Category Archives: invertebrates

Episode 390: The Wallaby and Wiwaxia

Posted on by

Podcast: Play in new window | Download (Duration: 11:50 — 13.1MB)

Subscribe: RSS | More

Thanks to Jaxon and Lorenzo for their suggestions this week!

Further reading:

Rock-wallaby bite size ‘packs a punch’

Tiny Australian wallaby the last living link to extinct giant kangaroos

Extraordinary Fossil of Giant Short-Faced Kangaroo Found in Australia

Wiwaxia corrugata – The Burgess Shale

The nabarlek:

The banded hare-wallaby:

Wiwaxia was a little less cute than wallabies are:

An artist’s rendition of what Wiwaxia might have looked like when alive [picture from last page linked above]:

Show transcript:

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

Every so often I get an animal suggestion that I’m positive we’ve already covered, but then I’m flabbergasted when it turns out we haven’t. That’s the case for the animals we’ll learn about this episode, with thanks to Jaxon and Lorenzo!

A while ago, Jaxon left us a nice review and suggested we talk about wallabies. I was CONVINCED we’d talked about the wallaby repeatedly, but I think I was thinking about the wombat. We’ve hardly ever mentioned the wallaby, and it’s such a great animal!

The wallaby is a marsupial that basically looks like a miniature kangaroo, although some species grow pretty large. The resemblance makes sense because kangaroos and wallabies are closely related, but everything else about the wallaby family tree is confusing. That’s because there are a lot of animals called wallabies that aren’t actually the same type of animal. “Wallaby” is just a catchall term used by people to describe any animal that looks kind of like a miniature kangaroo.

Wallabies are native to Australia and New Guinea, but various species have been introduced to other places where they’re invasive, including New Zealand, France, England, Scotland, and Hawaii. Most of these non-native populations happened by accident when pets or zoo animals escaped into the wild, but some were introduced on purpose by people who didn’t know they were causing damage to the local ecosystems.

One thing everyone knows about kangaroos, which is also true for wallabies, is that they hop instead of running. Their hind legs are extremely strong with big feet, and in fact the name of the family they share, Macropodidae, means big feet. So, you know, Bigfoot exists but maybe doesn’t look like most people think. The animal hops by leaning forward and jumping, with its big hind feet leaving the ground at about the same time, and landing at the same time too before it bounces again. Its big tail helps it balance. But there’s a lot more to this hopping than you might think.

While the wallaby or kangaroo has strong leg muscles, what’s even more important is that it has very strong, very elastic tendons in its legs. These basically act like massively strong rubber bands. When you stretch a rubber band, it stores energy that it releases when you let go of it and it snaps back and whips you in the thumb and you wonder why you did that because it hurt. The tendons in the wallaby’s legs store energy when it hops, and when it lands, the energy releases and helps bounce the animal right back into the next hop. Once it gets going, its muscles are only doing a fraction of the work to keep it hopping at high speed. Even better for the animal, a lot of its breathing is regulated by its movements when it’s hopping, so it always has plenty of oxygen to power its body while moving fast. When it lands after a bounce, the impact pushes its breath out of its lungs, but the action of bringing its legs forward helps suck fresh air in. It’s an incredibly efficient way to move, and allows the animal to travel long distances to find food and water without spending a lot of energy.

Wallabies eat plants, and naturally the bigger species can eat bigger, tougher plants than smaller species. The exception is the dwarf rock-wallaby, according to a study published in March of 2024. There are over a dozen species of rock-wallaby, but in general they live in small groups in rocky areas. They’re nocturnal and spend the day sleeping in shady areas among the rocks, under rock overhangs, or in small caves in cliffs. At night they come out to find plants, but because they live in such harsh environments, most of the plants are pretty tough. Two species of dwarf rock-wallaby in particular turn out to have incredibly strong jaws for their size, as strong as the jaws of much larger species. Their teeth are also larger to help them grind up tough plants, and one species, called the nabarlek wallaby, even grows new molars throughout its life as the old ones wear down. That’s the only marsupial known to grow new molars throughout its life.

The nabarlek is reddish-gray in color and only weighs about 3 ½ pounds at most, or 1.6 kilograms, and is barely more than a foot long, or 30 cm, with its fluffy tail almost doubling that length. When it hops, it curls its tail up over its back. It eats grass, ferns, and other tough plants. Like most species of wallaby, it’s endangered due to habitat loss and introduced predators like foxes.

Another very small wallaby is the banded hare-wallaby, which only has a few small populations remaining on a few islands. It’s almost exactly the same size and weight as the nabarlek and is gray with lighter speckles and darker stripes on its back. It’s also nocturnal and lives in brushy areas where it can hide easily.

Even though these wallabies are smaller than domestic cats, some 45,000 years ago there used to be a type of kangaroo that was extremely large. The short-faced kangaroo stood as tall as a big grey or red kangaroo, about five feet tall, or 1.5 meters, but was much bulkier—as much as twice the weight of a modern kangaroo. It was so heavy that some researchers think it couldn’t hop but actually walked on its hind legs instead like a person. (Bigfoot.)

