Episode 282: Little Longtailed Birds

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Thanks to Elaine for suggesting one of our long-tailed birds this week!

Happy birthday to Jasper!! Have a great birthday!

Further reading:

Fossil of Ancient Long-Tailed Bird Found in China

All adult scissor-tailed flycatchers have long tails:

The long-tailed sylph male is the one with the long tail:

The long-tailed widowbird male has a long tail:

The long-tailed widowbird female has a short tail:

The pin-tailed whydah male has a long tail:

A pin-tailed whydah baby (left) next to a common waxbill baby (right):

Kompsornis longicaudus had a really long tail:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week is a short episode all about little birds with really long tails. The tails are longer than the episode. Thanks to Elaine for suggesting one of the birds we talk about today!

But before we start learning about birds, we have a birthday shout-out! Happy birthday to Jasper, who has the best name and who will hopefully have the best birthday to go along with it!

Let’s start with Elaine’s suggestion, the scissor-tailed flycatcher. I’m embarrassed to admit that Elaine suggested this bird way back in 2020, so it’s about time we talked about it.

The scissor-tailed flycatcher lives in south-central North America during the summer, especially Texas and Oklahoma, and migrates to parts of Mexico and Central America in winter. It’s pale gray with black and white wings and tail, and salmon pink markings on its sides and under its wings. It also has a really long tail. It gets the name scissor-tail because its tail is so long and forked that it’s sort of the shape of an open pair of scissors. The male’s tail is typically longer than the female’s, longer than the rest of its body. The bird is about the size of an average songbird, with a body length of about 5 inches, or 13 centimeters, but with a tail that can increase its overall length to over 14 inches, or 36 cm.

The scissor-tailed flycatcher prefers open areas like pastures and fields, where there’s lots of space but some brush, trees, or fences nearby to perch in. It mostly eats insects, but it will also eat berries, especially in winter. It’s related to kingbirds and pewees and will even hybridize with the western kingbird where their ranges overlap. Its long tail is partly for display, but mostly it helps the bird maneuver in midair as it chases insects, or hover in midair as it looks around for an insect to catch. It especially likes grasshoppers, and when it catches one, it will usually kill it before eating it by smashing it against a tree limb or other perch.

Another little bird with a long tail is the long-tailed sylph, which is a type of hummingbird! It lives on the eastern slopes of the Andes Mountains in northwestern South America, mostly along forest edges, in gardens, grasslands, and other mostly open areas. It migrates to different parts of the mountains at different times of year to follow the flowering of its favorite plants. It’s larger than many species of hummingbird even if you don’t count the tail.

It eats nectar like other hummingbirds do, but also eats tiny insects and spiders. Its bill is black and not very long compared to most of its relations. Sometimes it will jab the tip of its bill straight through the base of a flower to get at the nectar, instead of inserting it into the flower like other hummingbirds do, and while it can hover, sometimes it perches to feed instead.

Both the male and female long-tailed sylph are a beautiful metallic blue and green in color, although the male is brighter and has purplish-brown wings. The female is about 4 inches long, or 10 cm, including her tail, and while the male is about the same size as the female, his tail is really long—up to 4.5 inches long, or 12 cm. His tail is forked like the scissor-tailed flycatcher’s, but unlike the flycatcher, the sylph’s tail makes it harder for the bird to fly. During breeding season the male attracts a mate by flying in a U-shaped pattern that shows off his tail and his flying ability.

The male long-tailed widowbird also attracts a mate with a flying display to show off his long tail. It lives in grasslands in a few parts of Africa, with the biggest population in South Africa. It forages in small flocks looking for seeds, and it also eats the occasional insect or spider. It’s a sparrow-like bird only about 4 inches long, or 10 cm, not counting its tail. The female is mostly brown with darker streaks and has a short tail. The male is black with red and white patches on the shoulders of his wings, called epaulets. His coloring, including the epaulets, is almost identical to that of a totally unrelated bird, the red-winged blackbird of North America, but he has something the blackbird doesn’t: a gigantically long tail.

The male widowbird’s tail is made up of twelve feathers, and about half of them grow up to 20 inches long. That’s nearly two feet long, or half a meter. Like the long-tailed sylph, the long-tailed widowbird’s tail actually makes it harder for him to fly. If it’s raining, he can’t fly at all. Fortunately for him, outside of the breeding season his tail is much shorter. During display flights, he spreads his tail feathers to show them off better and flies very slowly. Males with the longest tails attract the most females.

