Category Archives: cephalopods

Episode 174: MONSTER CEPHALOPODS!



It’s a bonus monster month in June, because everything is awful and learning about monsters will take our minds off the awfulness. This week let’s learn about some mysterious stories from around the world that feature huge octopus or squid!

Further watching:

River Monsters episode about the Lusca

A colossal squid, up close to that gigantic eyeball:

Blue holes in the ocean and on land:

A giant Pacific octopus swimming:

The popular image of the kraken since the 1750s:

Show transcript:

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

Last week’s mystery bird got me thinking about how far away Halloween feels and how we haven’t really had a lot of monsters or mystery animals lately. So let’s have an extra monster month in June! We’ll start with a topic I’ve touched on in past episodes but haven’t covered in depth, three stories of GIANT OCTOPUS TYPE MONSTERS from around the world.

If you haven’t listened to episode 142, about octopuses, that ran last October, I recommend you listen to it for information about octopus biology and habits. This week we are all about the mysterious and gigantic octopuses.

Let’s jump right in with a monster from Japan, Akkorokamui. Its origins trace back to the folklore of the Ainu, a group of people who in the past mostly lived on Hokkaido, the second largest island in the country. These days they live throughout Japan. The story goes that a monster lives off the coast of Hokkaido, an octopus-like animal that in some stories is said to be 400 feet long, or over 120 meters. It’s supposed to swallow boats and whales whole. But Akkorokamui isn’t just an octopus. It has human features as well and godlike powers of healing. It’s also red, and because it’s so big, when it rises near the surface of the water, the water and even the sky look red too.

Akkorokamui is supposed to originally be from the land. A humongous red spider lived in the mountains, but one day it came down from the mountains and attacked a town, stomping down buildings as the earth shook. The villagers prayed for help, and the god of the sea heard them. He pulled the giant spider into the water where it turned into a giant octopus.

The problem with folktales, as we talked about way back in episode 17, about the Thunderbird, is that they’re not usually meant to be taken at face value. Stories impart many different kinds of information, especially in societies where writing isn’t known or isn’t known by everyone. Folktales can give warnings, record historical events, and entertain listeners, all at once. It’s possible the story of Akkorokamui is this kind of story, possibly one imparting historic information about an earthquake or tsunami that brought down a mountain and destroyed a town. That’s just a guess, though, since I don’t understand Japanese—and even if I did, the Ainu people were historically treated as inferior by the Japanese since their ancestors came from other parts of Asia, so many of their stories were never recorded properly. The Ainu people today have lost some of their historic cultural memories as they assimilated into Japanese society.

So we don’t know if Akkorokamui was once thought of as a real living animal, a spiritual entity, or just a story. There are a few reported sightings of the monster, but they’re all old and light on details. One account from the 19th century is supposedly from a Japanese fisherman who saw a monster with tentacles as big around as a grown man. It was so big that the fisherman at first thought he was just seeing reflected sunset light on the ocean. Then he came closer and realized what he was looking at—and that it was looking back at him from one enormous eye. He estimated it was something like 260 feet long, or 80 meters. Fortunately, instead of swallowing his boat, the monster sank back into the ocean.

Whether or not the folktale Akkorokamui was ever considered to be a real animal, it’s possible that some people who have seen enormous octopuses or squids have called them Akkorokamui. If you’ve listened to episode 74 about the colossal and giant squids, you may remember that both can grow over 40 feet long, or 12 meters, although the giant squid has longer arms while the colossal squid has a longer mantle in proportion to its arms. The two feeding tentacles that squids have are even longer than its arms when extended, which increases the longest measured length to 55 feet, or almost 17 meters. Both squid species are deep-sea animals that are rarely seen near the surface. But both are usually pink or red in color. A squid that big would terrify anyone, especially if they’re fishing in a small boat.

Another octopus-like sea monster is the lusca, this one from Caribbean folklore. The Caribbean Sea is part of the Atlantic Ocean outside of the Gulf of Mexico. Within the Caribbean Sea are thousands of islands, some tiny, some large, including those known collectively as the West Indies. Many reports of the lusca come from the Bahamas, specifically the so-called blue holes that dot many of the islands.

Blue holes are big round sinkholes that connect to the ocean through underground passages. Usually blue holes contain seawater, but some may have a layer of fresh water on top. Some blue holes are underwater while some are on land. The islands of the Bahamas aren’t the only places where blue holes exist. Australia, China, and Egypt all have famous blue holes, for instance, but they’re not uncommon across the world.

Blue holes form in land that contains a lot of limestone. Limestone weathers more easily than other types of rock, and most caves are formed by water percolating through limestone and slowly wearing passages through it. This is how blue holes formed too. During the Pleistocene, when the oceans were substantially lower since so much water was locked up in glaciers, blue holes formed on land, and many of them were later submerged when the sea levels rose. They can be large at the surface, but divers who try to descend into a blue hole soon discover that it pinches closed and turns into twisty passages that eventually reach the ocean, although no diver has been able to navigate so far. Many, many divers have died exploring blue holes.

Andros Island in the Bahamas has 178 blue holes on land and more than 50 in the ocean surrounding the island. It’s also the source of a lot of lusca reports.

So what does the lusca look like? Reports describe a monster that’s sharklike in the front with long octopus-like legs. It’s supposed to be huge, with an armspan of 75 feet, or 23 meters, or even more. The story goes that the tides that rise and fall in the blue holes aren’t due to tides at all but to the lusca breathing in and out.

But people really do occasionally see what they think is a lusca, and sometimes people swimming in a blue hole are dragged under and never seen again. Since blue holes don’t contain currents, it must be an animal living in the water that occasionally grabs a swimmer.

The problem is, there’s very little oxygen in the water deep within a blue hole. Fish and other animals live near the surface, but only bacteria that can thrive in low-oxygen environments live deeper. So even though the blue holes are connected to the ocean, it’s not a passage that most animals could survive. Larger animals wouldn’t be able to squeeze through the narrow openings in the rock anyway.

But maybe they don’t need to. Most blue holes have side passages carved out by freshwater streams flowing into the marine water, which causes a chemical reaction that speeds the dissolving of limestone. Some blue holes on Andros Island have side passages that extend a couple of miles, or several kilometers. It’s possible that some of these side passages also connect to the ocean, and some of them may connect to other blue holes. Most of the blue holes and side passages aren’t mapped since it’s so hard to get equipment through them.

But as far as we know, there is no monster that looks like a shark with octopus-like legs. That has to be a story to scare people, right? Maybe not. The largest octopus known to science is the giant Pacific octopus, which we talked about in episode 142. The largest ever measured had an armspan of 32 feet, or almost 10 meters. It lives in deep water and like all octopuses, it can squeeze its boneless body through quite small openings. When it swims, its arms trail behind it something like a squid’s, and it moves headfirst through the water. A big octopus has a big mantle with openings on both sides for the gills and an aperture above the siphon. The mantle of the octopus could easily be mistaken for the nose of a shark, with a glimpse of the openings assumed to be its partially open mouth. And a large octopus could easily grab a human swimming in a blue hole and drag it to its side passage lair to eat. Big octopuses eat sharks.

The giant Pacific octopus lives in the Pacific, though, not the Atlantic. If the lusca is a huge octopus, it’s probably a species unknown to science, possibly one whose mantle is more pointy in shape, more like a squid’s. That would make it resemble a shark’s snout even more.

Finally, let’s look at a monster many of us are already familiar with, the kraken. Many people think the legend of the kraken was just an exaggerated description of the giant squid. But that’s actually not the case.

The kraken is a Scandinavian monster that dates back to at least the 13th century, when a Norwegian historian wrote about it. That historian, whose name we don’t know, said it was so big that sailors took it for land while it was basking at the surface. The sailors would stop to make camp on what they thought was an island, but when they lit a campfire the kraken submerged and drowned the sailors. It could swallow ships and whales whole.

Nothing about the story mentions squid-like arms until the 1750s when a bishop called Erik Pontoppidan wrote about the kraken. Pontoppidan repeated the story of the kraken appearing island-like and then submerging, but said that it wasn’t the submerging that was so dangerous, it was the whirlpool the kraken caused as it submerged. I’d say that’s just a little bit of hair-splitting, because those sailors were in trouble either way. But Pontoppidan also said that the kraken could pull ships down into the ocean with its arms, which immediately made people think of squid and octopuses of enormous size. The idea of a stupendously large squid or octopus with its arms wrapped around a ship made its way into popular culture and remains there today.

The kraken story was probably inspired by whales, which of course were well known to Scandinavian sailors and fishers. It also might have been inspired by remote islands that are so low in the water that they’re sometimes submerged.

All that aside, could a cephalopod of enormous size actually reach out of deep water and grab the railing or masts of a ship or boat? Actually, it can’t do that, no matter how big or small. Remember that cephalopods have no skeleton, and while their arms are remarkably strong, it takes a whole lot of energy to lift a body part out of the water. We don’t notice this when swimming because our bodies are naturally buoyant especially with our lungs filled with air, and we have bones to give our bodies structure. An octopus spends most of its life supported by the water. When it comes out of the water, it stays very flat to the ground. It can only lift an arm out of the water if it can brace itself against something.

So the dramatic movie scenes where massive kraken arms suddenly shoot out of the water to seize a ship are just fantasy. But an octopus could grab onto the side of a ship with its suction cups and even heave itself onboard that way, potentially capsizing it. So that’s something fun to think about the next time you’re in a boat.

You can find Strange Animals Podcast online 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 a rating and review on Apple Podcasts or wherever you listen to podcasts. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!


Episode 155: Extreme Sexual Dimorphism



Many animals have differences between males and females, but some species have EXTREME differences!

The elephant seal male and female are very different sizes:

The huia female (bottom) had a beak very different from the male (top):

The eclectus parrot male (left) looks totally different from the female (right):

The triplewart seadevil, an anglerfish. On the drawing, you can see the male labeled in very small letters:

The female argonaut, also called the paper nautilus, makes a delicate see-through shell:

The male argonaut has no shell and is much smaller than the female (photo by Ryo Minemizu):

Lamprologus callipterus males are much larger than females:

The female green spoonworm. Male not pictured because he’s only a few millimeters long:

Show transcript:

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

I still have a lot of listener suggestions to get to, and don’t worry, I’ve got them all on the list. But I have other topics I want to cover first, like this week’s subject of extreme sexual dimorphism!