A few years ago, scientists comparing the genetic sequence of the short-faced kangaroo to other macropods discovered that this big strong kangaroo’s closest living relative was the tiny banded hare-wallaby.

Our next animal is a suggestion from Lorenzo, who sent a bunch of requests a while back. Before we talk about the animal, I should probably explain the situation with the List. This is the list of topics that I want to cover, a lot of them suggestions from listeners and a lot of them animals I’ve added myself. It started out as a simple Word document, but after a few years I moved it over to a spreadsheet and divided it into categories. There’s a page for mammals, a page for birds, and so on. I copied and pasted Lorenzo’s suggestions into the reptiles page because I recognized the first few as reptiles, or at least therapsids.

Well, at some point I took a closer look at the list of Lorenzo’s suggestions and added a note, “these may not all be reptiles.” Then later I took an even closer look and added another note, “these down here are basal arthropods, why did you put them under reptiles?” But next to today’s animal, at some point I added the note “I think this is a bird.”

Dear listener, Wiwaxia is not a bird. Scientists aren’t actually sure what it is, but 100% it is not a bird. It lived just over half a billion years ago in the early to middle Cambrian period, which we talked about in episode 69 about the Cambrian explosion. That’s when life on earth evolved from relatively simple, tiny organisms to much larger and more complex ones. Many of the Cambrian animals look bizarre and confusing to us today because they’re so different from the animals we’re familiar with, and that’s the case for Wiwaxia.

Wiwaxia grew about 2 inches long at most, or 5 cm, and slightly less wide. It was flat underneath like a slug, and it probably moved sort of like a slug too. The upper part of its body was covered in overlapping plates called sclerites, which acted as armor. As the animal grew older, it also developed spines that grew between the sclerites in two rows, with the longest spines growing 2 inches long, or 5 cm. Modern marine invertebrates have mineralized spines and scales that make them harder, but this hadn’t evolved yet and wiwaxia’s were basically the same material as the rest of the body, but tougher. Both the scales and the spines were shed and regrown every so often.

Like all the other animals in the Cambrian, wiwaxia lived in warm, shallow ocean water. It had a feeding apparatus at its front that had tiny conical teeth, and scientists think it used this feeding apparatus to scrape bacteria off the microbial mats that lived on the sea floor in most places, or it might have lived directly on the sea floor or on rocks. Either way, its feeding apparatus is enough like the radula found in modern mollusks that it’s been tentatively placed in the phylum Mollusca. This means it may be a very distant ancestor of slugs, snails, clams, mussels, oysters, squid, octopuses, and lots of other animals.

Wiwaxia was originally classified as an ancestor or at least a relation of modern polychaete worms, and a lot of scientists still think that’s correct. Since the original description of wiwaxia in 1899, a lot of specimens have been discovered in the Burgess shale in Canada, along with lots more found in China, Russia, the Czech Republic, and Australia, with more fossils found in other places that might be wiwaxia spines.

Because all the Cambrian fossils discovered are flattened, there’s a limit to how much we know about its anatomy when alive. The best fossils are reexamined frequently as new and more powerful methods of study are invented. Wiwaxia was apparently very common throughout the world between about 520 and 505 million years ago, so as more and more fossils are discovered, we’ll definitely learn more about 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 389: Updates 7 and the Lava Bear

Posted on by

Podcast: Play in new window | Download (Duration: 17:50 — 19.8MB)

Subscribe: RSS | More

It’s our annual updates episode! Thanks to Kelsey and Torin for the extra information about ultraviolet light, and thanks to Caleb for suggesting we learn more about the dingo!

Further reading:

At Least 125 Species of Mammals Glow under Ultraviolet Light, New Study Reveals

DNA has revealed the origin of this giant ‘mystery’ gecko

Bootlace Worm: Earth’s Longest Animal Produces Powerful Toxin

Non-stop flight: 4,200 km transatlantic flight of the Painted Lady butterfly mapped

Gigantopithecus Went Extinct between 295,000 and 215,000 Years Ago, New Study Says

First-Ever Terror Bird Footprints Discovered

Last surviving woolly mammoths were inbred but not doomed to extinction

Australian Dingoes Are Early Offshoot of Modern Breed Dogs, Study Shows

A (badly) stuffed lava bear:

Show transcript:

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

This week we have our annual updates episode, and we’ll also learn about a mystery animal called the lava bear! As usual, a reminder that I don’t try to update everything we’ve ever talked about. That would be impossible. I just pick new information that is especially interesting.

After our episode about animals and ultraviolet light, I got a great email from Kelsey and Torin with some information I didn’t know. I got permission to quote the email, which I think you’ll find really interesting too:

“You said humans can’t see UV light, which is true, however humans can detect UV light via neuropsin (a non-visual photoreceptor in the retina). These detectors allow the body to be signaled that it’s time to do things like make sex-steroid hormones, neurotransmitters, etc. (Spending too much time indoors results in non-optimal hormone levels, lowered neurotransmitter production, etc.)

