Category Archives: fossils

Episode 098: River Dolphins

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This week let’s learn about some unusual cetaceans, river dolphins!

An Amazon river dolphin and the nose of another Amazon river dolphin:

Another Amazon river dolphin. Note the teeny eye and disk-like teeth:

A South Asian river dolphin. Note the almost nonexistent eye:

A Chinese river dolphin in better days:

Show transcript:

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

This week we’re going to learn about an animal I’ve wanted to cover for a long time but never got around to, the river dolphin.

All whales and almost all dolphins live in the ocean. They can survive for a short while in fresh water but need saltwater to thrive. But as the name suggests, the river dolphin lives in rivers, usually in fresh water and sometimes in the brackish water where rivers empty into oceans. Brackish just means a mixture of fresh and salt water, so it’s saltier than fresh water but not as salty as ocean water. When I was a kid I thought it meant ocean water with a lot of seeweed and dead leaves in it, because I thought the word brackish had something to do with bracken, which is a type of fern.

There are only a few species of river dolphin alive today. They live in warm water and have very little blubber as a result. They primarily use echolocation to navigate since river water tends to be muddy and hard to see through. Their flippers are broad and most have long snouts and flexible necks, or at least flexible compared to other cetaceans. All river dolphins are endangered due to pollution, habitat loss, and accidental drowning in fish nets, with the Chinese river dolphin only having been declared extinct in 2006.

River dolphins evolved from dolphins that once lived in the ocean, but most aren’t closely related to the marine dolphins alive today. Researchers think that when modern dolphins and other toothed whales evolved, they outcompeted their more primitive cousins, who moved into freshwater habitats as a result.

A few years ago, fossils of an extinct river dolphin that grew more than nine feet long, or almost three meters, were found in Panama. It lived around 6 million years ago in the Amazon River, but researchers don’t think modern river dolphins are closely related to it. In other words, freshwater dolphins have evolved repeatedly in different parts of the world to fit an available ecological niche.

In the case of the newly discovered fossil river dolphin, Isthminia panamensis, it probably lived in the warm, shallow Caribbean Sea between North and South America before the Isthmus of Panama formed. It took millions of years for the isthmus to form, with undersea volcanos first emerging from the ocean around 15 million years ago to form islands, then the land itself being pushed upward as the Pacific Plate slid underneath the Caribbean Plate. Researchers think the isthmus became fully formed around 3 million years ago, separating the Atlantic Ocean from the Pacific and connecting North and South America. Because we have Isthminia panamensis’s fossil from the Amazon River, we can hypothesize that by around 6 million years ago, there wasn’t enough of the original Caribbean Sea habitat to support the dolphins and they had already moved into the Amazon River and adapted to life in freshwater.

The river dolphin isn’t the only cetacean that lives in freshwater. There’s a species of porpoise called the finless porpoise that lives around Asia in shallow coastal waters, but often spends at least part of the time in mangrove swamps and in rivers not too far from the sea. Porpoises and dolphins look very similar but belong to different families, which means they aren’t actually very closely related at all. Like, seriously not related at all. Like, the difference between horses and cows. The finless porpoise can grow almost seven and a half feet long, or over two meters, and is called finless because it doesn’t have a dorsal fin. Instead, it has a dorsal ridge lined with tubercles, or bumps, that contain nerve endings. Researchers don’t know what purpose the tubercles serve. Porpoises use echolocation but their clicks are much higher in frequency than dolphins’, so high that humans can’t hear most of them.

There are three families of river dolphins still living today, Platanistidae, Iniidae, and Pontoporiidae.

Platanistidae are the Indian dolphins, with only one species alive today. The South Asian river dolphin lives in South Asia. There are two subspecies, the Ganges River dolphin and the Indus River dolphin. Young South Asian river dolphins have sharp, thin teeth, but as the dolphin matures, its teeth become flatter and squarish, almost like disks. It eats fish, crustaceans like shrimp, and some dolphins may also eat water birds and even turtles. Its rostrum, the word for a cetacean’s beak, is considerably longer in females than in males, sometimes like 8 inches longer, or about 20 cm.

The South Asian river dolphin is sometimes called the blind dolphin because its eyes are basically only useful for sensing light. They don’t even have lenses. It has a very small dorsal fin, not much more than a bump, a powerful tail, and is brown in color, and grows up to ten feet long, or almost 3 meters. It uses echolocation to navigate in the murky river water and find prey. It also usually swims on its side, which also gives it the name side-swimming dolphin. It does this so it can trail the tip of a flipper along the river bottom to feel for shrimp and mollusks.

It’s such an unusual dolphin, even for river dolphins, that researchers are studying fossil dolphins to figure out how the South Asian river dolphin evolved. Two years ago, a fossilized dolphin skull found in 1951 in Alaska and held in the Smithsonian’s collection ever since was evaluated and determined to be a distant relative of the South Asian river dolphin. It lived about 25 million years ago, around the time that ancient whales were evolving into the two groups we have today, toothed whales, which includes dolphins, and baleen whales.

The South Asian river dolphin has been evolving separately from marine dolphins for at least the 25 million years since its relative was swimming around in the Arctic Ocean. Research on its echolocation suggests that the Ganges River subspecies of the South Asian river dolphin probably has biosonar that more closely resembles that of ancient toothed whales than modern toothed whale and dolphin echolocation does. It has a much deeper voice than marine dolphins of about the same size have.

I tried very hard to find a recording of a Ganges River dolphin, or any South Asian river dolphin, but all I found was this, the echolocation of an Amazon river dolphin:

[river dolphin sound]

The Amazon river dolphin is a member of the Iniidae family of river dolphins. It’s the biggest of the river dolphins, and adults are often pink in color. In all other river dolphins, and most cetaceans in general, females are larger than males, but male Amazon river dolphins are larger than females. Babies are dark gray, fading to lighter gray as they grow up. Adults can appear pink because the skin is often pale and in warm water, the blood shows through the skin. The Amazon river dolphin has small eyes, but it sees a lot better than the South Asian river dolphin.

Most river dolphin species aren’t nearly as sociable as marine dolphins and are usually only found singly or in groups of two or three. Male Amazon river dolphins often fight each other when females are around. If a male Amazon river dolphin meets some females, he will pick up a branch or stone and carry it around to impress them.

Amazon river dolphins eat fish, including piranhas, freshwater crabs, turtles, and other small animals. Sometimes a dolphin will participate in cooperative hunting with giant otters and the tucuxi, another species of dolphin that lives in the Amazon basin. The three species eat different types of fish so they all benefit from hunting together.

The tucuxi isn’t actually a river dolphin although at least some individuals live in rivers. It’s considered a marine dolphin, and you can tell the difference just by looking at it. It looks like a small bottlenose dolphin, about five feet long, or 1.5 meters, and unlike river dolphins its rostrum is relatively short.

The third family of river dolphin is Pontoporiidae, and there’s only one species alive today. Just to show that nature isn’t cut and dried, the La Plata dolphin doesn’t always live in fresh water. It lives around the coast of southeastern South America and while some do spend their whole lives in rivers, most La Plata dolphins live in the ocean.

Finally, let’s talk about the Chinese river dolphin, the one that’s recently extinct, also called the baiji. Technically it’s functionally extinct because although there may be one or two still alive, there aren’t enough to continue the species into another generation. River dolphins do very poorly in captivity, usually dying within months, so even if conservationists had billions of dollars and the cooperation of every single person on earth to save the Chinese river dolphin, there’s nothing they could do at this point. In fact, in 2006 a research team searched for the dolphin for six weeks to put a conservation action plan into place for it, but they didn’t find any. That’s when it was declared extinct.

The Chinese river dolphin lived in the Yangtze River and grew up to 8 feet long, or 2.4 meters. It was blue-gray with a paler belly, and like many other river dolphins, its rostrum was slightly upturned. It also had poor vision. It was once common along much of the Yangtze, some 1,100 miles of river, or 1,700 km, but massive increases in pollution of the river, collisions with boats caused by the noise of boats overwhelming the dolphins’ echolocation, poaching, entanglement in fishing nets, loss of habitat due to damming of the river, and overfishing drove it to extinction within about five decades. The last confirmed sighting of a Chinese river dolphin was in 2002, with an unconfirmed sighting in 2007.

This is a depressing way to end the episode, so let’s finish up with a long-ago relative of the South Asian river dolphin. Zarhachis flagellator lived during the Miocene, about 16 million years ago, and had a really long rostrum. Like, super super long. Its skull was about four feet long, or 1.2 meters, which makes it sound like it must have been a really big dolphin, but it wasn’t. Its actual braincase was less than a foot long, maybe 8 inches or so, or 20 cm. The rest of the length was rostrum. In other words, it had a head about the size of your head, and a long thin beak full of sharp teeth that was something like three feet long, or almost a meter. Tonight when you brush your teeth, think about that. Think about how hard it would be to reach all your teeth if you had a mouth that stuck out three feet from your head. You’d need a really long toothbrush.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 092: Marine Reptiles

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This week we return to the sea to learn about some marine reptiles, both living and extinct!

A marine iguana, eatin:

Another marine iguana, swimmin:

Maybe Darwin was right about the marine iguana looking like imps of darkness:

A mosasaurus skeleton:

A plesiosaur skeleton:

Thalattosaurs:

Show transcript:

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

It’s been a while since we had an episode about the ocean, and I thought it would be interesting to learn about reptiles that evolved to live in a marine environment. Some marine reptiles we’ve already covered in previous episodes, including saltwater crocodiles, sea turtles, and sea snakes. But we haven’t talked much about extinct marine reptiles, and I don’t think we’ve ever had an episode about the marine iguana.

The marine iguana is only found on the Galapagos Islands. It eats seaweed and algae that grow in shallow water around the islands, so it swims and dives to find its food. It’s a large, strong iguana that can grow up to five feet long, or 1.5 meters, with short legs, a short snout, and a row of spines along its back. It’s black or gray in color, which absorbs heat from the sun and keeps the iguana warmer. Many have colorful markings, especially males during the breeding season. The markings might be red or pink, blue-green, yellow, or off-white, depending on subspecies. Some researchers think the kinds of algae eaten by the various subspecies of marine iguana also contributes to the colors of their markings. Males are larger than females.

The marine iguana is well adapted to swimming, although it’s not a fast swimmer. It uses its flattened tail and partially webbed toes to propel itself through the water, and the spines on its back keep it stable in the water. It has long claws that it uses to hold onto rocks to keep from being swept away. Newly hatched babies can swim immediately, but they stay out of the water whenever possible until they’re at least a year or two old. The water around the islands is cold, so the marine iguana will forage in the water for a short time, then come back on land to bask in the sun and warm up.

Only the biggest marine iguanas, mostly adult males, will dive for their food. Females and smaller males usually stay in shallow water, especially at low tide when the algae is easier to reach. A marine iguana can dive up to almost 100 feet, or 30 meters, and stay underwater for half an hour. During bad weather, the iguanas stay on shore, often gathered together to conserve body heat.

Researchers used to think the marine iguana evolved from land iguanas that were swept from Central or South America by storms and floated to the Galapagos islands on rafts of vegetation. Then genetic studies showed that the marine iguana started evolving separately from land iguanas around 8 to 10 million years ago. The Galapagos islands are of varying ages, formed by volcanic activity, but the oldest is only about 3.2 million years old. So obviously the two groups of iguana were separated long before the Galapagos formed. Researchers then speculated that there may have been other, older islands in the Galapagos or nearby that are now submerged, which were where the marine iguanas first started to evolve separately from land iguanas. Then new genetic studies indicated that marine and land iguanas actually separated about 4.5 million years ago, which is not that much of a difference from the oldest islands of the Galapagos, so researchers are back to the original hypothesis. As I’ve said before, science isn’t wrong or right, scientists learn new things and adapt their theories to account for the new information.

For instance, at the moment researchers aren’t sure how marine iguanas shrink during years when weather conditions keep them from finding as much food as they need. I don’t mean they lose weight, I mean they actually shrink. Results of a study published in the journal Nature say marine iguanas shrank up to 2.7 inches, or 6.8 cm, during years with El Nino weather patterns, which brings stormy weather. The iguanas’ bones actually shrunk, making them both shorter and smaller. Not only that, after weather patterns returned to normal and the iguanas were able to find more and better food, the shrinking reversed and they grew larger again. Shrinking reduces the iguanas’ dietary requirements, making them able to survive on less food without long-term health issues.

Because the marine iguana eats algae and other plants that grow in the ocean, it ingests a lot of salt. It has a special gland on the nose that filters excess salt from the blood, which the iguana then expels by sneezing. Many times marine iguanas look like they have white markings on the head, but in actuality it’s just dried salt that they’ve sneezed out.

Like most of the animals that live on the Galapagos Islands, the marine iguana is found nowhere else in the world. It would have been easy for early visitors to the islands to have eaten them to extinction the way they did so many other species. But sailors considered marine iguanas so ugly that they refused to eat them. Even Charles Darwin called them disgusting imps of darkness. That’s harsh, especially since I think they’re cute, but it kept them safe until people understood the need for conservation.

Many marine reptiles are extinct, including the ichthyosaurs we talked about in episode 63. These days the top predators in the ocean are sharks and whales, but mosasaurs and plesiosaurs used to fill those ecological niches.

Mosasaurs looked a lot like sharks in some ways, and like whales in other ways, but they were reptiles. There were a lot of them, from one barely more than three feet long, or 1 meter, up to some species that grew some 50 feet long or more, or up to 17 meters.