Sexual dimorphism is when the male of a species looks much different from the female. Not all animals show sexual dimorphism and most that do have relatively small differences. A lot of male birds are more brightly colored than females, for instance. The peacock is probably the most spectacular example, with the males having a brightly colored, iridescent fan of a tail to show off for the hens, which are mostly brown and gray, although they do have iridescent green neck feathers too.

But eclectus parrot males and females don’t even look like the same bird. The male is mostly green while the female is mostly red and purple. In fact, the first scientists to see them thought they were different species.

Males of some species are larger than females, while females of some species are larger than males. In the case of the elephant seal, the males are much larger than females. We talked about the northern elephant seal briefly last week, but only how big the male is. A male southern elephant seal can grow up to 20 feet long, or 6 meters, and can weigh up to 8,800 pounds, or 4,000 kg. The female usually only grows to about half that length and weight. The difference in this case is because males are fiercely territorial and fight each other, so a big male has an advantage over other males and reproduces more often. But the female doesn’t fight, so her smaller size means she doesn’t need to eat as much.

Another major size difference happens in spiders, but in this case the female is far larger than the male in many species. For instance, the body of the female western black widow spider, which lives throughout western North America, is about half an inch in length, or 16 mm, although of course that doesn’t count the legs. But the male is only half this length at most. Not only that, the male is skinny where the female has a large rounded abdomen, and the male is brown with pale markings, while the female is glossy black with a red hourglass marking on her abdomen. Female western widows can be dangerous since their venom is strong enough to kill many animals, although usually their bite is only painful and not deadly to humans and other mammals. But while the male does have venom, he can only inject a tiny amount with a bite so isn’t considered very dangerous in comparison.

The reason many male spiders are so much smaller than females is that the females of some species of spider will eat the male after or even during mating if she’s hungry. The smaller the male is, the less of a meal he would be and the less likely the female will bother to eat him. In the case of the western black widow, the male prefers to mate with females who are in good condition. In other words, he doesn’t want to spend time with a hungry female.

If you remember episode 139, about skunks and other stinky animals, we talked about the woodhoopoe and mentioned the bill differences between males and females. The male woodhoopoe has a longer, more curved bill than the female because males and females eat a slightly different diet of insects so they won’t compete for the same food sources.

But a bird called the huia took beak differences to the extreme. The huia lived in New Zealand, although it officially went extinct in 1907. It was a wattlebird, which gets its name from the brightly colored patch of skin on either side of the face, called wattles. In the case of the huia, the wattles were orange, while the feathers over most of the body were glossy black. It also had a strip of white at the tip of the long tail. The male’s beak was fairly long and pointy, although it also curved down slightly. But the female’s beak was much longer and more slender, curving downward in an arc.

The huia lived in forests in New Zealand, where it ate insects, especially beetle grubs that live in rotting logs. People used to think that a mated pair worked together to get at grubs and other insects. The male would use his shorter, stouter bill to break away pieces of rotting wood until the grub’s tunnel was exposed, and then the female would use her longer, more slender bill to fish the grub out of the tunnel. But actual observations of the huia before it went extinct indicate that it actually didn’t do this. Like the woodhoopoe, males and females preyed on different kinds of insects. The male did break open rotting wood with its beak in a way that’s very different from woodpeckers, though. Instead of hammering at the wood, it would wedge its bill into a crevice of the wood and open its beak, and the muscles and other structures it used to do so were so strong that it could easily break pieces of wood off. This action is known as gaping and other birds do it too, but the huia was probably better at it than any other bird known.

The huia went extinct partly due to habitat loss as European settlers cleared forests to make way for farming, and partly due to overhunting. Museums wanted stuffed huias for display, and the feathers were in demand to decorate hats. And as a result, we don’t have any huias left.

Sometimes the size difference between males and females reaches extreme proportions. We’ve talked about the anglerfish several times in different episodes, and it’s a good example. It’s a deep-sea fish with a bioluminescent lure on its head that it uses to attract prey. Different species grow to different sizes, but let’s just talk about one this time, the triplewart seadevil.

The triplewart seadevil is found throughout much of the world’s oceans, preferably in medium deep water but sometimes in shallow water and sometimes as deep as 13,000 feet, or 4000 meters. The female grows to about a foot long, or 30 cm. It’s black in color, although young fish are brown. Its body is covered with short spines and it has a lure on its head like other anglerfish. The lure is called an illicium, and it’s a highly modified dorsal spine that the fish can move around, including extending and retracting it. At the end of the illicium is a little bulb that contains bioluminescent bacteria. Whatever animals are attracted to the glowing illicium, the fish gulps down with its great big mouth.

But that’s the female triplewart seadevil. The male is tiny, only 30 mm long at the most. The male doesn’t have an illicium; instead, his jaws and teeth are specialized for one thing: to bite onto the female and never let go. When a male finds a female, he chooses a spot on her underside to latch on, and once he does, his mouth and one side of his body actually fuse to the female’s body. Their circulatory and digestive systems fuse too. Before the male finds a female, he has great big eyes, but once he fuses with a female his eyes degenerate because he no longer needs them. He’s fully dependent on the female, and in return she always has a male around to fertilize her eggs. But this attachment is actually pretty rare, because it’s hard for deep-sea fish to find each other.

Another sea creature where the females are much larger and very different from the males is the argonaut, or paper nautilus. The argonaut is an octopus that lives in the open ocean in tropical and subtropical waters. Instead of living on the bottom of the ocean, though, the paper nautilus lives near the surface, and while the female looks superficially similar to a nautilus, it’s only distantly related.

The female argonaut generally grows to about 4 inches long, or 10 cm, although the shell she makes can be up to a foot across, or 30 cm. In contrast, males are barely half an inch long, or 13 mm. The female’s eight arms are long because she uses them to catch prey, with two of her arms being larger than the others. She grabs small animals like sea slugs, crustaceans, and small fish and bites it with her beak, and like other octopuses she can inject venom at that point too. But the male has tiny little short arms except for one, which is slightly larger.

Like other cephalopods, the male uses one of his arms to transfer sperm to the female so she can fertilize her eggs. In most cephalopods that means an actual little packet of sperm that the male places inside the female’s mantle for her to use later. But in the argonaut, the male’s larger modified arm is called a hectocotylus, and it has little grooves that hold sperm. The male inserts the hectocotylus into the female’s mantle, then detaches it and leaves the arm inside her. Then he leaves and regrows the arm, as far as researchers know. We don’t actually know for sure since it’s never been observed, but octopuses do have the ability to regenerate lost arms. The female usually keeps the hectocotylus and sometimes ends up with several.

At that point the female creates a shell by secreting calcite from the tips of her two larger arms. The shell is delicate, papery, and white, and it resembles the shell of the ammonite, which we talked about in episode 86. The female lays her eggs inside the shell, then squeezes inside too, although she can come and go as she likes.

There’s still a lot we don’t know about the argonaut, but we know more than we used to. In the olden days people thought the female used her two larger arms as sails at the surface of the water. Eventually scientists figured out that was wrong, but they were still confused as to why there only seemed to be female argonauts. They didn’t know that the males were so small and so different, and in fact when early researchers found hectocotyluses inside the females, they assumed they were parasitic worms of some kind. Eventually they worked that part out too.

But still, for a very long time researchers thought the argonaut’s shell was just for protecting the eggs, but it turns out that the female uses the shell as a flotation device. She can control how much air the shell contains, which allows her to control how close to the surface she stays. In a 2010 study of argonauts rescued from fishing nets and released into a harbor, if the shell doesn’t contain enough air, the argonaut will jet to the surface and stick the top of its shell above the water. The shell has small openings at this point so air can get in, and once the argonaut decides it’s enough, she seals the holes by covering them with two of her arms. Then she jets downward again until she’s deep enough below the surface that the pressure compresses the air inside the shell and cancels out the weight of the shell. This means the argonaut won’t bob to the surface but she also won’t sink, and instead she can just swim normally by shooting water from her funnel like other octopuses.

A species of cichlid fish from Lake Tanganyika in Africa, Lamprologus callipterus, also differs in size due to a shell, but not like the argonaut. Instead, the male is much larger than the female. The male can be up to five inches long, or nearly 13 cm, while the female is less than two inches long, or 4 ½ cm. The females lay their eggs in shells, but not shells they make. The shells come from snails, so the male needs to be larger so he can pick up and carry a big empty shell. The female, though, still needs to be small enough to fit inside the shell.

A moth called the rusty tussock moth is also sexually dimorphic. Its caterpillar grows around 1 to 1.5 inches long, or 3 to 4 cm, with females being a little larger than male caterpillars but otherwise very similar. But after the caterpillars pupate, they’re much different. The male moth has orangey or reddish-brown wings and a wingspan of about 1.5 inches, or almost 4 cm. The female doesn’t have wings at all. She emerges from her cocoon and perches next to it, and releases pheromones that attract a male. After the female mates, she lays her eggs on her old cocoon and dies, as does the male.

Let’s finish up with an animal you may never have heard of, the green spoonworm. It’s a marine worm that lives throughout much of the Mediterranean and the northeastern Atlantic Ocean. It lives on the sea floor in shallow water, partly buried in gravel and sand. The female grows up to about six inches long, or 15 cm, and sort of looks like a mostly deflated dark green balloon, although it may also look kind of lumpy. It also has a feeding proboscis that it can extend several feet, or about a meter.

As a larva, the green spoonworm floats around in the water, but whether it becomes male or female depends on where it settles. If it lands on the seafloor it transforms into a female and starts secreting a toxin called bonellin. Bonellin is what gives the green spoonworm its dark green color. The bonellin is mostly concentrated in the feeding proboscis and allows the spoonworm to paralyze and kill the tiny animals it eats.

But if the larva happens to land on a female green spoonworm, contact with the bonellin causes it to become a male. And the male is only a few mm long, doesn’t produce bonellin, and can’t even survive on its own. The female sucks the male into her body through the feeding proboscis, but instead of digesting him, he lives inside her and fertilizes her eggs. In return she provides him with all the nutrients he needs. A female may have more than one male living inside her, making sure that her eggs will always be fertilized.

There are lots more animals that show extreme sexual dimorphism, of course, but that at least gives you an idea of how different animals evolve to fit different environmental pressures. Weird as they seem to us, to the animals in question, it’s just normal–and it’s our appearance and how we do things that would seem weird to them. Perspective is everything.

You can find Strange Animals Podcast online at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you like the podcast and want to help us out, leave a rating and review on Apple Podcasts or whatever platform you listen on. 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 and get twice-monthly bonus episodes.

Thanks for listening!


