Tag Archives: stingrays

Episode 397: Some Colorful Fishies

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Thanks to Cosmo, William, and Silas for their fishy suggestions this week!

You have until Sept. 13, 2024 to back the enamel pin Kickstarter!

Further reading:

The Handfish Conservation Project

Researchers Look in Tank and See Promising Cluster of Near-Extinct Babies

The unique visual systems of deep sea fish

A red handfish:

Another red handfish. This one is named Hector:

The black dragon fish:

The white-edged freshwater whipray [photo by Doni Susanto]:

Show transcript:

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

This week we return to the vertebrate world, specifically some strange and colorful fishies. Thanks to William, Cosmo, and Silas for their suggestions!

We’ll start with Silas’s suggestion, the red handfish. We talked about it before back in episode 189, but it’s definitely time to revisit it. When we last discussed it, scientists estimated there were fewer than 100 red handfish left in the wild, meaning it was in imminent danger of extinction. Let’s find out how it’s doing now, four years later.

The handfish gets its name because its pectoral fins look like big flat hands. It spends most of its time on the sea floor, and it uses its hands to walk instead of swimming. It can swim, although it’s not a very strong swimmer, and anyway if you had great big hands you might choose to walk on them too. It doesn’t have a swim bladder, which helps most fish stay buoyant.

All species of handfish are small, only growing to about 6 inches long at most, or 15 cm. This is surprising considering the handfish is closely related to anglerfish, and some anglerfish can grow over 3 feet long, or about a meter.

As for the red handfish specifically, it generally only grows about 4 inches long at most, or 10 cm, and it once lived in shallow water around much of Australia. These days, it’s only found on two reefs southeast of Tasmania. Some populations are bright red while some are pink with red spots. It has a wide downturned mouth that makes it look like a grumpy red toad with big hands.

So how is the red handfish doing? Four years ago it was almost extinct in wild, with fewer than 100 individuals alive. These days the Handfish Conservation Project estimates that the wild population is probably about the same, although because the red handfish is so small and hides so well among sea grass, algae, and rocks that make up its home, it’s hard to get a good count of how many are really alive. It’s also under even more pressure than before as an overpopulation of urchins is overgrazing the plants where it lives, which may sound familiar to you if you listened to episode 395 a few weeks ago. But there is one fantastic change that gives conservationists hope that the red handfish won’t go extinct after all.

The red handfish is so endangered, and its remaining habitat is so small, that a few years ago scientists decided they needed to start a captive breeding program. But even though the fish did just fine in captivity, they didn’t breed at first. Then, in November 2023, one of the fish laid 21 eggs and all 21 hatched safely. Hopefully it won’t be long until the babies are old enough to release into the wild.

The red handfish is one of very few fish that hatch into tiny baby fish instead of into a larval form. Newly hatched babies are only about 5 mm long. Most fish colonize new habitats after they float around aimlessly as larvae, until they grow enough to metamorphose into adults. Since the red handfish doesn’t have this larval stage, and babies just walk around on the sea floor finding tiny worms and other food, it’s hard for the fish to expand its range. Hopefully, as the captive breeding program continues and more young fish are released into the wild, scientists can start releasing red handfish into areas where they used to live.

Next, William asked about the dragon fish. We’ve talked about a few dragonfish before, in episodes 193 and 231, but there are lots of species in many genera in the family Stomiidae. Many have barbels with photophores at the end that lure prey, and most have long needle-like teeth and jaws that can open incredibly wide. They also have stretchy stomachs so they can hold whatever they manage to catch. As you may have guessed from these traits, the dragon fish lives in the deep sea where there’s little or no light from the surface.

You may wonder why deep-sea fish even have eyes if there’s no light. Fish that live in cave systems eventually evolve to be eyeless, since they don’t need their eyes to see and growing eyes is just a waste of their energy. It’s because even though there’s no sunlight in the deep sea, there is light from lots of different organisms. Many, many deep-sea animals produce bioluminescent light to attract mates or trick smaller animals into coming closer.

Any sunlight that does find its way to the depths of the ocean is blue, because blue has the shortest wavelength and can travel farther. Red wavelengths are longest so that red is the first color lost when you start descending into the water. One article that I’ve linked to in the show notes mentions that if a diver gets a cut, the blood looks brown or even black if the water is deep enough. That’s creepy.

As a result, deep-sea fish are most sensitive to the color blue. Most of them can’t perceive red at all because there just isn’t any red in their environment. And that’s where the dragon fish comes in, because some species of dragon fish can not only see red, they produce red light that illuminates everything around them. A fish or other animal swimming along has no idea that it’s lit up like it’s under a red spotlight because it can’t even see that color.