All species of mosasaur had four flippers, long powerful tails, and small heads with short necks. Its skull resembled a snake’s in that it was flexible, allowing the mosasaur to swallow prey larger than its head. It also had double-hinged jaws that could open extremely wide. It’s also possible that the mosasaur had a forked tongue. We have skin impressions of mosasaurs, so we know at least some species had finely scaled skins like snakes. Some species had fluked tails shaped like a shark’s tail. The mosasaur used its tail to propel itself through the water, with its flippers only helping it maneuver. Some researchers think the closest living relative of the mosasaur is the Komodo dragon and other monitor lizards, but others think the mosasaur was more closely related to snakes.

The mosasaur came to the surface to breathe every so often like other marine reptiles. It also gave birth to live young. It probably swallowed its prey whole, although some species had specialized teeth that allowed them to crush mollusk shells, such as ammonites. Some studies suggest the mosasaur may even have been warm-blooded. It went extinct at the same time as the dinosaurs.

The plesiosaur looks similar to the mosasaur in many ways, including overall shape and size, but was probably more closely related to turtles than to the mosasaur. Most plesiosaurs had a broad body, a very long neck and small head, and a fairly short tail. It propelled itself with its four long flippers like sea turtles do and was probably relatively slow. Some plesiosaurs, known as pliosaurs, had shorter necks and much larger heads, and swam much faster.

Like the mosasaur, the plesiosaur may have been warm-blooded, and gave birth to live babies instead of laying eggs. The longest plesiosaur was called elasmosaur, which had an extremely long neck. Some elasmosaur species had as many as 76 neck vertebrae. This is your reminder that almost all mammals have seven neck vertebrae. While the elasmosaur could grow up to 50 feet long, or 15 meters, much of its length was neck. Researchers used to think plesiosaur necks were flexible like a goose or swan’s neck, but new findings indicate that it was probably fairly stiff and could mostly just move side to side. Skin impressions show slightly wrinkled skin and some species may have had a tail fluke.

Long-necked plesiosaurs had large eyes and probably hunted by sight. Researchers hypothesize that the long neck might have allowed it to sneak up on fish before they could sense the movement of water from the plesiosaur’s approaching body.

At least one elasmosaur was a filter feeder, with interlocking teeth that it used to filter small prey from either the water or sand, or possibly both. It shows many similarities in skull shape to early baleen whales, too. Researchers think it had a valve at the base of the nostrils that closed them while the animal was feeding, since plesiosaurs and some other marine reptiles have nostrils that open into the mouth.

Like mosasaurs, plesiosaurs died out at the same time as the dinosaurs. They did not live on as the Loch Ness Monster, okay?

While mosasaurs and plesiosaurs lived throughout the world’s oceans, the various species of thalattosaur lived around what is now North America, western Europe, and parts of China. They lived during the mid-Triassic period, up to about 250 million years ago, and we don’t know a whole lot about them because we don’t have all that many fossils. We’re not even really sure where they fit in the reptile family tree.

The thalattosaur hunted in warm, shallow water but otherwise probably lived on land. It resembled a lizard, but with some interesting adaptations to the water. It had four short legs, probably had webbed toes, its body was slender and flexible, and its long tail widened at the end to form a paddle. Some species grew up to 13 feet long, or 4 meters. Some species had nostrils near the eyes, some had snouts that point downward, some had snouts that point upward. Some probably ate jellyfish and other soft foods, others probably ate fish, and a few had teeth that could crush mollusk shells—and had teeth on the roof of its mouth.

This actually isn’t unusual in reptiles and some amphibians. Most snakes have a double row of teeth in the upper jaw, one row growing from the jaw like normal, the other row growing from the roof of the mouth. Some lizards have small teeth that grow from the roof of the mouth, as do many frogs. These help the animal grasp its prey and keep it from escaping while it’s being swallowed whole. This is pretty neat, but it’s not as neat as shrinking iguanas. Nothing beats that.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 086: Ammonoids and Nautiloids

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Is it extinct? Is it alive? What is the difference between the ammonite and the nautilus? Did Kate get the two confused her whole life until a few months ago and thought they were both extinct? Maybe.

A fossilized ammonite shell:

Another fossilized ammonite shell of a different shape:

A third fossilized ammonite shell of a yet different shape:

A gigantic fossilized ammonite shell:

A fossilized ammonite shell of gem quality, called an ammolite:

This is what an ammonite might have looked like when it was alive. I drew this myself IN MS PAINT because I couldn’t find anything online I liked. There’s 15 minutes of my life I won’t get back:

This is an alive and not extinct nautilus:

Another alive and not extinct nautilus:

The slimy or crusty nautilus. Look, I don’t make these names up:

A nautilus tucked up in its shell and peeking out to see if that diver is going to eat it:

You can contribute to helping conserve the nautilus:

Save the Nautilus

Show transcript:

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

This week let’s learn about two groups of mollusks, ammonoids and nautiloids. One group is extinct, one is still around…but they both look a lot alike, and they’re way more interesting than the word mollusk makes them sound!

We’ll start with ammonoids, specifically ammonites. Ammonites first appear in the fossil record around 409 million years ago, but they died out at the same time as the dinosaurs, around 66 million years ago. 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. Some ammonites lived at the bottom of the ocean in shallow water, but many swam or floated throughout the ocean.

Comparing ammonites to snail shells may not give you the right idea about ammonites, though. Even big snails are pretty small. 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 eight and a half feet across, or 2.55 meters.

We have a lot of ammonite fossils, and many of them are beautifully preserved. Some still show a mother-of-pearl layer, a lustrous, iridescent layer of shell that modern molluscs still form. Some ammonite fossils are so lustrous that they’re considered gems, called ammolites. Ammolites are usually polished and made into jewelry. In the olden days people thought ammonites were petrified snakes, and would sometimes even carve the end of the ammonite shell into a snake’s head.

Many fossil ammonites aren’t fossils of the actual shell. When an ammonite died, its empty shell would fill with sediment. Frequently the shell itself wasn’t preserved, but the sediment inside was. That gives us elaborate casts of the insides of ammonite shells, in such good condition that researchers can determine the internal anatomy of the shell. We know mosasaurs frequently ate ammonites because we have fossils with tooth marks that match mosasaur teeth.

There are so many ammonite fossils that paleontologists can date layers of rock by examining which species of ammonite appear in it, called index fossils. Different species frequently had much different shells, some smooth, some with spines or ridges, with tight coils or open coils. Some didn’t coil at all, and instead were straight or had only one or two bends.

But despite all these thousands upon thousands of ammonite fossils, we still don’t know what the animal’s soft parts looked like. Hardly any impressions of ammonite bodies are preserved, only the shells. But ammonites are related to cephalopods like squid, so researchers believe they probably had tentacles.

Nautiloids are also cephalopods. They’re related to ammonites but not closely, about as closely as they’re related to squid. And nautiloids are still alive.

I only found that out recently. A few months ago I came across a picture of a man holding a big snail-like shell with eyes and a bunch of small tentacle things sticking out of the end. I thought it was photoshopped, because I knew those things were extinct! Then I realized that I’ve had nautilus and ammonite mixed up my whole life, and thought they were both extinct and basically the same animal.

They do look a lot alike. Nautilus shells are smooth and rounded like a snail shell, and like the ammonite, nautilus shells also contain chambers filled with gas that keeps the animal from sinking. The nautilus’s body is in the last chamber and extends outside of the shell, with a pair of simple eyes, a beak-like mouth, and as many as 90 small tentacles around the mouth. The top of the shell is striped with brown, while the bottom is white.

Nautilus tentacles are retractable and don’t have suckers the way other cephalopod tentacles do. They do have ridges and secrete sticky mucus that helps them keep hold of their prey. The nautilus also has tentacles around its eyes that are different from its mouth tentacles, and researchers think they act as sensory organs, detecting scent trails in the water. When a nautilus wants to rest, it holds onto a rock with its mouth tentacles so it won’t drift away.

Like squid, the nautilus has a tongue-like structure called a radula, which is studded with exactly nine teeth that it uses to cut up pieces of its prey, mostly crustaceans. It also eats carrion. Like other cephalopods, the nautilus has blue blood instead of red since it contains hemocyanin instead of hemoglobin. Also like squid and other cephalopods, the nautilus has a siphon, properly called a hyponome. In the nautilus, the hyponome is a flap that’s folded over to form a tube, instead of an actual tube in squid and octopus. The animal sucks in and expels water through the hyponome, which propels it through the ocean. If it’s threatened, the nautilus can actually withdraw all the way into its shell like a snail, covering the entrance with two large, folded tentacles.

The first fossil nautiloids are found in rocks dating to the Cambrian period, some 500 million years ago. Earlier nautiloids are sometimes straight, sometimes slightly curved, and sometimes coiled like ammonite shells. Even so, overall the nautilus hasn’t changed much since the Cambrian. Like the ammonite, some species of nautiloid once reached over 8 feet across, or 2.5 meters.

Today there are only six species of nautilus left, and they’re endangered due to habitat loss, pollution, and poaching. The shells of larger individuals can be worth a few hundred dollars to collectors, and while selling the shells is illegal in many countries, as long as there are unscrupulous or just clueless people who buy the shells, poaching of nautiloids will continue to be a problem. A good rule is that if you’re a tourist and someone is selling any kind of animal part, don’t buy it. Even if you think it’s harmless, you might be contributing to the extinction of an animal—plus, it’s probably going to get confiscated by customs anyway.

The problem is that the nautilus matures very slowly. It lives to be over 20 years old, but it isn’t mature until it’s about 15 years old. Its eggs take a long time to hatch too. So the nautilus is slow to recover from overhunting, which makes it vulnerable to extinction.

One species of nautilus is so rare it’s only been seen a few times, and hadn’t been seen in more than 30 years until one was spotted in 2015 off the coast of Papua New Guinea. It’s called Allonautilus scrobiculatus, and unlike other nautilus species, its shell is covered with a thick coating of hairy slime that gives it its popular name, the slimy nautilus or crusty nautilus. It grows to about 8 inches across, or 20 cm. Its close relative Allonautilus perforates is even rarer. In fact, it’s never been seen alive, and researchers don’t know much about it since all they have to study are empty shells found drifting in the water. It grows to about 7 inches across, or 18 cm.

Most living nautiloids are about that size, but the biggest is a subspecies of the chambered nautilus, often called the emperor nautilus. Before you get too excited, though, the biggest ones only grow to about ten inches across, or 25 cm.

Nautiloids don’t like water that’s too warm so they usually live near the bottom of the ocean, although their shells can’t withstand the pressures of abyssal depths. If a nautilus descends too far, its shell implodes and it dies instantly, like a hapless diver in a malfunctioning bathysphere. Nautiloids live in the Indo-Pacific Ocean and like the deeper parts of coral reefs.

So why did ammonites die out during the Cretaceous-Paleogene extinction event while nautiloids didn’t? Researchers think ammonites laid eggs that floated near the top of the ocean, while nautiloids lay eggs that stay on the bottom of the ocean. Specifically, female nautiloids attach their eggs to rocks in warm water, which take up to a year to hatch. Eggs at the bottom of the ocean were protected from most of the effects of the meteor impact, while those near the surface were killed.

Is it possible that some ammonites survived and still live in the deep sea, unknown to humans? I’m going to say probably not. Ammonites shared a lot of physical similarities with nautiloids, so they probably weren’t able to live in the deep sea without imploding. While it would be amazing if scientists discovered a living ammonite, we should celebrate that the humble nautilus is definitely still alive. It’s still blowing my mind, to be honest.

If you’d like to help nautilus conservation efforts, you can visit save the nautilus.com for more information. I’ll put a link in the show notes.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 085: Crocs, Gators, and Their Massive Terrifying Cousins

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This week’s episode is all about crocodiles, alligators, and their relations. Thanks to Damian, John Paul, and John Paul’s son for the recommendation!

A Chinese alligator:

It’s easy to tell alligators and crocodiles apart. Just ask them to stand side by side, then lean over and look down to see the head shape. Broad-headed alligator on left, slender-headed crocodile on right:

Saltwater crocodile. Look, I’m only going to say this once: DO NOT SIT ON A CROCODILE OKAY THAT IS JUST DUMB AND YOU WILL GET EATEN ONE DAY IF YOU KEEP ON DOING IT

A gavial:

Black caiman:

Further reading:

A newly discovered difference between alligators and crocodiles

Show transcript:

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

This week’s episode is about crocodiles and alligators, and their relations. Thanks to a couple of different listeners for the suggestion, Damian and John Paul, and John Paul’s son. We’ve touched on crocodiles before in a couple of different episodes, including episode 53 about dragons, but alligators have barely had a mention.

Crocs and gators aren’t actually that closely related, but both are members of the order Crocodilia. This order also includes caimans and gavials, as well as some verrry interesting extinct members.

Crocodilians are amphibious reptiles. They spend much of their time in the water but also spend time on land. They breathe air, lay eggs, and depend on air or water temperature to regulate their body temperature. All crocodilians have evolved to take advantage of their watery habitat: long tails that are flattened laterally, eyes and nostrils close to the top of the head, short legs with webbed toes, and a flap at the back of the mouth that keeps water from flowing into the throat and airways. They can stay underwater for at least 15 minutes without needing to surface for air, and some individuals can stay underwater for close to two hours under the right conditions.

Crocodilians have thick protective scales on much of the body, called scutes, strengthened by osteoderms, or bony plates. Some scutes contain sensory receptors that sense touch, heat and cold, chemical stimuli, and especially the movement of water. Crocodilians see well even in darkness and have good hearing and smell too.

Some mother crocodilians lay her eggs in holes in the sand, but most build a nest out of vegetation. As the vegetation rots, it generates heat that warms the eggs. If the temperature in the nest is constantly above 90 degrees Fahrenheit, or 32 Celsius, more babies develop into males. If the temperature is cooler than that overall, more babies develop into females.

