Category Archives: extinct

Episode 444: Diskagma and Horodyskia

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It’s Invertebrate August! These creatures are the most invertebrate-y of all!

Further reading:

Dubious Diskagma

Horodyskia is among the oldest multicellular macroorganisms, finds study

A painting of diskagma, taken from the top link above:

Little brown jug flowers (not related to diskagma in any way!):

Show transcript:

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

This episode started out as the March 2025 Patreon episode, but there was more I wanted to add to it that I didn’t have time to cover in that one. Here’s the expanded version to kick off Invertebrate August, which also happens to be episode 444 and releasing on August 4th! It’s about two mystery fossils.

The first is named Diskagma, which means disc-shaped fragment, and it was only described in 2013. That’s partly because it’s so small, barely two millimeters long at most, and partly because of where it’s found. That would be fossilized in extremely old rocks.

When I saw the illustration accompanying the blog post where I learned about Diskagma, I thought it was a cluster of cup-like flowers, sort of like the flowers of the plant called little brown jug. I was ready to send the link to Meredith Hemphill of the Herbarium of the Bizarre podcast, which by the way you should be listening to. But then I saw how old Diskagma is.

It’s been dated to 2.2 billion years old. That’s older than any plant, probably by as much as a billion years.

Even more astounding, it lived on land.

As a reminder, the Cambrian explosion took place about half a billion years ago, when tiny marine animals diversified rapidly to fill new ecological niches. That happened in the water, though, mainly in shallow, warm oceans. If you go back to around 850 million years ago, that may have been roughly the time that land plants evolved from green algae that lived in fresh water. Plant-like algae, or possibly algae-like plants, might be as old as 1 billion years old. But before then, scientists don’t find evidence of anything except microbes living on land, and they were probably restricted to lakes and other bodies of fresh water. That’s because there wasn’t much soil, just broken-up rock that contained very few nutrients and couldn’t retain much water.

Diskagma was shaped like a tiny elongated cup, or an urn or vase, with what looks like a stem on one end and what looks like an opening at the other end. The opening contained structures that look like little filaments, but the filaments didn’t fill the whole cup. Most of the cup was diskagma’s body, so to speak, although we don’t know what it contained. We also don’t know what the filaments were for. We do know that the stem actually did connect diskagma to other cups, so that they lived in little groups. We don’t know if it was a single animal with multiple cuplike structures or if it was a colony, or really anything.

That’s the problem. We don’t know anything about diskagma except that it existed, and that it lived on land 2.2 billion years ago. Tiny as it was, though, it wasn’t microscopic, and it definitely appears more complex than would be expected that long ago, especially from something living on dry land.

One suggestion is that the main part of its body contained a symbiotic bacteria that could convert chemicals to nutrients. As in many modern animals, especially extremophiles, the bacteria would have had a safe place to live and the diskagma would have had nutrients that allowed it to live without needing to eat.

Diskagma lived at an interesting time in the earth’s history, called the great oxygenation event, also called the great oxidation event. We talked about it in episode 341 in conjunction with cyanobacteria, because cyanobacteria basically started the great oxygenation event. Cyanobacteria are still around, by the way, and are doing just fine. They’re usually called blue-green algae even though they’re not actually algae.

Cyanobacteria photosynthesize, and they’ve been doing so for far longer than plants–possibly as much as 2.7 billion years, although scientists think cyanobacteria originally evolved around 3.5 billion years ago. The earth is about 4.5 billion years old, if you were wondering.

Like most plants also do, cyanobacteria produce oxygen as part of the photosynthetic process, and when they started doing so around 2.7 billion years ago, they changed the entire world. Before then, earth’s atmosphere hardly contained any oxygen. If you had a time machine and went back to more than two billion years ago, and you forgot to bring an oxygen tank, you’d instantly suffocate trying to breathe the air. But back then, even though animals and plants didn’t yet exist, the world contained a whole lot of microbial life, and none of it wanted anything to do with oxygen. Oxygen was toxic to the lifeforms that lived then, but cyanobacteria just kept producing it.

Cyanobacteria are tiny, but there were a lot of them. Over the course of about 700 million years, the oxygen added up until other lifeforms started to go extinct, poisoned by all that oxygen in the oceans and air. By two billion years ago, pretty much every lifeform that couldn’t evolve to use or at least tolerate oxygen had gone extinct.

Since Diskagma lived during the time of the great oxygenation event, some scientists suggest that it contained microbes that photosynthesized sunlight into nutrients diskagma could use. And, as in cyanobacteria, the side effect of photosynthesis is oxygen, so diskagma might have been contributing to the oxygen in the air that allows us to breathe these days. On the other hand, it might not have had anything to do with photosynthesis and the great oxygenation event might have driven diskagma to extinction. We have no way to know right now.

What we do know is that 700 million years after diskagma lived, something similar appears in the fossil record. It’s called Horodyskia and its fossils have been found in rocks dating between 1.5 billion years ago to 550 million years ago. Unlike diskagma, which has only been found in rocks from South Africa, horodyskia fossils have been found in Australia, China, and North America. That doesn’t mean diskagma wasn’t widespread, just that we haven’t found it anywhere else. There aren’t all that many rocks that are over two billion years old.

Horodyskia lived in the water, specifically at the bottom of the ocean, probably in shallow water. It’s been described as looking like a row of beads on a thread. The thread seemed to be buried in the sand, and growing up from it in intervals were little pear-shaped bulbs, each no larger than a millimeter long, that stuck up through the sand into the water. There may have been little root-like structures called holdfasts that grew from the bottom of the thread to help keep it in place.

