why its name ends in the word “suchus,” which refers to a crocodile or an animal that resembles a crocodilian. Inside, though, prionosuchus probably had more in common with its fish ancestors than with modern crocodiles, and of course it wasn’t a reptile at all. It was an amphibian, possibly the largest one that’s ever lived. The biggest specimen found so far had a skull that measured just over 5 feet long, or 1.6 meters. That was just the skull! The whole animal, tail and all, might have measured as much as 30 feet long, or about 9 meters, although most paleontologists think it was probably more like 18 feet long, or 5-1/2 meters. That’s still incredibly big, as large as the average saltwater crocodile that lives today.

The resemblance of many temnospondyls to crocodilians is due to convergent evolution, since researchers think a lot of temnospondyls filled the same ecological niche as modern crocodiles. If you’re an ambush predator who spends a lot of time hiding in shallow water waiting for prey to get close enough, the best shape to have is a long body, short legs, a long tail that’s flattened side to side to help you swim, and a big mouth for grabbing, preferably with a lot of teeth. A study published in March of 2023 examined some trace fossils found in South Africa that scientists think were made about 255 million years ago by a temnospondyl. The fossils were found in what had once been a tidal flat or lagoon along the shore of the ancient Karoo Sea. You didn’t need to know it was called the Karoo Sea but I wanted to say it because it sounds like something from a fantasy novel. Truly, we live in a wonderful world. Anyway, there aren’t very many footprints but there are swirly marks made by a long tail and body impressions where the animal settled onto the floor to rest.

From those trace fossils, scientists can learn a lot about how the animal lived and moved. The swirly tail marks show that it used it tail to swim, not its legs. Since there are hardly any footprints, it probably kept its legs folded back against its body while it was swimming. When it stopped to rest, it may have been watching for potential prey approaching from above, since its eyes were situated on the top of its head to allow it to see upward easily. All these traits are also seen in crocodiles even though temnospondyls aren’t related to crocodilians at all.

Other big temnospondyls that filled the same ecological niche as crocodiles were species in the family Benthosuchidae. Some grew over 8 feet long, or 2.5 meters. That may not seem very big compared to a dinosaur or a whale, but this is your reminder that it was an early amphibian, and that amphibians are usually little guys, like frogs and newts.

The newly discovered fossil I mentioned at the beginning of this episode has been identified as a member of the family Benthosuchidae. It’s been named Kwatisuchus rosai and was discovered in Brazil in 2022. That’s a big deal, because while temnospondyl fossils have been found throughout the world, until Kwatisuchus, benthosuchids have only been found in eastern Europe. It was five feet long, or 1.5 meters, and it was probably an ambush predator that mostly ate fish.

Kwatisuchus lived only a few million years after the end-Permian extinction event, also called the Great Dying, which we talked about in episode 227. That extinction event wiped out entire orders of animals and plants. Temnospondyls in general survived the Great Dying and hung on for another 100 million years afterwards.

The last temnospondyl that lived, as far as the fossil record shows, was Koolasuchus. It lived in what is now Australia and went extinct about 120 million years ago. This is a lot more recent than most temnospondyls, so much so that when it was first discovered, scientists at first didn’t think it could be a temnospondyl. It was only described in 1997, although it was first discovered in 1978.

Not only was Koolasuchus the most recently living temnospondyl, it was also big and heavy and very weird-looking. It was about 10 feet long, or about 3 meters, and might have weighed as much as 1,100 lbs, or 500 kg. It lived in fast-moving streams and filled the same ecological niche as crocodiles, which eventually replaced it after it went extinct.

Like its relations, Koolasuchus had a roughly crocodile-shaped body with short legs and a fairly long tail, but its head was almost as big as its body. Most temnospondyls had big heads, and Koolasuchus’s was broad and rounded with a blunt nose. It also had what are called tabular horns that projected from the rear of the skull, which gave its head a triangular appearance. Its body was relatively slender compared to the chonky head, which made it look kind of like a really really big tadpole.