The mother protects the nest, which is usually near her den. Sometimes several females nest close to each other to help each other protect the nests. When her babies start hatching, the mother crocodilian digs them out of the nest since they aren’t strong enough to do it themselves, and carries the babies to water where they are safer. She also protects them for a while after they hatch. This is important, because baby crocodilians are vulnerable to predators—including adults of their own species.

Different species of crocodilians communicate in different ways. Some roar or bellow, some hiss, grunt, slap the jaws shut loudly, splash the head or tail in the water, or blow bubbles. Males often growl infrasonically—a sound humans feel more than hear, and which can cause the water around the male to shiver. That’s creepy. Baby crocodilians still in the egg will mimic tapping sounds, and yelp or grunt to let their mother know when they’re hatching.

One interesting thing about crocodilians is the way they walk. Most of the time a crocodilian walks with its belly touching the ground and its tail dragging. This is called the low walk. But unlike most other reptiles, most crocodilian species have ankle joints that allow it to raise its body up off the ground and walk like a mammal, with only the end of the tail dragging. This is called the high walk. Some smaller species can even run, a bounding gait something like a rabbit’s. Crocodilians can also jump.

If you’ve ever heard the phrase “crocodile tears,” which refers to someone who pretends to feel bad while doing something mean, it comes from the belief that crocodiles wept while eating their prey. The belief goes back at least 900 years and probably longer, and it’s actually based on a real phenomenon. When a crocodilian is in the water, its eyes are protected by both a see-through third eyelid, properly called a nictitating membrane, and by a tear-like lubricant that washes any grit out of the eye. The lubricant is visible when the animal is out of the water, and it looks like the crocodile is crying.

Many crocodilians are ambush hunters. They lie mostly submerged, only their eyes and nostrils above the surface of the water, and wait for an animal to approach. Then they grab the animal with their powerful jaws and drag it into the water to drown. This requires massive bite strength, and crocodilians have the strongest bite of any animal alive. Recently, 3D modeling of an alligator’s head revealed a second jaw joint that stabilizes the jaw and helps distribute the bite force throughout the skull.

In case you were wondering how to tell a crocodile from an alligator, crocodile snouts are more slender than alligator snouts. It’s easy to tell the two apart when their mouths are closed, since only the upper teeth are visible when an alligator closes its mouth, while a crocodile shows both upper and lower teeth.

Besides, there are only two species of alligator alive today, the American alligator that lives in the southern United States, and the Chinese alligator, which lives in eastern China. The Chinese alligator is the smaller species, no more than 7 feet long, or 2.1 meters. While most crocodilians have soft bellies, the Chinese alligator has an armored belly. It lives in marshes, lakes, and rivers but these days it’s critically endangered and mostly restricted to the Anhui Chinese Alligator Nature Reserve. In 1999, conservationists estimated that there were only about 150 Chinese gators alive in the wild. Fortunately, since then more protected habitats have been developed for the gators and captive breeding programs have released many young gators into the wild. Their numbers in the wild are increasing slowly, but since the gators also do well in captivity, it’s estimated that as many as 10,000 individuals live in zoos around the world.

As for the American alligator, back in 1967 it was listed as endangered, mostly due to hunting and the sale of baby alligators as pets. Alligators do not make good pets, which you could probably figure out just by thinking about how big gators get. That would be more than 15 feet long for a big male, or 4.6 meters. Fortunately, conservation made a huge difference to the American alligator and it’s now considered fully recovered from its low point in the 1960s.

The American alligator lives in wetlands throughout the deep southern states, including parts of Texas, across to Florida and up through parts of North Carolina. It eats pretty much anything it can catch, including fish, crabs and other crustaceans, birds, mammals, frogs and other amphibians, and reptiles like turtles and snakes. It also sometimes eats fruit. Because the alligator can tolerate a certain amount of salt water, and frequently lives near the ocean, occasionally one will eat a shark. But sharks sometimes eat alligators too. Alligators also help control the spread of exotic species released in the Florida Everglades and other areas, including Burmese pythons. Full-grown alligators frequently hunt on land, but young alligators mostly stay in the water. Young American alligators have thin yellowish stripes that fade as the gator grows.

There’s another crocodilian with a range that overlaps with that of the American alligator, the American crocodile. It’s usually paler in color than the alligator with a relatively narrow snout. It mostly lives in central America, but some do live in southern Florida, which makes southern Florida the only place in the world where gators and crocs live side by side in the wild. But crocodiles can’t tolerate cool weather as well as alligators, so cold snaps in Florida can kill off crocodiles while not harming alligators. Occasionally a big alligator will eat a smaller crocodile, but on average the croc is the bigger animal. Big males can occasionally grow over 20 feet long, or 6.1 meters. It frequently lives in salt water where it mostly eats fish and birds, along with small mammals, reptiles, amphibians, and crustaceans. It especially likes to eat lemon sharks. I mean, who wouldn’t, right? They sound delicious. Or maybe I just like lemons.

Unlike the American alligator, the American crocodile is endangered due to habitat loss, poaching, and pollution. It’s more dangerous to humans than the alligator, but not nearly as dangerous as some other species of crocodile.

The saltwater crocodile and the Nile crocodile are the most dangerous species to humans. The Nile crocodile can grow over 21 feet long, or almost 6.5 meters, and lives throughout much of Africa. The saltwater crocodile is the biggest crocodilian alive, and can grow up to 23 feet long, or 7 meters.

Like the American crocodile, the saltwater crocodile can tolerate salt water and frequently lives in coastal areas like the mouths of rivers, lagoons, and mangrove swamps. It’s found in parts of India down to northern Australia, and occasionally one will swim across the ocean to areas far from its usual range, including Japan and Fiji. Saltwater crocodiles, especially males, are territorial, and researchers think that about half of attacks on humans result from the human straying into a croc’s territory. These attacks aren’t usually fatal, but I bet they’re scary.

There are other crocodilians besides just the alligator and the crocodile. The gavial, also called the gharial or fish-eating crocodile, has a long, narrow snout that helps it catch the fish it eats. It lives in parts of India these days, in a few rivers and along the coasts, since it can tolerate salt water. It used to live throughout India and other parts of Asia, but it’s been hunted almost to extinction. In 1976 conservationists estimated that there were fewer than 200 gavials alive in the wild. Even after India put protections in place for the gavial, it continued to decline. In 2006 there were only 182 adult gavials alive. Conservationists are working hard to increase the population, including breeding them in captivity and releasing the babies into protected wildlife preserves in the wild. The main problems these days are loss of habitat and pollution, everything from dams across the rivers where it lives, heavy metal poisoning from polluted water, and drowning after entanglement in fishing nets. But population numbers have grown thanks to the conservation efforts, although there are probably fewer than 1,000 in the wild today.

The gavial can grow as long as the saltwater crocodile, although it’s usually much less heavy, with the longest measured at 23 feet long, or 7 meters. Adult males have a bulb at the end of their snouts that researchers think help them blow bubbles and make hissing and buzzing sounds that attract females.

Baby gavials eat tadpoles, frogs, and small fish. Adults eat fish and crustaceans. The gavial’s jaws are too delicate for it to feed on larger prey. In the past, hunters found jewelry in gavial stomachs and assumed they were maneaters, but it’s more likely they just swallowed jewelry lost in the river because it was shiny like fish scales.

There’s also a false gharial, which looks superficially like a gavial but has a broader snout. It’s reddish-brown with black splotches and some striping on the back and tail. These days it only lives in swamps in Indonesia and some nearby areas, although it used to have a broader range and also lived in rivers and lakes. Like the gavial, it’s been hunted to extinction in much of its former range for its skin and meat, and because people are afraid of it. It’s also vulnerable to habitat loss, including water pollution and draining of wetlands. It eats fish and other water animals, but it also preys on birds and mammals, and can grow more than 13 feet long, or 4 meters.

Caimans are most closely related to alligators and live in Central and South America. Some species are relatively small, from the 5 foot long, or 1.5 meter, Cuvier’s dwarf caiman, to the black caiman that can grow over 16 feet long, or 5 meters. Some researchers think the black caiman may occasionally grow up to 20 feet long, or 6 meters. Caiman scales are stiffened by calcium deposits, which makes caiman hide less valuable to leatherworkers than other crocodilian hides because it’s less pliable.

All crocodilians share an ancestor that lived around 240 million years ago. That same ancestor was also the ancestor of the dinosaurs. So it’s no surprise that crocodilians are considered the closest living bird relatives.

Paleontologists have discovered many extinct crocodilians, some of which look really strange. Mourasuchus, for instance, was a type of caiman that lived in South America during the Miocene, around 13 million years ago. Mourasuchus had long, flat jaws that looked something like a duck’s bill full of tiny conical teeth. Researchers think it may have been a filter feeder, filtering small animals from the mud at lake bottoms. But it was enormously big, some 39 feet long, or 12 meters.

Another possible filter feeding crocodilian was Stomatosuchus, which lived in Northern Africa around 95 million years ago and grew to 33 feet long, or 10 meters. It had a long, flat snout with small conical teeth in the upper jaw and may have had no teeth in the lower jaw. Some researchers think it might have had a pouched lower jaw like a pelican, which it used to catch small fish. It would suck in water, filling its pouch, then close its jaws and push the water out through its teeth. Any fish or other animals left in its mouth when all the water was expelled, it swallowed. But we don’t know for sure because only one Stomatosuchus skull has ever been found, and it was destroyed in 1944 when the museum it was in was bombed during World War II.

Purussaurus was another extinct caiman that lived in South America around 5 to 20 million years ago, and is estimated to grow as much as 41 feet long, or 12.5 meters. We don’t know its length for sure since we don’t have a complete skeleton, but if estimates are right, it was one of the biggest crocodilians that ever lived. It had a strong skull and huge teeth that allowed it to hold onto large prey.

Sarcosuchus was about the same size as Purussaurus, around 40 feet long, or 12 meters, but lived about 112 million years ago in what is now Africa and South America. It ate dinosaurs.

The largest living crocodilian ever reliably measured was a captive saltwater crocodile from the Philippines. He was captured in 2011 after rumors started that he had killed at least two people. He was kept on display in a wildlife center, and caretakers named him Lolong after one of the men who helped capture him. Lolong the crocodile was measured at 20 feet 3 inches long, or 6.17 meters, and he weighed 2,370 lbs, or 1,075 kg.

But crocodilians even larger than Lolong have been measured, just not by wildlife experts. Another saltwater crocodile in India has been estimated at 23 feet, or 7 meters, and a saltwater croc skull from Cambodia suggests that the living animal might also have been 23 feet long. A crocodile killed in Queensland, Australia in 1958 was supposedly 28 feet 4 inches long, or 8.64 meters, but this is probably an exaggeration.

But size is relative. A crocodilian that lived in South America some 60 million years ago and grew to a respectable 18 feet long, or 5.5 meters, probably got eaten by the largest known snake that ever lived, titanoboa. Titanoboa grew up to 42 feet long, or 12.8 meters. But that is a story for another day.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 075: Archelon and Other Giant Sea Turtles

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This week we’re going to find out about the biggest turtles that ever lived! Spoiler: one of them is alive right now, swimming around eating jellyfish.

A green sea turtle. These guys are adorable:

A hawkbill glowing like a neon sign!

The majestic and enormous leatherback:

Bebe leatherback. LET ME GOW

Seriously, how are baby sea turtles so darn cute?

Archelon was a big tortle:

Further reading:

This is a link to a pdf of that “Historicity of Sea Turtles Misidentified as Sea Monsters” article

Show transcript:

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

This week we’re back in the sea, but not the deep sea this time, because we’re looking at marine turtles!

The oldest known turtle ancestor lived around 220 million years ago, but it wouldn’t have looked a whole lot like a modern turtle. For one thing, it had teeth instead of a bill. It resembled a lizard with wide ribs that protected its belly. It lived in the ocean, probably in shallow inlets and bays, but it may have also spent part of its time on land. Some researchers think it may have had at least a partial shell formed from extensions of its backbone, but that this didn’t fossilize in the three specimens we have.

The oldest sea turtle fossil found so far has been dated to 120 million years old. It was seven feet long, or 2 meters, and already showed a lot of the adaptations that modern sea turtles have. Researchers think it was closely related to the green sea turtle and the hawksbill sea turtle.

Seven species of sea turtle are alive today. They all have streamlined shells and flippers instead of feet. They all breathe air, but they have big lungs and can stay underwater for a long time, up to about an hour while hunting, several hours when asleep or resting. Like whales, they surface and empty their lungs, then take one huge breath. They can see well underwater but can probably only hear low-frequency sounds.

Sea turtles have a special tear gland that produces tears with high salt concentration, to release excess salt from the body that comes from swallowing sea water. They migrate long distances to lay eggs, thousands of miles for some species and populations, and usually return to the same beach where they were hatched. Female sea turtles come ashore to lay their eggs in sand, but the males of most species never come ashore. The exception is the green sea turtle, which sometimes comes ashore just to bask in the sun. Once the babies hatch, they head to the sea and take off, swimming far past the continental shelf where there are fewer predators. They live around rafts of floating seaweed call sargassum, which protects them and attracts the tiny prey they eat.

Six of the extant sea turtles are relatively small. Not small compared to regular turtles, small compared to the seventh living sea turtle, the leatherback. More about that one in a minute. The other six are the green, loggerhead, hawksbill, Kemp’s ridley and Olive ridley, and the flatback.