Similarly, the pin-tailed whydah is another little sparrow-like bird where the male grows a really long tail to attract females. It lives in grasslands, savannas, and open woodlands in sub-Saharan Africa, which just means south of the Sahara Desert. It mostly eats seeds.

During breeding season, the male is a striking pattern of black and white with a bright orangey-red bill and really long tail plumes. He’s about the size of the long-tailed widowbird but his tail grows about 8 inches long, or 20 cm. The female is brown with darker streaks and looks a lot like a sparrow, although it’s not related to sparrows. To impress a female, the pin-tailed whydah will hover in place near her, showing off his long tail plumes and his flying ability.

A lot of whydah species grow long tails. A lot of whydahs are also brood parasites, including this one, meaning that instead of building a nest and taking care of her own eggs, the female sneaks in and lays her eggs in the nest of a different species of bird. Then she flies away, probably whistling to make her seem extra nonchalant, and leaves the other bird to take care of her eggs and the babies when they hatch. She mostly lays her eggs in the nests of various species of finch, and not only do her eggs resemble the finch’s eggs except that they’re bigger, the babies resemble finch babies when they hatch, except they’re bigger.

Specifically, the babies have a really specific gape pattern. When an adult bird approaches its nest, a baby bird will gape its mouth wide to beg for food. This prompts the parent bird to shove some food down into that mouth. The more likely a baby is to be noticed by its parent, the more likely it is to get extra food, so natural selection favors babies with striking patterns and bright colors inside their mouths. Many finches, especially ones called waxbills, have a specific pattern of black and white dots in their mouths that pretty much acts as a food runway. Insert food here. The whydah’s mouth gape pattern mimics the waxbill’s almost exactly. But as I said, the whydah chick is bigger, which means it can push the finch babies out of the way and end up with more food.

The pin-tailed whydah is a common bird and easily tamed, so people sometimes keep it as a pet. This is a problem when it’s brought to places where it isn’t a native bird, because it sometimes escapes or is set free by its owners. If enough of the birds are released in one area, they can become invasive species. This has happened with the pin-tailed whydah in many parts of the world, including parts of Portugal, Singapore, Puerto Rico, and most recently southern California. Since they’re brood parasites, they can negatively impact a lot of other bird species in a very short time. But a study released in 2020 about the California population found that they mostly parasitize the nests of a bird called the scaly-breasted munia, a species of waxbill from southern Asia that’s been introduced to other places, including southern California, where it’s also an invasive species. So I guess it could be worse.

There are lots of other birds with long tails we could talk about, way too many to fit into one episode, but let’s finish with an extinct bird, since that seems to be the theme lately. In May 2020, an ancient bird was described as Kompsornis longicaudus, and it lived 120 million years ago in what is now China. Its name means long-tailed elegant bird. It was bigger than the other birds we’ve talked about today, a little over two feet long, or 70 cm, but a lot of that length was tail.

Kompsornis is only known from a single fossil, but that fossil is amazing. Not only is it almost a complete skeleton, it’s articulated, meaning it was preserved with all the body parts together as they were in life, instead of the bones being jumbled up. That means we know a lot about it, including the fact that unlike other birds of the time, it didn’t appear to have any teeth. It also shows other features seen in modern birds but not always found in ancient birds, including a pronounced keel, which is where wing muscles attach. That indicates it was probably a strong flier. It also had a really long tail, but unlike modern birds its tail was bony like a lizard’s tail although it was covered with feathers.

During their study of Kompsornis, the research team compared it to other birds in the order Jeholornithiformes, which seem to be its closest relations. There were six species known, with Kompsornis making a seventh—except that during the study, the team discovered that one species was a fake! Dalianraptor was also only known from one fossil, and that fossil was of a different bird with the arms of a flightless theropod added in place of its missing wings. Send that fossil to fossil jail!

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

Thanks for listening!

Episode 281: The Humpback Whale

Thanks to Clay for suggesting the topic of this week’s episode, the humpback whale!

Happy birthday to Emry!

Further reading:

How humpback whales catch prey with bubble nets

Study: Humpback whales aren’t learning their songs from one another

Stanford researchers observe unexpected flipper flapping in humpback whales

Ancient baleen whales had a mouthful

The humpback’s long, thin flippers help it maneuver:

Humpbacks are active, jumpy whales:

A humpback whale’s big mouth:

Show transcript:

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

Thanks to Clay for suggesting this week’s topic, the humpback whale!

