Tag Archives: octopus

Episode 191: Masters of Disguise!



Thanks to Nicholas and Pranav for their suggestions which led to this episode about animals that are especially good at disguising themselves!

If you’d like to listen to the original Patreon episode about animal mimics, it’s unlocked and you can listen to it on your browser!

Don’t forget to contact me in some way (email, comment, message me on Twitter or FB, etc.) if you want to enter the book giveaway! Deadline is Oct. 31, 2020.

Further watching:

An octopus changing color while asleep, possibly due to her dreams

Crows mobbing an owl!

Baby cinereous mourner and the toxic caterpillar it’s imitating:

The beautiful wood nymph is a moth that looks just like bird poop when it sits on a leaf, but not when it has its wings spread:

The leafy seadragon, just hanging out looking like seaweed:

This pygmy owl isn’t looking at you, those are false eyespots on the back of its head:

Is it a ladybug? NO IT’S A COCKROACH! Prosoplecta looks just like a (bad-tasting) ladybug:

The mimic octopus:

A flower crab spider with lunch:

Show transcript:

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

This week let’s look at some masters of disguise. This is a suggestion from Nicholas, but we’ll also learn about how octopuses and other animals change colors, which is a suggestion from Pranav. Both these suggestions are really old ones, so I’m sorry I took so long to get to them. A couple of years ago we had a Patreon episode about animal mimics, so I’ll be incorporating parts of that episode into this one, but if you want to listen to the original Patreon animal mimics episode, it’s unlocked so anyone can listen to it. I’ll put a link to it in the show notes.

Most animals are camouflaged to some degree so that they blend in with their surroundings, which is also called cryptic coloration. Think about sparrows as an example. Most sparrows are sort of brownish with streaks of black or white, which helps hide them in the grass and bushes where they forage. Disruptive coloration is a type of camouflage that breaks up the outlines of an animal’s body, making it hard for another animal to recognize it against the background. Many animals have black eye streaks or face masks that help hide the eyes, which in turn helps hide where their head is.

But some animals take camouflage to the extreme! Let’s learn about some of these masters of disguise.

We’ll start with a bird. There’s a bird that lives in parts of South America called the cinereous mourner that as an adult is a pretty ordinary-looking songbird. It’s gray with cinnamon wing bars and an orange spot on each side. It mostly lives in the tropics. In 2012, researchers in the area found a cinereous mourner nest with newly hatched chicks. The chicks were orangey-yellow with dark speckles and had long feather barbs tipped with white. While the researchers were measuring the chicks and making observations, they noticed something odd. The chicks started moving their heads back and forth slowly. If you’ve ever seen a caterpillar moving its head back and forth, you’d recognize the chicks’ movements. And, as it happens, in the same areas of South America, there’s a large toxic caterpillar that’s fluffy and orange with black and white speckles.

It’s rare that a bird will mimic an insect, but mimicry in general is common in nature. We’ve talked about some animal mimics in earlier episodes, including the orchid mantis in episode 187 that looks so much like a flower that butterflies sometimes land on it…and then get eaten. Stick insects, also known as phasmids, which we talked about in episode 93, look like sticks. Sometimes the name just fits, you know? Some species of moth actually look like bird poop.

Wait, what? Yes indeed, some moths look just like bird poop. The beautiful wood nymph (that’s its full name; I mean, it is beautiful, but it’s actually called the beautiful wood nymph) is a lovely little moth that lives in eastern North America. It has a wingspan of 1.8 inches, or 4.6 cm, and its wings are quite lovely. The front wings are mostly white with brown along the edges and a few brown and yellow spots, while the rear wings are a soft yellow-brown with a narrow brown edge. It has furry legs that are white with black tips. But when the moth folds its wings to rest, suddenly those pretty markings make it look exactly like a bird dropping. It even stretches out its front legs so they resemble a little splatter on the edge of the poop.

But it’s not just insects that mimic other things. We’ve talked about frogfish before in episode 165. It has frills and protuberances that make it look like plants, rocks, or coral, depending on the species. The leafy seadragon, which is related to seahorses and pipefish, has protrusions all over its body that look just like seaweed leaves. It lives off the coast of southern and western Australia and grows over nine inches long, or 24 cm, and it moves quite slowly so that it looks like a piece of drifting seaweed. Not only are the protuberances leaf-shaped, they’re green with little dark spots, or sometimes brown, while the body can be green or yellowish or brown like the stem of a piece of seaweed.

Many animals have false eyespots, which can serve different purposes. Sometimes, as in the eyed click beetle we talked about in episode 186, the false eye spots are intended to make it look much larger and therefore more dangerous than it really is. Sometimes an animal’s false eyespots are intended to draw attention away from the animal’s head. A lot of butterflies have false eyespots on their wings that draw attention away from the head so that a predator will attack the wings, which allows the butterfly to escape. Some fish have eyespots near the tail that can make a predator assume that the fish is going to move in the opposite direction when startled.