Let’s start with the green sea turtle, since I just mentioned it. Its shell is not always green. It can be brown or even black depending on where it spends most of its life. Green turtles that live in colder areas of the Pacific have darker shells, which probably helps them stay warm by absorbing more heat from sunlight. Young turtles have darker shells than old turtles for the same reason.

The green sea turtle can grow up to five feet long, or 1.5 meters, can live some 80 years, and mostly eats plants, especially seagrass, although babies eat small animals like worms, jellyfish, and fish eggs. A recent satellite tracking study of green sea turtles in the Indian Ocean tracked the turtles to a huge underwater seagrass meadow that no human realized existed until then. The meadows were farther underwater than the ones researchers knew about, up to 95 feet deep, or 29 meters. Researchers think the seagrass can grow at these depths because the water is so clear in the area, which means more light for the plants.

Unlike the green sea turtle, which lives throughout much of the world’s oceans, the flatback sea turtle is only found around Australia. It’s greenish or grayish and only grows around 3 feet long, or 95 cm, and eats invertebrates of various kinds, including jellyfish, shrimp, and sea cucumbers. It stays near shore in shallow water and doesn’t migrate, so it’s mostly safe from getting tangled in commercial fishing nets that kill a lot of other sea turtle species.

The smallest sea turtle is the olive ridley, which only grows around two feet long, or 60 cm. Its shell is roughly heart-shaped and is usually olive green. It mostly lives in tropical waters and is the most common sea turtle of all the living species, but getting rarer. It likes warm, shallow water and eats small animals like snails, jellyfish, and sea urchins.

Kemp’s ridley sea turtle is closely related to the olive ridley, and is not much larger. It grows to around 28 inches long, or 70 cm, and eats the same things as the olive ridley. It also likes the same warm, shallow waters, but it nests exclusively along the Gulf Coast of North America. Oil spills in the Gulf have killed so many turtles that the species is now listed as critically endangered. Conservationists sometimes remove eggs to safer, cleaner beaches where babies are more likely to hatch and survive. Besides oil spills and other types of pollution, Kemp’s ridley sea turtles are often killed when they get tangled in shrimp nets and drown. Fortunately, shrimp trawlers in the Gulf now use turtle excluders, which help keep turtles from getting tangled.

The hawksbill sea turtle grows to around three feet long, or 1 meter, and lives around tropical reefs. It has a more pointed, hooked beak than other sea turtles, which gives it its name. You might think it eats fish or something with a beak like that, but mostly it eats jellyfish and sea sponges. It especially likes the sea sponges, some of which are lethally toxic to most other animals. It also doesn’t have a problem eating even extremely stingy jellies and jelly-like animals like the Portuguese man-o-war. The hawkbill’s head is armored so the stings don’t bother it, although it does close its eyes while it chomps down on jellies. People used to kill hawksbill sea turtles for their multicolored shells, but don’t eat them. Its meat can be toxic due to the toxins it ingests.

The hawksbill is also biofluorescent! Researchers only found this out by accident in 2015, when a team studying biofluorescent animals in the Solomon Islands saw and filmed a hawksbill glowing like a UFO with neon green and red light. Researchers still don’t know why and how the hawksbill glows. They think the red color may be emitted by certain algae that grow on hawksbill shells, but the green appears to be emitted by the turtle itself. Since the hawksbill lives mostly around coral reefs, where many animals biofluoresce, researchers hypothesize it might be a way for the turtle to blend in. If everyone’s glowing, the big turtle-shaped spot that isn’t glowing would give it away. Then again, since male turtles glow more brightly than females, researchers also think it may be a way to attract mates.

Finally, the loggerhead sea turtle grows to a little longer than three feet, or 95 cm, and its shell is usually reddish-brown. It lives throughout the world’s oceans and while it nests in a lot of places, many loggerheads lay their eggs on Florida beaches. It eats invertebrates like bivalves and sponges, barnacles and jellyfish, starfish, plants, and lots of other things, including baby turtles. Its jaws are powerful and it has scales on its front flippers that stick out a little, called pseudoclaws, which allow it to manipulate its food or tear it into smaller pieces.

All sea turtles are endangered and are protected worldwide, although some countries enforce the protection more than others. Some people still eat sea turtles and their eggs, even though both can contain bacteria and toxic metals that make people sick. But mostly it’s habitat loss, pollution, and fishing nets and longlines that kill turtles.

People want to build houses on the beach, or drive their cars on the beach, and that destroys the habitat female turtles need to lay their eggs. Turtles also get stuck in fishing equipment and drown. And there’s so much plastic floating around in the sea that all sorts of animals are affected, not just turtles. A floating plastic bag or popped balloon looks like a jellyfish to a sea turtle that doesn’t know what plastic is. A turtle can eat so much plastic that its digestive system becomes clogged and it dies. One easy way you can help is to remember your reusable bag when you go shopping. The fewer plastic bags that are made and used, the fewer will find their way into the ocean. Some countries have banned plastic shopping bags completely.

Now let’s talk about the leatherback turtle. It’s much bigger than the others and not very closely related to them. It can grow some nine feet long, or 3 meters, and instead of having a hard shell like other sea turtles, its carapace is covered with tough, leathery skin studded with tiny osteoderms. Seven raised ridges on the carapace run from head to tail and make the turtle more stable in the water, a good thing because leatherbacks migrate thousands of miles every year. Not only is the leatherback the biggest and heaviest turtle alive today by far, it’s the heaviest living reptile that isn’t a crocodile. It has huge front flippers, is much more streamlined even than other sea turtles, and has a number of interesting adaptations to life in the open ocean.

The leatherback lives throughout the world, from warm tropical oceans up into the Arctic Circle. It mostly eats jellyfish, so it goes where the jellyfish go, which is everywhere. It also eats other soft-bodied animals like squid. To help it swallow slippery, soft food when it doesn’t have the crushing plates that other sea turtles have, the leatherback’s throat is full of backwards-pointing spines. What goes down, will not come back up, which is great when the turtle swallows a jellyfish, not so great when it swallows a plastic bag.

The leatherback can dive as deep as 4,200 feet, or almost 1,300 meters. Even most whales don’t dive that deep. But it’s a reptile, so how does it manage to survive in such cold water, whether in the Arctic Ocean or nearly a mile below the water’s surface?

The leatherback’s metabolic rate is high to start with, and it swims almost constantly. Its muscles generate heat as they work, which keeps the turtle’s body warmer than the surrounding water, as much as 30 degrees Fahrenheit warmer, or 18 degrees Celsius. Its flippers and throat also use a system called countercurrent heat exchange, where blood that has been chilled by outside temperatures returns to the heart in veins that surround arteries containing warm blood flowing from the heart. By the time the cool blood reaches the heart, it’s been warmed by the arterial blood. This keeps heat inside the body’s core.

Unlike other sea turtle species, leatherbacks don’t necessarily return to the same beach where they were hatched to lay their eggs. Females usually nest every two or three years and lay about 100 eggs per nest. No one is sure how long leatherbacks live, but it may be a very long time. Most turtles have long lifespans, and many sea turtle species don’t even reach maturity until they’re a couple of decades old.

One interesting thing about sea turtles, which is also true of many other reptiles, is that the temperature of the egg determines whether the baby turtle will develop into a male or female. Cooler temperatures produce mostly male babies, warmer temperatures produce mostly female babies. This is pretty neat, until you remember that the global temperature is creeping up. A new study of sea turtles around Australia’s northern Great Barrier Reef found that almost all baby turtles hatching there are now female—up to 99.1% of all babies hatched. Another study found the same results in sea turtle nests in Florida, where 97 to 100% of all babies are female. The studies also found that the amount of water in the nest’s sand also contributes to whether babies are male or female, with drier nests producing more females. Researchers are considering incubating some nests in climate-controlled rookeries to ensure that enough males hatch and survive to produce the next generation.

So those are the seven types of sea turtle alive today. Now let’s talk about an extinct sea turtle, a relative of the leatherback. This is archelon, and it was huge.

Archelon was the biggest turtle that has ever lived, as far as we know. The first fossil archelon was discovered in 1895 in South Dakota, in rocks that were around 75 million years old. The biggest archelon fossil ever found came from the same area, and measures 13 feet long, or 4 meters. It’s even broader from flipper to flipper, some 16 feet wide, or 5 meters. It lived in the shallow sea that covered central North America during the Cretaceous, called the Western Interior Seaway. I like that name. Its shell was leathery and probably flexible like the leatherback’s, but unlike the leatherback, it wasn’t teardrop shaped. In fact, it was very round. Since it lived at the same time as mosasaurs, its wide shell may have kept it from being swallowed by predators. It probably ate squid and jellyfish like the leatherback, and researchers think it was probably a slow swimmer. It went extinct at the same time as the dinosaurs, but fortunately its smaller relations survived.

We don’t know if that 13-foot-long archelon was an unusually large specimen, an average specimen, or a small specimen. It was probably on the large size, but it’s a good bet that there were larger individuals swimming around 75 million years ago. We don’t know if leatherbacks occasionally get bigger than nine feet long, for that matter. But we do have reports of sea turtles that are much, much bigger than any sea turtles known.

In August of 2008, a 14-year-old boy snorkeling in Hawaii reported swimming above a sea turtle that was resting on the bottom of a lagoon. He estimated the turtle was eight to ten feet across with a round shell. At the time he didn’t realize that was unusual. He also reported seeing a geometric pattern on the shell, which is not a feature of the leatherback or archelon but is present in other sea turtles. So if his estimation of size is correct, he saw a sea turtle far bigger than any living today.

In 1833, a schooner off the coast of Newfoundland came across what they thought was an overturned boat. When the crew investigated, they discovered it wasn’t a boat at all but an enormous leatherback turtle, which they reported was 40 feet long, or 12 meters.

Many sea serpent sightings may actually be misidentifications of sea turtles. Sea turtles do have relatively long necks which they can and do raise out of the water. A long neck with a small head sticking out of the water, with a hump behind it, describes a lot of sea serpent reports. It’s also possible that some sea serpent reports are actually sightings of sea turtles entangled with fishing nets and other debris that the turtle drags with it as it swims, which may look like a long snake-like tail behind a humped body.

For instance, in 1934 some fishermen off the coast of Queensland, Australia spotted what they thought was a sea serpent. I’ll quote the description, which is from an article with the lengthy title of “Historicity of Sea Turtles Misidentified as Sea Monsters: A Case for the Early Entanglement of Marine Chelonians in Pre-plastic Fishing Nets and Maritime Debris” by Robert France. I’ll put a link in the show notes in case you want to read the article, if I can find it again. I printed it out so I could keep it.

Anyway, the fishermen reported that the sea serpent looked like this:

“The head rose about eight feet out of the water, and resembled a huge turtle’s head…the colour was greyish-green. The eye…was small in comparison to the rest of the monster. The other part in view was three curved humps about 20 feet apart, and each one rose from six feet in the front to a little less in the rear. They were covered with huge scales about the size of saucers, and also covered in barnacles. We could not get a glimpse of the tail, as it was under the water.”

Robert France suggests that this was a sea turtle entangled with a string of fishing gear, specifically fishing floats. He also gives a number of other examples dating back hundreds of years. Fortunately for sea turtles and other animals in the olden days, most fishing nets were made from rope, usually hemp and sometimes cotton, which eventually rotted and freed the animal, if it survived being entangled for months on end.

So if you live around the ocean, or any kind of water for that matter, make sure to pick up any litter you find, especially plastic bags. You could save a lot of lives. Who knows, maybe the sea turtle you save from eating that one fatal plastic bag will grow up to become the biggest sea turtle alive.

As a companion piece to this episode, Patreon subscribers got an episode about the Soay Island Sea Monster sighted in 1959, which was probably a sea turtle of some kind. Just saying.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 072: Weird Whales

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It’s been too long since we discussed whales, so this week let’s learn about how whales evolved and some especially strange or mysterious whales!

Pakicetus was probably kind of piggy-looking, but with a crocodile snout:

Protocetids were more actually whale-like but still not all that whale-like:

Now we’re getting whaley! Here’s basilosaurus, with a dinosaur name because the guy who found it thought it was a reptile:

Here’s the skull of a male strap-toothed whale (left). Those flat strips are the teeth:

Another view. See how the teeth grow up from the lower jaw and around the upper jaw?

A dead pygmy right whale:

The walrus whale may have looked sort of like this:

The half-beak porpoise had a chin that just would not quit:

Show transcript:

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

This week’s topic is weird whales and some of their relations. If you think about it, all whales are weird, but these are the weirdest whales we know of. Some are living, some are extinct, and some…are mysteries.

Whales, dolphins, and porpoises are most closely related to—wait for it—HIPPOPOTAMUSES. About 48 million years ago an ancestor of both modern hippos and whales lived in Asia. It’s called Inodhyus and it was about the size of a cat, but looked more pig-like. It was at least partially aquatic, probably as a way to hide from predators, but it was an omnivore that probably did most of its hunting and foraging on land.

The earliest whale is generally accepted to be Pakicetus. It lived around the same time as Inodhyus and its fossils have been found in what is now Pakistan and India. It was about the size of a big dog, but with a long, thick tail. Its skull was elongated, something like a short-snouted crocodile with big sharp triangular teeth. It had upward-facing eyes like a crocodile or hippo, and it also had four long, fairly thin legs. It probably hunted on both land and in shallow water, and like the hippo it probably didn’t have much hair.

