Episodes

  • Episode 486: Two Rediscovered Birds
    May 25 2026
    Further reading: https://www.audubon.org/news/like-finding-unicorn-researchers-rediscover-black-naped-pheasant-pigeon-bird https://www.sci.news/paleontology/confuciusornis-shifan-11528.html The black-naped pheasant-pigeon: Confuciusornis: Show transcript: We’re going to learn about two birds that have been in the news lately. The first is the black-naped pheasant-pigeon. The word nape refers to the back of the neck, and this bird does have a black neck. It’s a dark blue-black all over, in fact, with reddish-brown wings, a red bill, red eyes, and long yellow legs. It looks almost identical to the other three species of pheasant-pigeons known, although some scientists think they’re subspecies. Those three are the white-naped, the green-naped, and the grey-naped pheasant-pigeons, and if you’re wondering if the spot of color on the back of the neck is the easiest way to tell these birds apart, you are exactly right. All four species are native to parts of New Guinea or small islands nearby. Pheasant-pigeons look a lot like pheasants and are about the size of a chicken, although they’re actually pigeons. They live in forests and eat seeds and fruit, and while they can fly they spend almost all of the time on the ground. We don’t know a whole lot about them because they’re so secretive and hard to spot in the wild, although the white-naped and green-naped birds are sometimes kept in zoos. In the case of the black-naped pheasant-pigeon, all scientists knew about it was from two specimens collected in 1882. It hadn’t been seen since…until September of 2022. A team of scientists visited Fergusson Island off the east coast of Papua New Guinea in September, as part of a worldwide collaboration of scientists called The Search for Lost Birds. This is similar to the Search for Lost Frogs that has been active for over a decade, discovering lots of new amphibians and rediscovering even more. The 2022 search was actually a follow-up to a 2019 expedition that had failed to find the bird, although it did make other discoveries. In 2022, the team brought more people and equipment, determined to make the best effort possible to find the black-naped pheasant-pigeon. They consulted with local hunters to find the best places to search, and talked to lots of residents to see if anyone had seen one, and spent day after day hiking through forested mountains. For weeks they had no luck. Then, in a remote mountain village, they finally met some people who were familiar with the bird. One man led them to the right part of the forest and they set up camera traps, but at that point they only had a few days left before they had to leave the island. When they checked the pictures captured by the camera traps, though, they’d found it! Two of the cameras had taken pictures and video of what were definitely black-naped pheasant-pigeons, and since the cameras were several kilometers apart the pictures were probably of different individuals. The black-naped pheasant-pigeon wasn’t extinct, which means it can be protected. Habitat loss, especially from commercial logging, and feral domestic cats are the two main threats to birds in the area. The other bird we’re going to talk about today hasn’t been seen in even longer: 119 million years, in fact. The article about this fossil was only released a few days ago as this episode goes live. You can check the show notes for links to this article and a good one about the pheasant-pigeon too. Paleontologists discovered the bird’s fossil remains in northeastern China, in fossil beds that contain incredibly well-preserved animals and plants. The Jiufotang Formation in China dates to the early Cretaceous, between about 122 and 119 million years ago, and researchers think it’s from an area that was once a shallow lake surrounded by forests. Every so often, a nearby volcano would erupt and the resulting ash would fall into the lake, causing anoxic conditions that helped preserve animals that died and sank into the mud at the bottom of the lake. There are lots of fish, pterosaurs, birds, and dinosaurs among the fossils discovered, most of them small but a few quite large. This includes a type of tyrannosaur that probably grew around 33 feet long, or 10 meters. A few early mammals have been discovered too. In one case, the remains of 40 individual birds were found on one big slab of stone, and scientists think an entire flock of birds was killed by a volcanic ashfall or poisonous gases from the volcano. The newly described fossil we’re talking about today was almost complete and almost completely articulated, preserved with the impression of feathers around its body. The bird has been named Confuciusornis shifan and was a little smaller than a modern crow. It had a toothless beak and a short tail, although it probably had long tail feathers. Other Confuciusornis species have been discovered with the impressions of long tail plumes. All of the Confuciusornis fossils ...