At least one species, the black dragon fish, perceives red light very differently from the way other animals do. As far as we know it’s unique among all animals. Its eyes contain a photosensitizer derived from chlorophyll, which allows it to see shorter lightwaves. Chlorophyll is found in plants and some bacteria, and it’s actually a specialized pigment that absorbs energy from light. It’s the reason why plants are green. But the black dragonfish uses the chlorophyll it digests to perceive red light.

But remember how dragon fish have giant sharp fangs and will eat pretty much anything they can swallow? Where does the black dragon fish get the chlorophyll it needs? There aren’t any plants in the deep sea anyway.

The answer seems to be that the black dragon fish eats a whole lot of copepods, tiny crustaceans that live throughout the world. The particular species of copepods that the black dragon fish prefers contain a type of chlorophyll.

Finally, Cosmo wanted to learn about the freshwater stingray. We talked about it in episode 296, but mostly we concentrated on the South American fish in that episode. There are freshwater stingrays that live in other parts of the world, such as Asia. This includes the white-edge freshwater whipray, which is extremely rare and only found in four rivers in Southeast Asia.

The white-edge freshwater whipray grows up to two feet across, or 60 cm, with a thin tail about two and a half times longer than the body itself so that technically it can grow around 6 and a half feet long, or 2 meters. Most of that length is tail, though. It’s mostly brown so it can hide in the sandy mud at the bottom of the river, with black dermal denticles down the middle of its back. The tail is mostly white, though, and has two long stinging spines that can be over 3 inches long, or 8 cm.

While the white-edged whipray lives in rivers, it can also tolerate brackish water where the ocean and the river waters mix. It eats small animals it finds on the bottom of the river, including crustaceans and mollusks. It’s endangered due to habitat loss, overfishing, and pollution.

The white-edged whipray is so rare these days that it’s unlikely that anyone would accidentally step on one in the water. But if they did, the ray would whip its long tail up and jab the spines into the person’s leg or foot. The spines can do a lot of damage on their own, but the venom they inject makes the wound incredibly painful and can even potentially kill the person.

If you plan to do some wading in a South Asian river anytime soon, make sure to shuffle your feet as you walk to scare away any potential whiprays before you step right on it.

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

Thanks for listening!

 

Episode 303: Weird and Mysterious Animal Sounds

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Thanks to Emory for suggesting this week’s topic, mysterious animal sounds!

Further reading/watching:

The Story of Elk in the Great Smoky Mountains

Terrifying Sounds in the Forests of the Great Smoky Mountains

Evidence found of stingrays making noise

This New AI Can Detect the Calls of Animals Swimming in an Ocean of Noise

The wapiti [pic from article linked above]:

The stingray filmed making noise [stills from video linked to above]:

The tawny owl makes some weird sounds:

The fox says all kinds of things:

Show transcript:

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

Emory suggested we do a new episode about strange and mysterious animal sounds a while back, which is one of my favorite topics. The problem is, it’s hard to find good audio clips to share. It’s taken me a while, but I think I’ve found some good ones.

In late September 2018, in the Great Smoky Mountains in North Carolina, some hikers recorded a terrifying animal sound. The sound wasn’t a mystery for long, though, because they soon saw the animal making it. Here’s what it sounded like:

[elk bugle]

It’s the bugle of a male elk, which I’m going to call wapiti to avoid confusion. It’s a sound that wasn’t heard in the Smoky Mountains for at least a century. The eastern wapiti was once common throughout eastern North America but was driven to extinction in the late 19th century, although the last wapiti in North Carolina was killed almost a century earlier than that. All North American wapiti almost went extinct by about 1900, and hunters and conservationists worked to get nature preserves set aside to save it and its habitat. Starting in the 1990s, wapiti from western North American subspecies were reintroduced in the southeast, with reintroductions in the Smokies starting in 2001. There are now at least 200 wapiti living in the mountains, probably more. I’ve seen them myself and they’re beautiful animals!

The wapiti is a type of deer. We talked about it way back in episode 30 along with the moose. Various species of wapiti live throughout Europe and Asia as well as North America, although it’s been hunted to extinction in many areas. As we mentioned in episode 30, the name elk is used for the moose in parts of Europe, which causes a lot of confusion, which is why I’ve chosen to call it by its Algonquin name of wapiti.

The wapiti is a really big animal, one of the biggest deer alive today. Only the moose is bigger. It’s closely related to the red deer of Eurasia but is bigger. A male, called a bull, can stand about 5 feet tall at the shoulder, or 1.5 meters, with an antler spread some four feet wide, or 1.2 meters. Females, called cows, are smaller and don’t grow antlers. Males grow a new set of antlers every year, which they use to wrestle other males in fall during mating season. At the end of mating season the wapiti sheds its antlers.

The bugling sound males make during mating season is extremely loud. The sound tells females that the bull is strong and healthy, and it tells other bulls not to mess with it.