Episode 142: Gigantic and Otherwise Octopuses



Happy birthday to me! For my birthday, we’re all going to learn about octopuses, including a mysterious gigantic octopus (maybe)! Thanks to Wyatt for his question about skeletons and movement that is a SURPRISE SPOOKY SKELETON SEGMENT of the episode, or maybe not that much of a surprise if you read this first.

Further reading:

How octopus arms make decisions

Octopus shows unique hunting, social and sexual behavior

Kraken Rises: New Fossil Evidence Revives Sea Monster Debate

The larger Pacific striped octopus is not especially large, but it is interesting and pretty:

The giant Pacific octopus is the largest species known. It even eats sharks, like this one:

Show transcript:

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

Today happens to be my birthday, and not just any birthday. It’s a significant birthday that ends with a zero. That’s right, I’m TWENTY! Or maybe a little bit older than that. So for my birthday celebration, and one week closer to Halloween, let’s learn about the octopus. The episode was going to be about possible giant octopuses, but as I researched, octopuses in general turned out to be so interesting and weird that that’s what the episode is about. But we will talk about some mystery gigantic octopuses at the very end.

The first thing to know about the octopus is what the correct plural is. Sometimes people say octopi but that’s actually technically incorrect, although it’s not like you’ll be arrested if you say octopi. The correct plural of octopus is octopuses, although octopodes is also correct. No one says octopodes because that sounds weird.

But who cares about that, because we’re talking about awesome creepy weird cephalopods! The octopus lives in the ocean but it can come out of the water and walk around on land if it wants to, although it usually only does so for a matter of minutes. The octopus breathes through gills but it can also absorb a certain amount of oxygen through its skin, as long as its skin stays moist. Generally people don’t see octopuses come out of the water because most octopuses are nocturnal.

Most octopuses spend their time on the ocean floor, crawling around looking for food. When it’s threatened or frightened, though, it swims by sucking water into its body cavity and shooting it back out through a tube called a siphon, which allows it to jet propel itself quickly through the water headfirst with its arms trailing, so that it looks like a squid. But most of the time the octopus doesn’t swim like this, because when it does, the heart that pumps blood through most of the body stops. The octopus has three hearts, but two of them are only auxiliary hearts that move blood to the gills to make sure the blood stays oxygenated.

Octopus blood is blue because it’s copper-based instead of iron-based like the blood of mammals and other vertebrates. This allows it to absorb more oxygen than iron-based blood can. Since many octopuses live in cold water that doesn’t contain very much oxygen, they need all the help they can get.

The octopus also uses its siphon to release ink into the water when it’s threatened. Of course it’s not ink, but it is black and resembles ink. Also, people have used octopus ink to write with so, you know, I guess maybe it is sort of ink. Anyway, when the octopus releases ink, it can choose to mix it with mucus. Without the mucus, the ink makes a cloud of dark water that hides the octopus while it jets away, and it may also interfere with the predator’s sense of smell. With the mucus, the ink forms a blob that looks solid and in fact looks a lot like a dark-colored octopus. This is called a pseudomorph or false body, and the octopus uses it to confuse predators into thinking it’s still right there, when in fact the octopus is jetting away while the predator attacks the false body. Researchers have found that young sea turtles who attack the false body thinking it’s the real octopus later ignore real octopuses instead of trying to eat them.

In addition to their ninja-like ability to disappear behind a smoke screen, or ink screen, the octopus can also change its color and even its texture to blend in with its background. Its skin contains cells with different-colored pigments, and tiny muscles can change both the color and the texture of the cells. Think of it like being able to shiver to give yourself goosebumps whenever you want, but at the same time you can change the color and shape of the goosebumps. An octopus species that lives in shallow water and is active during the day generally can camouflage itself better than a species that lives in deeper water and is nocturnal, and small species are typically better at camouflage than large ones. Some species mimic rocks or algae with six arms and use the other two arms to creep along the ocean floor, inching away from a potential predator without it noticing.

But the octopus doesn’t just use its ability to change colors to hide from predators. It also communicates with other octopuses by changing colors. And some species have a special threat display of bright colors that warns predators away. This is especially true of the blue-ringed octopus that lives in the Pacific and Indian Oceans, which will display bright blue spots if it feels threatened. Since the blue-ringed octopus has the strongest venom of any octopus, if you see this particular threat display, swim away quickly. I don’t know why I’m assuming my listeners include sharks and whales. Actually, the place you’re most likely to encounter a blue-ringed octopus is in a shallow tide pool on the beach, so watch where you step.

You probably already know what an octopus looks like, but I haven’t actually mentioned it yet. The octopus has a bulbous body with two large eyes, eight arms lined on the bottom with suckers, and in the middle of the arms, a mouth with a beak. The beak looks sort of like a parrot’s beak and is made of chitin, a tough material that’s similar to keratin. Inside the mouth, the octopus has a radula, a tongue-like structure studded with tiny tooth-like bumps.

Until about ten years ago, researchers thought that only the blue-ringed octopus was venomous. The blue-ringed octopus is tiny but super venomous. Its venom can kill humans, although that’s extremely rare. But now we’ve learned that all octopuses appear to have venomous saliva, most of it relatively weak, but enough to kill mollusks and other small animals. The octopus eats anything it can catch, for the most part, including crabs, shrimp, small fish, mollusks, and so forth. Its suckers can attach so firmly to a bivalve’s shells that it can pull the shells apart. If it can’t manage this, though, it will cover the shells with its toxic saliva. The toxin dissolves tiny holes in the shell and kills the mollusk, allowing the octopus to open the shells easily and eat the animal inside. It can also inject the toxins into crabs to paralyze them, then uses its beak to bite the shells open without the crab being able to fight back.

The octopus can regrow an arm if it’s bitten off or otherwise lost. Some species will even drop an arm like some lizards can drop their tails in order to distract a predator. In the case of the lizard, its tail thrashes around after it’s detached, while in the case of an octopus arm, the arm continues to crawl away and tries to escape from being hurt. This is creepy to the extreme, especially when you realize the arm acts this way because it contains a sort of brain of its own.

An octopus’s brain doesn’t fully control its arms. In fact, the arms contain about twice the number of neurons that the brain contains, which means they can act autonomously in a lot of ways. Basically, each octopus arm processes information the same way that a brain does, without involving the actual brain. The arms have an excellent sense of touch, naturally, and the suckers have chemical receptors that act as a sense of taste as well. When an arm touches something, the arm decides whether it’s food, or if it’s dangerous, or if it’s in the way, or so forth. Then it decides what it should do about it. The arms use the peripheral nervous system, again not the brain, to make decisions that require arms to work together. The result is that the arms can all work at different tasks, together or separately, while the central brain is processing other information, primarily from its eyes. But also as a result, the octopus doesn’t have a good sense of where its body is in space at all times. You don’t have to see your arms to figure out where they are in relation to your body, but the octopus does.

This is all very different from the way our brains work. Researchers study the octopus to determine how its brain works with the arms to help the octopus navigate its environment. Some researchers point out that the octopus’s intelligence is so different from the intelligence of other animals we’ve studied that it’s as close as we can come to studying intelligent life from another planet.

The main reason why the octopus has such a different nervous system is that it’s an invertebrate. Humans and other mammals, birds, reptiles, and fish are all vertebrates, meaning they have a backbone of some kind. The backbone contains a spinal cord that is the main pathway for the nervous system, connecting the brain with the rest of the body. The brain processes everything that the body does. But invertebrates and vertebrates started evolving separately over half a billion years ago, and while most invertebrates don’t demonstrate a lot of what we would consider intelligence, the octopus does. Instead of a central spinal cord of nerves, the octopus, like other invertebrates, has concentrations of neurons throughout its body, called ganglia. The ganglia form a sort of neural net. This actually means the octopus can process information much more quickly than a human or other vertebrate can.

And the octopus is intelligent, probably as intelligent as parrots, crows, and primates. An octopus can learn to recognize individual humans and solve complex puzzles, can learn from watching another octopus solve a problem, and many species use tools in the wild. Some species of octopus spend the day in dens that they make out of rocks, including a rock door that they close after they go inside. The veined octopus will collect pieces of coconut shells, stack them up, and carry them around. If it’s threatened, or if it just wants to take a nap or rest, it uses the coconut shells as a hiding place.

Octopuses in captivity can cause a lot of trouble because they’re so intelligent. They will dismantle their tanks out of curiosity or just escape. An octopus in an aquarium in Bermuda escaped repeatedly in order to eat the fish and other animals displayed in nearby tanks. A common New Zealand octopus named Inky, kept at the National Aquarium, was famous for causing mischief, and one day in 2016 he managed to move the lid to his enclosure just enough to squeeze out. Then he walked around until he found a small pipe. He squeezed into the pipe, and fortunately for him it was a pipe that led directly outside and into the ocean.

The reason that octopuses can squeeze through such tiny openings is that they have NO BONES. There is not a single bone in the octopus’s body. The only hard part of the body is its beak. As long as the octopus can get its beak through an opening, the rest of the body can squish through too.

And that brings us to a surprise spooky SKELETON SECTION, thanks to a suggestion by Wyatt!

[spooky scary skeletons song!]

Wyatt wants to know how bones work and move, which is a good question and will help us learn about octopuses too. Bones have many purposes, including making blood cells and protecting the brain—that would be the skull part of the skeleton, of course—but mainly bones help your body move. Muscles are attached to bones, and when you contract a muscle, it moves the bone and therefore the rest of that part of your body. Without muscles, your bones couldn’t move; but without bones, your muscles wouldn’t do much. Also, you’d look sort of like a blob because bones provide structure for your body.

But if you need bones to move, how does an octopus move? An octopus has no bones! Do I even know what I’m talking about?

The octopus’s muscles are structured differently than muscles in animals with bones. Our muscles are made up of fibers that contract in one direction. Let’s say you pick up something heavy. To do so, you contract the fibers in some muscles to shorten them, which makes the bone they’re attached to move. Then, when you push a heavy door closed, you contract other muscles and at the same time you relax the muscles you used to pick up something heavy. This pulls the arm bone in the other direction.

But in the octopus, the fibers in its muscles run in three directions. When one set of fibers contracts, the other two tighten against each other and form a hard surface for the contracted fibers to move. So they’re muscles that also sort of act like bones. It’s called a muscular hydrostat, and it actually can result in muscle movements much more precise than muscle movements where a bone is involved.

There are exceptions to the “bones and muscles work together” rule, of course. Your tongue is a muscle. So is an elephant’s trunk, or at least it’s made up of lots and lots of muscles that aren’t attached to bones. Tongues and elephant trunks and worms and things like that all use muscular hydrostatic functioning to move.