We don’t know a lot about horodyskia either. It wasn’t a plant, since it also lived long before plants evolved. A 2023 study determined that it was a multicellular creature and that it was most likely a protist. Protists are related to animals, plants, and fungi, but aren’t any of those things, and they’re an incredibly diverse group. Most are single-celled and microscopic, but not always. They include algae, amoebas, slime molds, and lots more. Horodyskia’s bulbs might have been encased in a jelly-like substance, as is common in a lot of protists. Some horodyskia specimens found in younger rocks, the ones about 550 million years old, are much smaller than the earlier specimens, with each bulb barely a fraction of a millimeter in size.

We might not know much about these strange life forms, but knowing they existed tells us that even two billion years ago, life was a lot more varied than we used to think. And that’s the most exciting thing of all.

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 442: Trees and Megafauna

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Further reading:

The Trees That Miss the Mammoths

The disappearance of mastodons still threatens the native forests of South America

Study reveals ancient link between mammoth dung and pumpkin pie

A mammoth, probably about to eat something:

The Osage orange fruit looks like a little green brain:

Show transcript:

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

Way back at the end of 2017, I found an article called “The Trees That Miss the Mammoths,” and made a Patreon episode about it. In episode 320, about elephants, which released in March of 2023, I cited a similar article connecting mammoths and other plants. Now there’s even more evidence that extinct megafauna and living plants are connected, so let’s have a full episode all about it.

Let’s start with the Kentucky coffeetree, which currently only survives in cultivation and in wetlands in parts of North America. It grows up to 70 feet high, or 21 meters, and produces leathery seed pods so tough that most animals literally can’t chew through them to get to the seeds. Its seed coating is so thick that water can’t penetrate it unless it’s been abraded considerably. Researchers are pretty sure the seed pods were eaten by mastodons and mammoths. Once the seeds traveled through a mammoth’s digestive system, they were nicely abraded and ready to sprout in a pile of dung.

There are five species of coffeetree, and the Kentucky coffeetree is the only one found in North America. The others are native to Asia, but a close relation grows in parts of Africa. It has similar tough seeds, which are eaten and spread by elephants.

The African forest elephant is incredibly important as a seed disperser. At least 14 species of tree need the elephant to eat their fruit in order for the seeds to sprout at all. If the forest elephant goes extinct, the trees will too.

When the North American mammoths went extinct, something similar happened. Mammoths and other megafauna co-evolved with many plants and trees to disperse their seeds, and in return the animals got to eat some yummy fruit. But when the mammoths went extinct, many plant seeds couldn’t germinate since there were no mammoths to eat the fruit and poop out the seeds. Some of these plants survive but have declined severely, like the Osage orange.

The Osage orange grows about 50 or 60 feet tall, or 15 to 18 meters, and produces big yellowish-green fruits that look like round greenish brains. Although it’s related to the mulberry, you wouldn’t be able to guess that from the fruit. The fruit drops from the tree and usually just sits there and rots. Some animals will eat it, especially cattle, but it’s not highly sought after by anything. Not anymore. In 1804, when the tree was first described by Europeans, it only grew in a few small areas in and near Texas. The tree mostly survives today because the plant can clone itself by sending up fresh sprouts from old roots.

But 10,000 years ago, the tree grew throughout North America, as far north as Ontario, Canada, and there were seven different species instead of just the one we have today. 10,000 years ago is about the time that much of the megafauna of North and South America went extinct, including mammoths, mastodons, giant ground sloths, elephant-like animals called gomphotheres, camels, and many, many others.

The osage orange tree’s thorns are too widely spaced to deter deer, but would have made a mammoth think twice before grabbing at the branches with its trunk. The thorns also grow much higher than deer can browse. Trees that bear thorns generally don’t grow them in the upper branches. There’s no point in wasting energy growing thorns where nothing is going to eat the leaves anyway. If there are thorns beyond reach of existing browsers, the tree must have evolved when something with a taller reach liked to eat its leaves.

The term “evolutionary anachronism” is used to describe aspects of a plant, like the Osage orange’s thorns and fruit, that evolved due to pressures of animals that are now extinct. Scientists have observed evolutionary anachronism plants throughout the world. For instance, the lady apple tree, which grows in northern Australia and parts of New Guinea. It can grow up to 66 feet tall, or 20 meters, and produces an edible red fruit with a single large seed. It’s a common tree these days, probably because the Aboriginal people ate the fruit, but before that, a bird called genyornis was probably the main seed disperser of the lady apple.

In episode 217 we talked about the genyornis, a flightless Australian bird that went extinct around 50,000 years ago but possibly more recently. It grew around 7 feet tall, or over 2 meters, and recent studies suggest it ate a lot of water plants. It would have probably eaten the lady apple fruit whenever it could, most likely swallowing the fruits whole and pooping the big seeds out later.

Way back in episode 19 we talked about a tree on the island of Mauritius that relied on the dodo’s digestive system to abrade its seeds so they could sprout. It turns out that study was flawed and the seeds don’t need to be abraded to sprout. They just need an animal to eat the flesh off the seed, either by just eating the fruit and leaving the seed behind, or by swallowing the entire fruit and pooping the seed out later, and that could have been done by any number of animals. The dodo probably did eat the fruits, but so did a lot of other animals that have also gone extinct on Mauritius.

In June of 2025, a study was published showing that the gomphothere Notiomastodon, which lived in South America until about 10,000 years ago, definitely ate fruit. Notiomastodon was an elephant relation that could probably grow almost ten feet tall, or 3 meters. It probably lived in family groups like modern elephants and probably looked a lot like a modern elephant, at least if you’re not an elephant expert or an elephant yourself. The 2025 study examined a lot of notiomastodon teeth, and it discovered evidence that the animals ate a lot of fruit. This means it would have been an important seed disperser, just like the African forest elephant that we talked about earlier.