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    8 mins
  • Episode 485: Cryodraken’s Very Bad Day
    May 18 2026
    Further reading: Rare pterosaur fossil reveals crocodilian bite 76m years ago Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. Let’s learn about a type of pterosaur that lived around 75 million years ago in what is now Canada, and we’ll specifically learn about an individual young pterosaur that had a very bad day, a bad day that’s preserved in the fossil record. Pterosaurs were flying reptiles that lived alongside dinosaurs, but weren’t actually dinosaurs. Some of them got as big as small airplanes while some were barely the size of chickens. Cryodrakon was one of the biggest ones, with an estimated wingspan of 33 feet, or 10 meters, for an adult animal—maybe even bigger. We don’t know the adults’ size for sure because we only have a few fossils of adult Cryodrakons, and those are incomplete. Mostly we have fossils of young individuals. The older juveniles had a wingspan of around 16 feet, or 5 meters, which is still pretty darn big. Cryodrakon was the first pterosaur discovered in Canada, with fossils found in Alberta in 1972. Since then more fossils have been discovered in the same province, especially in what’s called the Dinosaur Park Formation. Like other pterosaurs in the family Azhdarchidae, Cryodrakon had long legs and a very long neck with long jaws. Most scientists think it spent a lot of time on land, hunting small animals. It could fold the longest part of its wings up out of the way in order to walk on all fours. A flying animal’s wing, whether it’s a pterosaur or a bird or a bat, is a modified arm. Insects are different because they’re invertebrates. In bats, the fingers are elongated with strong skin stretched between them to form a wing. In birds, the fingers are fused into a sort of stump and most of the flying surface is feathers. In pterosaurs, one or two fingers were elongated like a bat’s, but the other fingers were short and blunt. These are the fingers that azhdarchids could walk on when the rest of the fingers, and therefore the wing, was folded up so it wouldn’t get in the way. We know it’s possible for a winged animal to walk this way because vampire bats do it just fine, and they’re able to run around quite fast on the ground. An adult Cryodrakon walking on all fours would have been about as tall as a modern giraffe because of its long neck. Its neck was strong and its head large, so it could easily grab a little running dinosaur and swallow it whole, maybe giving it a good chomp with its toothless jaws first. While azhdarchids probably couldn’t run, because the hind legs weren’t very strong and the feet were small, it could probably walk pretty quickly. And, of course, it could fly extremely well. Scientists think it launched into the air by pushing off the ground with its wings, not its back legs. In older episodes we’ve talked about some other species of pterosaur from this same family, especially Quetzalcoatlus, a genus of exceptionally large pterosaurs discovered in North America. The largest individuals may have had a wingspan potentially more than 36 feet, or 11 meters. But in 2002 a remarkably complete pterosaur fossil was discovered in Romania, and while we don’t have the complete wing bones, estimates suggest this new species might even be larger than Quetzalcoatlus. Some estimates put its wingspan at 39 feet across, or 12 meters. It had a shorter neck than other azhdarchids but a massive head. Its neck was about 5 feet long, or 1.5 meters, while its skull was at least that long and possibly as much as 8 feet long, or 2.5 meters. The Romanian specimen was named Hatzegopteryx but the specimen has been nicknamed Dracula (also the name of my cat). Some scientists initially argued that Dracula was just an especially big Quetzalcoatlus, but while it was probably a close relative, it’s too different to be the same species. Despite their huge size, pterosaur bones were delicate because the animals had to be light enough to fly. That means they had air pockets or spongy internal structures in their bones, and that means their bones were much less likely to preserve. The most likely reason we have so many more fossils from young pterosaurs than old ones is because many species of pterosaur appear to have nested together. It’s a sad fact of life for wild animals that many young ones don’t survive, so the fossils of young pterosaurs probably come from nesting areas. And that brings us to our young Cryodrakon who had a terminally bad day. In 2023, researchers found a neck bone of a cryodrakon that had a puncture right through it. The hole in the bone is about 4 mm across and circular, and the scientists who examined it think it’s from a crocodilian tooth. We don’t know if the baby pterosaur was chomped to death by a crocodilian or if it was already dead and the crocodilian was scavenging it. That’s not even the only Cryodrakon fossil that shows tooth marks. In 1995 the fossils of a young animal ...