Remember, as an amphibian, Koolasuchus would have laid eggs that hatched into a larval form the same way frogs do today. We have a lot of larval temnospondyl fossils and even some fossilized eggs that paleontologists think were laid by a temnospondyl, which were attached to water plants the same way many species of frog do today. Larval temnospondyls did look a lot like tadpoles. In other words, Koolasuchus looked like a tadpole in shape but its larval form was also probably tadpole-like. Extra, extra tadpole-shaped.

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

Thanks for listening!

Episode 347: Two (Sort of) Spooky Amphibians

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Thanks to Max for suggesting one of our slightly spooky amphibians this week!

Further reading:

New crocodile newt discovered in Vietnam

Further watching:

Brave Wilderness Giant Screaming Frog!

The new Halloween-y crocodile newt discovered in Vietnam [photo by Phung My Trung and taken from the article linked above]:

A smoky jungle frog:

A screenshot from the video linked above:

Show transcript:

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

It’s the end of September and you know what that means: we’re about to start Monster Month! This year I have so many awesome ideas for episodes that we’re starting monster month early, with a non-spooky episode about two sort of spooky-looking amphibians. Thanks to Max for suggesting one of the animals we’re about to talk about!

Instead of rating the monster month episodes on a spookiness scale from one to five ghosts, this year we’re rating them on a spookiness scale of one to five bats, which seems more appropriate. This episode is only one bat, meaning even our younger listeners shouldn’t find it scary.

But first, a quick correction. Thanks very much to Mary for catching a mistake I made in last week’s rhinoceros episode. I said that black rhinos can weigh 18 kilograms, when I should have said 1800 kilograms. 18 kg is about 40 pounds, so I think you can agree that I made a BIG mistake.

Now, on to the “spooky” amphibians.

Lots of amphibians live in southeast Asia, many of them never seen by scientists. In 2018, a team of scientists were studying crocodile newts in Vietnam when they discovered one that didn’t look like any of the many other crocodile newts that live in Asia. Since there are over 30 species known, with new ones being discovered all the time, including seven others from Vietnam alone, they suspected this might be a species new to science.

The new newt lives in high elevations in the central highlands in Vietnam, much farther south and in much higher elevations than the other known crocodile newt species. After the initial finding in 2018, the lead scientist, an amphibian and reptile expert named Phung My Trung (apologies because I probably pronounced his name wrong) spent four years searching for more specimens and learning about them before he described it as a new species.

One thing I love is that he was quoted as saying that the adult newts “were so beautiful that I was shaking and could hardly believe I was holding a live specimen in my hand.” And it is absolutely a gorgeous animal. It’s black with orangey-red markings on its back, lovely Halloween colors, and in fact the markings sort of look like the skull, backbone, and ribs of a cartoon skeleton. Females are bigger than males, and a big female can grow as much as 3 inches long, or 7.5 cm, from snout to vent, not counting its tail that’s almost as long as its body.

That’s pretty much all we know so far about this newt. Because it appears to have such a restricted range, it’s most likely endangered due to habitat loss and climate change, but now that we know it’s there, scientists and conservationists can work to keep it and its habitat safe.

Our other amphibian this week is one suggested by Max. Max, by the way, is an incredible artist who specializes in making reptiles and amphibians out of clay. Max asked specifically about the giant screaming frog, which definitely sounds like a Halloween-themed animal.

The giant screaming frog isn’t the actual name of the frog, or at least I couldn’t find a frog with that specific name. I think it’s from an awesome video posted in 2017. I’ll put a link in the show notes if you want to watch the video, which is a YouTube channel called Brave Wilderness. In the video, a man called Coyote Peterson catches a giant frog called the Smoky Jungle Frog. When he does, the frog makes this sound:

[screaming frog!]

That doesn’t actually sound all that spooky. But it is a warning call so I bet other smoky jungle frogs think it’s terrifying!

The smoky jungle frog lives in tropical and subtropical areas of Central and northern South America, where it lives in swamps, ponds, and even rivers, especially in rainforest environments. It’s a bit unusual in that males are larger than females, although only slightly. Both males and females grow about 7 inches long from snout to vent, or 18 cm, and are a mottled brown with darker spots and stripes that help them blend in with dead leaves on the forest floor.