But first, we have a birthday shout-out! A great big happy birthday to Emry! I hope your birthday is so epic that in the future, when people look up birthday in the dictionary, your name is listed there.

I’m amazed we haven’t talked about the humpback whale before because when I was little, it was my favorite whale until I learned about the narwhal. Sorry, humpback, you’re now my second favorite whale.

The humpback is a baleen whale, specifically a rorqual, which is a group of related baleen whales. I don’t think I’ve mentioned the term rorqual before because I find it really hard to pronounce. Rorquals are long, slender whales with throat pleats that allow them to expand their mouths when they gulp water in. We talked about this in episode 211 about the fin whale, which is another rorqual. I’ll quote from that episode to explain again what the throat pleats are.

A baleen whale eats tiny animals that it filters out of the water through its baleen plates, which are keratin structures in its mouth that take the place of teeth. The baleen is tough but thin and hangs down from the upper jaw. It’s white and looks sort of like a bunch of bristles at the end of a broom. The whale opens its mouth wide while lunging forward or downward, which fills its huge mouth with astounding amounts of water. As water enters the mouth, the skin stretches to hold even more, until the grooves completely flatten out.

After the whale fills its mouth with water, it closes its jaws, pushing its enormous tongue up, and forces all that water out through the baleen. Any tiny animals like krill, copepods, small squid, small fish, and so on, get trapped in the baleen. It can then swallow all that food and open its mouth to do it again. This whole operation, from opening its mouth to swallowing its food, only takes six to ten seconds.

The humpback mostly eats tiny crustaceans called krill, and little fish. Since gulp feeding takes a lot of energy, finding a lot of food in a relatively small space is important to the whale. Many little fish that live in schools will form what are called bait balls when they feel threatened, where the fish swim closer together and keep moving around. Any given individual fish has a good chance of avoiding being eaten when behaving this way. Think about last week’s episode, where the spinner shark swims straight up through a bait ball, biting biting biting. It eats some fish, but most are fine. But a big filter feeder like the humpback can gulp a whole lot of fish at once, so it really likes bait balls.

To help maneuver prey animals into a small area, groups of humpbacks sometimes employ a strategy called bubble-net feeding. The whales will dive below the fish or krill and swim in a ring, blowing bubbles the whole time. The bubbles startle the animals, who move away from them. But since the bubbles are all around them, and the whales swim closer and closer together so that the ring of bubbles shrinks, eventually the fish or krill are all clustered in a small space as though they’re caught in a net. Then the whales open their mouths and gulp in lots of food. This is actually a simplified explanation of how bubble-net feeding works, which requires several different types of bubbles and various actions by the whales to make it work right.

The humpback is closely related to the fin whale and the blue whale. In episode 211 we learned that fin and blue whales sometimes interbreed and produce offspring, and in at least one case a marine biologist identified a whale that appeared to be the hybrid of a blue whale and a humpback.

The humpback grows up to 56 feet long, or 17 meters, with females being a little larger than males on average. It’s mostly black in color, with mottled white or gray markings underneath and on its flippers. Its flippers are long and narrow, which allows it to make sharp turns. It also has tubercles on its jaws and the fronts of its flippers which are probably sensory organs of some kind, since they contain nerves attached to a very thin hair in the middle that’s about an inch long at most, or almost 3 cm.

This is a good time to remind you that even though they look very different from other mammals, all whales are mammals. Mammals are warm-blooded animals that produce milk for their babies. Mammals also have hair, unless they don’t have hair, except that the humpback whale does have hairs in its tubercles. So there you go, humpback whales have hair.

Despite its huge size, the humpback is an active whale. It frequently breaches, meaning it rises up out of the water almost its full length, then crashes back down into the water with a huge splash. It also often slaps its flippers or its tail on the surface. Some researchers think these behaviors may have something to do with communication with other whales, or that the whale is trying to get rid of parasites, or that the whale is just having fun.

Humpback whales are famous for their elaborate songs, which are produced by males. The whales breed in winter, and the males start singing as winter gets closer, so the songs must have something to do with mating season. Scientists aren’t sure what, though. Females don’t seem to be very interested in individual males who are singing, but they will sometimes be attracted to a group of singing males. Some researchers suggest that singing might be a general call to attract all whales in the area to the breeding grounds. Then again, sometimes a male will interrupt another male who is singing and the two will fight.