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    7 mins
  • Episode 484: The Sewellel and the Superflea
    May 11 2026
    The sewellel is a little rodent: The superflea is a big flea (left, compared to a regular flea, right): Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. Let’s learn about a rodent you may never have heard of, unless you live where it does, and a parasite that makes that rodent its host. It’s not an ordinary parasite, but don’t worry, it’s not icky. You can continue to snack. The rodent is called the sewellel, Aplodontia rufa. It’s also called the mountain beaver even though it doesn’t always live in the mountains and it isn’t a beaver. It doesn’t even look like a beaver. For one thing, it only has a little nub of a tail and it only grows around 20 inches long, or 50 cm. It has small eyes and ears, short legs, a chunky body, and long claws. This body shape should give you a hint about its lifestyle: the sewellel is a digger, although it can also swim just fine and can even climb small trees to eat young twigs and leaves. The sewellel is an aplodont, a large group of rodents that have been common in Europe, Asia, and North America for 40 million years. But it’s the only one left. All the other aplodonts went extinct several million years ago at least. We’ve actually talked before about one of the sewellel’s extinct relations, the horned gopher (which was not a gopher), in the Patreon episode about animals with nose horns. The sewellel itself hasn’t been around all that long, only appearing in the fossil record a few million years ago. It lives in a small area of northwestern North America, in parts of British Columbia, Washington state, Oregon, and a few parts of California. It lives in forests where it doesn’t get too cold in the winter, since it doesn’t hibernate and isn’t as good at keeping itself warm as other rodents are. It also needs to drink more water than other rodents and prefers to live in wet climates as a result. In fact, the sewellel is sometimes referred to as a living fossil since it lacks many features that all other living rodents have. Its teeth resemble a simpler version of squirrel teeth, so some researchers think it may be most closely related to squirrels, but even if that’s the case, it isn’t very closely related. The sewellel’s ancestors were more adapted to live in trees and a study published in 2018 determined that it had a larger brain than the sewellel. Since the sewellel is nocturnal and spends most of its life underground, it doesn’t need to see very well, and the part of the brain that processes vision is much smaller than in its ancestors. The sewellel mostly eats ferns, although it also eats other plants, and some of its favorite plants are toxic to other animals. It’s a solitary, mostly nocturnal animal that digs deep, complex burrows, and it stays as close as possible to the burrow entrance so it can hide easily if it needs to. Everything eats the sewellel, from owls to coyotes to bobcats to eagles. And that brings us to the parasite associated with the sewellel. Many animals have parasites that are specific to that particular species. The Patreon episode about whale lice has some information about how specific this can get. The male sperm whale has a different species of louse than the species that lives on female sperm whales, for instance. Also, the whale louse isn’t a louse, it’s a type of crustacean. The sewellel’s parasite is a type of flea. Big deal, you say, fleas are all about the same. Are they, though? Because the sewellel’s flea is actually kind of a big deal. It is, in fact, the largest flea known, called the superflea. It can grow up to 8 mm long (and possibly longer, reports vary). I just measured, and that’s the length of my little fingernail, from the base to the quick. Most species of flea are 3 mm long at most. The superflea is only found on the sewellel. It looks like an ordinary flea except for its size, meaning it’s laterally flattened with legs that allow it to jump long distances. So why is it so big compared to other fleas, especially considering that it lives on an animal that’s about the size of a chonky cat? No one knows. No one has even the slightest idea why this flea is so big. There used to be even bigger fleas, some up to two cm long. That’s 20 mm, or just a little more than twice the length of the superflea. Of course, those 20 mm fleas lived 165 million years ago and probably lived on dinosaurs. Also, they couldn’t jump and instead of being flattened laterally, or side to side, like modern fleas, they were flattened dorsoventrally, or top to bottom. So they weren’t very much like modern fleas. That’s all we know about the superflea, but let’s have one last sewellel fact before we go. With all this talk of the sewellel being a primitive rodent whose closest relations are all extinct, you might think there’s nothing really special about it beyond its giant fleas. You would be wrong, though, because the sewellel’s front paws have ...