That doesn’t sound much like a whale, but it had features that only appear in whales. These features became more and more exaggerated in its descendants. At first, these ancestral whales looked more like mammalian crocodiles. It’s not until Protocetids evolved around 45 million years ago that they started to look recognizably like whales. Some protocetids lived in shallow oceans throughout the world but probably still gave birth on land, while others were more amphibious and lived along the coasts, where they probably hunted both in and out of water. But they had nostrils that had migrated farther back up their snouts, although they weren’t blowholes just yet, reduced limbs, and may have had flukes on their large tails. But they still weren’t totally whale-like. One protocetid, Rodhocetus balochistanensis, still had nail-like hooves on its forefeet.

By around 41 million years ago, the basilosaurids and their close relations had evolved, and were fully aquatic. They lived in the oceans throughout the tropics and subtropics, and their nostrils had moved almost to the location of modern whales’ blowholes. Their forelegs were basically flippers with little fingers, their hind legs had almost disappeared, and they had tail flukes. They were also much bigger than their ancestors. Basilosaurus could grow up to 60 feet long, or 18 meters, and probably looked more like a gigantic eel than a modern whale. It was long and relatively thin, and may have mostly lived at the ocean’s surface, swimming more like an eel or fish than a whale. It ate fish and sharks. SHARKS.

So when did whales develop the ability to echolocate? Researchers think it happened roughly 34 million years ago, which also happens to be about the same time that baleen whales and toothed whales started to develop separately. Echolocation probably evolved to help whales track hard-shelled mollusks called nautiloids. By 10 million years ago, though, nautiloids were on the decline and mostly lived around reefs. Whales had to shift their focus to soft-bodied prey like squid, which meant their sonar abilities had to become more and more refined. Toothed whales echolocate, while baleen whales probably do not. Researchers aren’t 100% sure, but if baleen whales do use echolocation, it’s limited in scope and the whales probably mostly use it for sensing obstacles like ice or the sea floor.

Baleen whales are the ones that communicate with song, although the really elaborate songs are from humpback and bowhead whales. Of those species, humpback songs are structured and orderly, while bowhead whale song is more free-form. But humpback songs do change, and researchers have discovered that they spread among a population of whales the same way popular songs spread through human populations. This is what they sound like, by the way. A snippet of humpback song is first, then a snippet of bowhead song.

[examples of humpback and bowhead]

So now we’ve got a basic understanding of how whales evolved. Now let’s take a look at some of the weirder whales we know about. We’ll start with a living one, the strap-toothed whale. It’s one of 20-odd species of mesoplodont, or beaked whale, and we don’t know a whole lot about any of them. The strap-toothed whale is the longest beaked whale at 20 feet long, or 6.2 meters.

The strap-toothed whale lives in cold waters in the southern hemisphere. It’s rarely seen, probably since it lives in areas that aren’t very well traveled by humans. It mostly eats squid. Females are usually a little bigger than males, and adults are mostly black with white markings on the throat and back.

The weird thing about this whale is its teeth. Male beaked whales all have a pair of weird teeth, usually tusk-like, which they use to fight each other, but strap-toothed whales take the weird teeth deal to the extreme. As a male grows, two of its teeth grow up from the lower jaw and backwards, curving around the upper jaw until the whale can’t open its mouth very far and can only eat small prey. The teeth can grow a foot long, or 30 cm, and have small projections that cause more damage in fights with other males.

Most of what we know about the strap-toothed whale comes from whales that have been stranded on land and died. Males don’t seem to have any trouble getting enough to eat, and researchers think they may use suction to pull prey into their mouths. Other beaked whales are known to feed this way.

All beaked whales are deep divers, generally live in remote parts of the world’s oceans, and are rarely seen. In other words, we don’t know for sure how many species there really are. In 1963, a dead beaked whale washed ashore in Sri Lanka. At first it was described as a new species, but a few years later other researchers decided it was a ginkgo-toothed whale, which had also only been discovered in 1963. Male ginkgo-toothed whales have a pair of tusks shaped like ginkgo leaves, but they don’t appear to use them to fight each other. But a study published in 2014 determined that the 1963 whale, along with six others found stranded in various areas, belong to a new species. It’s never been seen alive. Neither has the ginkgo-toothed whale.

The pygmy right whale is a baleen whale, but it’s another one we know very little about. It lives in the southern hemisphere. Despite its name, it isn’t closely related to the right whale. It’s small for a baleen whale, around 21 feet long, or 6.5 meters, and it’s dark gray above and lighter gray or white underneath. Its sickle-shaped dorsal fin is small and doesn’t always show when the whale surfaces to breathe. It feeds mostly on tiny crustaceans like copepods, and probably doesn’t dive very deeply considering its relatively small heart and lungs.

The pygmy right whale was first described in 1846 from bones and baleen. Later studies revealed that it’s really different from other baleen whales, with more pairs of ribs and other physical differences. It also doesn’t seem to act like other baleen whales. It doesn’t breach, slap its tail, or show its flukes when it dives. It doesn’t even swim the same way other whales swim. Other whales swim by flexing the tail, leaving the body stable, but the pygmy right whale flexes its whole body from head to tail. It seems to be a fairly solitary whale, usually seen singly or in pairs, although sometimes one will travel with other whale species. In 1992, though, 80 pygmy right whales were seen together off the coast of southwest Australia. Fewer than 200 of the whales have been spotted alive, including those 80, so we have no idea how rare they are.

It wasn’t until 2012 that the pygmy right whale’s differences were explained. It turns out that it’s not that closely related to other baleen whales. Instead, it’s the descendant of a family of whales called cetotheres—but until then, researchers thought cetotheres had gone extinct completely around two million years ago. Not only that, it turns out that at least one other cetothere survived much later than two million years ago, with new fossils dated to only 700,000 years ago. But that particular whale, Herpetocetus, had a weird jaw joint that kept it from being able to open its mouth very far. It and the strap-toothed whale should start a club.

Sometimes whale fossils are found in unexpected places, which helps give us an idea of what the land and ocean was like at the time. For instance, fossils of an extinct beaked whale known as a Turkana ziphiid was found in Kenya in 1963, in a desert region 460 miles inland, or 740 kilometers. The fossil is 17 million years old. So how did it get so far inland?

It turns out that at the time, that part of east Africa was near sea level and grown up with forests. The fossil was found in river deposits, so the whale probably swam into the mouth of a river, got confused and kept going, and then couldn’t turn around. It kept swimming until it became stranded and died. Because of the finding, researchers know that 17 million years ago, the uplift of East Africa had not yet begun, or if it had it hadn’t yet made much progress. The uplift, of course, is what prompted our own ancestors to start walking upright, as their forest home slowly became grassland.

As an interesting aside, the fossil was stored at the Smithsonian, but at some point, like so many other fascinating items, it disappeared. Paleontologist Louis Jacobs spent 30 years trying to find it, and eventually located it at Harvard University in 2011. After he finished studying it, he donated it to the National Museum of Kenya.

More whale fossils were uncovered in 2010 in the Atacama Desert in Chile—in this case, over 75 skeletons, many in excellent condition, dated to between 2 and 7 million years ago. Researchers think they’re the result of toxic algae blooms that killed the whales, which then washed ashore. Over 40 were various types of baleen whales. Other fossils found in the same deposit include a sperm whale, marine sloths, and a tusked dolphin known as a walrus whale.

The walrus whale lived in the Pacific Ocean around 10 million years ago, and while it’s considered a dolphin, it’s actually more closely related to narwhals. But it probably looked more like a walrus than either. Unlike most whales, it had a flexible neck. It also had a face like a walrus. You know, flattish with tusks sticking down. It probably ate molluscs. But the right tusk was much longer than the left one, possibly in males only. In the case of one species of walrus whale, one specimen’s left tusk was about 10 inches long, or 25 cm, while its right tusk was over four feet long, or 1.35 meters. Some researchers suggest that the whale swam with its head bent so that the long tusk lay along the body. Possibly it only used it for display, either to show off for females or to fight other males. But we don’t know for sure.

Speaking of narwhals, if you were hoping to hear about them, you’ll need to go way back to episode five, about the unicorn. I talk about the narwhal a lot in that episode. The narwhal happens to be one of the best animals. A lot of people think the narwhal isn’t a real animal, that it’s made up like a unicorn. In fact, about a week ago, I was talking to a coworker and the subject of narwhals came up. She actually did not realize it was a real animal. Nope, it’s real, and that horn is real, but it’s actually a tusk rather than a horn. It grows through the whale’s upper lip, not its forehead. In another weird coincidence, this afternoon when I was about to sit down and record this episode, a friend sent me a link to an article that had some narwhal sounds. So we’re not really talking about narwhals in this episode, but hey, this is what they sound like.

[narwhal calls]

Another weird whale is the halfbeak porpoise, or skimmer porpoise, which lived off the coast of what is now California between 5 and 1.5 million years ago. While it probably looked mostly like an ordinary porpoise, its chin grew incredibly long. The chin, properly called a symphysis, was highly sensitive, and researchers think it used it to probe in the mud for food.

There’s still so much to learn about whales, both living ones and extinct ones. We definitely haven’t identified all the living whales yet. There are reports of strange whales from all over the world, including a baleen whale with two dorsal fins. It was first spotted in 1867 off the coast of Chile by a naturalist, and other sightings have been made since. It’s supposedly 60 feet long, or 18 meters, so you’d think it wouldn’t be all that hard to spot…but there’s a whole lot of ocean out there, and relatively few people on the ocean to look for rare whales.

Whales can live a really long time. In 2007, researchers studying a dead bowhead whale found a piece of harpoon embedded in its skin. It turned out to be a type of harpoon that was made around 1879. Bowheads can probably live more than 200 years, and may even live longer than that.

And, of course, whales are extremely intelligent animals with complex social and emotional lives, the ability to reason and remember, tool use, creative thinking and play, self-awareness, a certain amount of language use, and altruistic behaviors toward members of other species. Whales and dolphins sometimes help human swimmers in distress, dolphins and porpoises sometimes help beached whales, and humpback whales in particular sometimes rescue seals and other animals from orcas. Humans aren’t very good at thinking about intelligence except as it pertains to us, but it seems pretty clear that other apes, whales and their relations, elephants, and probably a great many other animals are a lot more intelligent than we’ve traditionally thought.

One last interesting fact about whales and their relations. Most of them sleep with half their brain at a time. The half that isn’t sleeping takes care of rising to the surface to breathe periodically, so the whale doesn’t drown. That does not sound very restful to me. But sperm whales sleep with their bodies vertical and their heads sticking up out of the water. But they don’t sleep very long, only around ten minutes at a time—and only in the hours before midnight. I’ve had nights like that.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 071: The Not-Elephants

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Not-Elephants! They’re like elephants but WEIRD! Let’s take a look at a lot of extinct proboscidea this week.

Oh, and the Casual Birder Podcast episode where I talk about indigo buntings should be released this week, not last week. Oops.

Gomphotheres, looking deceptively normal at first glance:

THEIR FACES AAAHHHH art by Pedro Toledo:

Cuvieronius and Notiomastodon, art also by Pedro Toledo. Note the spiral on Cuvieronius’s tusks:

Stegodon:

Deinotherium, just going totally weird with the tusks and chin:

It might have looked a little something like this when alive. What the actual heck:

Anancidae tusks were just out of control:

Guess what! These two proboscidae are still alive! Hooray for Asian elephants (left) and African elephants (right)!

Okay, what the heck is going on in these genealogy sites, pretty sure elephants don’t use them:

And finally, I swiped this picture of the Mystery Tusk from Karl Shuker’s blog, specifically this post.

Show transcript:

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

We haven’t had an episode about Pleistocene megafauna in a while, so this week we’re covering some interesting mammals that are related to elephants and mammoths, but aren’t elephants or mammoths. Oh, and I jumped the gun last week with our mystery birds episode. The Casual Birder podcast is running the finch episode this week, where I have a little spot talking about the indigo bunting. I’ll make sure to put a link in the show notes so you won’t miss it if you don’t already listen to the Casual Birder podcast.

We’ll start off this week with an elephant that…isn’t an elephant. Just wait till you hear about the gomphothere, oh man. I’ve been saving this one for a while.

Gomphothere is the name for a family of animals that lived throughout much of the world, except for Antarctica and Australia. Researchers aren’t sure yet whether it eventually gave rise to elephants and mammoths or whether gomphotheres and mammoths were just cousins with a shared ancestor. The first gomphotheres evolved in Africa and spread into Asia and Europe around 22 million years ago. From there they moved into North America and eventually even into South America during the Pleistocene, shortly before they all went extinct.

So what did gomphotheres look like, and how did they differ from elephants? I’m SO glad you asked. A big part of why gomphotheres would have looked weird to us today is because their bodies were very elephantine. But their faces…were just wrong.

For instance, several species of Gomphotherium had a relatively short trunk and four tusks. The upper two tusks were on the upper jaw and jutted forward and downward. Not too unusual. The other pair of tusks were in the lower jaw. They jutted forward side by side and were flattened to form a sort of shovel. For a long time researchers thought it lived in swamps and used its shovel jaw to scoop up water plants, but more recent research suggests it used its lower tusks to cut through tough vegetation. Some species may have used the shovel to gouge bark off trees, for instance. Its head was elongated as a result of the long lower jaw, so while its body looked like a pretty average elephant, size and all, its face would have been long and flattened compared to the elephants we’re used to. I’m picturing the big reveal in an elephant horror movie where the mysterious character in the shadows turns its head and the music goes BWAHHHH and all the elephants in the audience scream.