The songs vary and new song elements can spread quickly through a population. Generally, researchers think males hear a new element and incorporate it into their own songs, but results of a study published in 2021 found that similar new song elements often show up in whales that could not have heard other whales sing it. This indicates that instead of copying other songs, each whale modifies his own song individually and sometimes the changes are similar. That’s just one study, though. It’s probable that the way males change their songs depends on many factors, only one of which is hearing and imitating other songs.

The study suggests that the way we think about whale songs might be wrong to start with. Researchers generally think that a whale probably sings for the same reasons that birds sing: to stake out a territory, to advertise to potential mates that it’s healthy enough to spend energy singing, and to warn rivals away. But because whales live in an environment so different from birds, and so different from what we as humans understand, it’s possible that whalesong carries meanings and intentions that we can’t interpret. A different study published in 2019 discovered that male humpbacks sometimes sing in feeding grounds, especially when a population of whales decides to overwinter at their feeding grounds instead of migrating, as sometimes happens.

What, precisely, a whale’s song means to other whales is something that only the whales know for sure. This is what a humpback song sounds like:

[humpback song]

Humpbacks make other sounds other than songs, though. Mothers and calves need to communicate so that the calves get the care they need and don’t stray too far away, but since any sounds could attract predators, they have to communicate very quietly. They make little grunting sounds to each other.

The main predator of the humpback whale is the orca, which will attack and kill calves and sometimes even adults. As a result, the humpback really does not like orcas. Humpbacks will sometimes protect seals and other animals from orca attacks.

Humpbacks migrate from their summer habitats in either the Antarctic or the Arctic, depending on what hemisphere they live in, to their winter breeding grounds in tropical waters. Then they return to colder waters in summer where there’s more food, since krill is a cold-water species. These migrations can be as long as 5,000 miles, or 8,000 kilometers. Unlike some animals that migrate in huge herds, humpbacks mostly travel in small groups that are often widely spaced.

The humpback was almost driven to extinction by commercial whaling, but after it was declared a protected species, its numbers have increased. It still has the same human-caused dangers that many other marine animals face, including habitat loss and water pollution, climate change, drowning after being entangled in nets, and noise pollution that can keep whales from communicating.

There’s always a lot we don’t know about any given species of whale, since whales are hard to study. For instance, a 2017 study discovered that humpbacks sometimes swim in a way never documented in whales before. Whales swim by flexing their massively powerful tails, and use their flippers to maneuver. Think of the tail as the engine of a car and the flippers as the power steering system. The humpback’s flippers are uniquely shaped, which as we mentioned earlier means it can maneuver skillfully, turning much more quickly than a great big whale would otherwise be able to turn. But in video studies of whales in the wild, very rarely a whale would flap its flippers like a bird flapping its wings—or, more accurately, like a seal or sea lion swimming with its flippers. The researchers who analyzed the videos suggest that the flapping is used for accelerating quickly, and because it takes a lot of energy, the whales don’t do it often. The researchers also think the humpback may be the only whale species that can accelerate using the motion of its flippers, since other whales have much smaller flippers relative to their size.

As far as we know, baleen whales don’t use sonar the way toothed whales do. Their songs and sounds are for communication, not navigation. But while humpbacks mostly hunt for food near the surface of the water where there’s plenty of light, they do occasionally dive deeper and hunt for food near the bottom. They especially like an eel-like fish called the sand lance, which spends a lot of time buried in the sand on the sea floor. In 2014, a study of humpbacks diving to find these fish indicated that when a whale dives alone, it remains silent, but when it dives to hunt with some friends, they communicate with a sound described as a tick-tock. Not the app, just a sound like the ticking of a clock. Sometimes more humpbacks come to join the whales when they hear their tick-tock sounds. But we still don’t know how the whales find the fish in the first place, since there’s no light for them to hunt by. It’s possible they can detect the fish’s chemical signature in the water when they’re close enough to one.

Baleen whales don’t have teeth, although when a baby whale is developing in its mother’s womb it does grow teeth. But at some point during its development, these embryonic teeth are reabsorbed and baleen plates form instead.