The smoky jungle frog is nocturnal, and during the day it stays hidden in a burrow or buries itself in fallen leaves. At night it comes out to find food, and because it’s such a big, strong frog, it eats animals much larger than insects. It’s been observed eating small birds, especially baby birds, bats, snakes up to 19 inches long, or 50 cm, lizards, and sometimes even other frogs, including poison dart frogs. How embarrassing would that be if you were a bat, with strong wings and the amazing ability to echolocate, and you got eaten by a frog.

When a frog feels threatened, it has several ways to deter potential predators. It can make itself look even bigger by puffing its body up and standing up higher on its legs instead of sitting in a typical frog squat. It also secretes a toxin through its skin, which not only makes it really slippery but also makes it taste awful. It’s not dangerous to humans but can result in a painful burning sensation and rash if the toxin gets into a cut on the skin. If any of the mucus gets into your eyes, they will swell up painfully for hours.

The frog will also give its alarm call if something grabs it. Let’s listen to it again:

[frog ‘screaming’]

During mating season, the male develops little spikes near his wrists and on his chest. This helps him grasp a female without slipping off so he can fertilize her eggs as she lays them. The male uses his back legs to churn up the water and mix it with mucus and sperm to create a foamy nest for the female’s eggs, which protects the eggs from predators and makes sure they won’t dry out. The eggs hatch a few days later, and the tadpoles stay in the nest at first where they eat…well, they eat each other. The tadpoles that hatch first eat the other eggs, and the bigger tadpoles eat the smaller tadpoles. Soon, though, rain washes them out of the nest into open water, where they spend the next month or so eating small insects and algae until they metamorphose into little frogs that live on land. Unlike many frogs, the toes of the smoky jungle frog aren’t webbed since they don’t spend much time in the water.

So many times in this podcast I have to explain that an animal is endangered, so I’m happy to report that the smoky jungle frog is doing just fine. It’s a common animal throughout its range.

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

Thanks for listening!

Episode 338: Updates 6 and an Arboreal Clam!?!

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This week we have our annual updates and corrections episode, and at the end of the episode we’ll learn about a really weird clam I didn’t even think was real at first.

Thanks to Simon and Anbo for sending in some corrections!

Further reading:

Lessons on transparency from the glass frog

Hidden, never-before-seen penguin colony spotted from space

Rare wild asses spotted near China-Mongolia border

Aye-Ayes Use Their Elongated Fingers to Pick Their Nose

Homo sapiens likely arose from multiple closely related populations

Scientists Find Earliest Evidence of Hominins Cooking with Fire

153,000-Year-Old Homo sapiens Footprint Discovered in South Africa

Newly-Discovered Tyrannosaur Species Fills Gap in Lineage Leading to Tyrannosaurus rex

Earth’s First Vertebrate Superpredator Was Shorter and Stouter than Previously Thought

252-Million-Year-Old Insect-Damaged Leaves Reveal First Fossil Evidence of Foliar Nyctinasty

The other paleo diet: Rare discovery of dinosaur remains preserved with its last meal

The Mongolian wild ass:

The giant barb fish [photo from this site]:

Enigmonia aenigmatica, AKA the mangrove jingle shell, on a leaf:

Show transcript:

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

This week is our annual updates and corrections episode, but we’ll also learn about the mangrove jingle shell, a clam that lives in TREES. A quick reminder that this isn’t a comprehensive updates episode, because that would take 100 years to prepare and would be hours and hours long, and I don’t have that kind of time. It’s just whatever caught my eye during the last year that I thought was interesting.

First, we have a few corrections. Anbo emailed me recently with a correction from episode 158. No one else caught this, as far as I can remember. In that episode I said that geckos don’t have eyelids, and for the most part that’s true. But there’s one family of geckos that does have eyelids, Eublepharidae. This includes the leopard gecko, and that lines up with Anbo’s report of having a pet leopard gecko who definitely blinked its eyes. This family of geckos are sometimes even called eyelid geckos. Also, Anbo, I apologize for mispronouncing your name in last week’s episode about shrimp.