Another plant that nearly went extinct after the mammoth did is a surprising one. Wild ancestors of modern North American squash plants relied on mammoths to disperse their seeds and create the type of habitat where the plants thrived. Mammoths probably behaved a lot like modern elephants, pulling down tree limbs to eat and sometimes pushing entire trees over. This disturbed land is what wild squash plants loved, and if you’ve ever prepared a pumpkin or squash you’ll know that it’s full of seeds. The wild ancestors of these modern cultivated plants didn’t have delicious fruits, though, at least not to human taste buds. The fruit contained toxins that made them bitter, which kept small animals from eating them. Small animals would chew up the seeds instead of swallowing them whole, which is not what the plants needed. But mammoths weren’t bothered by the toxins and in fact probably couldn’t even taste the bitterness. They thought these wild squash were delicious and they ate a lot of them.

After the mammoth went extinct, the wild squash lost its main seed disperser. As forests grew thicker after mammoths weren’t around to keep the trees open, the squash also lost a lot of its preferred habitat. The main reason why we have pumpkins and summer squash is because of our ancient ancestors. They bred for squash that weren’t bitter, and they planted them and cared for the plants. So even though the main cause of the mammoth’s extinction was probably overhunting by ancient humans, at least we got pumpkin pies out of the whole situation. However, I personally would prefer to have both pumpkin pie and mammoths.

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 440: Trilobites!

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Thanks to Micah for suggesting this week’s topic, the trilobite!

Further reading:

The Largest Trilobites

Stunning 3D images show anatomy of 500 million-year-old Cambrian trilobites entombed in volcanic ash

Strange Symmetries #06: Trilobite Tridents

Trilobite Ventral Structures

A typical trilobite:

Isotelus rex, the largest trilobite ever found [photo from the first link above]:

Walliserops showing off its trident [picture by TheFossilTrade – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=133758014]:

Another Walliserops individual with four prongs on its trident [photo by Daderot, CC0, via Wikimedia Commons]:

Show transcript:

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

This week we’re going to learn about an ancient animal that was incredibly successful for millions of years, until it wasn’t. It’s a topic suggested by Micah: the trilobite.

Trilobites first appear in the fossil record in the Cambrian, about 520 million years ago. They evolved separately from other arthropods so early and left no living descendants, that they’re not actually very closely related to any animals alive today. They were arthropods, though, so they’re distantly related to all other arthropods, including insects, spiders, and crustaceans.

The word trilobite means “three lobes,” which describes its basic appearance. It had a head shield, often with elaborate spikes depending on the species, and a little tail shield. In between, its body was segmented like a pillbug’s or an armadillo’s, so that it could flex without cracking its exoskeleton. Its body was also divided into three lobes running from head to tail. Its head and tail were usually rounded so that the entire animal was roughly shaped like an oval, with the head part of the oval larger than the tail part. It had legs underneath that it used to crawl around on the sea floor, burrow into sand and mud, and swim. Some species could even roll up into a ball to protect its legs and softer underside, just like a pillbug.

Because trilobites existed for at least 270 million years, there were a lot of species. Scientists have identified about 22,000 different species so far, and there were undoubtedly thousands more that we don’t know about yet. Most are about the size of a big stag beetle although some were tinier. The largest trilobite found so far lived in what is now North America, and it grew over two feet long, or more than 70 centimeters, and was 15 inches wide, or 40 cm. It’s named Isotelus rex.

I. rex had 26 pairs of legs, possibly more, and prominent eyes on the head shield. Scientists think it lived in warm, shallow ocean water like most other trilobites did, where it burrowed in the bottom and ate small animals like worms. There were probably other species of trilobite that were even bigger, we just haven’t found specimens yet that are more than fragments.

Because trilobites molted their exoskeletons the way modern crustaceans and other animals still do, we have a whole lot of fossilized exoskeletons. Fossilized legs, antennae, and other body parts are much rarer, and preserved soft body parts are the rarest of all. We know that some trilobite species had gills on the legs, some had hairlike structures on the legs, and many had compound eyes. A specimen with preserved eggs inside was also found recently.

Some incredibly detailed trilobite fossils have been found in Morocco, including details like the mouth and digestive tract. The detail comes from volcanic ash that fell into shallow coastal water around half a billion years ago. The water cooled the ash enough that when it fell onto the trilobites living in the water, it didn’t burn them. It did suffocate them, though, since so much ash fell that the ocean was more ash than water.

The ash was soft and as fine as powder, and it covered the trilobites and protected their bodies from potential damage, while also preserving the body details as they fossilized over millions of years. The fossils were discovered in 2015, about 509 million years after the trilobites died, and are still being studied.

Two species of trilobite have been found at this Morocco site, and the team is using non-invasive technology to study the preserved insides in one exceptionally preserved specimen. Its entire digestive system is intact, probably because the poor trilobite ended up swallowing a lot of ash before it died. The ash kept the soft tissues from decomposing.

Some trilobites had spines growing from their head shields and even from the rest of the exoskeleton. Scientists think these may have helped protect the animals from being eaten, but they might also have helped them navigate more easily in the water without getting flipped over by currents. One genus of trilobite, Walliserops, even had a structure sticking out from the front of its head called a trident.

The trident grew forward and slightly upward from the head, then split into three prongs. Scientists aren’t sure what it was for, but suggest that it acted as a nose spike like some modern beetles have, which allowed trilobites to fight each other for resources or mates. The tridents weren’t completely symmetrical, and one individual has even been found with a four-pronged trident. (I guess you would call that a quadrent.) Some species had long tridents, some short, but there’s no evidence that only males or only females had them.

Electron microscopes and other modern imaging technology have allowed scientists to learn more about what the trilobite looked like when it was alive. This includes some hints about different species’ coloration and markings. Most trilobites had good vision and were probably as colorful as modern crustaceans. Some rare trilobite fossils show microscopic traces of spots and stripes. One species studied may have had a brown stripe that faded to white along the edges of the body.

All trilobites went extinct at the end of the Permian, about 250 million years ago, during the extinction event called the Great Dying. We talked about it in detail in episode 227 so I won’t go over its causes and effects again except to say that an estimated 95% of all marine animals went extinct during that event. The Great Dying ended the trilobite’s successful 270 million year run on this amazing planet.