Even some species of birds have false eyespots, including many species of pygmy owl. The Northern pygmy owl is barely bigger than a songbird, just six inches tall, or 15 cm. It lives in parts of western North America, usually in forests although it also likes wetlands. It’s mostly gray or brown with white streaks and speckles, but it has two black spots on the back of its head, fringed with white, that look like eyes. Predators approaching from behind think they’ve been spotted and are being stared at.

But some larger birds of prey have false eyespots too, including the American kestrel and northern hawk owl. What’s going on with that?

You’ve probably seen or heard birds mobbing potential predators. For instance, where I live mockingbirds will mob crows, while crows will mob hawks. The mobbing birds make a specific type of angry screaming call while divebombing the predator, often in groups. They mostly aim for the bird’s face, especially its eyes, in an attempt to drive it away. This happens most often in spring and summer when birds are protecting their nests. Researchers think the false eyespots that some birds of prey have help deflect some of the attacks from other birds. The mobbing birds may aim for the false eyespots instead of the real eyes. Despite its small size, the northern pygmy owl will eat other birds, and it’s also a diurnal owl, meaning it’s most active during the day, and it does sometimes get mobbed by other birds.

Sometimes, instead of blending in to its surroundings, an animal’s appearance jumps out in a way that you’d think would make it easy to find and eat. But like the cinereous mourner chicks mimicking toxic caterpillars, something in the mimic’s appearance makes predators hesitate.

A genus of cockroaches from the Philippines, Prosoplecta, have evolved to look like ladybugs, because ladybugs are inedible to many predators. But cockroaches don’t look anything like ladybugs, so the modifications these roaches have evolved are extreme. Their hind wings are actually folded up and rolled under their carapace in a way that has been found in no other insect in the world. The roach’s carapace is orangey-red with black spots, just like a ladybug.

In the case of a lot of milkweed butterfly species, including the monarch butterfly, which are all toxic and which are not related to each other, researchers couldn’t figure out at first why they all look pretty much alike. Then a zoologist named Fritz Müller suggested that because all the butterflies are toxic and all the butterflies look alike, predators who eat one and get sick will afterwards avoid all the butterflies instead of sampling each variety. That’s called Mullerian mimicry.

A lot of insects have evolved to look like bees, wasps, or other insects with powerful stings. The harmless milksnake has similar coloring to the deadly coral snake. And when the mimic octopus feels threatened, it can change color and even its body shape to look like a more dangerous animal, such as a sea snake.

And that brings us to the octopus. How do octopuses change color? Is it the same in chameleons or is that a different process? Let’s find out and then we’ll come back to the mimic octopus.

We’ve talked about the octopus in many episodes, including episodes 100, 142, and 174, but while I’ve mentioned their ability to change color before, I’ve never really gone into detail. Octopuses, along with other cephalopods like squid, have specialized cells called chromatophores in their skin. A chromatophore consists of a sac filled with pigment and a nerve, and each chromatophore is surrounded by tiny muscles. When an octopus wants to change colors, its nervous system activates the tiny muscles around the correct chromatophores. That is, some chromatophores contain yellow pigment, some contain red or brown. Because the color change is controlled by the nervous system and muscles, it happens incredibly quickly, in just milliseconds.

But that’s not all, because some species of octopus also have other cells called iridophores and leucophores. Iridophores are layers of extremely thin cells that can reflect light of certain wavelengths, which results in iridescent patches of color on the skin. While the octopus can control these reflections, it takes a little longer, several seconds or sometimes several minutes.

Leucophores are cells that scatter light, sort of like a mirrored surface, which doesn’t sound very helpful except when you remember how light changes as it penetrates the water. Near the surface, with full spectrum light from sunshine, the leucophores just appear like little white spots. But water scatters and absorbs the longer wavelengths of light more quickly than the shorter wavelengths. We’ve talked about this before here and there, mostly when talking about deep-sea animals.

To make it a little simpler, think of a rainbow. A rainbow is caused when there are a lot of water droplets in the air. Light shines through the droplets and is scattered, and the colors are always in the same pattern. Red will always be on the top of the rainbow because it has the longest wavelength, while violet, or purple, will always be on the bottom because it has the shortest wavelength. The same thing happens when sunlight shines into the water, but it doesn’t form a rainbow that we can see. Red light is absorbed by the water first, which is why so many deep-sea animals are unable to perceive the color red. There’s no reason for them to see it, so there’s no need for the body to put effort into growing receptors for that color.

Blue, by the way, penetrates water the deepest. That’s why clear, deep water looks blue. Solid particles in the water also affect how light scatters, so it can get complicated. But to get back to an octopus with leucophores, the leucophores reflect the color of the light that shines on them. So if an octopus is deeper in the water and the light shining on it is mostly in the green and blue spectrum, the leucophores will reflect green and blue, helping make the octopus look sort of invisible.