“Humans also have melanopsin detectors in the retina and skin. Melanopsin detectors respond to blue light. Artificial light (LEDs, flourescents, etc) after dark entering the eye or shining on the skin is sensed by these proteins as mid-day daylight. This results in an immediate drop in melatonin production when it should be increasing getting closer to bedtime.”

And that’s why you shouldn’t look at your phone at night, which I am super bad about doing.

Our first update is related to ultraviolet light. A study published in October of 2023 examined hundreds of mammals to see if any part of their bodies glowed in ultraviolet light, called fluorescence. More than 125 of them did! It was more common in nocturnal animals that lived on land or in trees, and light-colored fur and skin was more likely to fluoresce than darker fur or skin. The white stripes of a mountain zebra, for example, fluoresce while the black stripes don’t.

The study was only carried out on animals that were already dead, many of them taxidermied. To rule out that the fluorescence had something to do with chemicals used in taxidermy, they also tested specimens that had been flash-frozen after dying, and the results were the same. The study concluded that ultraviolet fluorescence is actually really common in mammals, we just didn’t know because we can’t see it. The glow is typically faint and may appear pink, green, or blue. Some other animals that fluoresce include bats, cats, flying squirrels, wombats, koalas, Tasmanian devils, polar bears, armadillos, red foxes, and even the dwarf spinner dolphin.

In episode 20 we talked about Delcourt’s giant gecko, which is only known from a single museum specimen donated in the 19th century. In 1979 a herpetologist named Alain Delcourt, working in the Marseilles Natural History Museum in France, noticed a big taxidermied lizard in storage and wondered what it was. It wasn’t labeled and he didn’t recognize it, surprising since it was the biggest gecko he’d ever seen—two feet long, or about 60 cm. He sent photos to several reptile experts and they didn’t know what it was either. Finally the specimen was examined and in 1986 it was described as a new species.

No one knew anything about the stuffed specimen, including where it was caught. At first researchers thought it might be from New Caledonia since a lot of the museum’s other specimens were collected from the Pacific Islands. None of the specimens donated between 1833 and 1869 had any documentation, so it seemed probable the giant gecko was donated during that time and probably collected not long before. More recently there was speculation that it was actually from New Zealand, since it matched Maori lore about a big lizard called the kawekaweau.

In June of 2023, Delcourt’s gecko was finally genetically tested and determined to belong to a group of geckos from New Caledonia, an archipelago of islands east of Australia. Many of its close relations are large, although not as large as it is. It’s now been placed into its own genus.

Of course, this means that Delcourt’s gecko isn’t the identity of the kawekaweau, since it isn’t very closely related to the geckos of New Zealand, but it might mean the gecko still survives in remote parts of New Caledonia. It was probably nocturnal and lived in trees, hunting birds, lizards, and other small animals.

We talked about some really big worms in episode 289, but somehow I missed the longest worm of all. It’s called the bootlace worm and is a type of ribbon worm that lives off the coast of Norway, Denmark, Sweden, and Britain, and it’s one of the longest animals alive. The longest worm we talked about in episode 289 was an African giant earthworm, and one was measured in 1967 as 21 feet long, or 6.7 meters. The bootlace worm is only 5 to 10 mm wide, but it routinely grows between 15 and 50 feet long, or 5 to 15 meters, with one dead specimen that washed ashore in Scotland in 1864 measured as over 180 feet long, or 55 meters.

When it feels threatened, the bootlace worm releases thick mucus. The mucus smells bad to humans but it’s not toxic to us or other mammals, but a recent study revealed that it contains toxins that can kill crustaceans and even some insects.

We talked about the painted lady butterfly in episode 203, which was about insect migrations. The painted lady is a small, pretty butterfly that lives throughout much of the world, even the Arctic, but not South America for some reason. Some populations stay put year-round, but some migrate long distances. One population winters in tropical Africa and travels as far as the Arctic Circle during summer, a distance of 4,500 miles, or 7,200 km, which takes six generations. The butterflies who travel back to Africa fly at high altitude, unlike monarch butterflies that fly quite low to the ground most of the time. Unlike the monarch, painted ladies don’t always migrate every year.

In October of 2013, a researcher in a small country in South America called French Guiana found some painted lady butterflies on the beach. Gerard Talavera was visiting from Spain when he noticed the butterflies, and while he recognized them immediately, he knew they weren’t found in South America. But here they were! There were maybe a few dozen of them and he noticed that they all looked pretty raggedy, as though they’d flown a long way. He captured several to examine more closely.

A genetic study determined that the butterflies weren’t from North America but belonged to the groups found in Africa and Europe. The question was how did they get to South America? Talavera teamed up with scientists from lots of different disciplines to figure out the mystery. Their findings were only published last month, in June 2024.

The butterflies most likely rode a well-known wind current called the Saharan air layer, which blows enough dust from the Sahara to South America that it has an impact on the Amazon River basin. The trip from Africa to South America would have taken the butterflies 5 to 8 days, and they would have been able to glide most of the time, thus conserving energy. Until this study, no one realized the Saharan air layer could transport insects.