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    8 mins
  • Episode 483: Animals with Nose Horns
    May 4 2026
    The horned gopher: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This time we’re going to learn about some mammals with weird horns. Specifically, weird nose horns. Nose horns are properly called rostral horns, but that’s not as funny. We’ll start with a family of extinct rodents called horned gophers, or more properly, mylagaulids. The horned gopher wasn’t a gopher, but it probably looked similar to ground squirrels like prairie dogs and marmots. It lived in what is now North America around twenty million years ago, and it had a pair of short, broad horns that pointed upwards between the nose and eyes, like a rhino’s horns but side by side and made of bone, not keratin. It was big for a rodent, about a foot long, or 30 cm, and ate plants. So what did the horned gopher use its horns for? Both males and females had the horns and they’re too short and placed too far back for males to use them to fight each other. Horned gophers had poor eyesight so males probably weren’t trying to look and act flashy to attract females anyway. At first researchers thought the horns helped in digging burrows. The horned gopher primarily used what’s called the head-lift method of digging, which means it pushed its nose into the dirt, then lifted its head with powerful neck muscles to remove a chunk of soil—basically using its nose as a shovel. But its horns pointed straight up and were set too far back on the nose to help with digging. Most researchers today think the horns were used for defense. If a predator tried to grab the animal by the neck, it could snap its head back and stab the predator right in the face. The horned gopher had tiny eyes and front feet that resembled a mole’s, with long claws. Researchers think its ancestors probably spent most of the time underground, but that as it evolved to become larger, it also spent more time foraging above-ground. That led to more predators being able to attack it, so evolving horns as a defensive weapon helped it survive. While the horned gopher was distantly related to modern squirrels, its family is completely extinct these days. But it’s still the smallest known horned mammal that ever lived. The horned gopher is also the only horned mammal known that lived mostly underground in burrows. Almost. There was once a type of armadillo, naturally called the horned armadillo but more properly referred to as Peltephilus [pelta-FEElus], that had a pair of horns over its eyes but a little in front of them, close to where the horned gopher’s horns were. The horned armadillo’s horns developed from scutes on its head, and if you remember, scutes are bony plates embedded in the skin as armor. It might also have had a smaller pair of horns over its nostrils. It lived in what is now South America and went extinct around 11 million years ago. The horned armadillo dug burrows liked the horned gopher did, but it was much bigger than the horned gopher, with some species as much as five feet long, or 1.5 meters. Despite its size, it probably resembled the pink fairy armadillo in overall shape rather than the more common nine-banded armadillo that lives in parts of North America. It had a short tail and its rump was squared off instead of rounded. It also had big sharp teeth. It may have eaten insects, possibly digging up ant nests, but more likely it mostly ate roots and other plant parts. Arsinoitherium was another animal with nose horns, this one from Africa. It lived around 30 million years ago and was related to modern-day elephants, but it lived in swampy areas and tropical rainforests and ate plants. It probably looked a little like a rhinoceros and a little like a small elephant without a trunk. Different species were different sizes, but they were all pretty big, probably no smaller than about six feet tall at the shoulder, or 1.75 meters. And they had two pairs of horns, a little pair more like bumps over the eyes and two side-by-side forward-pointing giant nose horns that looked a lot like rhino horns but thicker. But they were real horns made of bone, not keratin, although they may have been covered in skin and hair like ossicones. You know, ossicones are those hornlike structures giraffes have. Brontotherium looked a lot like a rhinoceros too, but that’s because it was distantly related to the rhino, although it was more closely related to the horse. It lived in North America around 35 million years ago and was enormous, standing around 8 feet tall at the shoulder, or 2.5 meters. It was a selective browser, probably preferring tender leaves to tough grass. It carried its massive head low like modern rhinos and buffalo do, and had a humped shoulder like both those animals where its massive neck muscles attached. And it had a pair of nose horns. Both males and females had the nose horns, but the males’ horns were much larger. The horns were blunt and shaped sort of like a V, and researchers are pretty sure males ...