Cuvieronius and Notiomastodon are the only gomphotheres that lived in South America. Despite its name, Notiomastodon was not closely related to actual mastodons. Both Cuvieronius and Notiomastodon evolved in North America just over 5 million years ago, then migrated into South America around 3 million years ago. Cuvieronius preferred cooler environments and lived along the Andes Mountains, and may have had thick hair to keep it warm, while Notiomastodon lived in open forests in the lowlands and along the coast, and probably had very little hair, much like modern elephants. Both stood over 8 feet tall at the shoulder, or 2.5 meters. Both also probably looked pretty normal compared to elephants, and probably acted a lot like modern elephants too. Both had a single pair of tusks. But while Notiomastodon’s tusks were relatively ordinary and usually curved upward like a modern elephant’s, Cuvieronius’s grew in a spiral—although not a tight spiral like narwhal tusks. A band of enamel spiraled along the tusk’s length, and the tusk could be over eleven feet long, or 3.5 meters. Some other gomphothere tusks have enamel coverings, unlike elephant and mammoth tusks, which do not contain enamel.

Notimastodon died out in South America about the time humans migrated into the area, or maybe a little before, but it lived longer in parts of North America, as recently as 28,000 years ago in Mexico. Cuvieronius lived even longer before going extinct, with fossils dated to only about 11,500 years ago found in Chile.

Researchers are still working out the relationships between various gomphotheres and their relations. Gomphotheres, elephants, and some other relations are all in the same order, proboscidea, but different families.

Let’s jerk everything to a halt for a second while I explain the scientific classification system for those of you who aren’t familiar with it. Every living creature that has been described scientifically is assigned a place in the classification system so other researchers can get an idea of what the organism is most closely related to. Classifications can and do change as more information is learned.

The top tier is kingdom, extremely broad groups. All mammals, reptiles, amphibians, fish, birds, insects, sponges, worms, jellyfish, and basically anything else that could possibly be called an animal is part of the kingdom Animalia. Kingdoms are divided into phyla, which is the plural of phylum. You may remember me talking at length about phyla in the Cambrian explosion episode a few weeks ago, and I probably should have put this explanation in that episode. Any animal with a backbone or notochord or some similar structure is in the Chordate phylum. The next section under phylum is class, and that’s where we separate mammals from birds from reptiles from fish, and so forth. Elephants, Gomphotheres, and humans are all part of the class Mammalia. But when we reach the next big section down, Order, we separate humans from elephants and gomphotheres, because those are part of the order Proboscidea while humans are in the order Primate. Under Order is family, then genus, then species. The genus and species give an organism its scientific name, such as Homo sapiens or Stegodon zdansky. There are finer gradations, like subfamily and subspecies and clade and so forth, but we won’t go over those here. Let’s get back to the not-elephants.

So, what’s Stegodon zdansky? It’s in the proboscidea order along with elephants and gomphotheres, but it’s not either. And the reason I bring it up is because it was really, really big. It could stand some 13 feet high at the shoulder, or 4 meters, and its tusks were similarly enormous—not just long, although they were over ten feet long, or more than three meters, but so big and close together that it had to drape its trunk to one side or the other of the tusks, not in between like most other proboscideans. Stegodon zdansky lived in China. Other species of Stegodon also lived in Asia, mostly in forested areas, and like zdansky they all had long tusks set close together.

Remember the island of Flores, where the Flores little people lived, Homo floresiensis? We learned about them in episode 26. Popular articles about the Floes little people often say they hunted a dwarf elephant, but it wasn’t an elephant at all. It was a Stegodon that had adapted to life on an island by becoming smaller, not much bigger than a cow. But it’s not clear if it was actually hunted by the Flores little people or if it went extinct before they arrived.

There are more proboscideans, believe me. Deinotherium, for instance, which was simply enormous. It could stand more than 13 feet tall, or 4 meters, but some big males may have stood nearly 16 feet tall, or 5 meters. Only paraceratherium, which you may remember from our tallest animals episode, was taller and heavier.

It had such weird tusks that researchers aren’t sure what it used them for. It had one pair on the lower jaw. Not only did the tusks grow almost straight downward, its lower jaw also curved downward. Some researchers think it dug up plants with the tusks, while others think it used its tusks to pull branches down so it could strip leaves off with its trunk. But no one knows for sure. Researchers also think it had a strong trunk, although we don’t know whether it was a long trunk or a short one. It lived in parts of Asia, Africa, and Europe, and went extinct around a million years ago.

Amebelodontidae was a family that paleontologists thought for a long time were gomphotheres, but new research has separated them into their own family. Like many Gomphotheres, the lower jaw is elongated with a pair of flat, short tusks at the end. The upper tusks are straight and reach only to the end of the jaw, or not as far as the end of the jaw in some species. Reseachers think it used its tusks to cut through tough plants. Similarly, Anancidae were once thought to be Gomphotheres but are now considered their own family. It looked a lot like modern elephants, although its legs were relatively short. Even so, it stood around ten feet tall, or three meters, and lived in forests. It had one pair of tusks…but that’s where the resemblance to modern elephants ends, because its tusks were ridiculously long: 13 feet long, or four meters, and they just pointed straight ahead. Researchers think the Anancidae used their tusks for defense and to dig up plants.

All the proboscidea are extinct now except for Asian and African elephants. It’s a shame so many amazing animals are gone, but just think about how sad it would be if we didn’t have elephants at all. We’re lucky they’re still around.

In 1904 a couple of French zoologists noticed part of a strange tusk in a market stall in Ethiopia. The tusk was darker than regular elephant ivory, oddly shaped with a single groove along its length, and only a couple of feet long, or around 60 cm. The seller didn’t know where it was from. The zoologists bought it to study, and in 1907 published a paper on the tusk. It wasn’t a complete tusk and had apparently been broken off, not sawed off. Their conclusion was that it was from a proboscidean that was not yet known to science. Unfortunately the tusk has been lost, possibly gathering dust in the depths of the National Museum of Natural History in Paris where it was donated.

While the zoologists stated that the tusk wasn’t fossilized and that they thought it might have been almost semicircular when complete, it’s possible they were wrong on both counts. It might have been a walrus tusk, possibly a fossilized one, which could explain its dark brown patina. It might have been a fossilized deinotherium tusk. But the zoologists learned something interesting soon after they bought the tusk. Some Somali hunters told them that there were hippo-like animals that lived in large lakes of East Africa, and that the animals had tusks like the one they’d bought. If you’ve listened to episode 18, where we talk about mystery elephants, you might remember the water elephant reportedly seen in East Africa prior to 1912. Could the water elephant be a real animal, and the source of the mystery tusk? Until the tusk actually turns up so it can be tested, we can’t know for sure what animal it’s from. But it’s sure fun to think about.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 069: The Cambrian Explosion

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This week let’s find out a little something about the Cambrian explosion, where the relatively simple and tiny life on earth suddenly proliferated and grew much larger…and definitely stranger.

The Burgess shale area: beautiful AND full of fascinating fossils:

Anomalocaris, pre-we-figured-out-what-these-things-are:

What anomalocaris probably actually looked like, plus a couple of the “headless shrimp” fossils:

More “headless shrimp” fossils because for some reason I find them hilarious:

Marrella. Tiny, weird, looks sort of like those creepy house centipedes that freak me out so much, but with horns:

Hallucigenia, long-time mystery fossil:

What hallucingenia probably looked like, maybe:

Show transcript:

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

This week’s topic is one I’ve been fascinated by for years but I’ve never read much about it: the Cambrian explosion. That refers to the explosion of life forms in the Cambrian period, which started about 540 million years ago. That was long before the dinosaurs, long before fish, basically long before almost all life on earth that wasn’t simple squidgy things living in warm, shallow seas.

To learn about the Cambrian explosion, let’s go back even farther first and learn about the first life on earth.

Obviously, the more recently an animal lived, the more likely we are to find fossils and other remains: footprints in fossilized mud, gastroliths and coproliths, and so forth. The farther back we go, the fewer remains we have. The earth is continually changing, with mountains rising up and continents moving around, volcanoes erupting, old mountains being worn down by wind and weather. That’s good for the earth and therefore for life in general, since nutrients are cycled through the ecosystem and habitats are continually renewed. But it’s bad when paleontologists are trying to find out what lived a billion years ago, because most of those rocks are gone, either weathered into sand long ago, melted into magma, or buried under the ocean or otherwise out of our reach.

The Earth formed about 4.5 billion years ago, oceans formed 4.4 billion years ago, and the oldest rocks we can find are about 4 billion years old. The first life on earth, single-celled organisms, dates back to about 3.8 billion years ago, maybe earlier. By 3.5 billion years ago, complex single-celled microorganisms had evolved—we know because we’ve found eleven microscopic fossils in rocks from western Australia. Researchers have concluded that the fossils belonged to five different taxonomical groups, which means that by 3.5 billion years ago, life was already well established and diverse.

By 2.5 billion years ago, the earth had continents roughly the same size as the ones today, although not anything like the same shapes or in the same places. Land also didn’t have dirt on it, just sand and bare rock, since dirt is largely decomposed organic matter and nothing was living or dying on the land yet. Not long after, 2.45 billion years ago, oxygen started to make up a large part of the earth’s atmosphere. That’s right, before then we literally could not have breathed the air. I mean, we could have, but we would die of suffocation because the air contained only trace amounts of oxygen. While having oxygen in the air sounds great to us now, the single-celled organisms living then couldn’t process it and died off—probably the greatest extinction event in the earth’s history. Only organisms that were able to evolve quickly enough to use oxygen survived and thrived.

One particular type of microorganism dating back 2.3 billion years, sulfur bacteria, again known from ancient rocks from western Australia, is still around. Modern sulfur bacteria live in the deep sea off the coast of Chile, and they literally have not needed to change at all in 2.3 billion years. That’s what you call success.

The earliest multicellular organisms date to around 2.1 billion years ago, or at least those are the oldest fossils we’ve found. Algae and fungi evolved soon after. The earliest animal fossils date from about 580 million years ago and include small jellyfish and sea anemones, but all the oldest fossils we’ve found are of specialized animals so they probably arose much earlier. At about the same time, fossils of more complex shelled animals start appearing in the fossil record, animals which may have been the ancestors of arthropods, echinoderms, and mollusks. We also have fossils of burrows made in the sea floor, although we don’t know what kind of animal made them—some kind of wormy creature, but none have been found, just their burrows. Clearly a lot was going on back then, but it was all on a small scale: tiny worms, colonies of bacterial mats, and shelled animals measured in millimeters.

Then came the Cambrian explosion, starting about 540 million years ago, where diverse and often bizarre-looking animals suddenly appear in the fossil record, proliferating at a rate unheard-of in the previous eras. We’re not completely sure why, but it was probably a combination of factors, possibly including increased oxygen levels, the development of an ozone layer in earth’s atmosphere that protects cells from lethal UV radiation, an increase of calcium in ocean water, and many other factors, large and small. As animals grew larger and more diverse, more species could exploit more ecological niches; and when all the available niches were occupied, competition grew even more fierce, leading to even bigger and more specialized animals.

The first Cambrian fossils found were those of trilobites, first described in 1698 but not recognized as extinct fossil animals until the 18th century. By the 19th century so many forms of trilobite were known that geologists used them to help date rock strata. While trilobites had probably been around before the Cambrian, during the Cambrian they evolved exoskeletons and became much larger and more common.

You’ve probably heard of the Burgess shale, and you’ve probably heard of it because of the book Wonderful Life, published in 1989 by paleontologist Stephen Jay Gould. The book is out of date now, but when it was new it caused a lot of popular interest in the Cambrian explosion in general and the Burgess shale fossils in particular.

Shale, if you’re not familiar with the term, is a type of sedimentary rock formed from mud containing a lot of clay, generally mud from slow-moving water, floodplains, and quiet lagoons. It’s common, generally gray in color, and splits into flat pieces that you can draw on with other pieces of shale like a chalkboard. People sometimes confuse shale with slate, but slate is actually shale that’s been hardened by pressure and heat within the earth into a metamorphic rock. Because shale is formed from fine particles instead of sand, it can preserve fossils in incredible detail, although usually flattened.

So the Burgess shale is a large deposit of shale some 30 miles across, or 50 km, and 520 feet thick, or 160 meters. The area was once the bottom of a shallow sea next to a limestone cliff, around 505 million years ago, right in the middle of the Cambrian period. When the Rocky Mountains were created by tectonic forces around 75 million years ago, the Burgess shale was lifted 8000 feet above sea level, or 2500 meters. It’s in Canada, specifically Mount Stephen in Yoho National Park in British Columbia, and it’s properly called the Stephen Formation.

In the late 19th century a construction worker found some fossils in the loose shale weathered out of the formation. A geologist working for the Geological Survey of Canada heard reports of the fossils and in 1886 visited the area. He found trilobites and told his supervisor. Eventually paleontologist Joseph Whiteaves took a look and collected some Burgess shale fossils he thought were headless shrimps. They weren’t, by the way. We’ll come back to them in a minute.

In a nearby section of the Stephen Formation, paleontologist Charles Doolittle Walcott set up a fossil quarry in 1910. He and his team worked the quarry intermittently for the next few decades, collecting more than 60,000 specimens. But he didn’t publish very much about his findings, and after his death no one was very interested in the Burgess shale until the 1960s and 70s, when a couple of paleontologists started poking through Walcott’s collection. Their findings are what Gould writes about in Wonderful Life. Since then, paleontologists have continued to find amazing fossils in the Stephen Formation, and research continues on Walcott’s collection.

Part of the reason Gould’s book was such a sensation, apart from the fact that he’s a great writer and fossils are just interesting, was that he suggested the Cambrian explosion was caused by an unknown event that forced new evolutionary mechanisms into play, leading to many animals that are completely unrelated to those living today. He and some of the paleontologists working on the Burgess shale animals in the 1970s thought many of them belonged to phyla unknown today. There are only 33 designated phyla, although they do get looked at and changed around occasionally as new information comes to light. Humans and all other mammals, as well as reptiles, birds, amphibians, and fish, belong to the Chordata phylum. Gould suggested that if the Burgess shale animals had continued to evolve instead of dying out, life on earth today might look radically different.