When I was little, I found trilobites fascinating. They were so common for so long, and then they were gone. I’ve always wondered if some trilobites survived the Great Dying and were still alive in the deep sea. I’m not the only one who’s wondered that, so let’s talk a little more about why the trilobites went extinct and how some of them might have survived.

Almost all trilobites we know of lived in shallow coastal water. We have trilobite tracks of an ancient low tide shore, which tells us that at least some species could leave the water and venture onto land occasionally, possibly the first animals on earth to do so. Coastal water is well oxygenated and we know trilobites had trouble surviving anoxic events, when the water where they lived had much less oxygen than usual. Anoxic events are actually what led to the Great Dying, but it wasn’t the first time the world’s oceans became less oxygenated. It happened in earlier extinction events too during the Devonian, around 372 and 359 million years ago, and each time many species and genera of trilobites went extinct. The trilobite was already in decline when the Great Dying occurred, with only a handful of genera left, and the extinction event finished them off once and for all according to the fossil record.

But we do know of a few species of trilobite that were adapted to the deep sea. Deep-sea animals have to evolve to be tolerant of low-oxygen conditions. The deep sea is also very little known by humans. It’s possible, even if it’s unlikely, that deep-sea trilobites survived the Great Dying and that their descendants are still around, unknown to science.

One interesting note, and an ongoing mystery about trilobites, is that while we know they were arthropods, we don’t actually know which branch of the phylum Arthropoda they’re most related to. That’s because there are no ancestral versions of the trilobite that have ever been found. When they appear in the fossil record, they’re already recognizably trilobites. It’s possible that the ancestral forms didn’t have exoskeletons that were likely to fossilize, or that we just haven’t found the right fossil bed yet. Until we learn more, it’ll remain a mystery.

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 438: The Dragon Man Skull

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This week we’re going to learn about a new finding about the skull referred to as the Dragon Man!

Further reading:

We’ve had a Denisovan skull since the 1930s—only nobody knew

The proteome of the late Middle Pleistocene Harbin individual

Show transcript:

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

It never fails that only a few days after our annual updates episode, a study is published that’s an important update to an older episode. This time it’s an update so important that it deserves its own episode, so let’s learn more about one of our own extinct close relations, the Denisovan people.

We didn’t know about the Denisovans until 2010, when DNA was sequenced from a finger bone found in Denisova Cave in Siberia in 2008. Scientists were surprised when the DNA didn’t match up with Neanderthal DNA, which is what they expected, since they knew Neanderthals had lived in the cave at various times over thousands of years. Instead, the DNA was for a completely different hominin, a close relation of both humans and Neanderthals.

Since then, researchers have found some Denisovan teeth, two partial mandibles, a rib fragment, and some other bone fragments, but nothing that could act as a type specimen. The type specimen is the preserved specimen of a new species, which is kept for scientists to study. It needs to be as complete as possible, so a handful of fragments just won’t work.

Even without a type specimen, having Denisovan DNA answered some questions about our own history as a species. Ever since scientists have been able to sequence genetic material from ancient bones, they’ve noticed something weird going on with our DNA. Some populations of people show small traces of DNA not found in other human populations, so scientists suspected they were from long-ago cross-breeding with other hominin species. When the Neanderthal genome was sequenced, it matched some of the unknown DNA traces, but not all of them.

Mystery DNA sequences in a closely related population are called ghost lineages. The Denisovan DNA matched the ghost lineage scientists had identified in some populations of people, especially ones in parts of east Asia, Australia, and New Guinea. This is your reminder that despite tiny genetic differences like these, all humans alive today are 100% human. We are all Homo sapiens.

Naturally, we as humans are interested in our family tree. We even have an entire field of study dedicated to studying ancient humans and hominins, paleoanthropology. Lots of scientists have studied the Denisovan remains we’ve found, along with the genetic material, but they really need a skull to learn so much more about our long-extinct distant relations.

Luckily, we’ve had a Denisovan skull since the 1930s. But wait, you may be saying, you just said we didn’t have anything but bone fragments and teeth! Why didn’t you mention the skull?

It’s because the skull was hidden by its finder, a Chinese construction worker. The man was helping build a bridge and was ashamed that he was working for a Japanese company. That region of China was under Japanese occupation at the time, and the man didn’t want anyone to know that he was working for people who were treating his fellow citizens badly. He thought the skull was an important find similar to the Peking Man discovery in 1929, so he hid the skull at the bottom of an abandoned well to keep it safe. He didn’t dare share any information about it until he was on his death-bed, when he whispered his secret to his son.

It wasn’t until 2018 that the man’s family took another look at the skull and realized it definitely wasn’t an ordinary human skull. It was obviously extremely old and had a pronounced brow and really big teeth.

In 2021 the skull was classified as a new species of hominin, Homo longi, where the second word comes from the Mandarin word for dragon. That’s because the area where it was found is called Dragon River.

But not everyone agreed that the Dragon Man skull, as it came to be known, was actually a new species. Scientists continued to study the skull, and finally, a paleoanthropologist named Qiaomei Fu and her team managed to extract DNA from the skull and one of its teeth. The resulting genetic profile indicated that the Dragon Man was a Denisovan.

The skull has been dated to 146,000 years ago, possibly older. It’s nearly complete, which provides a lot of information to scientists. Scientists are pretty sure Dragon Man was a fully grown male, but less than 50 years old when he died.

So what did Dragon Man look like when he was alive? We don’t know how tall he was or his overall build, although from the other Denisovan bones we have, we know Denisovans were a strong, robust people, similar to Neanderthals, and were more closely related to Neanderthals than humans. Dragon Man would have had a pronounced brow that would probably make his eyes look deep-set, and a large nose but a receding chin. Genetic markers indicate he probably had dark hair and eyes, and a medium shade of skin. If you had a time machine and could go back and meet Dragon Man when he was alive, you’d know at a glance that he wasn’t a Homo sapiens but he would probably look pretty normal in most respects.