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    9 mins
  • Episode 482: Smoky Mountain Mystery Animals
    Apr 27 2026
    I took this episode from an article I wrote for Flying Snake magazine, which was published in December 2020 (Vol. 6, #18). Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. The Great Smoky Mountains is a subrange of the Appalachian Mountains, which stretches from the middle of Alabama in the United States north into southeastern Canada. The Appalachians formed when the world’s continents crunched together to form the supercontinent Pangaea. The southern Appalachians formed separately and later than the northern Appalachians, around 270 million years ago. The Appalachians were once as high as the Rockies or Himalayas, but by the time the dinosaurs went extinct, they had eroded down to the mountain cores. Sediment weathered from the peaks and filled in valleys. But during the Pleistocene, when massive glaciers covered the northern parts of North America, the weight of the ice pushed the North American plate down, causing the southern part of the plate to rise. Eventually the ancient mountains’ roots were a thousand feet (300 m) above sea level again. Rivers that once flowed east into the Atlantic Ocean or west into the remains of the shallow Western Interior Seaway shifted their courses to flow northward. Streams that once meandered across the land now plunged down steep slopes and dug gorges into the rock. And over thousands of years, animals and plants retreating from the ice migrated southward along the mountain range. When the climate warmed some 11,000 years ago and the ice age glaciers melted, many cold-adapted species were trapped in the peaks of the southern Appalachians. One of the highest peaks is Mount LeConte, with its highest point, High Top, measured at 6,593 ft, or 2,010 meters. I hiked Mount LeConte on 7 May, 2016 when the weather in nearby Knoxville, Tennessee was a warm 82 Fahrenheit, or 27.8 Celcius, but there was snow on the mountain that morning. I wrote my name in it. A spruce-fir forest grows on the upper slopes, a remnant of forest that grew throughout the mountains during the last ice age. The climate at the peak of Mount LeConte is more like that of southern Canada than the warm, humid southeastern United States. The Great Smoky Mountains National Park was established in 1934 to protect the mountains along the Tennessee/North Carolina border. No one lives in the park’s 800 square miles (2,072 square km), which receives up to 90 inches [2.29 m] of rain a year, some of it from hurricanes that sweep up from the southern Atlantic or the Gulf of Mexico. Large tracts of old-growth forest still remain in the park too. So as you can see, the Smokies are a biodiversity hotspot. In 2018, the park announced its 1,000th species discovered that is new to science, which by July 2020 had grown to 1,025. Overall, 20,000 known species live in the park as of 2019 and scientists estimate that up to 100,000 more are yet to be discovered. The Smokies are heavily forested, of course, but some mountain summits and crests have no trees. Instead, native grasses and shrubs grow. They’re called grassy balds and no one is sure why they exist. The prevailing theory is that Pleistocene megaherbivores opened the forests for grazing, and after their extinction, the balds remained open due to bison, elk (wapiti), and deer. When white settlers moved into the area, they used the balds to graze cattle and other livestock. Remains of mammoth and mastodon, musk ox, ground sloth, and other megaherbivores have been excavated from various balds throughout the park. Amphibian enthusiasts call the Smokies the Salamander Capital of the World, with 30 known species. Largest of these is the hellbender, which we talked about in episode 14, a giant salamander that can grow nearly 2 ½ feet long, or 74 cm, and which lives in swift-moving mountain streams. It’s most closely related to the Chinese and Japanese giant salamanders, which can grow over twice as long as the hellbender. Twenty-seven of the salamanders found in the Smokies are lungless, in the family Plethodontidae. Instead of breathing with lungs or gills, the lungless salamanders absorb oxygen through their skin. Of these, the red-cheeked salamander is endemic to the Smokies—that is, it’s found nowhere else in the world. The red-cheeked salamander lives in forests in high elevations. It can grow up to seven inches long, or 18 cm, and is gray or black with bright red patches on its face. It spends the day in a burrow, then comes out at night to find insects in the leaf litter. But it’s hard to tell apart from the imitator salamander, although the imitator only grows a little over four inches long, or 11 cm. The imitator has red cheeks but its body is patterned black and brown instead of solid gray or black. Sometimes its cheeks are yellow, too, while the red-cheeked salamander only ever has red cheeks. Another animal found only in the Smoky Mountains, although it may also be present in mountains outside of the park, is a ...