[elk bugle]

Our next sound is from an animal that scientists didn’t realize could even make sounds. There’ve been reports for a long time of stingrays making clicking noises when they were alarmed or distressed, but it hadn’t been documented by experts. A team of scientists recently decided to investigate, with their report released in July of 2022. They filmed stingrays of two different species off the coasts of Indonesia and Australia making clicking sounds as divers approached. They think it may be a sound warning the diver not to get too close. This is what it sounds like:

[Stingray making clicking sounds]

One exciting new technological development is being used to detect underwater sounds and hopefully help identify them. It’s called DeepSqueak, because it was originally developed to record ultrasonic calls made by mice and rats. This is an example of a mouse sound slowed down enough that humans can hear it, specifically a male mouse singing to attract a mate, which we talked about in episode 8:

[mouse song]

But DeepSqueak also works really well to detect sounds made by whales and their relatives, and researchers are currently using it to determine whether offshore wind farms cause problems for whales.

With DeepSqueak and other listening software, it turns out that a lot of animals we thought were silent actually make noise. For instance, this sound:

[Pelochelys bibron]

That’s a grunting sound made by the southern New Guinea giant softshell turtle.

And here’s a caecilian, a type of burrowing reptile that we talked about in episode 82:

[Typhlonectes compressicauda]

Let’s finish with a strange and mysterious sound heard on land. In January and February of 2021, some residents of London, England started hearing a weird sound at night.

[mystery sound]

Because the animal making the sound moved around so much, some people thought it must be a bird. One suggestion is that it was a tawny owl, especially the female tawny owl who makes a chirping sort of sound to answer the male’s hoot. This is what the male and female tawny owl sound like:

[owl sounds]

The tawny owl also sometimes makes an alarm call that sounds like this:

[tawny owl alarm call]

But the sound didn’t really match up with what residents were hearing. Here it is again:

[mystery sound]

Finally someone pointed out that red foxes make a lot of weird sounds, mostly screams and sharp barks, but occasionally this sound:

[fox sound]

That seems to be a pretty good match for what people were hearing in early 2021, although since no one got a look at the animal they heard, we can’t know for sure. So it’s still a mystery.

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

Thanks for listening!

Episode 296: The Hide and the Blood-Sucking Blanket

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Monster month is upon us, October, where all our episodes are about spooky things! This episode is only a little bit spooky, though. I give it one ghost out of a possible five ghosts on the spooky scale.

Happy birthday to Casey R.!

Further reading:

All you ever wanted to know about the “Cuero”

Mystery Creatures of China by David C. Xu

Freshwater stingrays chew their food just like a goat

A 1908 drawing of the hide (in the red box) [picture taken from first link above]:

The Caribbean whiptail stingray actually lives in the ocean even though it’s related to river stingrays:

The short-tailed river stingray lives in rivers in South America and is large. Look, there’s Jeremy Wade with one!

The bigtooth river stingray is awfully pretty:

Asia’s giant freshwater stingray is indeed giant:

Show transcript:

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

It’s finally October, and you know what that means. Monster month! We have five Mondays in October this year, including Halloween itself—and, in the most amazing twist of fate, our 300th episode falls on Halloween!

I know some of our listeners don’t like the really spooky episodes because they’re too scary, especially for our younger listeners. To help people out, I’m going to rate this year’s monster month episodes on a scale of one ghost, meaning it’s only a little tiny bit spooky, to five ghosts, which means really spooky. This week’s episode is rated one ghost, so it’s interesting but won’t make you need to sleep with a night light on.

Before we get started, we have two quick announcements. Some of you may have already noticed that if you scroll all the way down in your podcast app to find the first episode of Strange Animals Podcast, it doesn’t appear. In fact, the first several episodes are missing. That’s because we actually passed the 300 episode mark several weeks ago, because of the occasional bonus episode and so forth, and podcast platforms only show the most recent 300 episodes of any podcast. That’s literally the most I can make appear. However, the early podcasts are still available for you to listen to, you’ll just have to click through to the website to find them.

Second, we have a birthday shout-out this week! A very very happy birthday to Casey R! I hope your birthday is full of all your favorite things.

Now, let’s learn about the hide of South America and the blood-sucking blanket of Asia.

The first mention of a creature called El Cuero in print comes from 1810, in a book called Essay on the Natural History of Chile by a European naturalist named Fr. Juan Ignacio Molina. In his book Molina wrote, “The locals assure that in certain Chilean lakes there is an enormous fish or dragon…which, they say, is man-eating and for this reason they abstain from swimming in the water of those lakes. But they are not in agreement the appearance that they give it: now they make it long, like a serpent with a fox head, and now almost circular, like an extended bovine hide.”