One exciting note is that paleoanthropologists now think that three other ancient skulls from China may actually be Denisovan skulls. With luck they’ll be able to extract genetic material from them soon so we can learn more about our ancient cousins.

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 434: The Real Life Dragon

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Thanks to Jaxon for suggesting this week’s topic, Coelurosauravus!

Further reading:

Coelurosauravus

New Research Reveals Secrets of First-Ever Gliding Reptile

The modern Draco lizard glides on “wings” made from extended rib bones:

Coelurosauravus glided on wings that were completely different from any other wings known [art from the first link above]:

Show transcript:

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

This week we’re going to learn about an extinct animal suggested by Jaxon. It’s called Coelurosauravus and it lived around 255 million years ago in what is now Madagascar.

Coelurosauravus was a member of the Weigeltisauridae family, reptiles whose fossils have been found not just in Madagascar but in parts of Europe, and maybe even North America (although we’re not sure yet). They were gliding reptiles that probably lived in trees and ate insects and other small animals, sort of like modern gliding lizards. But while most gliding lizards are very small, Coelurosauravus grew over a foot long, or around 40 cm, and that’s nowhere near the weirdest thing about it.

To explain why Coelurosauravus was so very peculiar, we have to learn a little about other gliding reptiles. Back in episode 255 we learned about kuehneosaurids, and that’s a good place to start.

Kuehneosaurids lived around 225 million years ago in what is now England. This wasn’t all that long after Coelurosauravus lived and not that far away from where some of its relations lived, but the two weren’t related. Kuehneosaurus looked like a big lizard although this was before modern lizards evolved, but it was a reptile and it was even larger than Coelurosauravus. Kuehneosaurus grew about two feet long, or 70 cm, including a long tail, and probably lived in trees and ate insects.

Kuehneosaurus glided on sail-like structures on its sides that were made from extended ribs with skin stretched over them. Its wings weren’t all that big, although they were big enough that they could act as a parachute if the animal fell or jumped from a branch. Another gliding reptile, Kuehneosuchus, had wings that were much longer. In a study published in 2008, a team of scientists built models of kuehneosuchus and tested them in a wind tunnel used for aerospace engineering. It turned out to be quite stable in the air and could probably glide very well.

We don’t know a whole lot about the kuehneosaurids because we haven’t found very many fossils. We’re not even sure if the two species are closely related or not. We’re not even sure they’re not the same species. Individuals of both were uncovered in caves near Bristol in the 1950s, and some researchers speculate they were males and females of the same species. Despite the difference in wings, otherwise they’re extremely similar in a lot of ways.

Generally, researchers compare the kuehneosaurids to modern draco lizards, which we talked about in episode 237, even though they’re not related. Draco lizards are much smaller, only about 8 inches long including the tail, or 20 cm, and live throughout much of southeastern Asia. Many gliding animals, like the flying squirrel, have gliding membranes called patagia that stretch from the front legs to the back legs, but the draco lizard is different. It has greatly elongated ribs that it can extend like wings, and the skin between the ribs acts as a patagium. This skin is usually yellow or brown so that the lizard looks like a falling leaf when it’s gliding. Draco lizards can fold their wings down and extend them, which isn’t something the kuehneosaurids appear to have been able to do.

But now let’s return to Coelurosauravus. It too had wing-like structures on its sides that consisted of skin stretched over bony struts. But in this case, the bones weren’t elongated ribs.

Coelurosauravus had about 30 pairs of long, flexible bones that extended from the sides of its belly, and it could open and close its wings like draco lizards do. Scientists think the bones developed from osteoderms, which are bony structures that many animals have on their skin, that act as a sort of built-in armor. As far as we know, no other animal in the entire history of life on earth has developed what are basically wings from osteoderms.

Coelurosauravus had long, slender legs with sharp claws that it used to climb around in trees, and a long tail to help it keep its balance as it climbed. Its head was decorated with a bony frill that had spikes along the edges. The frill might have been brightly colored, a way to attract mates or intimidate potential predators, and it might also have been an attachment site for strong jaw muscles.

In other words, Coelurosauravus had four legs, two wings, and horns on its head. This little reptile was basically a dragon.

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 431: The New Dire Wolf

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Thanks to Jayson for suggesting this week’s topic, the new “dire wolf”! Also, possibly the same but maybe a different Jayson is the youngest member of the Cedar Springs Homeschool Science Olympiad Team, who are on their way to the Science Olympiad Nationals! They’re almost to their funding goal if you can help out.

Further reading:

Dire wolves and woolly mammoths: Why scientists are worried about de-extinction

The story of dire wolves goes beyond de-extinction

These fluffy white wolves explain everything wrong with bringing back extinct animals

Dire Wolves Split from Living Canids 5.7 Million Years Ago: Study

This prehistoric monster is the largest dog that ever lived and was able to crush bone with its deadly teeth – but was wiped out by cats

“Dire wolf” puppies:

An artist’s interpretation of the dire wolf (red coats) and grey wolves (grey coats) [taken from fourth link above]:

The “mammoth fur” mice:

Show transcript:

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

This week we have a suggestion from Jayson, who wants to learn about the so-called “new” dire wolf.

Before we get started, a big shout-out to another Jayson, or maybe the same one I’m honestly not sure, who is the youngest member of the Cedar Springs Homeschool Science Olympiad Team. They’ve advanced to the nationals! There’s a link in the show notes if you want to donate a little to help them with their travel expenses. This is a local team to me so I’m especially proud of them, and not to brag, but I’ve actually met Jayson and his sister and they’re both smart, awesome kids.