That brings us to Whiteaves’s headless shrimp. Its name is Anomalocaris, which means abnormal shrimp. If you’re familiar with shrimp—you know, the things you eat, especially with rice or grits and I am so hungry right now—you have probably seen a headless one. The heads are typically removed before shrimp are sold, even though the rest of the shrimp may be intact, including shell, legs, and those little finny bits on the tail. That’s more or less what the fossil Whiteaves found looked like, except that its legs weren’t jointed. It was a little over 3 inches long, or around 8.5 cm. Whiteaves described it as a type of crustacean in 1892.

But to find out what it really was, we have to look at a couple of other discoveries. Walcott discovered what he identified as a type of jellyfish, around two inches across, or 5 cm, a circular segmented creature with a hole in the middle that looks a lot like a fossilized pineapple ring. Walcott also found what he thought was a feeding appendage or tail of an arthropod called Sidneyia, but didn’t realize it was the same anomalocaris Whiteaves had described. And paleontologist Simon Conway Morris discovered another of Walcott’s pineapple ring jellyfish, preserved together with what he took to be a sponge.

Harry Whittington, a paleontologist working on the Burgess shale fauna in the late 20th century, finally realized all these fossils belonged together—not as a crustacean, a sponge, and a jellyfish, but as one large animal. The shrimp tail was its feeding appendage, of which it had a pair in the front of its head, and the unjointed legs were spines. The pineapple ring jellyfish was its round mouthpiece consisting of plates that it contracted to crush prey. The sponge was its lobed body, which was softer and didn’t preserve as well as its other pieces.

Whiteaves’s feeding appendage came from a larger species, Anomalocaris canadensis, which grew some three feet long, or about a meter. It probably ate soft-bodied animals. Peytoia nathorsti was much smaller and may have used its feeding appendages to filter tiny prey from the mud.

In the 1990s anomalocaris and its relatives were identified as stem arthropods, ancestors of or at least relations to modern arthropods like insects, crustaceans, and spiders, and not belonging to a new phylum at all. Another anomalocarid was found in rocks 100 million years younger than the Burgess shale, which means at least some of the strange Cambrian animals persisted well into the Devonian.

Another confusing animal is called Marrella, a common fossil in the Burgess shale. Walcott found the first one in 1909 and called it a lace crab, then decided it was a strange trilobite. It’s small, less than an inch long, or under 2 cm, and has long antennae and legs, and head appendages that sweep back into rear-facing spikes that may have protected its gills. It was probably a scavenger that lived on the bottom of the ocean, and we know some interesting things about it. We have one Marrella fossil that shows an individual partly moulted, so we know it moulted its exoskeleton periodically. We also have some specimens so well preserved that researchers have found a pattern on them that would have diffracted light. In other words, its exoskeleton was iridescent and colorful. Charles Whittington examined Marrella in 1971 and determined that it wasn’t a trilobite, wasn’t a crab or other crustacean, and wasn’t any kind of horseshoe crab. Instead, it’s a stem arthropod like anomalocaris.

Hallucigenia may be the most famous Burgess shale animal, although it’s also been found in fossil beds in other parts of the world. It was first described by Walcott as a polychaete worm. Simon Conway Morris redescribed it in 1977, pointed out that it definitely was not a worm, and gave it its own genus. But no one was really sure what it would have looked like when alive, how it would move around and eat, or what it might be related to. Fossils show a thin, flexible worm-like body with long spines sticking out along its length on one side, and flexible tentacles sticking out along its length on the other side. One end of the body is sort of bulbous and the other blunt, but it’s not clear which is the head and which is the tail. It’s small, only an inch or so long at most, or a few centimeters. Conway Morris thought the animal walked on its stiff spikey legs and the tentacles were for feeding, and that each tentacle might even end in a mouth. Other paleontologists suggested the fossil might be part of a bigger animal, the way Anomalocaris feeding appendages were initially thought to be separate animals.

But after more and better fossils were discovered in China, paleontologists in 1991 realized Hallucigenia had been reconstructed upside down and backwards by Conway Morris. The tentacles were paired legs and the stiff spines probably protected the animal from other things that wanted to swallow it. The bulbous end seems to be a head with two simple eyes and a round mouth, possibly with teeth. Its closest living relation is probably a caterpillar-like land animal called a velvet worm or lobopodian worm, although it’s not actually a worm.

Other Burgess shale animals include a bristle worm, an actual relative of modern shrimp, a relative of the horseshoe crab, something that may be related to modern mantis shrimp, a rare mollusk ancestor that was an active swimmer, and a fishlike animal with short tentacles on its tiny head that may have been a primitive chordate.

Most of the Burgess shale animals that have been studied are now classified as arthropod ancestors. But there are hundreds, if not thousands, of fossil species that paleontologists are still puzzling over, with more yet to be discovered in the Stephen Formation and elsewhere. It’s always possible that some animals that evolved during the Cambrian will surprise us as belonging to a completely new group of animals, and that we really will need to add a couple of phyla to the list.

Another exciting thing to remember is that because life on earth is common and arose relatively soon after the earth was formed, it’s almost 100% certain that some other planets also have life—maybe not planets in our own solar system, although we don’t know for sure yet, but astronomers have discovered lots of planets outside of our solar system. They estimate the Milky Way galaxy alone may contain 100 billion planets. In the past researchers have insisted that only planets similar to ours can support life, but that’s not the right approach. Only planets similar to ours can support life like ours. That’s because we evolved to fit our planet. Life on other planets naturally will evolve to fit those planets. Even here on earth we have extremophiles that survive in environments where most other organisms would be destroyed immediately. So next time you’re outside at night, look up at the stars and give them a little wave. Some curious creature might be standing on a planet’s surface untold light years away, staring into the sky and waving a greeting too.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 066: TYRANNOSAURUS REX

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Thanks to Damian, who suggested T. rex as a topic! Let’s learn all about the T. rex and especially the most famous and controversial specimen ever found, Sue.

A T. rex:

Sue, also a T. rex:

Show transcript:

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

Our topic this week is a suggestion from Damian, who wants to hear about the one, the only, the tyrant lizard king with massive everything except arms, Tyrannosaurus rex. Aw yeah

You probably know a lot about T. rex without realizing it. It’s THE dinosaur, the one people think of first when you say dinosaur. But a lot of popular knowledge about the T. rex is actually out of date, so let’s find out what’s really going on with that big toothy theropod.

First of all, T. rex did not live in the Jurassic period. It lived much later, in the late Cretaceous, around 66 million years ago. But I guess Late Cretaceous Park doesn’t have quite the same ring to it. It was one of the last non-avian dinosaurs, dying off in the Cretaceous-Paleogene extinction. It lived in what is now western North America, with close relatives in many other parts of the world.

T. rex was a big animal, no doubt about it. The biggest individual we know of, called Sue, stood around 12 feet tall, or a little over 3 ½ meters at the hips. The weight of its massive head was balanced by its long tail. Nose to tail it was around 40 feet long, or about 12 meters. Plenty of other dinosaurs were bigger than T. rex, but T. rex was the biggest land predator we know of.

While T. rex had long legs, its arms are famously teeny, only about three feet long, or one meter. That’s barely longer than an adult human’s arm. But recent research shows that the arms weren’t weak. The bones were strong and so were the muscles, although the arm had a limited range of motion and only two toes. Many researchers think T rex used its arms to hold onto struggling prey.

Since all we have are fossils, we don’t really know what T. rex looked like beyond its bones and muscles, which we know about from study of muscle attachment sites on the bones. Some researchers think it probably had at least some feathers, since we have feather impressions from some of T rex’s close relations. Baby T rex might have had feathers and shed them as it grew up, or it might have had feathers its whole life. We have fossilized skin impressions from a specimen found in 2002 that show scales on the tail, neck, and hip, so many researchers suggest that T rex only had feathers on its head and back, possibly for decoration or protection from the elements. Closely related species show feather impressions over all of the body, so we know T rex’s cousins were feathered.

We also know that T rex had large flat scales on its snout with patches of keratin in the middle, which probably contained sensory bundles. These same patches are present in crocodilians, which help crocs move their eggs and babies without harming them, and help them sense the temperature of their nests.

In 2016, researchers discovered that T rex’s teeth contained enamel. This makes the teeth harder, but enamel has to stay damp. That means T rex probably had lips and its teeth wouldn’t have been visible except when the mouth was open. If that sounds weird, most reptiles have lips. Crocodilians don’t, so some of their teeth show when their mouths are closed, but they also live in the water so don’t have to worry about dry mouth.

Just to be clear, reptile lips aren’t big kissy lips. They’re just skin that allows the teeth to be completely enclosed within the mouth when the jaws are closed, keeping the mouth from drying out.

In 2005, paleontologist Mary Schweitzer found soft tissue in the femur, or thigh bone, of a 68 million year old T rex. The tissue contained blood vessels and a substance called medullary bone, which is only present in female birds right before they lay eggs. Medullary bone helps the bird’s body make shells for her eggs. Since then, researchers have found soft tissue within bones of two more T rexes and a hadrosaur. They’re not yet sure how the soft tissue was preserved. The blood vessels resemble those of ostriches more than they resemble crocodilian blood vessels.

For a long time scientists thought that dinosaurs like T rex stood upright with the tail acting as a prop. You know, sort of like Barney. This was recognized as wrong by around the 1970s, but paleontologists are still figuring out the details about how T rex moved around. For instance, we still don’t know if T rex could run. Many researchers now think it probably could, although it might not have been able to run faster than around 25 mph, or 40 km/h. That’s about the speed of a human sprinter. Some of T rex’s bones are hollow to reduce weight, and its feet show adaptations to withstand stresses. But we don’t know for sure, and studies continue using ever more sophisticated mathematical models.

We also don’t know if T rex was warmblooded like birds, or cold-blooded like reptiles. Considering its close relationship to birds, many researchers think it was warm-blooded, properly called endothermic. An endothermic animal can regulate its body temperature internally regardless of the air temperature.

T rex had excellent vision and sense of smell. It could hear very well too, especially low-frequency sounds. It had a massively strong bite, probably the strongest bite force of any land animal. Its bite could crush bone. It would have been a deadly hunter but probably also scavenged, either by stealing kills from other predators or eating anything dead it came across.

We have fossils that show damage from T rex bites, including to other T rexes. It’s possible T rexes fought, either over food or mates, or that bigger T rexes sometimes ate smaller ones. All T rex remains show damage, though, since the life of a predator is a tough one, and the bigger the animals you hunt, the more damage you’re going to take.

So that’s a lot of up-to-date information about Tyrannosaurus rex, or as up-to-date as I could find. Lots of paleontologists are studying T rex, so more information gets published all the time. While I was researching, though, I kept running across interesting details about the specimen nicknamed Sue.

Sue was discovered in August 1990 in South Dakota, on the Cheyenne River Indian Reservation, by paleontologist Sue Hendrickson. It was the last day of the dig and in fact the group was about to head home with a bunch of Edmontosaurus fossils when they noticed their truck had a flat tire. While the tire was getting changed, Sue Hendrickson took the opportunity to poke around for any last-minute fossils. She spotted some loose bones that had weathered out of a cliff, and saw bigger bones sticking out of the cliff above her, so she took the loose bones back to the dig supervisor and president of the Black Hills Institute, Peter Larson. Larson recognized them as T rex bones and immediately decided they weren’t going to leave that day after all.

It was a good decision, because once the bones were excavated, it turned out to be not only the biggest T rex skeleton ever discovered, but the most complete, and in excellent condition.

The group took the fossils back to the Black Hills Institute to clean and prepare them, and that should have been that. But unfortunately, T rex remains are worth a lot of money and that caused issues almost immediately.

The Black Hills Institute had gotten permission to excavate Sue the dinosaur, and had paid the landowner $5,000. The land was owned by Maurice Williams, a member of the Sioux tribe, and since his land was also part of the Sioux reservation, the tribe said the fossils belonged to the tribe, not just Williams.

It’s easy to think of Williams as greedy, but the situation was far more complicated than it sounds. Peter Larson’s group weren’t just in it for the science. They were commercial bone hunters, which means they would have sold the T rex fossil after it was prepared and kept all the money. They had already started taking offers for the sale when Williams sued. Not only that, Williams’s land was held in trust by the government, which meant Larson was supposed to get permission from not just Maurice Williams but the Department of the Interior to excavate fossils on the land, and he hadn’t even asked.

It was a lengthy, complicated trial. Even the FBI had to get involved. They and the South Dakota National Guard seized the fossils and kept them in storage until the trial ended. Peter Larson was charged with fossil theft—not of Sue the T rex, but of other fossils that didn’t have anything to do with Williams. He was found guilty of theft of fossils from public land and lying on customs documents about fossil deals in Peru and Japan, and spent 18 months in jail.

The court decided that Maurice Williams did own the fossils. Williams contacted the auction house Sotheby’s to sell them.

The paleontological community panicked at this, because when I say T rex fossils are worth a lot of money, I don’t mean it’s just scientists who fight each other to buy them. I mean rich people want them for private collections. Fossils in private collections are usually never studied, so they’re nothing more than decorations and don’t add anything to our collective knowledge of creatures that lived in the past. There’s nothing wrong with owning fossils of common animals, of course, but when it’s an important find like this one, it needs to be prepared properly, studied by experts all over the world, and put on public display.