Later scholars pointed out that the reason Molina thought the locals couldn’t decide what the animal looked like was because locals were talking about two different monsters. Molina just confused them. One monster was called a fox-snake and one was the cuero, which means “cow hide” in Spanish. And it’s the hide we’re going to talk about.

During the century or so after Molina wrote his book, folklorists gathered stories and legends from the native peoples of South America, trying to record as much about the different cultures as they could before those cultures were destroyed or changed forever by European colonizers. The hide appears to be a monster primarily from the Mapuche people of Patagonia.

Most stories about the hide go something like this: a person goes into the water to wash, or maybe they have to cross the lake by swimming. The hide surfaces and folds its body around the person like a blanket, dragging them under the water, and the person is never seen again. Sometimes the monster is described as resembling a cowskin or calfskin, sometimes a goat- or sheepskin. It’s usually black or brown and sometimes is reported as having white spots, and some reports say it has hooks or thorns around its edges. It may bask at the water’s surface or in shallow water in daytime, waiting for a person or animal to come too close.

The safest way to kill a hide is to trick it into coming to the surface to catch an animal or person. When it’s close enough, people throw the branches of a cactus with really long, sharp thorns at it. The hide folds its body around the cactus pieces, which pierce it through and kill it. The least safest way to kill a hide is to make sure you’re carrying a sharp knife, and when the hide grabs you, cut your way out of its enveloping folds before you drown or are eaten.

The main suggestion, starting in 1908, was that the hide was a giant octopus that lived in freshwater and had hooks on its legs or around the edges of its mantle. The main problem with this hypothesis is that there are no known freshwater octopuses. There aren’t any freshwater squid either, another suggestion.

A much better suggestion is that the hide is actually some kind of freshwater ray. And, as it happens, there are lots of freshwater stingrays native to South America. Specifically, they’re members of the family Potamotrygonidae, river stingrays.

River stingrays are pretty much round and flat with a slender tail equipped with a venomous stinger. The round part is called a disc, and some species can grow extremely large. The largest is actually a marine species called the Caribbean whiptail stingray, which can grow about 6 1/2 feet across, or 2 meters. But the short-tailed river stingray can grow about 5 feet across, or 1.5 meters, and it lives in the Río de la Plata basin in South America. The short-tailed river stingray is dark gray or brown mottled with lighter spots, while many other river stingrays are black or dark brown with light-colored spots.

Even better for our hypothesis, river stingrays are covered with dermal denticles on their dorsal surface, more commonly called the back. Dermal denticles are also called placoid scales even though they’re not actually scales. They’re covered with enamel to make them even harder, like little teeth. If that sounds strange, consider that rays are closely related to sharks, and sharks are well known to have skin so rough that you can hurt your hand if you try to pet a shark. Please don’t try to pet a shark. Admire sharks from a safe distance like you should with any wild animal.

River stingrays don’t eat people, of course. They mostly eat fish, crustaceans, worms, insects, mollusks, and other small animals. Females are much larger than males and give birth to live young. The ray’s mouth is underneath on the bottom of the disc near the front, and it has sharp teeth. Unlike pretty much every fish known, it chews its food with little bites like a mammal, which if you think about it too much is kind of creepy.

River stingrays also don’t hunt by wrapping animals in their disc, but the disc is involved in hunting in a way. The disc is formed by the ray’s fins, which are extremely broad and encircle the center part of its body, and the disc as a whole is pretty flat. The stingray will lie on the bottom of the river until a little fish or an insect gets too close. Then it will lift the front part of its disc quickly, which sucks water under it. If you’ve ever stood up in the bathtub before the water has completely drained, you can feel the suction as your body leaves the water. Quite often, the stingray’s prey gets sucked under it with the water. The ray then drops back down, trapping the animal underneath it, and chews it up.

That doesn’t mean stingrays aren’t dangerous to humans, though. The stingray’s sting is barbed and very strong, and can cause a painful wound even without its venom. A ray often hides by burying itself in the sand or mud, and if someone steps on it by accident, the ray whips its tail up and jabs its sting into their leg.

In other words, we have a large, flat creature with little pointy denticles on its back that may be dark-colored with white spots, and it’s dangerous to people and animals. That sounds a lot like the hide. There’s just one problem with this theory.

The stingray is a tropical or temperate animal. It needs warm water to survive. Patagonia is at the extreme southern end of South America, much closer to Antarctica than to the equator. No river stingray known lives within at least 500 miles of Patagonia, or 800 km, and the Patagonian lakes where the hide is supposed to live are extremely cold even in summer.

That doesn’t mean there isn’t a stingray unknown to science living in remote areas of Patagonia, of course. Many river stingray species were only discovered in the last decade or so, some of them quite large, and there are still some undescribed species. There’s always the possibility that at least one river stingray species has become adapted to the cold but hasn’t been discovered by scientists yet. It might be endangered now or even extinct.