We talked about the giant great ape relation Gigantopithecus in episode 348, and only a few months later a new study found that it went extinct 100,000 years earlier than scientists had thought. The study tested the age of the cave soils where Gigantopithecus teeth have been discovered, to see how old it was, and tested the teeth again too. As we talked about in episode 348, Gigantopithecus ate fruit and other plant material, and because it was so big it would have needed a lot of it. It lived in thick forests, but as the overall climate changed around 700,000 years ago, the forest environment changed too. Other great apes living in Asia at the time were able to adapt to these changes, but Gigantopithecus couldn’t find enough food to sustain its population. It went extinct between 295,000 and 215,000 years ago according to the new study, which is actually later than I had in episode 348, where I wrote that it went extinct 350,000 years ago. Where did I get my information? I do not know.

The first footprints of a terror bird were discovered recently in Argentina, dating to 8 million years ago. We talked about terror birds in episode 202. The footprints were made by a medium-sized bird that was walking across a mudflat, and the track is beautifully preserved, which allows scientists to determine lots of new information, such as how fast the bird could run, how its toes would have helped it run or catch prey, and how heavy the bird was. We don’t know what species of terror bird made the tracks, but we know it was a terror bird.

We talked about the extinction of the mammoth in episode 256, especially the last population of mammoths to survive. They lived on Wrangel Island, a mountainous island in the Arctic Ocean off the coast of western Siberia, which was cut off from the mainland about 10,000 years ago when ocean levels rose. Mammoths survived on the island until about 4,000 years ago, which is several hundred years after the Great Pyramid of Giza was built. It’s kind of weird to imagine ancient Egyptians building pyramids, and at the same time, mammoths were quietly living on Wrangel Island, and the Egyptians had no idea what mammoths were. And vice versa.

A 2017 genetic study stated that the last surviving mammoths were highly inbred and prone to multiple genetic issues as a result. But a study released in June of 2024 reevaluated the population’s genetic diversity and made a much different determination. The population did show inbreeding and low genetic diversity, but not to an extent that it would have affected the individuals’ health. The population was stable and healthy right to the end.

In that case, why did the last mammoths go extinct? Humans arrived on the island for the first time around 1700 BCE, but we don’t know if they encountered mammoths or, if they did, if they killed any. There’s no evidence either way. All we know is that whatever happened, it must have been widespread and cataclysmic to kill all several hundred of the mammoths on Wrangel Island.

We talked about the dingo in episode 232, about animals that are only semi-domesticated. That episode came out in 2021, and last year Caleb suggested we learn more about the dingo. I found a really interesting 2022 study that re-evaluated the dingo’s genome and made some interesting discoveries.

The dingo was probably brought to Australia by humans somewhere between 3,500 and 8,500 years ago, and after the thylacine was driven to extinction in the early 20th century, it became the continent’s apex predator. Genetic studies in the past have shown that it’s most closely related to the New Guinea singing dog, but the 2022 study compared the dingo’s genome to that of five modern dog breeds, the oldest known dog breed, the basenji, and the Greenland wolf.

The results show that the dingo is genetically in between wolves and dogs, an intermediary that shows us what the dog’s journey to domestication may have looked like. The study also discovered something else interesting. Domestic dogs have multiple copies of a gene that controls digestion, which allows them to eat a wide variety of foods. The dingo only has one copy of that gene, which means it can’t digest a lot of foods that other dogs can. Remember, the dingo has spent thousands of years adapting to eat the native animals of Australia. When white settlers arrived, they would kill dingoes because they thought their livestock was in danger from them. The study shows that the dingo has little to no interest in livestock because it would have trouble digesting, for instance, a lamb or calf. The animals most likely to be hurting livestock are domestic dogs that are allowed to run wild.

We’ll finish with a mystery animal called the lava bear. In the early 20th century, starting in 1917, a strange type of bear kept being seen in Oregon in the United States. Its fur was light brown like a grizzly bear’s, but otherwise it looked like a black bear—except for its size, which was very small. The largest was only about 18 inches tall at the back, or 46 cm, and it only weighed about 35 pounds, or 16 kg. That’s the size of an ordinary dog, not even a big dog. Ordinarily, a black bear can stand 3 feet tall at the back, or about 91 cm, and weighs around 175 pounds, or 79 kg, and a big male can be twice that weight and much taller.

The small bear was seen in desert, especially around old lava beds, which is where it gets its name. A shepherd shot one in 1917, thinking it was a bear cub, and when he retrieved the body he was surprised to find it was an adult. He had it taxidermied and photographs of it were published in the newspapers and a hunting magazine, which brought more hunters to the area.

People speculated that the animal might be an unknown species of bear, possibly related to the grizzly or black bear, and maybe even a new species of sun bear, a small bear native to Asia.

Over the next 17 years, many lava bears were killed by hunters and several were captured for exhibition. When scientists finally got a chance to examine one, they discovered that it was just a black bear. Its small size was due to malnutrition, since it lived in a harsh environment without a lot of food, and its light-colored fur was well within the range of fur color for an American black bear. Lava bears are still occasionally sited in the area around Fossil Lake.