Now, let’s find out about this new dire wolf that was announced last month. In early April 2025, a biotech company called Colossal Biosciences made the extraordinary claim that they had produced three dire wolf puppies. Since dire wolves went extinct around 13,000 years ago, this is a really big deal.

Before we get into the details of Colossal’s claim, let’s refresh our memory about the dire wolf. We talked about it in episode 207, so I’ve taken a lot of my information from that episode.

According to a 2021 study published in Nature, 5.7 million years ago, the shared ancestor of dire wolves and many other canids lived in Eurasia. Sea levels were low enough that the Bering land bridge, also called Beringia, connected the very eastern part of Asia to the very western part of North America. One population of this canid migrated into North America while the rest of the population stayed in Asia. The two populations evolved separately until the North American population developed into what we now call dire wolves. Meanwhile, the Eurasian population developed into many of the modern species we know today, and some of those eventually migrated into North America too.

By the time the gray wolf and coyote populated North America, a little over one million years ago, the dire wolf was so distantly related to it that even when their territories overlapped, the species avoided each other and didn’t interbreed. We’ve talked about canids in many previous episodes, including how readily they interbreed with each other, so for the dire wolf to remain genetically isolated, it was obviously not closely related at all to other canids at that point.

The dire wolf looked a lot like a grey wolf, but researchers now think that was due more to convergent evolution than to its relationship with wolves. Both lived in the same habitats: plains, grasslands, and forests. The dire wolf was slightly taller on average than the modern grey wolf, which can grow a little over three feet tall at the shoulder, or 97 cm, but it was much heavier and more solidly built. It wouldn’t have been able to run nearly as fast, but it could attack and kill larger animals.

The dire wolf went extinct around 13,000 years ago, but Colossal now claims that they’re no longer extinct. There are now exactly three dire wolves in the world, two males and a female, born to two different dogs who acted as surrogate mothers. But are these really dire wolves, or are they something else?

Colossal’s scientists claim that the 2021 Nature study that determined gray wolves and dire wolves weren’t closely related and couldn’t interbreed was based on poor-quality DNA studies. They redid the genetic scans and determined that dire wolves were more wolf-like than the 2021 study thought. But the 2021 study was published in the foremost peer-reviewed journal in the scientific world. Colossal’s study hasn’t been published at all.

Extraordinary claims require extraordinary evidence. In other words, until a study is published in a respected peer-reviewed journal that contradicts the 2021 Nature study, all the genetic evidence we have now points to dire wolves and gray wolves being extremely genetically different.

Colossal’s scientists made 20 edits to 14 gray wolf genes to make the puppies more similar to dire wolves in size, with white coats even though there’s no evidence that real dire wolves were white. Colossal claims that the genomes of grey wolves and dire wolves are 99.5% identical, but those 20 changes are out of 12,235,000 genetic differences. Genetically these puppies are just modern grey wolves.

The biggest problem with the claim that the puppies are actually dire wolves is that it implies that bringing back an extinct species is really easy. Not only can this make people think that extinction isn’t a big deal after all, it also ignores the issues that make animals go extinct in the first place, especially recently, like pollution, habitat loss, climate change, invasive species, and over-hunting or capture of wild animals to sell as exotic pets.

In the very first, very terrible Strange Animals Podcast episode, I talked about the quagga, a species of zebra from South Africa that went extinct very recently due to human causes. I was excited about the de-extinction attempts for that species, which mostly involved breeding zebras with the most quagga genetic material to select for quagga-like traits. I still think this is a good project, since the quagga’s ecosystem is still in place and still has a quagga-shaped hole in it. Colossal has also done good work with red wolves in North America, helping to keep that critically endangered species genetically healthy.

Also in an early episode, I talked about Colossal’s de-extinction plans for the mammoth. I was all for that too, tongue-in-cheek, because I said I wanted a pet mammoth. Now I’ve changed my mind. Awesome as it would be to see real live mammoths, there’s not any real habitat left for them. Between climate change, habitat loss due to human activity, and more than ten thousand years of evolution of other animals to move into the mammoth’s empty ecological niche, where does Colossal plan to put its mammoths? We don’t even have safe habitats for elephants anymore, which are still around.

Earlier this year, Colossal announced another genetically modified animal, mice with long golden-brown fur inspired by woolly mammoth fur. Mammoths were highly adapted for cold far beyond long fur, while modern elephants are highly adapted for hot climates. If Colossal’s mammoths are anything like its so-called dire wolves, they’ll be editing genes to change appearance, not anything else. That’s unethical, basically taking an endangered heat-adapted animal, giving it a heavy coat, and sticking it into a cold climate. It will have no herd mates and no knowledge of how to survive in the wild in a climate it was never intended to live in, meaning it will be dependent on human help. Once the novelty of “oh look, a furry elephant” wears off, and Colossal either goes out of business or moves on to the next big thing, what will happen to the mammoth?

That’s one of the concerns about the new dire wolves. They don’t have a wolf family. They’re completely dependent on humans and will never be able to survive in the wild, even if they were allowed to try.

Let’s return to extinct canids to finish on a brighter note, something that Richard from NC brought to my attention recently. It’s an animal called epicyon, a canid that may have lived as recently as 5 million years ago in North America. It’s the largest canid ever discovered, around 3 feet tall, or 90 cm, at the shoulder and as much as 8 feet long, or 2.5 meters. It probably weighed as much as a small bear, and it was strong and powerful so that it was probably more bear-like or lion-like in body shape than wolf-like.

It had a short, powerful muzzle and strong jaws with huge teeth meant for crushing bone, similar to modern hyenas. It wasn’t anywhere near as fast a runner as modern wolves, but it could probably move pretty fast when it needed to. Some scientists think it was a pack animal, but it may have been an ambush predator instead of hunting in packs like wolves and other modern canids do.