Or the hide might not be a real animal, just a legend inspired by the river stingrays in other parts of South America. The Mapuche people are not closely related to the other peoples of Patagonia, even though they’ve lived there for at least 2,500 years, and some archaeologists think they might have migrated to Patagonia relatively late. If they brought memories of big river stingrays from their former home north of Patagonia, the memories might have inspired stories of the hide.

On the other side of the world, in China, there’s a similar legend of a monster sometimes called the xizi. The name means “mat” but it’s also referred to as a blood-sucking blanket. It lives in rivers and other waterways, and can even slide out of the water onto land. And like the hide, it’s described as a sort of living blanket that wraps itself around people or animals that venture into the water, where it pulls them under and sucks all the blood out of them.

In the case of the blood-sucking blanket, though, it’s supposed to have sharp round suckers on its underside that it uses to stick to its victims and slurp up their blood. It varies in size, sometimes about a foot across, or 30 cm, sometimes as much as 6 1/2 feet across, or 2 meters. Sometimes it’s described as reddish, sometimes green or covered with fuzzy moss on its back.

One story is that a hunter witnessed an elephant and her calf crossing a shallow river when the calf was dragged underwater by something. The mother elephant grabbed her calf and pulled it to safety, then trampled its attacker. Once the elephants were gone, the hunter went to investigate and found a dead creature that resembled a wool blanket, with a greenish, mossy back but with big suckers underneath the size of rice bowls, sort of like an octopus’s suckers.

And there is a freshwater stingray that lives in Asia, although it isn’t closely related to the river stingrays found in South America. Most of its closest relatives live in the ocean, but the giant freshwater stingray lives in rivers in southeast Asia. It’s dark gray-brown on its back and white underneath, and it has a little pointy nose at the front of its disc. It has denticles on its back and tail just like its distant South American cousins.

It’s also enormous. A big female can grow over 7 feet across, or 2.2 meters. Its tail is long and thin with the largest spine of any stingray known, up to 15 inches long, or 38 cm. In fact, its tail is so long that if you measure the giant freshwater stingray by length including its tail, instead of by width of its disc, it can be as much as 16 feet long, or about 5 meters. Some researchers think there might be individuals out there much larger than any ever measured, possibly up to 16 feet wide. The length and thinness of the tail gives the ray its other common name, the giant freshwater whipray, because its tail looks like a whip.

Even though it’s endangered due to habitat loss and hunting, and it only lives in a few rivers in South Asia these days, the giant freshwater stingray was once much more widespread. Because stingrays have cartilaginous skeletons the same way sharks do, we don’t have very many fossils or subfossil remains except for stingray teeth and denticles, so we don’t know for sure where the giant freshwater stingray used to live. But even if it didn’t live in China, travelers who had seen one in other places might have brought stories of it to China, where it spread as a scary legend.

Or, of course, there might be another freshwater stingray in China that’s unknown to science, possibly endangered or even extinct. It might even still be around, just waiting for someone to go swimming.

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

Thanks for listening!

 

Episode 016: Jellyfish

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If you look at this episode and think, “Oh, ho hum, think I’ll skip this one because snore, jellyfish,” you are so wrong! Jellies are fascinating, creepy, and often beautiful. Come learn all about our squishy friends in the sea!

A Portuguese man o’war. Creepy as heck:

A lion’s mane jelly. You do not want this guy on your ship. Incidentally, a lot of the photos you find of divers with enormous lion’s mane jellies are fakes that make the jellies look gigantic.

The cosmic jelly, a deep-sea creature:

The creepy Stygiomedusa gigantea, guardian of the underworld:

A newly discovered golden jelly.

Further reading:

Jelly Biologist (I’ve been enjoying browsing this site)

Show transcript:

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

This week’s episode is about jellyfish—also called jellies, which is more accurate since they’re not fish at all.

Originally, I was going to focus on the Portuguese man o’war, another in the ongoing feature of “animals that scared me as a kid” and technically not even a jelly. But there’s so much to learn about jellies that we’re going to cover a whole lot more than that.

Jellies are interesting animals, to say the least. Their bodies have radial symmetry, meaning they’re the same in all directions. While the body shape varies, most jellies have a bell-like shape. The bell is generally rather thin, made up of an external covering, an internal covering, and an elastic gel-like material in between. Inside, the jelly has a digestive cavity with four to eight oral arms surrounding the mouth and long tentacles hanging beneath. The jelly also has a simple nerve net that can detect light and react to other stimuli, and which takes the place of a brain.

Jellies don’t have brains. They don’t have hearts, specialized sensory organs, or much of anything else. But they’ve been around for some 650 million years, possibly much longer, so clearly it all works.