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 375: The Praying Mantis Re-Revisited

Posted on by

Podcast: Play in new window | Download (Duration: 8:33 — 9.5MB)

Subscribe: RSS | More

Thanks to Elijah and an anonymous listener for suggesting that we talk about some more species of praying mantis!

Further reading:

The luring mantid: Protrusible pheromone glands in Stenophylla lobivertex (Mantodea: Acanthopidae)

Dragons and unicorns (mantises) spotted in Atlantic forest

Citizen scientists help discover new mantis species

The dragon mantis [photo from first article linked above]:

The possibly new species of unicorn mantis [picture from second article linked above]:

Inimia nat, or I. nat, discovered after a citizen scientist posted its photo to iNat [photo from third article linked above]:

Show transcript:

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

This week we’re going to revisit a popular topic that we’ve covered before, especially in episode 187, but which has been suggested by a couple of listeners who want to know more. It’s the praying mantis. Thanks to Elijah and an anonymous listener who suggested it. Elijah even keeps mantises as pets and sent me some pictures of them, which was awesome.

The praying mantis gets its name because it holds its spiny front legs forward and together, which sort of resembles someone holding their hands together while praying. That’s the type of praying spelled p r a y ing, not p r e y ing, which refers to killing and eating other organisms, but the praying mantis does that too. It’s a predator that will eat anything it can catch, including birds, fish, mice, lizards, frogs, and of course lots of insects.

There are thousands of mantises, also called mantids, with most species preferring tropical and subtropical climates. In general, a mantis has a triangular head with large eyes, an elongated body, and enlarged front legs that it uses to catch prey. Most species have wings and can fly, some don’t. Most are ambush predators.

We talked about several species of mantis in episode 187, and some more in episode 201. You can go back to those episodes to find out general information about mantises, such as how their eyes work and whether they have ears and whether they actually eat their mates (they do, sometimes). This week we’re going to focus on some findings about mantises that are new since those episodes came out.

The dragon mantis, Stenophylla lobivertex, was only discovered in the year 2000. Its body is covered with gray-green or green-brown lobes that help it blend in with the leaves in its forest home, but that also kind of make it look like a tiny dragon covered with scaly armor. Even its eyes are spiky. It lives in the tropics of South and Central America where it’s quite rare, and it usually only grows about an inch and a half long, or 4 cm. It spends most of the time in treetops, where it hunts insects, spiders, and other small animals.

Unlike many mantis species, the dragon mantis is mostly nocturnal. That’s one of the reasons why we don’t know a lot about it. In late 2017 through mid-2018, one member of a team of scientists studying animals in Peru noticed something weird in a captive female dragon mantis. Frank Glaw isn’t an expert in insects but in reptiles and amphibians, but he happened to observe what looked like two tiny maggots emerge from the mantis’s back, roughly above her last pair of legs, but then disappear again into her back. He thought he was seeing the results of parasitism, but a mantis expert suspected it was something very different.

Some praying mantis females release pheromones from a gland in about the same place on the back. Pheromones are chemicals that can be sensed by other insects, usually ones in the same species. They’re most often used to attract a mate. It turns out that the female dragon mantis has a Y-shaped organ that’s up to 6 mm long that can release pheromones in a particular direction. The mantis can even move the prongs of the Y around if she wants to. Because she only does this at night when she’s sure she’s safe, and only when she hasn’t found a mate yet, and because this species of mantis is really rare, no one knew that any mantis had this specific organ. It’s possible that other mantis species have the organ too, but that scientists just haven’t seen it yet.

As we learned in our previous mantis episodes, not only are there well over 2,000 known species of mantis alive today, there are more being discovered all the time. In 2019, Project Mantis went to Brazil to look for mantises, and not only did they find two of the extremely rare dragon mantises, they discovered what may be a species new to science. It hasn’t been described yet as far as I can find, but it appears to be a member of a group called unicorn mantises because it has a spike sticking up from the top of the head. Scientists have no idea what the spike is for, but it’s funny that they found unicorn mantises and dragon mantises in the same forest.

Late in 2023, two new species of Australian mantis were described, one of which is so different from other known species that it was placed in its own genus. They’re small mantises that live on tree trunks and are camouflaged to look like pieces of bark, so they’re hard to spot. Luckily, a citizen scientist named Glenda Walter noticed them and posted pictures to iNaturalist. A lot of scientists watch iNaturalist posts, and it’s a good thing because Glenda’s mantises turned out to be completely new to science. One of them has been named Inimia nat, which is abbreviated I. nat, which is also the abbreviation for iNaturalist. A citizen scientist is anyone who is interested in science and works to help improve scientific knowledge in general, for instance by taking pictures of interesting bugs and posting them to iNat.