Epicyon probably preyed on megaherbivores like camels, horses, pronghorn, rhinoceroses, and peccaries, all of which were common in North America several million years ago. It probably also scavenged a lot of its food, since it could break bones other animals couldn’t. We’re not sure why epicyon went extinct, but some scientists suggest it was out-competed by saber-tooth cats and more modern canids–including the dire wolf.

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 427: The Other Cephalopods

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Further reading:

Reconstructing fossil cephalopods: Endoceras

Retro vs Modern #17: Ammonites

Hammering Away at Hamites

An endocerid [picture by Entelognathus – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=111981757]:

An ammonite fossil:

A hamite ammonoid that looks a lot like a paperclip [picture by Hectonichus – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=34882102]:

Show transcript:

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

When you think about cephalopods, if that’s a word you know, you probably think of octopuses and squid, maybe cuttlefish. But those aren’t the only cephalopods, and in particular in the past, there used to be even more cephalopods that are even weirder than the ones we have today.

Cephalopods are in the family Mollusca along with snails and clams, and many other animals. The first ancestral cephalopods date back to the Cambrian, and naturally we don’t know a whole lot about them since that was around 500 million years ago. We have fossilized shells that were only a few centimeters long at most, although none of the specimens we’ve found are complete. By about 475 million years ago, these early cephalopod ancestors had mostly died out but had given rise to some amazing animals called Endocerids.

Endocerids had shells that were mostly cone-shaped, like one of those pointy-ended ice cream cones but mostly larger and not as tasty. Most were pretty small, usually only a few feet long, or less than a meter, but some were really big. The largest Endoceras giganteum fossil we have is just under 10 feet long, or 3 meters, and it isn’t complete. Some scientists estimate that it might have been almost 19 feet long, or about 5.75 meters, when it was alive.

But that’s just the long, conical shell. What did the animal that lived in the shell look like? We don’t know, but scientists speculate that it had a squid-like body. The head and arms were outside of the shell’s opening, while the main part of the body was protected by the front part of the shell. We know it had arms because we have arm impressions in sections of fossilized sea floor that show ten arms that are all about the same length. We don’t know if the arms had suckers the way many modern cephalopods do, and some scientists suggest it had ridges on the undersides of the arms that helped it grab prey, the way modern nautiluses do. It also had a hood-shaped structure on top of its head called an operculum, which is also seen in nautiluses. This probably allowed Endoceras giganteum to pull its head and arms into its shell and use the operculum to block the shell’s entrance.

We don’t know what colors the shells were, but some specimens seem to show a mottled or spotted pattern. The interior of Endoceras giganteum’s shell was made up of chambers, some of which were filled with calcium deposits that helped balance the body weight, so the animal didn’t have trouble dragging it around.

3D models of the shells show that they could easily stick straight up in the water, but we also have trace fossils that show drag marks of the shell through sediment. Scientists think Endoceras was mainly an ambush predator, sitting quietly until a small animal got too close. Then it would grab it with its arms. It could also crawl around to find a better spot to hunt, and younger individuals that had smaller shells were probably a lot more active.

We talked about ammonites way back in episode 86. Ammonites were really common in the fossil record for hundreds of millions of years, only going extinct at the same time as the dinosaurs. Some ammonites lived at the bottom of the ocean in shallow water, but many swam or floated throughout the ocean. Many ammonite fossils look like snail shells, but the shell contains sections inside called chambers. The largest chamber, at the end of the shell, was for the ammonite’s body, except for a thin tube that extended through the smaller inner chambers, which allowed the animal to pump water or air into and out of the chambers in order to make itself more or less buoyant in the water.

While many ammonites were no larger than modern snails, many others were bigger than your hand, sometimes twice the size of your hand even if you have really big hands. But during the Jurassic and part of the Cretaceous, some ammonites got even bigger. One species grew almost two feet across, or 53 cm. Another grew some 4 ½ feet across, or 137 cm, and one species grew as much as 6 ½ feet across, or 2 meters. It was found in Germany in 1895 and dates to about 78 million years ago–and it wasn’t actually a complete fossil. Researchers estimate that in life it would have been something like 8 and a half feet across, or 2.55 meters.

Ammonites look a lot like a modern cephalopod called the nautilus, so much so that I thought for a long time that they were the same animal and they were all extinct. Imagine my surprise when I started researching episode 86! But although nautiluses look similar, it turns out they’re not all that closely related to ammonites. Ammonites were probably more closely related to squid, octopuses, and cuttlefish than to modern nautiluses.

Until very recently, we had no idea what the ammonite’s body looked like, just its shell. Scientists hypothesized that they had ten arms. Then, in 2021, three years after episode 86 because I have been making this podcast for a really long time, scientists found a partial fossil of an ammonite’s body. That was followed by two more discoveries of ammonite bodies, so we know a lot more about it now. We now know that ammonites resembled squid with shells a lot more than they resembled nautiluses. We still don’t know how many arms they had, but they do appear to have had two feeding tentacles like squid have, with hook-like structures that would help the ammonite hold onto wiggly prey.

Not all ammonoids had shells that resembled a snail’s spiral shell. Heteromorph ammonites had a wide variety of shell shapes. They were extremely common starting around 200 million years ago, so common that they’re used as index fossils to help scientists determine how old a particular segment of rock is. Some of the shells look a lot like ram horns, loosely coiled with ribs on the upper surface, while others were almost straight.

Baculites are a genus of ammonoid that had straight or only gently curved shells, sort of like Endocerids but living about 300 million years later and only very distantly related to them. The longest baculite shell found so far was about 6 and a half feet long, or 2 meters. Nipponites were a more complicated shape, as though a ram’s horn somehow got twisted up and crumpled into a lopsided ball. Turrilites grew in a tight spiral but with the coils on top of each other like a spiral staircase. But the best to my mind are the hamites, because some of them had shells shaped like paper clips.