The jelly’s life cycle is pretty weird. Most start out as polyps that stick to rocks or shells and use their little tentacles to catch microscopic organisms. A polyp can bud, producing new polyps that are clones of the original. Eventually, a polyp will constrict its body and develop into a stack of larvae. Each larva develops into a tiny jelly, which separates from the stack and swims away.

Once it’s grown, a jelly reproduces by releasing sperm, if it’s male, which the water carries to the female to fertilize her eggs. Some female jellies have brood pouches on the oral arms, some just carry the fertilized eggs inside the body while they develop. The embryos develop into swimming larvae called planula, which leave the female and attack themselves to something firm, where they transform into polyps.

This seems needlessly complicated, but again, it works for the jelly.

Polyps can live for years, while adult jellies, which I’m delighted to report are called medusas, usually only live a few months. The immortal jellyfish throws another step into this process. It can transform back into a polyp from any stage of its life if it needs to. As a polyp, the immortal jellyfish is tiny, only about a millimeter long. As a full-grown medusa it’s not all that much bigger, less than four millimeters in diameter. Because it can transform back into a polyp as many times as it needs to, apparently without any kind of degradation or injury, the immortal jellyfish is effectively, well, immortal.

Before you get too excited, though, keep in mind that there’s not a whole lot of research into the immortal jellyfish yet. It’s not even known if they will transform back into polyps in the wild, since it’s only ever been observed in captivity.

Almost all jellies have stinging cells, usually concentrated on the tentacles or oral arms, which they use to stun and kill prey. The stinging cells contain venom-filled nematocysts, which are coiled structures that uncoil and sting when touched. Humans are not jelly prey, but jelly stings can still be uncomfortable—and sometimes fatal—to humans.

You’ve probably heard of the infamous box jellyfish, the most dangerous species of which is common around Australia. Unlike most jellies, box jellyfish have true eyes and a relatively well-developed nervous system. They’re active, hard for humans to detect while swimming since they’re nearly transparent, and in the case of Chironex fleckeri, their venom can kill a human in as little as two minutes. Most fatalities occur in children, but most stings don’t result in death.

Another vicious and occasionally fatal stinger is the Portuguese man o’war, although it isn’t actually a jelly. It’s not even a single animal, it’s a colony. One member is the float, another the feeding polyps, and so forth. The man o’war takes its name from a type of ship, which the float somewhat resembles. The float is bluish or purplish, generally under a foot long [30 cm], and filled with gas. Underneath the float are feeding polyps from which hang purple tentacles, typically around 30 feet long [9 m] but sometimes up to 200 feet long [61 m]. If something attacks the man o’war, it can vent some of the gas in its bladder and submerge temporarily.

When I was a kid, my family occasionally went to the beach in North Carolina. Man o’wars are tropical animals but they do occasionally drift farther north. I was fully aware of this as a kid and did not want to get in the water farther than my waist. My grandfather and one of my aunts reassured me that they’d both been stung by a man o’war once, and it wasn’t any more painful than a wasp sting.

That did not make me feel any better. In fact, it made me even more scared because then I KNEW there were man o’wars out there. I wasn’t afraid of being stung, I was afraid of touching those creepy tentacles.

As it happens, my grandfather and Aunt Barbara probably had not encountered a Portuguese man o’war but a smaller animal called a by-the-wind sailor, which is now my favorite name of anything. It has a blue bladder float like the man o’war, but its sting is much milder, A man o’war sting is incredibly painful, more of a shock, that can lead to intense muscle and joint pain, open wounds on the skin at the sting site, headache, chills and fever, nausea, and can cause victims to faint and drown. Occasionally the venom travels to the lymph nodes and causes even more serious symptoms, including swelling of the larynx, an inability to breathe, and cardiac distress. Even a dead man o’war can sting if you touch its tentacles. Why would you touch its tentacles.

I’m not the only one who feels this way about man o’wars, clearly, because one of its other names if the floating terror. That sounds like the title of a pulp science fiction novel.

The bluebottle is a smaller related species found in the Indian and Pacific Oceans. The man o’war is found in those oceans and the Atlantic. A few weeks ago, in early May 2017, hundreds of man o’wars washed ashore in Georgia and South Carolina. Man o’wars are pretty common around Florida, especially in winter, and occasionally they wash ashore in the thousands.

The man o’war eats fish and other organisms that get caught in the stinging tentacles, but there are some fish that live among the tentacles, even feeding on them, like the man o’war fish and the clownfish. Not a lot of things eat Portuguese man o’wars, but the loggerhead turtle and ocean sunfish do. I like them both. The blanket octopus is immune to the man o’war’s venom and may carry broken-off tentacles to deter predators.