After episode 307, about the coquí and glass frogs, Simon pointed out that Hawaii doesn’t actually have any native frogs or amphibians at all. It doesn’t even have any native reptiles unless you count sea snakes and sea turtles. The coqui frog is an invasive species introduced by humans, and because it has no natural predators in Hawaii it has disrupted the native ecosystem in many places, eating all the available insects. Three of the Hawaiian islands remain free of the frogs, and conservationists are working to keep it that way while also figuring out ways to get them off of the other islands. Simon also sent me the chapter of the book he’s working on that talks about island frogs, and I hope the book is published soon because it is so much fun to read!

Speaking of frogs, one week after episode 307, an article about yet another way the glass frog is able to hide from predators was published in Science. When a glass frog is active, its blood is normal, but when it settles down to sleep, the red blood cells in its blood collect in its liver. The liver is covered with teensy guanine crystals that scatter light, which hides the red color from view. That makes the frog look even more green and leaf-like!

We’ve talked about penguins in several episodes, and emperor penguins specifically in episode 78. The emperor penguin lives in Antarctica and is threatened by climate change as the earth’s climate warms and more and more ice melts. We actually don’t know all that much about the emperor penguin because it lives in a part of the world that’s difficult for humans to explore. In December 2022, a geologist named Peter Fretwell was studying satellite photos of Antarctica to measure the loss of sea ice when he noticed something strange. Some of the ice had brown stains.

Dr Fretwell knew exactly what those stains were: emperor penguin poop. When he obtained higher-resolution photos, he was able to zoom in and see the emperor penguins themselves. But this wasn’t a colony he knew about. It was a completely undiscovered colony.

In episode 292 we talked about a mystery animal called the kunga, and in that episode we also talked a lot about domestic and wild donkeys. We didn’t cover the Mongolian wild ass in that one, but it’s very similar to wild asses in other parts of the world. It’s also called the Mongolian khulan. It used to be a lot more widespread than it is now, but these days it only lives in southern Mongolia and northern China. It’s increasingly threatened by habitat loss, climate change, and poaching, even though it’s a protected animal in both Mongolia and China.

In February of 2023, a small herd of eight Mongolian wild asses were spotted along the border of both countries, in a nature reserve. A local herdsman noticed them first and put hay out to make sure the donkeys had enough to eat. The nature reserve has a water station for wild animals to drink from, and has better grazing these days after grassland ecology measures were put into place several years ago.

In episode 233 we talked about the aye-aye of Madagascar, which has weird elongated fingers. Its middle finger is even longer and much thinner than the others, which it uses to pull invertebrates from under tree bark and other tiny crevices. Well, in October of 2022 researchers studying aye-ayes started documenting another use for this long thin finger. The aye-ayes used it to pick their noses. It wasn’t just one aye-aye that wasn’t taught good manners, it was widespread. And I hope you’re not snacking while I tell you this, the aye-aye would then lick its finger clean. Yeah. But the weirdest thing is that the aye-aye’s thin finger is so long that it can potentially reach right through the nose right down into the aye-aye’s throat.

It’s pretty funny and gross, but wondering why some animals pick their noses is a valid scientific question. A lot of apes and monkeys pick their noses, as do humans (not that we admit it most of the time), and now we know aye-ayes do too. The aye-aye is a type of lemur and therefore a primate, but it’s not very closely related to apes and monkeys. Is this just a primate habit or is it only seen in primates because we have fingers that fit into our nostrils? Would all mammals pick their nose if they had fingers that would fit up in there? Sometimes if you have a dried snot stuck in your nose, it’s uncomfortable, but picking your nose can also spread germs if your fingers are dirty. So it’s still a mystery why the aye-aye does it.

A recent article in Nature suggests that Homo sapiens, our own species, may have evolved not from a single species of early human but from the hybridization of several early human species. We already know that humans interbred with Neandertals and Denisovans, but we’re talking about hybridization that happened long before that between hominin species that were even more closely related.