The octopus has a lifespan that seems abbreviated compared to other intelligent animals. It typically only lives a year or two and dies soon after it has babies. After the female lays her eggs, she stops eating and instead just takes care of the eggs, which she attaches to a rock or other hard surface. It usually takes several months for the eggs to hatch, and all that time the female protects them and makes sure they have plenty of well-oxygenated water circulating around them. She dies about the time the babies hatch. As for the male, he doesn’t take care of the eggs but after he mates with a female he starts showing signs of old age and usually dies within a few weeks. That’s if the female doesn’t just decide to eat him after mating. Most male octopuses stay as far away as they can from a female while mating, and uses one of his arms to transfer a packet of sperm into her mantle, which she uses to fertilize her eggs.

At least one octopus species has been observed to brood its eggs for four and a half years, guarding them from predators and keeping them clean. Researchers studying life in an area of Monterey Bay called Monterey Canyon, off the coast of western North America, regularly survey animals in the area. In May of 2007 they saw a female octopus on a rocky ledge about 4,600 feet, or 1,400 meters, below the surface. She had distinctive scars so the researchers could identify her, and she didn’t leave her eggs once during the next four and a half years. She also didn’t appear to eat or even be interested in the small crabs and other delicious octopus food within easy reach of her. As the years went by she became thinner and paler. She and her eggs were still there in September of 2011 but when the researchers returned in October, she was gone and her eggs had hatched.

Babies are teensy when they’re first hatched, typically only a few millimeters long. The babies drift with the currents and eat tiny animals like zooplankton as they grow. One exception is the same deep-sea octopus species that spends so long protecting its eggs, Graneledone boreopacifica. Because they develop in the egg for so long, babies of this species are much larger than most baby octopuses and can even hunt for small prey immediately.

Another exception to the usual octopus habit of only reproducing once before dying is the larger Pacific striped octopus, which lives in the eastern Pacific Ocean in warm, shallow water. Not only is it gregarious, instead of mostly solitary like other octopus species, it can reproduce repeatedly without dying. Mated pairs sometimes live and hunt together and even share food. Despite the word “larger” in its name, the larger Pacific striped octopus only grows to about three inches across, or 7 cm. It is striped, though. It’s quite attractive, in fact. And its many differences from other octopus species show just how little we know about octopuses.

So how big can an octopus grow? We don’t actually know. The species that grows the largest is called the giant Pacific octopus, and the biggest one ever measured had an armspan of about 30 feet, or 9 meters.

But there are always rumors and sightings of octopuses of colossal sizes, often referred to as the gigantic octopus or the colossal octopus. In 2002 a fishing trawler brought up the incomplete carcass of a dead octopus near New Zealand, and estimates of its armspan when it was alive are around 32 feet, or 10 meters. In 1928 a man named Robert Todd Aiken reported seeing six octopuses off the coast of Oahu, Hawaii with armspans of nearly 40 feet, or 12.5 meters. In 1950, also off the coast of Oahu, a diver named Madison Rigdon reported seeing an octopus with each arm alone measuring almost 30 feet, or over 9 meters.

But because octopuses are soft-bodied animals that are eaten by so many predators, and because the biggest ones typically live in deeper water, we just don’t know that much about how big they can get. When we do find a big dead octopus, its size is difficult to estimate since cephalopods actually shrink quite quickly after they die.

We only have a few remains of ancient octopuses, mostly body impressions and fossilized beaks. In 2009, paleontologists working in Lebanon reported finding five specimens of fossilized octopus that date to 95 million years ago. The specimens are remarkably well preserved, too, which allows researchers to determine that the octopuses belong to three different species that appear to be unchanged from their modern counterparts. In 2014 the impressions of cephalopod beaks dated to around 80 million years ago were found in Hokkaido, Japan. The impressions were well preserved and paleontologists have determined that all but one belonged to an extinct species related to the vampire squid, that we talked about in episode 11. They estimate its body to have been about two feet across, or 60 cm, without the arms. The other beak impression was from a different species, one related to modern squid.

If you listened to episode 86 about ammonoids and nautiloids, which are related to octopuses, you may remember that some extinct species grew enormous, probably over 19 feet long, or 6 meters. Since those species have shells, we have a lot more fossilized remains.

But we have almost no remains of ancient octopuses, so we have no way of knowing how big some species once grew. The colossal squid was only determined to be a real animal a matter of years ago (and we talked about it and giant squid in episode 74). I wouldn’t be one bit surprised if the colossal octopus was one day found to be a real animal too.

Let’s finish with an ancient cephalopod mystery. The octopus is a messy eater, so sometimes researchers can identify an octopus’s territory by the way it leaves shells lying around. Some species of octopus arrange shells and other items in heaped-up patterns around its den. In 2011 a pair of paleontologists named Mark McMenamin and Dianna Schulte McMenamin examined an unusual pattern of ichthyosaur remains in Nevada and suggested that they might have been arranged by an octopus after eating them. But since the nine ichthyosaurs are 45 feet long, or 14 meters, the octopus would have had to be equally enormous. Dr. McMenamin and other Dr. McMenamin think the octopus might have killed the ichthyosaurs by either breaking their necks or drowning them, or both. In 2013 the team investigating the site found what may be part of a fossilized cephalopod beak, further backing up the theory. Then again, that species of ichthyosaur, Shonisaurus, ate squid and other cephalopods, so it’s possible the beak was actually inside an ichthyosaur stomach when it died and that a giant octopus or other cephalopod had nothing to do with the deaths. Still, it’s fun to think about, and it might be true!

You can find Strange Animals Podcast online at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!


Episode 101: Flying Without Wings



What better way to start out the new year than by learning about some animals that fly (or glide) without wings! Thanks to Llewelly for suggesting the colugo!

Colugo looking startled:

A colugo, flying, which startles everyone else:

Flying fish! ZOOM!

A flying gurnard, not flying:

Flying squid! ZOOM!

Flying squid close-up, mid-zoom:

Show transcript:

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

It’s the first week of a new year, so let’s start it off right and learn about some animals that fly without wings.

The first of our non-winged flying animals is a suggestion from Llewelly, who sent me some links about it and we both freaked out a little because it’s such an awesome animal. It’s called the colugo, and technically it doesn’t fly, it glides. It looks kind of like a big squirrel and kind of like a small lemur, and in fact it’s also sometimes called a flying lemur. But it’s not closely related to squirrels or lemurs. It’s actually not related closely to anything alive today.

Before we learn about the colugo specifically, let me explain a little bit about gliding animals. Gliding animals have a flap of skin called a gliding membrane or patagium. In the case of gliding mammals, like the flying squirrel or the colugo, the patagium connects each foreleg with the hindleg on that side. When the animal wants to glide, it stretches its legs out, which also stretches out the patagium. For a long time scientists assumed that the patagium was just skin and didn’t do anything except increase the animal’s surface area and act as a sort of parachute. But it turns out that the patagium contains tiny muscles like those recently discovered in the membranes of bat wings. And the skin between the fingers of the bat’s forelimbs, which creates the wings, are actually considered patagia. In fact, any gliding membrane, even if it’s part of a real wing, is considered a patagium, so birds actually have them too.

The colugo has a patagium between its legs like other gliding mammals, but it also has a patagium between its hind legs and its tail, and even its fingers and toes are connected with small patagia. It’s the most well-adapted mammal known for gliding, so well-adapted that it can glide incredible distances. One was measured as having glided almost 500 feet in one jump, or 150 meters. This is almost the length of two football fields.

The colugo lives in South Asia and is endangered mainly due to habitat loss. It grows to about 16 inches long, or 40 cm, with a small head, big eyes, and little round ears. It’s gray with some mottled white and black markings that help hide it against tree trunks, and its legs are long and slender. It eats plants. We don’t know a whole lot about the colugo, because it’s shy and lives in the treetops of tropical forests, but what we do know is really weird.

For instance, its babies. If you listened to episode 45 about monotremes, where we also discuss the differences between marsupial and placental mammals, you may remember that placental mammal babies are born mostly developed while marsupial mammal babies are born very early and finish developing outside of the mother, either in a pouch or just clinging to the mother’s fur. Well, the colugo is a placental mammal, but its babies are born extremely early, more like a marsupial. They finish developing outside of the mother, which takes six months or so, and the mother colugo keeps her tail curved up most of the time so that her patagium is wrapped around her babies like a pouch.

The colugo has weird teeth, too. The front teeth, or incisors, are shaped like tiny combs. This is similar to the incisors of lemurs, which look like tiny combs because the lemur uses them as tiny combs to groom its fur. But unlike any other mammal known, some of the colugo’s upper incisors have two roots instead of just one. Why? No one knows.

So what is the colugo related to? For a long time, no one was sure. Researchers even thought it might be a close relation of bats. These days, the two species of colugo make up their own order, Dermoptera. Order is the classification right below mammal so that’s kind of a big deal. While they’re not closely related to anything alive today, researchers place them in the same general group of animals that gave rise to the primates. But they’re about as closely related to rabbits as they are to monkeys.

In 2017 a team of scientists surveying bats in Malaysia picked up a recording of some unusual ultrasonic calls. They weren’t bat calls. Eventually they determined the calls came from colugos in the trees around the microphones, although some researchers have doubts and think the calls may actually be from other animals known to make ultrasonic sounds, like the tarsier. The colugo has been recorded making sounds audible to humans in other studies. There’s no evidence that the colugo uses echolocation like bats do.

Mammals took to gliding very early on. A few years ago, two fossils discovered in China and dated to about 160 million years ago—you know, 100 million years before the dinosaurs died out—show two different species of mammal that were able to glide. We know they could glide because the fossils are so well preserved that researchers can see the patagium between the front and hind legs of both. They’re the earliest known gliding mammals. Both the fossils belonged to a branch of mammals that have completely died out, so they’re not related to the colugo or anything else.

So what other animals fly, or glide, without real wings? You’ve heard of flying fish, of course. Do they really jump out of the water and glide on their fins? They do, and it’s a lot more awesome even than it sounds.

There isn’t just one species of flying fish but over 60, all of them with elongated pectoral fins that act like an airplane’s wings when they jump out of the water. Some species have two pairs of elongated fins. Back in the early 20th century, engineers studied flying fish fins to help design better airplane wings. But the flying fish has a lot of other adaptations that make it good at gliding, including a stiffened body and robust spine, and strong muscles that allow it to jump out of the water at high speeds.