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    18 mins
  • Episode 481: The Pictish Beast
    Apr 20 2026
    This week we’ll learn about a long-forgotten animal of folklore! Further reading: https://www.anomalist.com/ The Pictish Beast: A dragonesque brooch: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. The Picts were a population of Celtic people who lived in what is now northern and eastern Scotland between around the third and tenth centuries. They had their own language, which is lost to time except for a handful of place-names, and made beautiful rock carvings and metal art, but we know very little about them even though their descendants still live in Scotland today. Vikings conquered the area, which led to upheavals among the many small kingdoms, so that by the 11th century, all the Picts had been absorbed into the greater Scottish population and had completely forgotten their heritage. The carvings are what we’re interested in today. The Picts carved lots of different animals along with more abstract designs, and although the carvings are often stylized, we generally know what animals they represent. There are roe deer, red deer, dogs, boars, horses, cattle, salmon and other fish, otters, eagles, and more. But there’s one animal no one can identify, referred to as the Pictish Beast. The Pictish Beast isn’t rare, either. One estimate is that 40% of all the animal carvings depict the Pictish beast, so it was obviously important. That makes it even more baffling that we don’t know what it is. There are variations, but generally the Pictish Beast has a long snout or beak with a line showing that the mouth was long too. There’s a horn-like design that emerges from the top or rear of the head and bends backwards, with a little curl at the end. The body looks superficially doglike, with a little curled dog tail, but the legs don’t resemble any real animal’s legs. They appear stiff, not jointed, and often bend backwards slightly. The feet are simplified designs that curl backwards in a little spiral. The head is usually bent as though it’s staring downward. It has no ears or nostrils. Naturally there are lots of theories as to what the Pictish Beast represents. One theory is that it’s not a real animal at all but a type of dragon. Specifically, some experts consider it to be a version of a design called dragonesque brooches. These were pieces of jewelry made throughout southern Scotland and northern England during the first and second century. They were roughly S-shaped, made to look like a double-headed animal with a curly nose and distinctive round ears. Instead of dragons, though, the dragonesque brooch animals were probably actually stylized rabbits or hares. They were also popular at least 200 years before the Pictish Beast started being carved so often, so while there is a superficial resemblance, it’s not a perfect match by any means. Then again, there is one stone, called the Mortlach 2 stone, that depicts both a Pictish Beast and what seems to be a simplified version of the dragonesque brooch design. Some researchers think the artist was depicting what was at the time the modern Pictish Beast and the old-timey dragonesque brooch that inspired it. One suggestion is that the beast was inspired by the dragonesque brooch, but isn’t otherwise related. Remember that the brooches would have been considered super old at the time and were probably rare even then as a result. Think about how many pieces of jewelry you own that are several hundred years old. If an artist saw one of the brooches and thought it looked neat, but had no idea what it was supposed to represent, they might have recreated it with details that made sense to them, trying to imitate what they saw. But that doesn’t explain why the design became so incredibly popular. There are other suggestions, of course. Sometimes the beast is depicted vertically, which makes it look superficially like a weird seahorse. Seahorses do live off the coast of Scotland, but that doesn’t explain why the Pictish Beast has large legs and such a little tail. Most of the time the beast is shown horizontally, legs down. Sometimes the beast is referred to as an elephant, but knowledge of elephants in the British Isles over a thousand years ago was unlikely at best. And the beast has zero resemblance to an elephant so I don’t know who came up with that idea but let’s just set it aside and move on. Because of the horn-like appendage on its head, some people suggest the beast might depict a stylized deer. That’s more likely than an elephant but Pictish carvings of deer exist and are obviously deer. That doesn’t mean the beast couldn’t have started out as a deer that took on more and more stylized and exaggerated components until no one remembered it was actually a deer, but that could be said about any animal, not just a deer. Another suggestion is that it’s supposed to be a water animal of folklore, possibly a kelpie, or water horse, or a water bull. Both creatures were supposed to lure ...