The most genetically diverse population of humans alive today are the Nama people who live in southern Africa, and the reason they’re so genetically diverse is that their ancestors have lived in that part of Africa since humans evolved. Populations that migrated away from the area, whether to different parts of Africa or other parts of the world, had a smaller gene pool to draw from as they moved farther and farther away from where most humans lived.

Now, a new genetic study of modern Nama people has looked at changes in DNA that indicate the ancestry of all humans. The results suggest that before about 120,000 to 135,000 years ago, there was more than one species of human, but that they were all extremely closely related. Since these were all humans, even though they were ancient humans and slightly different genetically, it’s probable that the different groups traded with each other or hunted together, and undoubtedly people from different groups fell in love just the way people do today. Over the generations, all this interbreeding resulted in one genetically stable population of Homo sapiens that has led to modern humans that you see everywhere today. To be clear, as I always point out, no matter where people live or what they look like, all people alive today are genetically human, with only minor variations in our genetic makeup. It’s just that the Nama people still retain a lot of clues about our very distant ancestry that other populations no longer show.

To remind everyone how awesome out distant ancestors were, here’s one new finding of how ancient humans lived. We know that early humans and Neandertals were cooking their food at least 170,000 years ago, but recently archaeologists found the remains of an early hominin settlement in what is now Israel where people were cooking fish 780,000 years ago. There were different species of fish remains found along with the remains of cooking fires, and some of the fish are ones that have since gone extinct. One was a carp-like fish called the giant barb that could grow 10 feet long, or 3 meters.

In other ancient human news, the oldest human footprint was discovered recently in South Africa. You’d think that we would have lots of ancient human footprints, but that’s actually not the case when it comes to footprints more than 50,000 years old. There are only 14 human footprints older than that, although there are older footprints found made by ancestors of modern humans. The newly discovered footprint dates to 153,000 years ago.

It wouldn’t be an updates episode without mentioning Tyrannosaurus rex. In late 2022 a newly discovered tyrannosaurid was described. It lived about 76 million years ago in what is now Montana in the United States, and while it wasn’t as big as T. rex, it was still plenty big. It probably stood about seven feet high at the hip, or a little over 2 meters, and might have been 30 feet long, or 9 meters. It probably wasn’t a direct ancestor of T. rex, just a closely related cousin, although we don’t know for sure yet. It’s called Daspletosaurus wilsoni and it shows some traits that are found in older Tyrannosaur relations but some that were more modern at the time.

Dunkleosteus is one of a number of huge armored fish that lived in the Devonian period, about 360 million years ago. We talked about it way back in episode 33, back in 2017, and at that time paleontologists thought Dunkleosteus terrelli might have grown over 30 feet long, or 9 meters. It had a heavily armored head but its skeleton was made of cartilage like a shark’s, and cartilage doesn’t generally fossilize, so while we have well-preserved head plates, we don’t know much about the rest of its body.

With the publication in early 2023 of a new study about dunkleosteus’s size, we’re pretty sure that 30 feet was a huge overestimation. It was probably less than half that length, maybe up to 13 feet long, or almost 4 meters. Previous size estimates used sharks as size models, but dunkleosteus would have been shaped more like a tuna. Maybe you think of tuna as a fish that makes a yummy sandwich, but tuna are actually huge and powerful predators that can grow up to 10 feet long, or 3 meters. Tuna are also much heavier and bigger around than sharks, and that was probably true for dunkleosteus too. The study’s lead even says dunkleosteus was built like a wrecking ball, and points out that it was probably the biggest animal alive at the time. I’m also happy to report that people have started calling it chunk-a-dunk.

We talked about trace fossils in episode 103. Scientists can learn a lot from trace fossils, which is a broad term that encompasses things like footprints, burrows, poops, and even toothmarks. Recently a new study looked at insect damage on leaves dating back 252 million years and learned something really interesting. Some modern plants fold up their leaves at night, called foliar nyctinasty, which is sometimes referred to as sleeping. The plant isn’t asleep in the same way that an animal falls asleep, but “sleeping” is a lot easier to say than foliar nyctinasty. Researchers didn’t know if folding leaves at night was a modern trait or if it’s been around for a long time in some plants. Lots of fossilized leaves are folded over, but we can’t tell if that happened after the leaf fell off its plant or after the plant died.