So how well does the flying fish glide? This is where it gets crazy amazing. The longest recorded flight of a flying fish was 1,300 feet, or 400 meters. That’s way better than the colugo. It’s been recorded as reaching 20 feet, or 6 meters, above the water’s surface and flying at speeds of about 45 mph, or 70 km/h. And as if this wasn’t amazing enough, when the fish starts to descend, it can choose to slide back into the water or it can put its tail down and push off against the surface of the water to get back in the air for another glide. It can even change directions when it pushes back off. It will sometimes flap its fins like wings, but so far researchers haven’t found any evidence that this helps it fly. It may just flap its fins to stabilize its flight.

Most flying fish species are fairly small, although the biggest is a respectable 1 1/2 feet long, or about half a meter. Most flying fish live in the ocean, usually in warmer waters, and they’re all extremely slender and streamlined. They mostly eat plankton.

Sometimes flying fish land in boats or even on the decks of small ships. It’s considered a delicacy, with a taste similar to that of a sardine, and many species have started to decline as a result of overfishing.

Gliding flight has evolved in fish more than once in species that aren’t related, so there are more flying fish than there are flying fish, if you see what I mean. No, you don’t. That only made sense to me. The earliest known flying fish is a fossil dated some 240 million  years old, totally unrelated to the flying fish of today. And there are species alive today not related to the various flying fish species that can glide, if not as well as actual flying fish.

One fish that may or may not glide is called the flying gurnard. It’s a bulky fish that grows more than a foot and a half long, or 50 cm, and can weigh four lbs, or 1.8 kg. It lives in the warmer parts of the Atlantic Ocean in shallow coastal areas, where it mostly stays on the seafloor and eats crustaceans, bivalves, and other small invertebrates. It will also eat small fish if it can catch them. It has a face sort of like a frog’s and can be reddish, brown, or greenish, with spots and patches of other colors. But most importantly, its pectoral fins are extremely large, looking more like fan-like wings than fins. The so-called wings are shimmery, semi-transparent, and lined with bright blue. They sort of look like butterfly wings and can be more than 8 inches long, or 20 cm. The fins actually have two parts, a smaller section in front that looks more like an ordinary fin, and the larger wing-like section behind.

The flying gurnard’s popular name refers to its wing-like fins, which it uses to scare potential predators and to walk around on the sea floor with and poke into the sand to find food. But there are stories dating back thousands of years that not only can the flying gurnard jump out of the water to fly, its flight resembles a swallow’s swooping flight. But it’s much too heavy to fly, so those stories are only tall tales. OR ARE THEY? At least one ichthyologist, a Dr. Humphrey Greenwood, reports having seen a flying gurnard leap out of the water, spread its fins, and glide in a controlled manner for a short distance.

The last animal that flies, or glides, without wings is one I bet you would never guess. It’s the flying squid. And yes, I thought it was a made-up animal when I first heard about it. Squid can’t fly! But there one squid that does regularly leap out of the water and glide for short distances.

The Japanese flying squid lives near the ocean’s surface in schools, where it eats fish and crustaceans. Despite its name, it doesn’t just live around Japan but throughout much of the Pacific Ocean. It doesn’t live very long, less than a year, but has a complicated migratory life. Not as complicated as an eel, but pretty complicated. A squid hatches only five days or so after its mother lays the eggs. The baby squid, called a paralarva, eats plankton and doesn’t yet have arms or tentacles, since they’re fused together at first. The fused tentacles split once the baby has grown to about half an inch long, or some 10 mm, which gives you an idea of how tiny it is when it first hatches.

As the baby squid grows, it begins its migration with the other baby squids that hatched at the same time. The migration follows the ocean surface currents and different subspecies have different migration patterns. Males mature first and transfer their packets of sperm, called spermatophores, to the females for later. Then the males die and the females continue their migration back to the same area where they were hatched. They lay a few hundred to a few thousand tiny eggs and then die, leaving the eggs to hatch only a few days later and start the whole process again.

I can hear you thinking, Why yes, Kate, this is all very interesting BUT YOU HAVE NOT TOLD US HOW SQUIDS FLY. Okay, I’ll do that now.

The Japanese flying squid has a mantle, or main part of the body and head, with a pair of fins at the end that stick out quite a bit. Its eight legs and two feeding tentacles are relatively short, shorter than its mantle length of about a foot and a half long in a big female, or 50 cm. Males are smaller. Like all squids and octopuses, the flying squid moves by shooting water out of its siphon, making it jet-propelled. It travels mantle first with the legs trailing behind.

Well, the Japanese flying squid jumps out of the water and shoots through the air this way, with the fins on its mantle helping to stabilize the squid when it’s in the air and keep it flying straight. It also holds its legs and tentacles out so that the membrane between the legs is stretched taut, making a flat surface that it can angle to catch the most air. It can “fly” some 150 feet, or 50 meters, per jump, traveling at about 25 mph, or 11 meters per second. Researchers used to think it only jumped out of the water to avoid predators, but more recent studies show that it’s also a more efficient way to travel long distances than just staying in the water. Oh, and no one knew for sure that the Japanese flying squid could actually fly until about 15 years ago when researchers caught video of it happening.

Like other squids, the Japanese flying squid can change colors and release a cloud of ink to confuse predators. It also has three hearts.

There are other gliding animals and they’re all weird and interesting, so I’ll probably revisit this topic again in the future. In the meantime, if you want to learn about flying snakes, you can go back and listen to episode 56 about strange snakes. Since that’s currently my 8th most popular episode, you may have listened to it already. Thanks.

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 100: The Centipede of Episodes!



It’s our 100th episode! Thanks to my fellow animal podcasters who sent 100th episode congratulations! Thanks also to Simon and Julia, who suggested a couple of animals I used in this episode.

An Amazonian giant centipede eating a mouse oh dear god no:

The kouprey:

The Karthala scops owl:

A sea mouse. It sounds cuter than it is. Why are you touching it? Stop touching it:

A sea mouse in the water where it belongs:

Mother and baby mountain goats. Much cuter than a sea mouse:

A hairy octopus:

Further reading:

Silas Claiborne Turnbo’s giant centipede account collection

Show transcript:

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

This is our 100th episode! I’ll be playing clips from some of my favorite animal podcasts throughout the show, and I highly recommend all of them if you don’t already listen!

For our big 100 show, I’ve decided to cover several animals, some mysterious, some not so mysterious, and all weird. But we’ll start with one that just seems to fit with the 100th episode, the centipede—because centipedes are supposed to have 100 legs.

So do they have 100 legs? They don’t, actually. Different species of centipede have different numbers of legs, from only 30 to something like 300. Centipedes have been around for some 430 million years and there are thousands of species alive today.

A centipede has a flattened head with a pair of long mandibles and antennae. The body is also flattened and made up of segments, a different number of segments depending on the centipede’s species, but at least 15. Each segment has a pair of legs except for the last two segments, which have no legs. The first segment’s legs project forward and end in sharp claws with venom glands. These legs are called forcipules, and they actually look like pincers. No other animal has forcipules, only centipedes. The centipede uses its forcipules to capture and hold prey. The last pair of legs points backwards and sometimes look like tail stingers, but they’re just modified legs that act as sensory antennae. Each pair of legs is a little longer than the pair in front of it, which helps keep the legs from bumping into each other when the centipede walks.

Like other arthropods, the centipede has to molt its exoskeleton to grow larger. When it does, some species grow more segments and legs. Others hatch with all the segments and legs they’ll ever have.

The centipede lives throughout the world, even in the Arctic and in deserts, which is odd because the centipede’s exoskeleton doesn’t have the wax-like coating that other insects and arachnids have. As a result, it needs a moist environment so it won’t lose too much moisture from its body and die. It likes rotten wood, leaf litter, soil, especially soil under stones, and basements. Some centipedes have no eyes at all, many have eyes that can only sense light and dark, and some have relatively sophisticated compound eyes. Most centipedes are nocturnal.

Many centipedes are venomous and their bites can cause allergic reactions in people who also react to bee stings. Usually, though, a centipede bite is painful but not dangerous. Small centipedes can’t bite hard enough to break the skin. I’m using bite in a metaphorical way, of course, since scorpions “bite” using their forcipules, which as you’ll remember are actually modified legs.

The largest centipedes alive today belong to the genus Scolopendra. This genus includes the Amazonian giant centipede, which can grow over a foot long, or 30 cm. It’s reddish or black with yellow bands on the legs, and lives in parts of South America and the Caribbean. It eats insects, spiders, including tarantulas, frogs and other amphibians, small snakes, birds, mice and other small mammals, and lizards. It’s even been known to catch bats in midair by hanging down from cave ceilings and grabbing the bat as it flies by. Because it’s so big, its venom can be dangerous to children. A four-year-old in Venezuela died in 2014 after being bitten by one, but this is unusual, and bites generally only lead to a few days of pain, fever, and swelling.

You’ll often hear that the Amazonian giant centipede is the longest in the world, but this isn’t actually the case. Its close relation, the Galapagos centipede, is substantially longer. The Galapagos Islands have EVERYTHING. The Galapagos centipede can grow 17 inches long, or 43 cm, and is black with red legs.

Another member of Scolopendra is the waterfall centipede, which grows a mere 8 inches long, or 20 cm, but which is amphibious. The waterfall centipede was only discovered in 2000, when entomologist George Beccaloni was on his honeymoon in Thailand. Naturally he was poking around looking for bugs, and I trust his spouse was aware that that’s what he would do on his honeymoon, when he spotted a dark greenish-black centipede with long legs. It ran into the water and hid under a rock, which he knew was extremely odd behavior for a centipede. They need moisture but they avoid entering water. Beccaloni noted that the centipede was able to swim in an eel-like manner. He captured it and later determined it was a new species. Only four specimens have been found so far in various parts of South Asia. Beccaloni hypothesizes that it eats insects and other small animals found in the water.

There are stories of huge centipedes found in the depths of jungles throughout the world, centipedes longer than a grown man is tall. These are most likely tall tales, since centipedes breathe through tiny notches in their exoskeleton like other arthropods and don’t have proper lungs. As we learned in the spiders episode a few months ago, arthropods just can’t get too big or they can’t get enough oxygen to live. But some of the stories of huge unknown centipedes have an unsettling ring of truth.

There are stories from the Ozark Mountains in North America about centipedes that grow as long as 18 inches, or almost 46 cm. Historian Silas Claiborne Turnbo collected accounts of giant centipede encounters in the 19th century, which are available online. I’ll put a link in the show notes.