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    9 mins
  • Episode 480: Old, Old Life
    Apr 13 2026
    Let’s learn about some of the oldest life ever discovered! Further reading: Microbiologists Find Living Microbes in 2-Billion-Year-Old Rock Chart of life extended by nearly 1.5 billion years Show transcript: Back in episode 168 we talked about the longest-lived organisms known, and finished the episode by discussing endoliths. I’ll quote from that episode as a refresher. An endolith isn’t a particular animal or even a group of related animals. An endolith is an organism that lives inside a rock or other rock-like substance, such as coral. Some are fungi, some lichens, some amoebas, some bacteria, and various other organisms, many of them single-celled and all of them very small if not microscopic. Some live in tiny cracks in a rock, some live in porous rocks that have space between grains of mineral, some bore into the rock. Many are considered extremophiles, living in rocks inside Antarctic permafrost, at the tops of the highest mountains, in the abyssal depths of the oceans, and at least two miles, or 3 km, below the earth’s surface. Various endoliths eat different minerals, including potassium, sulfur, and iron. Some endoliths even eat other endoliths. We don’t know a whole lot about them, but studies of endoliths found in soil deep beneath the ocean’s floor suggest that they grow extremely slowly. Like, from one generation to the next could be as long as 10,000 years, with the oldest endoliths potentially being millions of years old—even as old as the sediment itself, which dates to 100 million years old. That episode was almost five years ago, and in October of 2024 some new information was published. The study mentions the 100-million-year-old limit known so far, where living microorganisms were indeed discovered in geological layers below the ocean floor. But what they found was even older. The scientific team analyzed rock samples from northeastern South Africa, specifically rock that formed when magma cooled below the surface of the earth. It’s called the Bushveld Igneous Complex and is very large, very old, and very stable. The team drilled core samples of the rock from 50 feet down, or 15 meters, and cut it into thin slices to examine. To their surprise, they discovered microbial life in the rock’s cracks, which were sealed tightly with clay so that nothing should be able to get in or out of the rocks. To be sure the microbes hadn’t been introduced during the drilling or preparing process, they used infrared spectroscopy to compare the proteins in the microbes with the proteins caught in the clay. They matched, meaning the microbes had been there as long as the clay had been there, which was basically almost as long as the rocks had been in place. They were also able to verify that yes, the microbes were definitely alive. So, how old are the rocks? TWO BILLION YEARS OLD. Billion with a B! While the individual microbes probably aren’t actually that old, the population of microbes has been living in those cracks far within the rock for two billion years. Scientists are excited to learn more about them, because by studying organisms that have been separated from all other life for that long, they can learn about how early life on earth evolved. Even more exciting, at least if you’re me, NASA’s Perseverance rover on Mars is going to be bringing some rocks back to earth that are about 2 billion years old. Scientists are really excited to see if there is any evidence for microbial life inside the Martian rocks! I know I won’t live long enough to see the first macrobial life from another planet, but I really hope I’m alive when we discover the first microbial life. I don’t think life is rare on other planets, it’s just that the distances are so enormous that getting to another planet and sending information back home is an almost insurmountable problem right now. The closest planets to us are Mars and Venus, and these days Mars just doesn’t seem like it would be very habitable for anything but microbes. But microbes can live just about anywhere! Also in 2024, a team from Virginia Tech has put together a chart marking when various life forms started appearing in the fossil record and when they also stopped appearing in the fossil record. Versions of this chart of life have been made before, but they typically only go back to about half a billion years ago, around the time of the Cambrian. Before that, life was much less likely to fossilize, or the rocks containing the fossils have been worn away. The team gathered fossil data from scientists and institutions around the world and compiled it into a chart of life that extends back two billion years. The farther back you look, the less changes there are among the type and differences in species. There’s even a huge stretch of time called the boring billion where things really weren’t changing much at all, at least not according to the fossil record we have available. It wasn’t until the earth’s climate became...