If you’re stung by a man o’war, treat the sting the same way you’d treat other jelly stings. Rinse with vinegar to remove any remaining bits of tentacle or nematocysts, then apply heat for 45 minutes, either with a hot pack or by immersing in hot water. Don’t rinse with urine or vodka; it can make the stings worse—and definitely don’t rinse with fresh water. If you don’t have vinegar, rinse with sea water, but keep in mind that you may be pouring nematocysts back onto the patient with the water. This treatment is from a very recent study conducted by researchers at the University of Hawaii at Manoa, released only a few weeks ago as this episode goes live, so if you’ve heard differing advice for jelly stings, it may be out of date.

Jellies are related to some surprising things: coral, sea anemones, a rare parasitic worm, the freshwater hydra—a ten mm long tubular animal with stinging tentacles at one end that it can stretch four or five times the length of the body to catch its tiny prey. Like jellies, the hydra can regenerate parts of its body if they’re injured or bitten off. And the hydra doesn’t appear to age, making it biologically immortal, although in a different way than the immortal jellyfish.

So what’s the largest jelly known, not counting ridiculously long tentacles like the man o’war’s? That would be the lion’s mane jellyfish. Its bell can have a diameter of over seven feet [2 m] and it has pretty darn long tentacles, too—sometimes over 120 feet long [36.5 m]. It likes cold water and the biggest individuals live where it’s coldest. While small individuals are brown or tan in color, the big ones are usually red or purple. The sting of a lion’s mane jellyfish isn’t usually that bad, but it has a lot of tentacles, so it can inflict thousands of stings upon contact.

In 1973, the Australian ship Kuranda collided with a huge jelly in the South Pacific while traveling through a storm on her way to the Fiji Islands. The jelly was so enormous that the deck was covered in jellyfish goo and tentacles up to two feet deep [61 cm]. One crew member died after getting stung. The weight of the jelly was so great, an estimated 20 tons [18 metric tons] that it started to push the ship nose-down and the captain, Langley Smith, sent out an SOS. The salvage tug Hercules arrived and sprayed the Kuranda’s deck with a high-pressure hose, dislodging the jelly. Samples were sent to Sydney and tentatively identified as a lion’s mane jelly.

But remember, lion’s mane jellies don’t live in the warm waters near Fiji and Australia. There are other reports of lion’s mane jellies seen in the area, though, so it’s possible there’s a gargantuan warm-water variety that hasn’t been discovered yet.

Most jellies live near the surface of the ocean, but there are some deep-sea species known, with more being discovered every year. A gorgeous jelly, dubbed the cosmic jellyfish by the press, was spotted 9,800 feet [2987 m] below the surface near American Samoa this February. It has an umbrella-like bell with short tentacles that point both downward and upward. You may have seen it in the news described as looking like a flying saucer, which it does. A similar jelly was discovered in the Mariana Trench in 2016, almost two and a half miles underwater [4 km]. These are lovely jellies with translucent bells and glowing red and yellow innards, but there are less lovely ones down there.

The big red jellyfish discovered in 2002 is an ugly cuss. It lives in waters up to 4900 feet deep [1493 m] and is over a foot in diameter [30 cm]. It’s dull red in color and doesn’t have tentacles, just thick oral arms.

Stygiomedusa gigantea, also known as the guardian of the underworld by at least one website, and now by me, isn’t so much ugly as horrifying. Its bell is some three feet across [1 m], and while it doesn’t have tentacles or even stinging cells, it does have four 30-foot-long [9 m] oral arms that resemble dark brown or reddish strips of cloth that drift in the ocean currents.

Some deep-sea jellies don’t have tentacles or oral arms. Deepstaria enigmatica, a rare jelly described in 1967, basically just looks like a big mesh bag. Its close relative, Deepstaria reticulum, is very similar, but it’s reddish instead of whitish. The Deepstaria hangs motionless in the deep with its three-foot-wide [1 m] bell open, waiting for something to swim into it. When it does, the bell contracts like a bag, the fish or other organism is stung by nematocysts lining the bell, and the jelly pushes its stunned prey into its mouth with tiny cilia inside the bell.

Isopods, which are small crustaceans, frequently hitch rides inside Deepstaria bells. It’s not known if they’re parasites or confer some benefits to the jellies, but they don’t seem to be affected by the stings.

There are plenty of mysteries associated with enormous jellies, although the two most famous ones I dug into started to seem less and less likely once I got closer to the primary sources. According to Eric Frank Russell in his 1957 book Great World Mysteries, in 1953 a diver testing a new type of deep-sea diving suit in the South Pacific saw an enormous jelly-like monster kill a shark. The diver had been testing how deep he could dive in the suit and noticed a fifteen-foot [4.6 m] shark following him down. I’m going to quote the relevant section instead of paraphrasing, because it’s pretty amazing.