So the Chicago Field Museum of Natural History scrambled to find funding to bid on the T rex. They asked lots of companies and individuals to donate, and those companies and individuals stepped up—companies like McDonald’s and Walt Disney Parks, so good for them.

The auction was held in October 1997. The starting bid was $500,000. At the time, the top amount paid for a fossil had been around $600,000, but Sotheby’s expected this sale to top one million. We don’t know who bid because Sotheby’s keeps this information a secret, but we do know that the Smithsonian had been prepared to spend 2 ½ million.

The auction only lasted eight minutes and the Field Museum won. It paid $8.3 million dollars for Sue the T rex, of which 7.6 million went to Williams. Disney was given a replica of Sue’s skeleton for display and McDonald’s was given two replicas.

It’s great that Sue was bought by an institution that has made the fossil available for study and put it on permanent display to the public. But because the auction went for so much, and was so well publicized, it had some negative repercussions. For a few years after the auction, all fossil auctions were much higher than before, stretching museum budgets to the limits. It is now much harder for paleontologists to get permission to dig on private property, and people started stealing fossils from dig sites, thinking they might get rich.

Williams was fined for selling dinosaur bones without a business license. He died in 2011 at the age of 85and I couldn’t find out what he did with the money he received from the auction, but apparently he kept it in his family and did not donate any to his tribe. While the Cheyenne River tribe’s policy is to leave fossils undisturbed, the nearby Standing Rock Reservation has its own paleontology department and museum. The group visits local schools to give presentations on dinosaurs found in the area.

In 2002 Larson and his then-wife, Kristin Donnan, published a book called Rex Appeal, and in 2014 made a documentary from the book called Dinosaur 13. Critics have pointed out that both book and film tell a one-sided story, painting Larson as an innocent who was wronged by the system and ignoring Williams’s point of view entirely.

It sounds like Williams was actually kind of a jerk. But it also sounds like Larson was kind of a jerk. People get weird when a lot of money is on the line, and at least Larson truly loves paleontology and has contributed a lot to the field—you know, when he’s not selling fossils to private collectors.

As for Sue the T rex, we don’t actually know if the dinosaur was male or female, but it usually gets referred to as a she because it’s named after Sue Hendrickson, the discoverer. Sue the T rex has been studied extensively so we know a lot about her. She was 28 years old when she died and had arthritis in her tail, had recovered from some serious injuries including broken ribs and a torn tendon in her right arm, and her skull shows pathology that might have killed her. Some researchers think Sue died from a parasitic infection from eating diseased meat. Modern birds sometimes contract what may be the same parasite, which causes swelling of the throat that ultimately starves the bird to death.

A few months ago as of this recording, in February of 2018, Sue was dismantled and removed temporarily from display so that some missing small bones can be added to the skeleton and adjustments made to her posture. She will then be moved to her own room in the Field Museum in 2019. Sue also has her own Twitter account, @SUEtheTrex. It’s actually pretty funny. I just followed it.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

 

Episode 063: The Hammerhead Worm and the Ichthyosaur

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This week we’re learning about the hammerhead worm and the ichthyosaur, two animals that really could hardly be more different from each other. Thanks to Tania for the hammerhead worm suggestion! They are so beautifully disgusting!

Make sure to check out the podcast Animals to the Max this week (and always), for an interview with yours truly. Listen to me babble semi-coherently about cryptozoology and animals real and maybe not real!

Here are hammerhead worms of various species. Feast your eyes on their majesty!

An ichthyosaur:

More ichthyosaurs. Just call me DJ Mixosaurus:

Show transcript:

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

This week we’re looking at a couple of animals that have nothing in common. But first, a big thank you to the podcast Animals to the Max. The host, Corbin Maxey, interviewed me recently and the interview should be released the same day this episode goes live. If you don’t already subscribe to Animals to the Max, naturally I recommend it, and you can download the new episode and listen to me babble about cryptozoology, my favorite cryptids, and what animal I’d choose if I could bring back one extinct species. There’s a link to the podcast in the show notes, although it should be available through whatever app you use for podcast listening.

This week’s first topic is a suggestion from Tania, who suggested hammerheaded animals. We’ve covered hammerhead sharks before way back in episode 15, but Tania also suggested hammerhead worms. I’d never heard of that one before, so I looked it up. I’ve now been staring at pictures of hammerhead worms in utter fascination and horror for the last ten minutes, so let’s learn about them.

There are dozens of hammerhead worm species. They’re a type of planarian, our old friend from the regenerating animals episode, and like those freshwater planarians, many hammerhead worms show regenerative abilities. They’re sometimes called land planarians. Most are about the size of an average earthworm or big slug, with some being skinny like a worm while others are thicker, like a slug, but some species can grow a foot long or more. Unlike earthworms, and sort of like slugs, a hammerhead worm has a flattened belly called a creeping sole. Some hammerhead worms are brown, some are black, some have yellow spots, and some have stripes running the length of their bodies. Hmm, it seems like I’m forgetting a detail in their appearance. …oh yeah. Their hammerheads! Another name for the hammerhead worm is the broadhead planarian, because the head is flattened into a head plate that sticks out like a fan or a hammerhead depending on the species.

The hammerhead worm’s head contains a lot of sensory organs, especially chemical receptors and some eye-like spots that probably can only sense light and dark. Researchers think the worms’ heads are shaped like they are to help the worm triangulate on prey the same way many animals can figure out where another animal is just by listening. That’s why most animals’ ears are relatively far apart, too.

One species of hammerhead worm, Bipalium nobile, can grow over three feet long, or one meter, although it’s as thin as an earthworm. It has a fan-shaped head and is yellowish-brown with darker stripes. It’s found in Japan, although since it wasn’t known there until the late 1970s, researchers think it was introduced from somewhere else. That’s the case for many hammerhead worms, in fact. They’re easily spread in potted plants, and since they can reproduce asexually, all you need is one for a species to spread and become invasive.

While hammerhead worms do sometimes reproduce by mating, with all worms able to both fertilize other worms and also lay eggs, when they reproduce without a mate it works like this. Every couple of weeks a hammerhead worm will stick its tail end to the ground firmly. Then it moves the rest of its body forward. Its body splits at the tail, breaking off a small piece. The piece can move and acts just like a new worm, which it is. It takes about a week to ten days for the new worm to grow a head. Meanwhile, the original worm is just fine and is busy growing another tail piece that will soon split off again into another worm.

One common hammerhead worm accidentally introduced to North America from Asia is frequently called the landchovy. It’s slug-like, tan or yellowish, with a thin brown stripe and a small fan-shaped head. It looks like a leech and if I saw one I would assume that I was about to die. But I would be safe, because hammerhead worms only eat invertebrates, mostly earthworms but also snails, slugs, and some insects.

When a hammerhead worm attacks its prey, say an earthworm, it hangs on to it with secretions that act like a sort of glue. The earthworm can’t get away no matter what it does. The hammerhead worm’s mouth isn’t on its head. It’s about halfway down its body. Once it’s stuck securely to the earthworm, the hammerhead worm secretes powerful enzymes from its mouth that start to digest the earthworm. Which, I should add, is still alive, at least for a little while. The enzymes turn the worm into goo pretty quickly, which the hammerhead worm slurps up. The hammerhead worm’s mouth is also the same orifice that it expels waste from. I’m just going to leave that little factoid right there and walk away.

Hammerhead worms haven’t been studied a whole lot, but some recent studies have found a potent neurotoxin in a couple of species. That could explain why hammerhead worms don’t have very many predators. Or many friends.

[gator sound]

Our next animal is a little bit bigger than the hammerhead worm, but probably didn’t have a hammerhead. We don’t know for sure because we don’t have a complete skeleton, just a partial jawbone. It’s the giant ichthyosaur, and its discovery is new. In May of 2016 a fossil enthusiast named Paul de la Salle came across five pieces of what he suspected was an ichthyosaur bone along the coast of Somerset, England. He sent pictures to a couple of marine reptile experts, who verified that it was indeed part of an ichthyosaur’s lower jawbone, called a surangular. They got together with de la Salle to study the fossil pieces, and after doing size comparisons with the largest known ichthyosaur, determined that this new ichthyosaur probably grew to around 85 feet long, or 26 meters.

So what is an ichthyosaur? Ichthyosaur means fish-lizard, which is a pretty good name because they are reptiles that adapted so well to life in the ocean that they came to resemble modern fish and dolphins. This doesn’t mean they’re related to either—they’re not. But if you’ve heard the phrase convergent evolution, this is a prime example. Convergent evolution describes how totally unrelated animals living in similar habitats often eventually evolve to look similar due to similar environmental pressures.

The first ichthyosaurs appear in the fossil record around 250 million years ago, with the last ones dated to about 90 million years ago. In 1811, a twelve-year-old English girl named Mary Anning took her little brother Joseph to the nearby seashore to look for fossils they could sell to make a little money, and they discovered the first ichthyosaur skeleton. That sounds pretty neat, but Mary’s story is so much more interesting than that. First of all, when Mary Anning was barely more than a year old, a neighbor was holding her and standing under a tree with two other women, when the tree was struck by lightning. The three women all died, but Mary survived. She had been considered a sickly child before that, but after the lightning strike she was healthy and grew up strong.

Mary’s family was poor, so anything she and her brother could do to make money helped. At the time, no one quite understood what fossils were, but people liked them and a nice-looking ammonite or other fossilized shell could bring quite a bit of money when sold as a curio. Mary’s father was a carpenter, but the whole family was involved in collecting fossils from the nearby cliffs at Lyme Regis in Dorset, where they lived, and selling them to tourists. After her father died, selling fossils was the only way the family could make money.

As Mary and her brother became more proficient at finding and preparing fossils, geologists became more and more interested. She made detailed drawings and notes of the fossils she found, and read as many scientific papers as she could get her hands on. At the time, women weren’t considered scholars and certainly not scientists, but Mary taught herself so much about fossils and anatomy that she literally knew more about ichthyosaurs than anyone else in the world.

When Mary was 27 years old, she opened her own shop, called Anning’s Fossil Depot. Fossil collectors and geologists from all over the world visited the shop, including King Frederick Augustus II of Saxony, who bought an ichthyosaur skeleton from her. Collecting fossils could be dangerous, though. In 1833 she almost died in a landslide. Her little dog Trey was just in front of her, and he was killed by the falling rocks. Probably Trey had not heard about the lightning incident or he wouldn’t have stuck so close to Mary.

Although Mary Anning was an expert, and every collection and museum in Europe contained fossil specimens she had found and prepared, she got almost no credit for her work. She was not happy about this, either. Her discoveries were claimed by others, just because they were men. Mary was the one who figured out that the common conical fossils known as bezoar stones were fossilized ichthyosaur poops, called coproliths. Her expertise wasn’t just with ichthyosaurs, either. She was also an expert on fossil sharks and fishes, pterosaurs, and plesiosaurs, and she discovered ink sacs in belemnite fossils. Her friends Anna Pinney and Elizabeth Philpot frequently accompanied Mary on collecting expeditions. I picture them frowning and kicking scientific butt.

Okay, back to ichthyosaurs. Ichthyosaurs were warm-blooded, meaning they could regulate their body temperature internally, without relying on outside sources of heat. They breathed air and gave birth to live babies the way dolphins and their relations do. They had front flippers and rear flippers along with a tail that resembled a shark’s except that the lower lobe was larger than the upper lobe. Some species had a dorsal fin too. They had huge eyes, which researchers think indicated they dived for prey. Many ichthyosaur bones show damage caused by decompression sickness, when an animal surfaces too quickly from a deep dive—called the bends by human scuba divers. Not only were their eyes huge, they were protected by a bony eye ring that would help the eyes retain their shape even under deep-sea pressures.

Ichthyosaurs had long jaws full of teeth, but different species ate different things. Many ate fish and cephalopods like squids, while other specialized in shellfish, and others ate larger animals. We have a good idea of what they ate because we have a lot of high quality fossils, so high quality that we can see the contents of the animals’ stomachs. We also have all those coproliths that paleontologists cut open to see what ichthyosaur poop contained.

Ichthyosaurs lived before plesiosaurs and weren’t related to them. Plesiosaurs are usually depicted with long skinny necks, but more recent reconstructions suggest their necks were actually thick, protected by muscles and fat. Ichthyosaurs appear to have been outcompeted by plesiosaurs once they began to evolve, but ichthyosaurs were already on the decline at that point, although we don’t know why.

Until very recently, the biggest known species of ichthyosaur was Shonisaurus sikanniensis, which grew to almost 70 feet long, or 21 meters. It was discovered by Elizabeth Nicholls, continuing Mary Anning’s legacy of kicking butt and finding ichthyosaurs, and described in 2004. But the new ichthyosaur just discovered was even bigger.

In the mid-19th century, some fragments of fossilized bones were found near the village of Aust in England. They were assumed to be dinosaur bones, but now researchers think they may have been from giant ichthyosaurs, maybe even ones bigger than the one whose jawbone was recently found.

As a comparison, the biggest animal ever known to have lived is the blue whale. It’s alive today. Every time I think about that, it blows my mind. A blue whale can grow almost 100 feet long, or 30 meters. Until very recently, researchers didn’t think any animal had ever approached its size. Even megalodon, the biggest shark known, topped out at about 60 feet, or 18 meters. If the estimated size of the giant ichthyosaur, 85 feet or 26 meters, is correct, it’s possible there were individuals that were bigger than the biggest blue whale, or it’s possible that the jawbone we have of the giant ichthyosaur was actually from an individual that was on the small side of average. Let’s hope we find more fossils soon so we can learn more about it.

Mary Anning would have been out there looking for more of its fossils, I know that.

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