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    8 mins
  • Episode 479: Metal Animals
    Apr 6 2026
    Further reading: Beavers Have Metal Teeth Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. Let’s find out about some animals that incorporate metal into their bodies in more than just trace amounts. We’ll start with the scaly-foot gastropod, a deep-sea snail. It lives around hydrothermal vents in the Indian Ocean, about 1 and ¾ miles below the surface, or about 2800 meters. The water around these vents, referred to as black smokers, can be more than 350 degrees Celsius. That’s 660 degrees F, if you even need to know that that’s too hot to live. The scaly-foot gastropod was discovered in 2001 but not formally described until 2015. The color of its shell varies from almost black to golden, depending on which population it’s from, and it grows to almost 2 inches long, or nearly 5 cm. It doesn’t have eyes, and while it does have a small mouth, it doesn’t use it for eating. Instead, the snail contains symbiotic bacteria in a gland in its esophagus. The bacteria convert toxic hydrogen sulfide from the water around the hydrothermal vents into energy the snail uses to live. It’s a process called chemosynthesis. In return, the bacteria get a safe place to live. The snail’s shell contains an outer layer made of iron sulfides. Not only that, the bottom of the snail’s foot is covered with sclerites, or spiky scales, that are also mineralized with iron sulfides. While the snail can’t pull itself entirely into its shell, if something attacks it, the bottom of its foot is heavily armored and its shell is similarly tough. Researchers are studying the scaly-foot gastropod’s shell to possibly make a similar composite material for protective gear and other items. The inner layer of the shell is made of a type of calcium carbonate, common in mollusk shells and some corals. The middle layer of the shell is regular snail shell material, organic periostracum, which helps dissipate heat as well as pressure from squeezing attacks, like from crab claws. And the outer layer, of course, is iron sulfides like pyrite and greigite. Oh, and since greigite is magnetic, the snails stick to magnets. The scaly-foot gastropod is the only animal known that incorporates iron sulfide into its skeleton, but other animals use metals in their teeth. Some spiders have tiny amounts of zinc in the tips of their fangs. Some mollusks have small amounts of iron in the teeth of their radulas—you know, the tongue-like structure used to scrape food off rocks. The teeth of the limpet, a type of mollusk, may be one of the strongest structures in the world. It contains goethite nanofibers, and goethite is a type of iron. The teeth of beavers and some other rodents contain iron in the enamel coating. This makes the teeth much harder, although the amount of iron is quite small and unstructured. Most other mammals, including humans, have magnesium in tooth enamel instead of iron. The iron content makes the teeth look orange because of rust. Bloodworms are disgusting horrible worms that my uncle used to fish with when we visited the beach when I was a kid. I was scared of the bloodworms, which irritated my uncle, because I was very vocal about hating the worms and he wasn’t catching any fish with them. Bloodworms live in the sand or silt of shallow water, usually in the ocean but since they can tolerate low salt levels, they may also live farther inland in canals and inlets. Some species can grow nearly 15 inches long, or 37 cm. They’re usually pink or reddish in color with bristles along the body and four little antennae on the head. But the reason I’m talking about them here is that their teeth are reinforced with copper that makes them nearly as hard as teeth coated with enamel. Its jaw also contains copper ions. Copper is toxic to most animals, which may be the source of the bloodworm’s venom. That’s right: horrible worms are also venomous. Another invertebrate that incorporates metal in its body is the parasitic fig wasp. Fig wasps are interesting and there are a lot of them. Figs are pollinated by fig wasps that are not parasitic. The fig flower has a bulb at its base containing a tiny hole. The pollinating fig wasp crawls into the hole, pollinating the flower at the same time, and lays her eggs inside the bulb. She then dies. As the fig developes, the wasp eggs hatch into larvae and then develop into adult wasps. Males mate with females, then chew a hole out of the fig, but only the female wasps have wings, so the males remain and die. As the fig ripens, it actually digests the dead wasps, and—and this is important to those of us who really like figs—leaves no bits of dead wasp inside the fig. So that’s how the pollinating fig wasps work. It’s a symbiotic relationship between the fig tree and the wasp. But the parasitic fig wasp is different. The female has a long ovipositor, which it uses to drill into developing figs and into the pollinating fig wasp larvae. When its eggs ...
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    8 mins