But wait, it gets even more complicated, because some octopuses can also change the texture of the skin. Sometimes that just means it can make its skin bumpy to help it blend in with rocks or coral, but some species can change the shape of the skin more drastically.

We still don’t fully understand how cephalopods know what colors they should change to. While octopuses mostly have good eyesight, at least some species are colorblind. But they can still match the background colors exactly. Some preliminary research into cuttlefish skin appears to show that the cuttlefish has a type of photosensor in the skin that allows it to sense light wavelengths and brightness without needing to use its eyes. Basically the skin acts like its own eye. This is getting weirder and weirder, but that happens when we talk about cephalopods because they are peculiar and fascinating animals. In 2019, marine biologists released footage of a captive octopus changing colors in her sleep. Some researchers think she may have been dreaming, and her dream prompted the color changes.

Let’s get back to the mimic octopus now that we’ve learned the basics of how octopuses change color. The mimic octopus lives throughout much of the Indo-Pacific, especially around Indonesia, and has an armspan of about two feet across, or 60 cm. It generally lives in shallow, murky water, where it forages for small crustaceans and occasionally catches small fish. It’s usually light brown with darker brown stripes, but it’s good at changing both its color and its shape to mimic other animals.

So far, researchers have documented it mimicking 15 other animals, including a sea snake where it hides all but two of its legs, a lion fish where it holds its legs out to look like spines, jellyfish, sting rays, frogfish, starfish, sponges, tube-worms, flatfish, and even a crab. It actually imitates a crab in order to approach other crabs, which it then grabs and eats. So obviously it’s not using its mimicry ability randomly. It will imitate a sea snake if it feels threatened by an animal that is eaten by sea snakes, for instance. And it was only discovered in 1998 and hasn’t been studied very well yet.

Unfortunately, the mimic octopus is rare to start with and threatened by pollution and habitat loss. Once it was discovered, people immediately wanted to own them. But the mimic octopus doesn’t do well in captivity, usually dying within weeks or even days. Even octopus experts have trouble keeping them alive for very long. One expert reported that the mimic octopus is incredibly shy and spends most of its time hiding deep under the sand. It’s mostly active at night and doesn’t like bright light. It’s incredibly sensitive to temperature changes, water quality, and even the type of salt used in saltwater aquariums, and most importantly, he reported that in captivity, it doesn’t do any imitating.

Chameleons are also famous for their ability to change color and pattern, but not every species can do so. The ones who can use a very different process for color changing compared to octopuses. The chameleon has a layer of skin that contains pigments with a layer beneath that contains crystals of guanine, a reflective molecule that’s used in cosmetics to make things look shimmery, like nail polish. The chameleon can move the crystals to change the way light reflects off them, which affects the color, especially when combined with the pigments in the upper layer of skin. The color change takes about 20 seconds and different species are able to change into different colors and patterns.

Not all mimics use appearance. A number of moths are toxic to bats, but it’s no use evolving bright colors to advertise their toxicity to predators who use echolocation to hunt. Instead, the moths generate high-pitched clicks that the bats hear, recognize, and avoid. And naturally, some non-toxic moths also generate the same sounds to mimic the toxic moths.

Let’s finish with a tiny spider that also changes color. It’s called the white crab spider or the goldenrod crab spider or the banana crab spider, or just the flower spider. It’s a small, common spider that lives throughout the northern hemisphere. You’ve probably seen a few of them in your time, probably when you’re leaning down to sniff a flower. It hangs out on flowers and can be white or yellow in color. A big female can be 10 mm long, not counting her legs, while males are barely half that size. They’re called crab spiders because they often run sideways like a crab. The flower spider doesn’t build a web. Instead, it just sits on a flower.

The male flower spider climbs around from flower to flower, looking for a mate. The female generally stays put on a particular flower until it fades, and then she’ll find a new one. If she moves from a yellow flower to a white one, or vice versa, she can change color to match, but it’s not a quick process. It takes at least ten days and sometimes up to 25 days to change from white to yellow, since the spider has to secrete yellow pigment into its cells, while changing from yellow to white usually takes less than a week. If she’s on a flower that is another color, she’ll usually remain white. Only the female can change color, and some females may have small red or pink markings that don’t change color. The male is usually yellow or off-white in color.

The flower spider is so well camouflaged that it can be hard to spot even if you’re looking for it. It eats butterflies and moths, bees, and other insects that visit the flowers. Males will also eat pollen. Its venom is especially toxic to bees, although it’s harmless to humans. It really likes to eat bumblebees. Its first pair of legs are longest and curve forward to make it easier for the spider to grab a bumblebee and sink its fangs into it. Meanwhile, the bumblebee has black and yellow stripes to advertise to potential predators that it will sting, but that doesn’t help it when it comes to the little crab spider. Danger in the bee world!

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.

Don’t forget to contact me if you want to enter the book giveaway contest, which will run through October 31, 2020! If you want to enter, just let me know by any means you like.

Thanks for listening!


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 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 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 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!