The extinct ancestors of modern baleen whales still had teeth. One genus was called Aetiocetus, which lived between about 34 and 23 million years ago in the north Pacific Ocean. It probably wasn’t directly related to modern whales, since baleen whales do actually appear in the fossil record before Aetiocetus. It was a small whale that probably only grew about 11 feet long, or 3.5 meters, although some species might have grown twice that length. The first Aetiocetus fossils were discovered in the 1960s and it was initially described as a toothed whale, since it had teeth.

But not everyone agreed. Aetiocetus showed some adaptations to filter feeding seen in modern baleen whales. For instance, its lower jaw bones weren’t fused at the chin end as they are in toothed whales. Modern baleen whales don’t have connected lower jaw bones, and in fact they have a sensory organ at that spot that scientists think helps the whale keep from engulfing too much water and hurting itself.

Recently, a team of scientists examined a CT image of a skull of Aetiocetus weltoni and discovered something surprising. Baleen is made of keratin, and keratin is only preserved in fossils very rarely, but in baleen whale fossils, the upper jawbones do show grooves where the baleen once connected. These grooves were present in the Aetiocetus skull, even though it also had teeth.

Researchers think Aetiocetus may have used its teeth to filter larger fish from the water the way some animals like crab-eater seals do today. Its teeth interlocked, which would allow it to trap fish in its mouth while pushing water out between its teeth. Its baleen probably helped catch smaller fish and other animals. The baleen was far enough away from the teeth that the whale would have still been able to bite at fish and other prey without accidentally biting its own baleen. But, as the researchers mention in their 2021 paper, Aetiocetus had a really crowded mouth.

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

Thanks for listening!

Episode 280: Lesser-Known Sharks

Thanks to Tobey and Janice this week for their suggestions of lesser-known sharks!

Further reading/watching:

CREATURE FEATURE: The Spinner Shark [this site has a great video of spinner sharks spinning up out of the water!]

Acanthorhachis, a new genus of shark from the Carboniferous (Westfalian) of Yorkshire, England

150 Year Old Fossil Mystery Solved [note: it is not actually solved]

The cartoon-eyed spurdog shark:

The spinner shark spinning out of the water:

The spinner shark not spinning (photo by Andy Murch):

A Listracanthus spine:

Show transcript:

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

This week we’re going to learn about three sharks you may have never heard of before! The first was suggested by my aunt Janice and the second by listener Tobey. The third is a mystery from the fossil record.

You may have heard about the findings of a study published in November of 2021, with headlines like “Venomous sharks invade the Thames!” My aunt Janice sent me a link to an article like this. Nobody is invading anything, though. The sharks belong where they are. It was their absence for decades that was a problem, and the study discovered that they’re back.

The Thames is a big river in southern England that empties into the North Sea near London. Because it flows through such a huge city, it’s pretty badly polluted despite attempts in the last few decades to clean it up. It was so polluted by the 1950s, in fact, that it was declared biologically dead. But after a lot of effort by conservationists, fish and other animals have moved back into the river and lots of birds now visit it too. It also doesn’t smell as bad as it used to. One of the fish now found again in the Thames is a small shark called the spurdog, or spiny dogfish.

The spurdog lives in many parts of the world, mostly in shallow water just off the coast, although it’s been found in deep water too. A big female can grow almost three feet long, or 85 cm, while males are smaller. It’s a bottom dweller that eats whatever animals it finds on the sea floor, including crabs, sea cucumbers, and shrimp, and it will also eat jellyfish, squid, and fish when it can catch them. It’s even been known to hunt in packs.

It’s gray-brown in color with little white spots, and it has large eyes that kind of look like the eyes of a cartoon shark. It also has a spine in front of each of its two dorsal fins, which can inject venom into potential predators. The venom isn’t deadly to humans but would definitely hurt, so please don’t try to pet a spurdog shark. If the shark feels threatened, it curls its body around into a sort of shark donut shape, which allows it to jab its spines into whatever is trying to grab it.

The spurdog used to be really common, and was an important food for many people. But so many of them were and are caught to be ground into fertilizer or used in pet food that they’re now considered vulnerable worldwide and critically endangered around Europe, where their numbers have dropped by 95% in the last few decades. It’s now a protected species in many areas.