The praying mantis has been around since at least the early Cretaceous, around 120 million years ago. The oldest remains found don’t look that much like modern mantises, though. They look more like cockroaches, which isn’t too surprising since mantises are closely related to cockroaches. By about 110 million years ago mantises had started to evolve the deadly front legs that they have now. Most fossilized mantis remains are actually impressions of wings, but experts can learn a lot from just the wings. Baby praying mantises have even been found preserved in amber from up to 87 million years ago.

A lot of people are scared of praying mantises because they look dangerous. They’re not dangerous to humans or pets at all, though. If you get pinched or nipped by a mantis, just wash your hands to clean out the wound and you’ll be fine. Mantises are extremely beneficial insects, especially in the garden, because they eat other insects that eat plants that humans don’t want eaten, like flowers and vegetables. Some people release mantises in the garden as a natural way to control insect pests. And, as Elijah can tell you, mantises actually make really interesting pets.

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 370: Animals Discovered in 2023

Posted on by

Podcast: Play in new window | Download (Duration: 16:03 — 19.0MB)

Subscribe: RSS | More

Let’s look at some of the most interesting animals discovered last year!

Further reading:

Newly-discovered ‘margarita snails’ from the Florida Keys are bright lemon-yellow

Tiny spirits roam the corals of Japan—two new pygmy squids discovered

Strange New Species of Aquifer-Dwelling Catfish Discovered in India

Bizarre New Species of Catfish Discovered in South America

Unicorn-like blind fish discovered in dark waters deep in Chinese cave

New Species of Hornshark Discovered off Australia

Cryptic New Bird Species Identified in Panama

New Species of Forest Hedgehog Discovered in China

New species of voiceless frog discovered in Tanzania

The weird new spiny katydid:

Show transcript:

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

It’s time for our annual discoveries episode, where we learn about some animals discovered in the previous year! There are always lots more animals discovered than we have time to talk about, so I just choose the ones that interest me the most.

That includes the cheerfullest of springtime-looking marine snails discovered in the Florida Keys. The Florida Keys are a group of tropical islands along a coral reef off the coast of Florida, which is in North America. A related snail was also discovered off the coast of Belize in Central America that looks so similar that at first the scientists thought they were the same species with slightly different coloration. A genetic study of the snails revealed that they were separate species. The one found in the Keys is a lemony yellow color while the one from Belize is more of a lime green.

The snails have been placed into a new genus but belong to a group called worm snails. When a young worm snail finds a good spot to live, it sticks its shell to a rock or other surface and stays there for the rest of its life. Its shell isn’t shaped like an ordinary snail shell but instead grows long and sort of curved or curly. The snail spreads a thin layer of slime around it using two little tentacles, and the slime traps tiny pieces of food that float by.

The new snails are small and while the snail’s body is brightly colored, its shell is drab and helps it blend in with the background. Scientists think that the colorful body may be a warning to potential predators, since its mucus contains toxins. It mainly lives on pieces of dead coral.

Another invertebrate discovery last year came from Japan, where two new species of pygmy squid were found living in seagrass beds and coral reefs. Both are tiny, only 12 mm long, and are named after little forest spirits from folklore. Despite its small size, it can eat shrimp bigger than it is by grabbing it with its little bitty adorable arms. Both species have been seen before but never studied until now. The scientists teamed up with underwater photographers to find the squid and learn more about them in their natural habitats.

As for invertebrates that live on land, an insect called the blue-legged predatory katydid was discovered in the rainforests of Brazil. It’s a type of bush-cricket that’s dark brown in color except for the last section of its legs, which are greenish-blue. Those parts of its legs are also really spiny. That is literally all I know about it except for its scientific name, Listroscelis cyanotibiatus, but it’s awesome.

Let’s leave the world of invertebrates behind and look at some fish next. This was the year of the catfish, with new species discovered in both India and South America. Catfish can be really weird in general and both these new species are pretty strange.

The first is tiny, only 35 mm long at most, or a little over an inch, and it has four pairs of barbels growing from its face. It looks red because its blood shows through its skin, because its skin doesn’t have any pigment. The fish also doesn’t have any eyes. If this makes you think it’s a cave-dwelling fish, you’re exactly right, but instead of an ordinary cave it actually lives in an aquifer.

An aquifer is a source of water underground. It’s actually a layer of rock that’s broken up or otherwise permeable so that water can get through it, but with a non-permeable layer underneath. The water is trapped in the layer, sometimes far underground. If you’ve ever seen a spring, where water bubbles up from the ground, that water comes from an aquifer that has found its way to the surface. If you’ve ever drunk water pumped or dipped up from a well, the well-water also comes from an aquifer. The water gets into the aquifer in the first place when rain soaks into the ground, but it takes a long time to fill up.

There are really deep aquifers that are completely sealed off from the surface, created thousands or even millions of years ago. As far as we know, nothing lives in those, although we could be wrong. Aquifers that are closer to the surface with some surface openings develop unique ecosystems, including animals that are found nowhere else on earth. That’s the case with the tiny red catfish found in the state of Kerala in India.

Scientists asked people in the area to watch out for any unusual animals when they had a new well dug or cleaned, and before long people from four towns reported finding the little red fish. Three other related species had previously been found in the state.