We don’t know much about heteromorph ammonites, and scientists aren’t even sure how they moved around and found food. Their shell shapes would have made them slow swimmers. Many scientists now think they floated around in the water and caught tiny food as they encountered it. They even survived the end-cretaceous extinction event, although they only lived for about half a million years afterwards.

Let’s finish with a living animal, the Dana octopus squid. It’s a squid but as an adult it doesn’t have the two feeding tentacles that most squid have. It just has eight arms, which is why it’s called the octopus squid. The Dana octopus squid is a deep-sea animal that can grow quite large, although it doesn’t have very long arms. The largest specimen measured was 7 and a half feet long including its arms, or 2.3 meters, but most of that length was the mantle. The arms are only about two feet long, or 61 cm.

Because it lives in deep water, we don’t know very much about the Dana octopus squid. We know it’s eaten by sperm whales, sharks, and other large animals, and occasionally part of a dead one will wash ashore. In 2005 a team of Japanese researchers filmed a living Dana octopus squid in deep water and discovered something surprising. The undersides of the squid’s arms contain photophores that can emit light, which is pretty common in deep-sea animals. The squid’s photophores are the largest known, and now we know why.

The video showed the squid attacking the bait, and before it did, its photophores flashed extremely bright. It was so bright that the scientists think the light disorients the squid’s prey as well as allowing the squid to get a good look at where its prey is. Even better, young Dana octopus squid have been observed flashing their photophores at large predators and swimming toward them in a mock attack, startling and even scaring away a much larger animal.

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

Thanks for listening!

Episode 413: The Great American Interchange

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

Further reading:

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

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

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

Glyptodonts were big armored mammals:

The porcupine, our big pointy friend:

Show transcript:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Thanks for listening!

Episode 403: Predator X

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Thanks to Eesa for suggesting this week’s topic, the pliosaur Predator X!

Further reading:

Predator X / Pliosaurus funkei [you can find lots of interesting pictures here, some artwork and some skeletal diagrams]

Kronosaurus had a big skull with big teeth:

Show transcript:

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

We’re one week closer to Halloween, and that means the monsters are getting more monster-y, at least in name, although I wouldn’t want to meet this one in person. It’s referred to as Predator X, and thanks to Eesa for suggesting it!

Fortunately for everyone who likes to swim and boat in the ocean, Predator X has been extinct for around 145 million years. It’s a type of marine reptile called a pliosaur, Pliosaurus funkei, but there was nothing funky about it. It was huge, fast, and incredibly strong. Also, the funky part of the name comes from the couple who originally discovered the first specimen, who had the last name of Funke.

We only have two Predator X specimens right now, both of them found in the same rock formation from a Norwegian island. The remains were first discovered in 2004 but the process of recovering them took many years. Because winters in Norway are very cold, the exposed rocks were subject to freezing temperatures that had broken a lot of the fossils into fragments, and some of the fossils crumbled into pieces as they dried out. All told, 20,000 pieces were recovered and painstakingly fit back together like a gigantic jigsaw puzzle made of fossilized bones.

Neither specimen is complete but we have enough bones that scientists can estimate the animal’s size when it was alive—and it was huge! It probably grew up to 39 feet long, or 12 meters, and some individuals would certainly have been bigger. Initial estimates were even longer, up to 50 feet, or over 15 meters, but that was before the specimens were fully studied.

Like other pliosaurs, predator X had a short tail and big teeth in its long jaws. Its head was massive, around 7 feet long, or 2 meters, and its front flippers were probably about the same length. It had four flippers, and researchers think its front flippers did most of the work of swimming, with the rear flippers acting as a rudder, but it could probably use its back flippers for a little extra boost of speed when it needed to. But it was a strong, fast swimmer no matter what, probably as fast as a modern orca, and very maneuverable. It had to be, because it ate other marine reptiles like plesiosaurs that were themselves very fast swimmers. It undoubtedly also ate sea turtles and fish, and probably pretty much anything else it could catch. It didn’t eat whales because this was long, long before whales evolved.

Predator X got its nickname from reporters back when the paleontologists thought it was 50 feet long. It didn’t have a name yet so it got called Predator X because that sounded impressive (and it is), but it isn’t the only giant pliosaur known.

Kronosaurus was originally described in 1924 from fossils discovered in Australia, and current estimates of its size agree that it could probably grow to around 33 feet long, or 10 meters. This may be a low estimate, though, because the size of the biggest skull found might have been over 9 feet long, or 2.85 meters, although the skull isn’t complete so its full size is just an estimate. Pliosaurs do have big heads, but if Kronosaurus’s skull really is longer than predator X’s skull, it was probably a bigger animal overall.

Kronosaurus’s fossils have only been found in an ancient inland sea that covered most of Queensland and Central Australia until about 100 million years ago. It was probably a relatively shallow, cold sea, and although it had all the marine animals you’d expect for the time, like sharks, ammonites, ichthyosaurs, plesiosaurs, lungfish, sea turtles, and lots more, Kronosaurus was the apex predator. It was so big and deadly that a full-grown Kronosaurus didn’t have to worry about anything in the water.

Trying to figure out how big an extinct animal was from its fossil remains isn’t easy. It’s rare that an entire skeleton is discovered, so scientists have to make estimates of how big the missing pieces were, such as how long its tail was. Then they have to deal with the problem of how rare it is to find fossil specimens in the first place. The fewer specimens we have, the harder it is to decide how big a species may have grown overall. If you have 100 fossilized animals, you can measure them all and get a good idea how big most adults of that species got. If you have one fossilized animal, you don’t know if that particular individual was extra small or average or maybe the biggest one that ever lived.

All that aside, some of Kronosaurus’s teeth grew an entire 12 inches long, or 30 cm. Predator X had teeth the same size. So if you somehow invent a time machine and go back to the Cretaceous or Jurassic to look around, you might want to stay out of the water—or just bring an extra strong shark cage.

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!