All the accounts come across as truthful and not exaggerated at all. I think it’s worth it to read the last few paragraphs of the centipedes chapter of Turnbo’s manuscript verbatim, because they’re really interesting and I kept finding garbled accounts of the stories in various places online. Whenever possible, go to the primary source.

“R. M. Jones, of near Protem, Mo., tells of finding a centipede once imprisoned in a hollow tree. Mr. Jones said that after his father, John Jones, settled on the flat of land on the east side of Big Buck Creek in the southeast part of Taney County, his father told him one day in the autumn of 1861 to split some rails to build a hog pen. Going out across the Pond Hollow onto the flat of land he felled a post oak tree one and one-half feet in diameter. There was a small cavity at the butt of the tree. After chopping off one rail cut he found that the hollow extended only four or five feet into the rail cut, and was perfectly sound above it. After splitting the log open he was astonished at finding a centipede eight inches in length, coiled in a knot in the upper part of the cavity. At first there appeared to be no life about it. ‘I took two sticks,’ said he, ‘and unrolled it and found that it was alive. It was wrapped around numerous young centipedes which were massed together in the shape of a little ball. The old centipede was almost white in color. After a thorough examination of the stump and the ground around it, I found no place where the centipede could have crawled in. Neither, in the log, was there any place where it could enter. How it got there I am not able to explain and how long it had been an inhabitant there is another mystery to me.’

“William Patton, who settled on Clear Creek in Marion County, Ark., in 1854 and became totally blind and is dead now, says that one day while his eyesight was good he was in the woods on foot stock hunting. When about 1 ½ miles west of where the village of Powell now is, he noticed something a short distance from him crawl into a hollow tree at the ground. ‘On approaching the tree to identify the object,’ remarked Mr. Patton, ‘I saw a monster centipede lying just on the inside of the hollow which was the object I had just observed crawl into the tree. I placed the muzzle of my rifle near the opening and shot it nearly in twain, and taking a long stick I pulled it out of the hollow and finished killing it with stones. I had no way of measuring it accurately, but a close estimation proved that it was not less than 14 inches long and over an inch wide.’

“The biggest centipede found in the Ozarks that I have a record of was captured alive by Bent Music on Jimmies Creek in Marion County in 1860. Henry Onstott an uncle of the writer and Harvey Laughlin who was a cousin of mine kept a drugstore in Yellville and collected rare specimens of lizards, serpents, spiders, horned frogs and centipedes and kept them in a large glass jar which sat on their counter. The jar was full of alcohol, and the collection was put in the jar for preservation as they were brought in. Amongst the collection was the monster centipede mentioned above. It was of such unusual size that it made on almost shudder to look at it. Brice Milum, who was a merchant at Yellville when Mr. Music brought the centipede to town, says that he assisted in the measuring of it, before it was put in the alcohol and its length was found to be 18 inches. It attracted a great deal of attention and was the largest centipede the writer ever saw. The jar with its contents was either destroyed or carried off during the heat of the war. Henry Onstott died in Yellville and is buried in the old cemetery one half a mile west of town.”

There are large centipedes around the Ozarks, including the red-headed centipede that can grow over eight inches long, or 20 cm. A hiker was bitten by a six-inch red-headed centipede a few years ago in Southwestern Missouri and had to be treated at a hospital. The red-headed centipede mostly stays underground during the day, although it will come out on cloudy days. It has especially potent venom and lives in the southwestern United States and northern Mexico. And, interestingly, females guard their babies carefully for a few days after they hatch. Since the red-headed centipede is a member of the genus Scolopendra, the ones that grow so long, I wouldn’t be a bit surprised if individuals sometimes grow much longer than eight inches.

One story of a giant centipede called the upah turned out to have a much different solution. Naturalist Jeremy Holden was visiting a village in western Sumatra in the early 2000s when he heard stories of the upah. It was supposed to be a green centipede that grew up to about a foot long, or 30 cm, and had a painful bite. It was also supposed to make an eerie yowling sound like a cat. Holden discounted this as ridiculous, since no centipedes are known to make vocalizations of any kind, until he actually heard one. He was in the forest with a guide, who insisted that this was the upah. The sound came from high up in the treetops so Holden couldn’t see what was making it. But on a later trip to Sumatra with a birdwatcher friend, Holden heard the same sound, but this time the friend knew exactly what was making it. It wasn’t a centipede at all but a small bird called the Malaysian honeyguide. The honeyguide has a distinctive catlike call followed by a rattling sound, but is extremely hard to spot even for seasoned birdwatchers with powerful binoculars. This is what a Malaysian honeyguide sounds like, if you’re curious:

[honeyguide call]

The worst kind of centipede is the house centipedes. I hate those things. I’d rather have a pet spider that lives in my hair than touch a house centipede. House centipedes are the really fast ones that have really long legs that sort of make them look like evil feathers running around on the walls.

Next, let’s take a look at the kouprey, a bovine that is rare and possibly extinct. Thanks to Simon who suggested this ages ago, after the mystery cattle episode, or at least he mentioned it to me while we were talking on Twitter.

The kouprey is a wild ox from Southeast Asia and may be closely related to the aurochs. It’s big and can stand over six feet tall at the shoulder, or almost two meters. It has long legs, a slightly humped back, and a long tail. Males have horns that look like typical cow horns, but females have horns that spiral upward like antelope horns. Cows and calves are gray with darker bellies and legs, while grown bulls are dark brown with white stockings. It lives in small bands led by a female and eats grass and other plants. Males are usually solitary or may band together in bachelor groups. It likes open forest and low, forested hills. Sometimes it grazes with herds of buffalo and other types of wild ox.

The kouprey wasn’t known to science until 1937, when a bull was sent to a zoo in Paris from Cambodia. It was already rare then. A 2006 study that showed the kouprey was actually a hybrid of a domestic cow and another species of wild ox, the banteng, was later rescinded by the researchers as inaccurate. Genetic studies have since proven that the hybrid hypothesis was indeed wrong.

Unfortunately, if the kouprey still exists, there are almost none left. In the late 1960s only about 100 were estimated to still remain. While it’s protected, it’s poached for meat and horns, and is vulnerable to diseases of domestic cattle and habitat loss. The last verified sighting of a kouprey was in 1983, and there are no individuals in captivity. But conservationists haven’t given up yet. They continue to search for the kouprey in its historical range, including setting camera traps. Since the kouprey looks very similar to other wild oxen, it’s possible there are still some hiding in plain sight.

Next up, let’s look at a rare owl. Thanks to Julia who suggested the Karthala scops owl, which only lives in one place in the world. That one place in the world happens to be an active volcano. Specifically, it lives on the island of Grande Comore between Africa and Madagascar, in the forest on the slopes of Mount Karthala.

It’s a small owl with a wingspan of only 18 inches, or 45 cm. Some of the owls are greyish-brown and some are dark brown. It probably eats insects and small animals, but not much is known about it. It’s critically endangered due to habitat loss, as more and more of its forest is being cut down to make way for farmland. It sounds like this, and if you don’t think this is adorable I just can’t help you:

[owl call]

The Karthala scops owl wasn’t discovered by science until 1958, when an ornithologist named C.W. Benson found a feather living a sunbird nest. He thought it might be a nightjar feather, but it turned out to belong to an unknown owl. At first researchers thought it was a subspecies of the Madagascar scops owl, but it’s now considered to be a new species. Unlike many other scops owl species, the Karthala scops owl doesn’t have ear tufts.

That’s pretty much all that’s known about the Karthala scops owl right now. Researchers estimate there are around 1,000 pairs living on the volcano, and hopefully conservation efforts can be put into place to protect their habitat.

The sea mouse has been on my ideas list from the beginning, so let’s learn a little bit about it today too. It’s not a mouse, although it does live in the sea. It’s actually a genus of polychaete worm that lives along the coasts of the Mediterranean Sea and the Atlantic Ocean, although it doesn’t really look like a worm. It looks kind of mouse-like, if you’re being generous, mostly because it has setae, or hairlike structures, on its back that look sort of like fur. Some species grow up to a foot long, or 30 cm, but most are usually smaller, maybe half that size or less. It’s shaped roughly like a mouse with no head or tail, and is about three inches wide, or 7.5 cm, at its widest.

The sea mouse is usually a scavenger, although at least one species hunts crabs and other polychaete worms. It spends a lot of its time burrowing in the sand or mud on the ocean bed, looking for decaying animal bodies to eat. It also has gills and antennae, although these aren’t readily noticeable because of the setae covering the animal’s back.

Underneath the setae, the sea mouse is segmented. It doesn’t have real legs but it does have appendages along its sides called parapodia, which it uses like little leglets to push itself along. Sometimes a sea mouse is found washed ashore after a storm. Often it scurries through the wet sand and looks even more like a mouse.

The most interesting thing about the sea mouse is its setae. The setae are about an inch long and are dark red, yellow, black, or brown under ordinary circumstances, depending on species. But when light shines on them just right, they glow with green and blue iridescence. The setae are hollow and made of chitin. The setae are much thinner than a human hair, and nanotech researchers have used them to create nanowires.

Here’s a sweet little mystery animal I got from one of my favorite books, Karl Shuker’s Search for the Last Undiscovered Animals. In 1858, French missionary Emmanuel Domenech published a book called Missionary adventures in Texas and Mexico. A personal narrative of six years’ sojourn in those regions, and in that book he mentions an interesting animal. This event apparently took place in or near Fredericksburg, Texas, sometime before about 1850. The woman in question may have been Comanche. I’ll quote the relevant passage, from pages 122 and 123 of the book.

“An American officer assured me that he had seen an Indian woman, dressed in the skin of a lion which she had killed with her own hand—a circumstance which manifested on her part no less strength than courage, for the lion of Texas, which has no mane, is a very large and formidable animal. This woman was always accompanied by a very singular animal about the size of a cat, but of the form and appearance of a goat. Its horns were rose-coloured, its fur was of the finest quality, glossy like silk and white as snow; but instead of hoofs this little animal had claws. This officer offered five hundred francs for it; and the commandant’s wife, who also spoke of this animal, offered a brilliant of great value in exchange for it; but the Indian woman refused both these offers, and kept her animal, saying that she knew a wood where they were found in abundance; and promised, that if she ever returned again, she would catch others expressly for them.”