The female spurdog retains her fertilized eggs in her body like a lot of sharks do. The eggs hatch inside her and the babies develop further before she gives birth to them and they swim off on their own. It takes up to two years before a pup is ready to be born, and females don’t reach maturity until they’re around 16 years old, so it’s going to take a long time for the species to bounce back from nearly being wiped out. Fortunately, the spurdog can live almost 70 years and possibly longer, if it’s not killed and ground up to fertilize someone’s lawn. The sharks like to give birth in shallow water around the mouths of rivers, where the water is well oxygenated and there’s lots of small food for their babies to eat, which is why they’ve moved back into the Thames.

Next, Tobey suggested we talk about the spinner shark. It’s much bigger than the spurdog, sometimes growing as much as 10 feet long, or 3 meters. It lives in warm, shallow coastal water throughout much of the world. It has a pointy snout and is brown-gray with black tips on its tail and fins, and in fact it looks so much like the blacktip shark that it can be hard to tell the two species apart unless you get a really good look. It and the blacktip shark also share a unique feeding strategy that gives the spinner shark its name.

The shark eats a lot of fish, especially small fish that live in schools. When the spinner shark comes across a school of fish, it swims beneath it, then upward quickly through the school. As it swims it spins around and around like an American football, but unlike a football it bites and swallows fish as it goes. It can move so fast that it often shoots right out of the water, still spinning, up to 20 feet, or 6 meters, before falling back into the ocean. The blacktip shark sometimes does this too, but the spinner shark is an expert at this maneuver.

There’s a link in the show notes to a page where you can watch a video of spinner sharks spinning out of the water and flopping back down. It’s amazing and hilarious. Tobey mentioned that the spinner shark is an acrobatic shark, and it certainly is! It’s like a ballet dancer or figure skater, but with a lot more teeth. And fewer legs.

Because spinner sharks mainly eat fish, along with cephalopods, they almost never attack humans because they don’t consider humans to be food. Humans consider the spinner shark food, though, and they’re listed as vulnerable due to overhunting and habitat loss.

We’ll finish with a mystery shark. I’ve had Listracanthus on my ideas list for a couple of years, hoping that new information would come to light, but let’s go ahead and talk about it now. It’s too awesome to wait any longer.

We know very little about Listracanthus even though it was around for at least 75 million years, since it’s an early shark or shark relative with a cartilaginous skeleton. Cartilage doesn’t fossilize very well compared to bone, so we don’t have much of an idea of what the shark looked like. What we do have are spines that grew all over the fish and that probably made it look like it was covered with bristles or even weird feathers. The spines are a type of denticle that could be up to 4 inches long, or 10 cm. They weren’t just spines, though. They were spines that had smaller spines growing from their sides, sort of like a feather has a main shaft with smaller shafts growing from the sides.

The spines are fairly common in the fossil record from parts of North America, dating from about 326 million years ago to about 251 million years ago. Listracanthus was closely related to another spiny shark-like fish, Acanthorhachis, whose spines have been found in parts of Europe and who lived around 310 million years ago, but whose spines are less than 3 inches long at most, or 7 cm.

Some researchers think the spines were only present on parts of the shark, maybe just the head or down the back, but others think the sharks were covered with the spines. Many times, lots and lots of the spines are found together and probably belong to a single individual whose body didn’t fossilize, only its spines. Some researchers even think that the flattened denticles from a shark or shark relation called Petrodus, which is found in the same areas at the same times as Listracanthus, might actually be Listracanthus belly denticles.

The spines probably pointed backwards toward the tail, which would reduce drag as the fish swam, and they might have been for display or for protection from predators, or of course both. The main parts of the spine were also hollow and there’s evidence there were capillaries inside, so they might have had a chemosensory or electrosensory function too.

Modern sharks have denticles that make their skin rough, sort of like sandpaper. One modern shark, the sandy dogfish, Scyliorhinus canicula, which is common in shallow water off the coasts of western Europe and northern Africa, and in the Mediterranean, has especially rough denticles on its tail. They aren’t precisely spines, but they’re more than just little rough patches. The sandy dogfish is a small, slender shark that barely grows more than about three feet long, or about a meter, and it eats anything it can catch. Young dogfish especially like small crustaceans, and sometimes they catch an animal that’s too big to swallow whole. In that case, the shark sticks the animal on the denticles near its tail, which anchors it in place so it can tear bite-sized pieces off. Some other sharks do this too, so it’s possible that Listracanthus and its relations may have used its spines for similar behavior.