Then a team of paleontologists from China and Sweden studying insect damage to leaves noticed that some leaves had identical damage on both sides, exactly as though the leaf had been folded and an insect had eaten right through it. That’s something that happens in modern plants when they’re asleep and the leaves are folded closed.

The team looked at fossilized leaves from a group of trees called gigantopterids, which lived between 300 and 250 million years ago. They’re extinct now but were advanced plants at the time, some of the earliest flowering plants. They also happen to have really big leaves that often show insect damage. The team determined that the trees probably did fold their leaves while sleeping.

In episode 151 we talked about fossils found with other fossils inside them. Basically it’s when a fossil is so well preserved that the contents of the dead animal’s digestive system are preserved. This is incredibly rare, naturally, but recently a new one was discovered.

Microraptor was a dinosaur that was only about the size of a modern crow, one of the smallest dinosaurs, and it probably looked a lot like a weird bird. It could fly, although probably not very well compared to modern birds, and in addition to front legs that were modified to form wings, its back legs also had long feathers to form a second set of wings.

Several exceptionally well preserved Microraptor fossils have been discovered in China, some of them with parts of their last meals in the stomach area, including a fish, a bird, and a lizard, so we knew they were generalist predators when it came to what they would eat. Now we have another Microraptor fossil with the fossilized foot of a mammal in the place where the dinosaur’s stomach once was. So we know that Microraptor ate mammals as well as anything else it could catch, although we don’t know what kind of mammal this particular leg belonged to. It may be a new species.

Let’s finish with the mangrove jingle shell. I’ve had it on the list for a long time with a lot of question marks after it. It’s a clam that lives in trees, and I actually thought it might be an animal made up for an April fool’s joke. But no, it’s a real clam that really does live in trees.

The mangrove jingle shell lives on the mangrove tree. Mangroves are adapted to live in brackish water, meaning a mixture of fresh and salt water, or even fully salt water. They mostly live in tropical or subtropical climates along coasts, and especially like to live in waterways where there’s a tide. The tide brings freshly oxygenated water to its roots. A mangrove tree needs oxygen to survive just like animals do, but it has trouble getting enough through its roots when they’re underwater. Its root system is extensive and complicated, with special types of roots that help it stay upright when the tide goes out and special roots called pneumatophores, which stick up above the water or soil and act as straws, allowing the tree to absorb plenty of oxygen from the air even when the rest of the root system is underwater. These pneumatophores are sometimes called knees, but different species of mangrove have different pneumatophore shapes and sizes.

One interesting thing about the mangrove tree is that its seeds actually sprout while they’re still attached to the parent tree. When it’s big enough, the seedling drops off its tree into the water and can float around for a long time before it finds somewhere to root. If can even survive drying out for a year or more.

The mangrove jingle shell clam lives in tropical areas of the Indo-Pacific Ocean, and is found throughout much of coastal southeast Asia all the way down to parts of Australia. It grows a little over one inch long, or 3 cm, and like other clams it finds a place to anchor itself so that water flows past it all the time and it can filter tiny food particles from the water. It especially likes intertidal areas, which happens to be the same area that mangroves especially like.

Larval jingle shells can swim, but they need to find somewhere solid to anchor themselves as they mature. When a larva finds a mangrove root, it attaches itself and grows a domed shell. If it finds a mangrove leaf, since mangrove branches often trail into the water, it attaches itself to the underside and grows a flatter shell. Clams attached to leaves are lighter in color than clams attached to roots or branches. Fortunately, the mangrove is an evergreen tree that doesn’t drop its leaves every year.

So there you have it. Arboreal clams! Not a hoax or an April fool’s joke.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or Podchaser, or just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us for as little as one dollar a month and get monthly bonus episodes.

Thanks for listening!