“The shark was still hanging around some 30 feet [9 m] from me and about 20 feet [6 m] higher, when I reached a ledge below which was a great black chasm of enormous depth. It being dangerous to venture farther, I stood looking into the chasm while the shark waited for my next move. Suddenly the water became distinctly colder. While the temperature continued to drop with surprising rapidity, I saw a black mass rising from the darkness of the chasm. It floated upwards very slowly. As at last light reached it I could see that it was of a dull brown color and tremendous size, a flat ragged-edged thing about one acre in extent. It pulsated sluggishly and I knew that it was alive despite its lack of visible limbs or eyes. Still pulsating, this frightful vision floated past my level, by which time the coldness had become most intense. The shark now hung completely motionless, paralyzed either by cold or fear. While I watched fascinated, the enormous brown thing reached the shark, contacted it with its upper surface. The shark gave a convulsive shiver and was drawn unresisting into the substance of the monster. I stood perfectly still, not daring to move while the brown thing sank back into the chasm as slowly as it had emerged. Darkness swallowed it and the water started to regain some warmth.”

I am skeptical, I admit. Eric Frank Russell was primarily a science fiction writer and this sounds like something from a novel, probably one called The Floating Terror. If he described the monster as 20 feet across or even 30 or 40 [6, 9, 12 m], I’d be going, “Hmm, but hey, the deep sea is full of amazing things.” But an acre? That’s 208 feet 9 inches across. 43,450 square feet. A lot of meters [4,046 square meters]. It’s three times the size of my yard, which takes me like an hour to mow. It’s just too big to believe, not without corroborating details—like a first-hand account of the actual diver. We don’t even know his name. And what about the diver’s buddy? Divers don’t go down alone, although maybe they did back in 1953. The whole story is just too thin, too fantastical to be believed.

The other promising mystery I looked into is a supposed legend from Chile, a sea monster that resembles a cow hide stretched flat but with eyes all around the edges and four big eyes in the middle. It rises to the ocean’s surface and swallows animals it encounters.

At first glance this sounds ridiculous, until you realize that many jellies have semi- or fully transparent bells and their internal organs, such as they are, may resemble eye-like blobs in the center of their bodies. Some jellies do have light-sensitive eye spots near their edges too. But the research I did to follow up this story, which I took from Karl Shuker’s blog, but which is originally from Jorge Luis Borges’ 1969 book called The Book of Imaginary Beings, indicated that the actual legend is much different and much less jelly-like.

El Cuero is a cowhide monster called Threquelhuecuvu among the Mapuche of Patagonia. It lives in rivers, lakes, and the ocean. It’s nearly circular, has claws around its edges, and one pair of red eyes. It also has tentacles on its head and a mouth in its middle, which it uses to suck bodily fluids from its prey. It’s supposed to come out of the water and come on land, and when an animal steps on it, it wraps its body around the animal and suffocates it. Then it drags its prey into the water to eat it. The only way to kill it is to throw cacti into the water. When the monster grabs the cacti, it’s pierced through with spines and dies.

It’s generally supposed that the monster is based on freshwater stingrays, although they’re not known to live in Patagonia. But in 1976, after a bus full of tourists ended up on the bottom of Lake Moreno, divers who retrieved the drowned victims reported enormous rays in the depths.

There is a freshwater stingray species in South America which has thorn-like denticles on its body and a closely related species, also with denticles, sometimes travels upriver from the ocean off the Chilean Patagonian coast. That might be the source of the cowhide monster.

So those two mysteries are almost certainly bust. But don’t feel discouraged. Not only was that 20-ton ship-sinking 1973 lion’s mane jelly a real, documented thing that happened [note from episode 248: sorry, it turns out it wasn’t real], there are lots of jelly species being discovered all the time.

Not all are deep-sea species. In 2013, a fisherman in northeast Italy hauled up a net full of golden jellies he’d never seen before. He contacted the local university, and a researcher came out and determined that the lovely golden jellies were completely unknown to science. In 2015, a 9-year-old boy caught a new species of box jelly that’s only around an inch long [3 cm].

There are freshwater jellies too, but not a lot is known about them. To add to the confusing and complex life cycle of marine jellies, many freshwater jellies also have a dormant stage where they basically turn into tiny jelly seeds, tough and capable of surviving even if dried out.

And back in the Cambrian era, some 500 million years ago, some jellies actually had skeletons. Fossil impressions show plates, spines, and spokes from comb jellies, which today are completely soft-bodied. Comb jellies are different from the kind of jellies I’ve mostly talked about in this episode, and not even closely related to them. I’d dig into them next, but we’re already pushing 20 minutes and there’s a limit to how much jellyfish information I can expect my listeners to tolerate in one sitting. We’ll save the comb jellies for another episode.

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