We don’t know much about these sharks because all we have are their spines. Only one probable specimen has been found, by a paleontologist named Rainer Zangerl. Dr. Zangerl found the remains of an eel-like shark in Indiana that was covered in spines, but unfortunately as the rock dried out after being uncovered, the fossil literally disintegrated into dust.

In August of 2019, a fossil hunter posted on an online forum for fossil enthusiasts to say he’d found a Listracanthus specimen. He posted pictures, although since the fossil hasn’t been prepared it isn’t much to look at. It’s just an undulating bump down a piece of shale that kind of looks like a dead snake. Fortunately, the man in question, who goes by RCFossils, knew instantly what he’d found. He also knew better than to try to clean it up himself. Instead, he’s been working on trying to find a professional interested in taking the project on. In May of 2022 he posted again to say he’d managed to get an X-ray of the fossil, which shows a backbone but no sign of a skull. He’s having trouble finding anyone who has the time and interest in studying the fossil, but hopefully he’ll find someone soon and we’ll all learn more about this mysterious pointy shark.

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

Thanks for listening!

Episode 279: Mean Piggies

Thanks to Molly for suggesting andrewsarchus and entelodont, our mean “piggies” we learn about this week!

Further reading:

Andrewsarchus, “Superb Skull of a Gigantic Beast”

Dark Folklore by Mark Norman and Tracey Norman

Further listening:

The Folklore Podcast

Andrewsarchus (taken from article linked above):

Andrewsarchus’s skull. I’m not sure who the guy holding it is, but I like to think his name is Andrew:

Entelodont:

Show transcript:

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

I’m getting really backed up on listener suggestions, so over the next few months I plan to cover as many of them as possible. We’ll start with two suggestions by Molly, who wanted to learn about Andrewsarchus and the related Entelodont. We talked about entelodonts briefly back in episode 116, and if you remember that episode, you may remember that entelodonts are sometimes referred to as the terminator pig or the hell pig. So yes, we are going to learn about some mean piggies this week, with a bonus fun mystery piggy at the end.

Andrewsarchus mongoliensis lived in what is now central Asia about 42 million years ago. It’s only known from a single skull found in 1923 in Inner Mongolia, which is part of China these days. The skull has a long snout and is big and wide, over 2.5 feet long, or 83 cm. It has huge, strong teeth that look ferocious.

When the skull was first found, some paleontologists on the team thought it was from a huge wolf-like carnivore. But others weren’t so sure. They thought it was the skull of a pig relative, and pigs are omnivores. Without more fossil remains, we can’t know for sure what Andrewsarchus’s body looked like, but these days scientists mostly think it was closely related to entelodonts.

Despite being called the terminator pig, entelodonts weren’t very closely related to pigs, although they and Andrewsarchus are in the order Artiodactyla. That’s the order that includes all even-toed hoofed mammals and their close relations, including pigs, but also including hippos and whales. Hippos and whales are actually pretty closely related, and entelodonts and Andrewsarchus were more closely related to hippos than to pigs.

Daeodon [DIE-oh-don] was the biggest entelodont known, and it may have stood up to 7 feet tall at the shoulder, or just over 2 meters. It lived in North America, but there was another species from Eurasia, Paraentelodon intermedium, that was probably close to the same size. Both lived about 22 million years ago.

Entelodonts had big, wide skulls with flared cheekbones and knob-like bony protrusions, so its head may have looked something like a warthog’s head. It also had cloven hooves. We don’t know if Andrewsarchus had hooves since we haven’t found anything but that one huge skull. The larger species of Entelodont had a humped shoulder something like a bison for the attachment of strong neck muscles to support the head’s weight, and Andrewsarchus probably had this too. The rest of the body was much more lightly built, with short, slender legs and a skinny little tail.

Even though Entelodont teeth are fearsome-looking, and at least some species of Entelodont were probably active hunters, they’re considered omnivores and Andrewsarchus probably was too. In fact, because Andrewsarchus was found on what was once a beach along the ocean, some researchers think it might have used its big forward-pointing front teeth to dig shellfish out of the sand. Most likely it ate pretty much anything it could find or catch, including shellfish, turtles, and other small animals, carrion, and plant material like fruit, nuts, and roots.

The teeth of some entelodont species show wear marks that indicate it probably bit through bones pretty frequently, possibly while scavenging already dead animals but possibly also when killing prey. One fossil skull of a herbivorous artiodactyl that lived in North America was found with an entelodont incisor embedded in it.