On the other side of the world, in South America, a much different type of catfish was discovered in Bolivia and Brazil. This one is an armored catfish, and the male actually grows short dermal teeth on the sides of his head that he uses to fight other males. Dermal teeth are teeth that grow on the skin instead of in the mouth, and it’s surprisingly common in fish, especially armored catfish.

The new catfish has been named Sturisoma reisi and it grows about 8 inches long, or 20 cm. It’s actually been known to scientists for a long time, but until recently no one realized it wasn’t one of five other catfish in the genus Sturisoma. They all look kind of similar. It’s a slender, active catfish with a long tail and a pointy rostrum that lives in swift-moving rivers. It was actually described in 2022, not 2023, but I only just realized I have the wrong year so let’s just move along quickly to another fish.

This one isn’t a catfish but it looks like one at first glance since it has barbels around its mouth. These are the whisker-like feelers that give the catfish its name. The newly discovered fish needs feelers because it doesn’t have working eyes, and it also doesn’t have scales or pigment in its skin. It was found in a cave in China, and in fact it’s only been found in a single pool of water in a single cave. The pool is only about 6 feet across, or 1.8 meters, and about two and a half feet deep, or 80 cm, but it’s home to a perfectly healthy population of fish. The fish grow about 5 inches long on average, or 13 cm.

The fish is a new member of the genus Sinocyclocheilus, and of the 76 known species in the genus, most live in caves. The new fish has been named S. longicornus because of a structure on its head that kind of looks like a unicorn horn, if the unicorn was a pink cave fish and its horn was shaped sort of like the tip of a ballpoint pen, also called a biro.

Some other species in this genus also have a so-called horn, although the new fish’s is larger than most. It juts forward and extends above what we can describe as the fish’s forehead. Scientists have absolutely no idea what it’s for. Since the fish can’t see, it can’t be to attract a mate. It’s also not likely to be a navigational aide since the fish has its barbels and a well-developed lateral line system to find its way around. Besides, it lives in a pool of water not much bigger than the desk I’m sitting at. It doesn’t exactly travel very far throughout its life.

Scientists have a lot of other questions about the fish, including how it survives in such a tiny pool of water.

Speaking of fish with horns, a new species of hornshark was discovered last year off the northern coast of Australia. Hornsharks live in shallow warm waters throughout much of the Pacific and Indian oceans, where they spend most of the time at the bottom looking for small invertebrates like crustaceans to crunch up, although sea urchins are their favorites. They’re also called bullhead sharks because they all have short snouts and broad heads with prominent brows. The name hornshark comes from the fins, some of which have spines.

One species of hornshark is the zebra hornshark, which lives in the Indo-Pacific, from southern Japan down to northern Australia. As you may guess from the name, it has stripes, which makes it popular in aquariums and zoos. It only grows to about 4 feet long, or 1.25 meters. Until last year, scientists thought that all the zebra hornsharks around Australia belonged to the same species. Then they noticed that one population that lives off of northwestern Australia has a different stripe pattern and only grows about two feet long, or 60 cm. After a genetic study, it turns out that it’s a totally different species.

A lot of animal discoveries are like this, where everyone thinks an animal is one species, but after close study and genetic testing they find out it’s two or more species that just look very similar. That’s one of the great things about DNA testing being so effective and quick these days, but it’s not always as cut and dried as it sounds. There’s no easy way to determine for sure if animals are different species, subspecies, or just the same species with population variants. Scientists can’t just rely on genetics, but they also can’t always rely on observations of the animal’s physical traits or its behavior in the wild. They have to look at all the data available, and then they still argue about the best interpretation of the data.

The notion of a separate species or subspecies is an artificial one that gives us a way to better understand a natural process. If a population of animals is separated from another population, eventually both will develop separately until they’re two related but very different animals. There’s no way to point at a specific generation and say, “well, NOW they’re different from the last generation” because the process is so slow and the changes are usually so small. It’s like looking at a rainbow and trying to determine exactly the point where red turns into orange and orange turns into yellow.

Take the slaty-backed nightingale-thrush as an example. It’s a dark gray songbird with a short tail and bright orange legs and beak, and it lives in the mountains of Central and northern South America. It spends most of its time in thickets where it’s hard to see but easy to hear, since it has a lovely song. This is an example of what it sounds like, although its song varies depending on where it lives.

[bird song]

It turns out that there’s a lot of variation in the bird’s song because the slaty-backed nightingale-thrush probably isn’t all one species. In late 2023 a team of researchers published a ten-year study of the bird, looking at everything from song variations to genetics. They determined that not only was it not a single species, it was most likely seven different species and four subspecies. Because the bird lives in the mountains and doesn’t fly very far during its lifetime, populations that are separated by steep mountains and valleys have developed into separate species.

Naturally, not everyone agrees with these findings, but it’s always good when a little-studied animal gets some attention. Until last year, no one knew much about this shy little bird, and the controversy of whether it’s one species or lots of closely related species will hopefully lead us to learn even more about it. One population of the bird discovered in Panama had never been documented before, too.