So what could this strange little animal be? It sounds like a mountain goat. Mountain goats live in mountainous areas of western North America, but might well have been unknown elsewhere in the mid-19th century. They’re pure white with narrow black horns and hooves, but an albino individual might have horns that appear to be pinkish, at least at the base where the horn core is, due to lack of pigment in the horns allowing blood to show through the surface. While male mountain goats can grow more than three feet tall at the shoulder, or 1 meter, females are much smaller and have smaller horns. Most tellingly, mountain goats have sharp dewclaws as well as cloven hooves that can spread apart to provide better traction on rocks. To someone not familiar with mountain goats, this could look like claws rather than feet. My guess is the woman had a young mountain goat she was keeping as a pet, possibly an albino one, which would explain its size and appearance. It’s nice to think that she cared so much for her little pet that she refused huge amounts of money for it.

Let’s finish up with a rare and tiny cephalopod called the hairy octopus. It’s tiny, only two inches across, or five centimeters, and covered with strands of tissue that give it its name. The so-called hair of the hairy octopus camouflages it by making it look like a piece of seaweed or algae. It can also change colors like other octopuses, to blend in even more with its surroundings. It can appear red, brown, cream, or white, with or without spots and other patterns. It’s only ever been seen in the Lembeh Strait off the coast of Indonesia, and then only rarely.

It’s so rare, in fact, that it still hasn’t been formally described by science. So if you’re thinking about becoming a biologist and you find cephalopods like octopus and squid interesting, this might be the field for you. You might get to give the hairy octopus its official scientific name one day!

Thanks so much to all of you, whether you’re a fellow podcaster, a Patreon subscriber, a regular listener, or someone who just downloaded your first episode of Strange Animals Podcast to see if you like it. I’m having a lot of fun making these episodes, and I’m always surprised at how many people tell me they enjoy listening. I tend to forget anyone listens at all, so whenever I get an email or a review or someone tweets to me about an episode, I’m always startled and pleased. I’ve been trying hard to make the show’s sound quality better, and while I don’t always have the time to do as much research for each episode as I’d like, I do my best to make sure all the information I present is up to date and as accurate as possible.

As always, 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, and happy new year!


Episode 086: Ammonoids and Nautiloids



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 074: Colossal Squid and the Things That Eat Them



We’re going to learn about the colossal squid in this episode, with bonus info about the giant squid…and then we’re going to learn about the massive things that eat this massive squid!

A giant squid, looking slightly guilty for eating another squid:

A colossal squid, looking less than impressive tbh:

THAT EYEBALL:

A sperm whale looking baddass:

A southern sleeper shark, looking kind of boring:

Show transcript:

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

This week we’re going to learn first about the colossal squid, and then we’re going to learn about what eats the colossal squid.

You’ve probably heard of the giant squid, but maybe you haven’t. Let’s start with it, because the giant squid and the colossal squid are both massive, amazing deep-sea animals.

Stories of huge squid go back to ancient times. Aristotle and Pliny wrote about it, the legend of the kraken may be at least partially inspired by it, and sailors have told stories about it for time out of mind. Naturalists of the mid-19th century knew it must exist because whalers had found enormously long tentacles and huge beaks in sperm whale stomachs. But except for the occasional badly damaged specimen washed up on shore, no one had seen a giant squid. Certainly no one had seen a living giant squid.

It wasn’t until 2001 that a live giant squid was caught on film, and then it was only a larval squid. In 2002 a live adult giant squid was caught off the coast of Japan. It wasn’t especially big, just 13 feet long, or 4 meters, but up until then an adult giant squid had never been captured or even photographed. Its body is now on display at the National Science Museum of Japan. It wasn’t until 2004 that a research team got photographs of a live giant squid in its natural habitat, also off the coast of Japan. Since then researchers have taken more photographs and footage of giant squid, and we’re starting to learn more about it.

Squids in general have a body called a mantle, with small fins at the rear and eyes near the base above the arms, eight arms, and two long tentacles. The arms and tentacles are lined with suction cups that contain rings of serrated chitin, which allows the squid to hang on to its prey. Chitin is the same stuff lobster shells and fish scales are made of. It’s the invertebrate version of keratin. In the middle of the arms, at the base of the mantle, is the squid’s mouth, which looks for all the world like a gigantic parrot beak, also made of chitin. Instead of actual teeth, the squid has a radula, which is basically a tongue studded with chitinous teeth that it uses to shred its prey into pieces small enough to swallow.

Most of the length of a giant squid comes from its tentacles. Researchers estimate that the longest giant squid’s mantle is about 7 ½ feet long, or 2.25 meters. The longest giant squid’s mantle and arms together reach around 16 feet long, or 5 meters. That’s still pretty huge, but it’s not until you add in the tentacles that the length just gets ridiculous. The longest giant squid known—and this is an estimate based on the size of the biggest beak ever found—was 43 feet, or 13 meters. Females are typically much bigger than males and can weigh twice as much.

The giant squid is a deep-sea animal, probably solitary, and eats fish and smaller squid, including other giant squid. It’s an active hunter and catches prey by grabbing it with its super-long tentacles, reeling it in to hold it more securely with its arms, then biting it with its beak and shredding it into pieces with its radula.

The giant squid has the largest eye of any living animal, as big as 11 inches in diameter, or 27 cm. Since it mostly lives in the deep sea, it probably needs such big eyes to see bioluminescent light given off by the animals it eats and to detect predators. Only ichthyosaurs had larger eyes. Well…except for the colossal squid, which may have eyes even bigger than the giant squid’s.

So if the giant squid can grow to some 43 feet long, is the colossal squid even longer? Only a little. Researchers estimate the colossal squid can grow to around 46 feet long, or 14 meters, but it has shorter tentacles and a much longer mantle than the giant squid so is an overall much bigger and heavier animal.

But that size estimate is only that, an estimate. We know very little about the colossal squid. It was first described from parts of two arms found in the stomach of a sperm whale in 1925, and for more than 50 years that was pretty much all we had. Then a Russian trawler caught an immature specimen in 1981 off the coast of Antarctica. Since then researchers have been able to study a few other specimens caught or found dead, mostly from the Antarctic seas.

As far as we know, the colossal squid is an ambush predator rather than an active hunter like the giant squid. It lives in the deep seas in the Southern Ocean, especially around Antarctica, as far down as 7,200 feet or 2.2 km beneath the surface of the ocean, and it mostly eats fish. While its tentacles are much shorter than the giant squid’s, they have something the giant squid does not. Its suckers have hooks, some of them triple-pointed and some of which swivel. When it grabs onto something, it is not going to let go until somebody gets eaten.

The largest colossal squid ever found was caught in 2007 in the Antarctic. It was caught by a trawler when they hauled in a fishing line. The squid was eating an Antarctic toothfish caught on the line and wouldn’t let go, so the fishermen hauled it aboard in a net and froze it. It was 33 feet long, or ten meters, and by the time it was thawed out for study, its tentacles had shrunk so that it was even shorter. Its eye was 11 inches across, or 27 cm, but when the squid was alive its eye was probably bigger, maybe as much as 16 inches across, or 40 cm—in which case, it wins the biggest eye category and deserves a trophy. With an eyeball on it.

So if the biggest colossal squid we’ve ever seen is only 33 feet long, how do we know it can grow to 46 feet long? Because whalers have found colossal squid beaks in the stomachs of sperm whales that are much larger than the 33-foot squid’s beak.

And that brings us to the first predator of the colossal squid, the sperm whale. Lots of things eat young colossal squids, from fish and albatrosses to seals and bigger squids, but today we’re talking about predators of full-grown colossal squid. There aren’t many. In fact, there are only two that we know of.

The sperm whale eats pretty much anything it wants, frankly, but mostly what it wants is squid. It eats both giant and colossal squid, and we know because squid beaks aren’t digestible. They stay in the whale’s stomach for a long time. Specifically they stay in the whale’s second stomach chamber, because sperm whales have a four-chambered stomach like cows and other ruminants do. Sometimes a whale will puke up squid beaks, but often they just stay in the stomach. Some whales have been found with as many as 18,000 squid beaks in their stomachs. 18,000! Can you imagine having 18,000 of anything riding around in your stomach? I wouldn’t even want 18,000 Cap’n Crunches in my stomach and I really like Cap’n Crunch cereal.

Sometimes squid beaks do make it deeper into the whale’s digestive system, and when that happens, researchers think it stimulates the body to secrete a greasy substance called ambergris to coat the beak so it won’t poke into the sides of the intestines. Small lumps of ambergris are sometimes found washed up on shore after the whale poops them out, and it can be valuable. Once it’s been out of the whale for a while it starts to smell really good so has been traditionally used to make perfume, but these days most perfume companies use a synthetic version of ambergris.

The sperm whale can grow to at least 67 feet long, or 20.5 meters, and may possibly grow much longer. It’s an active hunter and a deep diver, with the biggest whales routinely diving to almost 7,400 feet or 2,250 meters to catch that tasty, tasty squid. It can stay underwater for over an hour. It has teeth only in the lower jaw, which is long and thin. The upper jaw has holes in the gum called sockets where its lower teeth fit into, which is kind of neat. But because male sperm whales sometimes fight by ramming each other, occasionally a whale’s jaw will become broken, dislocated, or otherwise injured so that it can’t use it to bite squid. But that actually doesn’t seem to stop the whale from eating squid successfully. They just slurp them up.

Sperm whales use echolocation to find squid, but researchers also think the whale can use its vision to see the squid silhouetted against the far-off water’s surface. Sperm whales have big eyes, although not nearly as big as squid eyes, and a whale can retract its eyeballs into its eye sockets to reduce drag as it swims. It can also protrude its eyes when it wants to see better. Researchers have tagged sperm whales with radio transmitters that tell exactly where the whale is and what it’s doing, at least until the tag falls off. The tags occasionally show that a sperm whale will hunt while swimming upside down, which researchers think means the whale is looking up to see squid silhouettes.

You’ll often hear people talk about sperm whales and giant squids battling. Sperm whales do often have sucker marks and scars from giant and colossal squid arms, but that doesn’t mean the squid was trying to drown the whale. Squid have no real defense against getting eaten by sperm whales. All a squid can do is hang on to the whale in hopes that it won’t actually end up in the whale’s belly, which is not going to happen, squid. Some researchers even theorize that the sperm whale can stun prey with a massive burst of powerful sonar impulses, but so far there’s no evidence for this frankly pretty awesome hypothesis.

The other main predator of full-grown colossal squid are a few species of sharks called sleeper sharks. They’re slow-moving deep-sea sharks that mostly live in cold waters around the Arctic and Antarctic. We don’t know much about a lot of sleeper sharks species. Many of them were only discovered recently, and some are only known from one or a few specimens. Sleeper sharks are generally not much to look at. They don’t have great big mouths full of huge teeth like great whites, they don’t have weird-shaped heads like hammerheads, and they’re just plain grayish all over, maybe with some speckles.