On the other hand, we have a set of fossil tracks in Nebraska, in the United States, that shows the behavior of what may have been an entelodont called Archaeotherium. Archaeotherium lived around 30 million years ago and grew up to 5 feet tall at the shoulder, or 1.5 meters, although most specimens found were closer to 4 feet tall, or 1.2 meters. The fossil tracks are from three animals: a type of rhinoceros, a predator of some kind, possibly the hyena-like Hyaenodon, and a species of Archaeotherium. The rhinoceros tracks show that it was walking along, then suddenly took off at a run. The Hyaenodon tracks are nearby and possibly indicate pursuit of the rhino, or it might have just happened to be nearby and frightened the rhino. The Archaeotherium tracks, meanwhile, zigzag back and forth. What on earth is going on with that?

Entelodonts had a very good sense of smell, much like pigs do, and walking in a zigzag pattern would allow Archaeotherium to smell things more efficiently. Some researchers suggest it might have been keeping an eye on the rhino hunt, and that if the Hyaenodon managed to bring down its prey, Archaeotherium might have decided to chase Hyaenodon away from its kill. It might also have been waiting for one or both animals to become tired, and then it could attack. Then again, it might just have been looking for some yummy fruit to eat. While some places online will tell you Archaeotherium was hunting the rhino, that’s not what the tracks indicate.

Entelodonts could open their mouths really, really wide. If you’ve ever seen a hippo with its humongous mouth open, that’s what we’re talking about here. Male hippos sometimes fight by jaw-wrestling each other, and researchers think entelodonts might have done something similar. A lot of entelodont skulls show healed puncture wounds in places consistent with jaw-wrestling. The knobby protrusions on its skull might have been an adaptation to this behavior, with thickened skin over them to keep a rival’s teeth from biting too deeply. This is the case with some pigs with similar skull protrusions, which we talked about in episode 128. The head bite wounds are only seen in adult animals, and younger animals didn’t have the massive cheek and jaw muscles seen in adults.

The big question is whether Andrewsarchus was actually an entelodont or just closely related to the entelodonts. That’s the same thing paleontologists have been discussing for the last century. Until we find more Andrewsarchus fossils, though, there’s only so much we can determine about the animal, including how similar it was to the entelodonts. For instance, while entelodonts did have cloven hooves, the two halves of the hoof could spread apart like fingers, which is similar to the way camel feet are structured. This would have helped it walk on soft ground, like sand or mud. If Andrewsarchus turns out to have similar feet, it was probably an entelodont.

Finding more Andrewsarchus remains will allow us to get a good idea of how big it could grow, too. Estimates based on the same proportions seen in entelodonts suggest it might have stood about 6 feet tall at the shoulder, or 1.8 meters.

As we’ve established, entelodonts and Andrewsarchus weren’t actually pigs, although they probably looked a lot like weird oversized warthogs with some features seen in wild boars. There’s no evidence they had a pig-like snout, called a nasal disk, which is flattened at the end. Entelodonts had nostrils on the sides of the snout, something like a horse’s nostrils.

But let’s finish with an actual pig, the mystery of the sewer pig. I got this information from a fantastic book called Dark Folklore by Mark and Tracey Norman, and I read the book because I listen to The Folklore Podcast, which is by folklorist Mark Norman, although I think Tracey Norman helps out with it too. I’ll just quote from the book, and definitely check the show notes for a link if you want to order your own copy.

“Foreshadowing the 1980s panic about baby alligators being taken home as pets and subsequently flushed down the toilet into the sewer system of New York, 1859 London was overtaken by a panic about the Sewer Pigs of Hampstead.

“The sewer pigs were thought to be a monstrous porcine family living entirely below ground in the London sewer system, and even featured in the Daily Telegraph newspaper. A sow had apparently become trapped, it was said, and had given birth to a litter of piglets, the entire family living off the rubbish that accumulated in the sewers and producing litter after litter. The population lived in fear of these terrible creatures escaping from the sewer system and running riot throughout London.

“Obviously, there is nothing within a sewer system that would sustain a pig, let alone a number of them. The fear connected to this particular urban legend is disease and it arose after the hot summer of 1858 caused a devastating outbreak of typhoid and cholera in the city. Unsurprisingly, there has never been any evidence of pigs in London’s sewers, monstrous, lost or otherwise.”

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

Thanks for listening!