The Greenland shark is one type of sleeper shark. It’s the one with the longest known lifespan of any vertebrate, as much as 500 years old. The Greenland shark is also one of the largest sharks alive, up to 24 feet long, or 7.3 meters, and possibly longer. But the Greenland shark isn’t one of the sleeper sharks that eat colossal squid, since it lives around the Arctic and the colossal squid lives around the Antarctic. But the Southern sleeper shark lives around the Antarctic and is so closely related to the Greenland shark that for a long time many researchers thought it was the same species. The Southern sleeper shark is overall shorter, only around 14 feet long, or 4.4 meters, although since we don’t know a lot about it, we don’t really know how big it can get. It’s probably an ambush predator and it definitely eats colossal squid because colossal squid beaks are sometimes found in its stomach.

In 2004 a team of researchers examined the stomach contents of 36 sleeper sharks that had been accidentally killed by fishing trawlers around and near Antarctica. They found remains of at least 49 colossal squid, bigger on average than the squid sperm whales typically eat.

Just going by what we know about the Greenland shark, it’s safe to say that the southern sleeper shark is an extremely slow swimmer, barely exceeding more than two miles an hour, or 3.5 km per hour. That’s about the speed you walk if you’re not in any particular hurry. It may also be prey to the same parasitic copepod, which is a type of crustacean, that infests a lot of Greenland sharks. The parasite attaches itself to the shark’s EYEBALL. But some researchers think the parasite actually gives something back to the shark, by glowing with a bioluminescence that attracts prey, which the shark then eats. Greenland sharks don’t appear to need to see in order to find prey anyway. That doesn’t make it any less gross.

I’m very sorry to end this episode with an eyeball parasite, so here’s one last thing to take your mind off it. As long as there have been reports of gigantic squid, there have been reports of gigantic octopuses. The largest octopus currently known is the giant Pacific octopus with a 20 foot legspan, or 6 meters. But there may be a gigantic octopus much larger than that. In 1928, six octopuses were sighted off the coast of Oahu in Hawaii by a sailor in the US Navy, who estimated their legs spanned 40 feet across, or 12.5 meters. In 1950, a diver in the same area reported seeing an octopus with a body the size of a car, and with tentacles estimated as 30 feet long each, or 9.3 meters.

Remember the study I mentioned earlier, about researchers finding lots of colossal squid remains in sleeper shark stomachs? They found something else in one of the sharks, remains of a huge octopus. Species unknown.

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 011: The Vampire Squid and the Vampire Bat



This week we’re going all goth in April for the vampire squid and the vampire bat. They’re so awesome I want to die.

The vampire squid looking all menacing even though it’s barely a foot long.

“I love you, vampire bat!!” “I love you too, Kate.”

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Show transcript:

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

I thought about waiting to run this episode in October, but that’s a really long way away. So we’ll have Halloween in April and talk about the vampire squid and the vampire bat.

The vampire squid has one of the coolest Latin names going, Vampyroteuthis infernalis, which means “vampire squid from hell.” It’s a deep-sea squid and until recently, not a lot was known about it. It was discovered in 1903 and originally classified as an octopus. Its body is about six inches long [15 cm], with another six inches or so of tentacles, which are connected with webbing called a cloak. Actually I’m not sure if scientists refer to this as a cloak, but if you’ve called your animal the vampire squid from hell, you can’t complain if podcasters, for instance, refer to web-connected octopus legs as a cloak.

So is it an octopus or a squid? It’s both, in a way. The vampire squid is the last surviving member of its own order, Vampyromorphida, which shares similarities with both.

The vampire squid’s color varies from deep red to velvety black. The inside of its cloak is black and the parts of its legs inside the cloak are studded with spines. Its beak is white. Basically the only thing this little guy needs to be the world’s ultimate goth is a collection of Morrissey albums.

It lives in the lightless depths of the ocean below 3,000 feet [914 meters]. There’s not a lot of oxygen down there so there aren’t very many predators. The vampire squid doesn’t need oxygen because it’s a vampire—or at least it can live and breathe just fine with oxygen saturations as little as 3%. Its metabolic rate is the lowest of any cephalopod.

The vampire squid doesn’t move a lot. It drifts gently, aided in buoyance because its gelatinous tissues are roughly the same density as seawater. Adults have two small fins sticking out from their mantle, which they flap to propel them through the water.

If something threatens a vampire squid, it brings its legs up to expose the spiny insides of its cloak and hide its body. If something really threatens a vampire squid, even though it doesn’t have ink sacs, it can eject a cloud of bioluminescent mucus, and can flash its photophores in a dazzling display of lights. These photophores are concentrated on the outside tips of its arms. If the end of an arm is bitten off, the vampire squid can regenerate it.

So we have a creepy-looking, if small, cephalopod that lives in the deep, deep sea called a vampire squid. WHAT. DOES. IT. EAT?

I hate to disappoint you, but the vampire squid eats crap. In fact, it eats the crap of animals that eat crap. There’s not a lot of food in the ocean depths. Mostly there’s just a constant rain of fish poop, algae, bits of scales and jellyfish, and other waste. Lots of little creatures live on this stuff and their poop joins the rain of barely-food that makes it down to the abyssal depths where the vampire squid waits.

The squid had two retractable filaments—not the same thing as the two feeding tentacles true squids have, but used for feeding. The filaments are extremely long, much longer than the vampire squid itself. It extends the filaments, organic detritus falls from above and sticks to them, and the vampire squid rolls the detritus up with mucus from its arm tentacles into little sticky balls and pops the balls into its mouth.

That’s not very goth. Or it might be incredibly goth, actually.

Most cephalopods only spawn once before they die. A 2015 paper in Current Biology reports that the vampire squid appears to go through multiple spawning phases throughout its life. It may live for a long time too, but we don’t know for sure. There’s still a lot we don’t know about the vampire squid.

Because squids and octopuses are soft bodied, we rarely find them in the fossil record. In 1982, though, a beautifully preserved octopus body impression was found in France in rocks dating to 165 million years ago. And guess what kind of octopus it turned out to be! Yes, it’s related to the vampire squid.

If the vampire squid is the kind of pensive goth who listens to The Smiths and reads Poe in cemeteries, the vampire bat is out clubbing with its friends, blasting Combichrist, and spending its allowance in thrift shops. There are three species of vampire bat, but they’re different enough from each other that each belongs to its own genus. They’re native to the Americas, especially tropical and subtropical environments, although they haven’t been found any further north than Mexico. And yes, vampire bats do actually feed on blood. It’s all they eat.

Vampire bats are small, active, and lightweight. They’re only about 3 ½ inches long [9cm] with a 7-inch wingspan [18 cm], and weigh less than two ounces [57 grams]. They live in colonies that consist of big family groups: a small number of males and many more females and their babies. Males without a colony hang out together and probably never clean up their apartments.

Vampire bats belong to the leaf-nosed bat family, and like other leaf-nosed bats they sleep during the day and hunt at night. But the vampire bat doesn’t actually have a nose leaf. That’s a structure that aids with echolocation, and vampire bats don’t need the high level echolocation ability that insect-eating bats do. They get by with a reduced ability to echolocate, but they have another highly developed sense that no other mammal has: thermoreception. They use it to determine the best place to bite their prey. The warmer, the better. That’s where the blood is.

The vampire bat also has good eyesight, a good sense of smell, and hearing that’s attuned to the sound of breathing. A bat frequently remembers the sound of an individual animal’s breathing, and returns to it to feed night after night. What vampire bats don’t have is a very good sense of taste. They don’t really need it. In fact, they don’t have the kind of bad food avoidance that every other mammal has. In a study where vampire bats were given blood with a compound that tasted bad and made them throw up, the next time they were offered the bad-tasting blood, they ate it anyway.

Most bats are clumsy on the ground. They’re built for flying and for hanging from perches. But vampire bats are agile. They crawl around and even run and jump with no problems.

Two species of vampire bat prey mainly on birds, while the third—the common vampire bat—feeds on mammals. Bird blood has a much higher fat content than mammal blood, which is higher in protein. But results of a study released in January 2017 found that hairy-legged vampire bats, which usually prey on large wild birds, had started feeding on domestic chickens as their wild prey became scarcer—and then they started feeding on human blood.

A vampire bat doesn’t suck blood. It makes a small incision with extremely sharp fangs and laps up the blood with its grooved tongue. It may even trim hair from the bite site first with its teeth. Its saliva contains an anti-coagulate called draculin that keeps the blood flowing. The bat doesn’t eat much, because let’s face it, it’s just a little guy. In order to hold more blood, as soon as it starts to feed its digestion goes into overdrive. Within some two minutes after it starts to eat, the bat is ready to urinate in order to get rid of the extra fluid so it can hold more blood. A feeding session may last about 20 minutes if the bat isn’t disturbed, and the bat may drink about an ounce of blood in all.

A vampire bat needs to eat at least every two days or it will starve. A bat that hasn’t found prey in two nights will beg for food from its colony mates, which often regurgitate a little blood for the hungry bat to eat. New mother bats may be fed this way by her colony for as much as two weeks after she’s given birth so that she doesn’t have to hunt. Baby vampire bats drink their mother’s milk just like any other mammal.

If a mother bat doesn’t return from hunting, other colony members will take care of her baby so it won’t die. Colony members groom each other and are generally very social. Even the male bats that aren’t part of the colony are allowed to roost nearby. Nobody fights over territory. These are nice little guys.

Vampire bats do sometimes carry rabies, but it’s pretty rare compared to infection rates in dogs. They are more dangerous to livestock than to humans. Attempts to kill off vampire bat colonies to stop the spread of rabies actually has the opposite effect, since bats from a disturbed colony will seek out another colony to join.

Vampire bats have considerable resistance to rabies and frequently recover from the disease, after which they’re immune to reinfection, and there’s some preliminary evidence to suggest that native human populations in areas where vampire bats are common may also have developed some resistance to rabies. Researchers hope that this finding will lead to better treatment of rabies in the same way that the draculin anticoagulant in vampire bat saliva led to advances in blood-thinning medications.

I like to imagine a vampire bat hanging out with a vampire squid. The bat would sip blood from a tiny wineglass and fidget with its jewelry while it tries to conversation. The squid would just stare at the bat. Then it would eat a globule of crap. The bat would pee on itself and the whole evening would just be a bust. Also, one of them would drown but if I can imagine a tiny wineglass I can imagine a tiny bat-sized bathysphere or something. Never mind.

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

Thanks for listening!