This episode is getting pretty long for someone who just got over a cold, so let’s cover one newly discovered mammal and a newly discovered frog. A new species of forest hedgehog was discovered in China last year and it’s adorable! It’s related to the hedgehogs found in Europe and other areas, but is most closely related to four known species of forest hedgehog that live mostly in central Asia. The new species was discovered in eastern China, over 1,000 km away from the nearest population of other forest hedgehogs. Another species was only discovered in 2007 from southwestern China.

Unlike most hedgehogs, the new species is sexually dimorphic, meaning that males and females don’t look identical. Males are mostly gray while females are more reddish-brown in color.

Let’s finish with another adorable animal, a little frog from Tanzania, a country in east Africa. It’s a type of spiny-throated reed frog, which are all rare and increasingly threatened. They’re also very small, not much bigger than an inch long, or about 30 mm. The male has tiny little spines on his throat that researchers think might be a way that females recognize the males of their own species during mating season instead of by a distinctive croaking sound. That’s because spiny-throated reed frogs can’t make sounds, leading to their other common name of the voiceless frog.

In 2019, researchers were in the Ukaguru Mountains in Tanzania looking for a completely different frog, the beautiful tree toad, which may be extinct. While they didn’t find any of the toads, they did find a little greenish-brown frog with copper-colored eyes that turned out to be completely new to science. It was found in a nature reserve and appears to be common locally, which is good, but the nature reserve is also very small, which is not so good. Hopefully now that we know the little frog exists, it will lead to further protections of the area that will help all the other animals and plants where it lives, including the beautiful tree toad.

This is what the voiceless frog sounds like:

[silence]

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 364: Animals Who Will Outlive Us All

Posted on by

Podcast: Play in new window | Download (Duration: 15:52 — 18.5MB)

Subscribe: RSS | More

Thanks to Oz from Las Vegas for suggesting this week’s topic!

Further reading:

Bobi, the supposed ‘world’s oldest dog’ at 31, is little more than a shaggy dog story

Greenland sharks live for hundreds of years

Scientists Identify Genetic Drivers of Extreme Longevity in Pacific Ocean Rockfishes

Scientists Sequence Chromosome-Level Genome of Aldabra Giant Tortoise

Giant deep-sea worms may live to be 1,000 years old or more

A Greenland shark [photo by Eric Couture, found at this site]:

The rougheye rockfish is cheerfully colored and also will outlive us all:

An Aldabra tortoise all dressed up for a night on the town:

Escarpia laminata can easily outlive every human. It doesn’t even know what a human is.

Show transcript:

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

This week we have a great suggestion by Oz from Las Vegas. Oz wanted to learn about some animals that will outlive us all, and gave some suggestions of really long-lived animals that we’ll talk about. We had a similar episode several years ago about the longest lived animals,where for some reason we talked a lot about plants, episode 168, but this is a little different.

But first, a quick correction! Last week we talked about the dodo and some of its relations, including the Nicobar pigeon. I said that the Nicobar pigeon lived in the South Pacific, but Pranav caught my mistake. The Nicobar pigeon lives in the Indian Ocean on the Nicobar Islands, which I should have figured out because of the name.

Anyway, back in the olden days when I was on Twitter all the time, I came across a tweet that’s still my absolute favorite. Occasionally I catch myself thinking about it. It’s by someone named Everett Byram who posted it in January 2018. It goes:

“DATE: so tell me something about yourself

“ME: I am older than every dog”

Not only is it funny, it also makes you thoughtful. People live a whole lot longer than dogs. The oldest living dog is a chihuahua named Spike, who is 23 years old right now. A dog who was supposed to be even older, 31 years old, died in October of 2023, but there’s some doubt about that particular dog’s actual age. Pictures of the dog taken in 1999 don’t actually look like the same dog who died in 2023.

The oldest cat who ever lived, or at least whose age is known for sure, died in 2005 at the age of 38 years. The oldest cat known who’s still alive is Flossie, who was born on December 29th, 1995. If your birthday is before that, you’re older than every cat and every dog.

The oldest human whose age we know for sure was Jeanne Calment, who died in 1997 at the age of 122 years. We talked about her in episode 168. The oldest human alive today, as far as we know, is Maria Branyas, who lives in Spain and will turn 117 years old on her next birthday in March 2024.

It’s not uncommon for ordinary people to live well into their 90s and even to age 100, although after you reach the century mark you’re very lucky and people will start asking you what your secret for a long life is. You might as well go ahead and make something up now to tell people, because it seems to mainly be genetics and luck that allow some people to live far beyond the lives of any dog or cat or most other humans. Staying physically active as you age also appears to be an important factor, so keep moving around.

But there are some animals who routinely outlive humans, animals who could post online and say “I am older than every human” and the others of its species would laugh and say, “Oh my gosh, it’s true! I’m older than every human too!” But they don’t have access to the internet because they are, for instance, a Greenland shark.

We talked about the Greenland shark in episode 163. It lives in the North Atlantic and Arctic Oceans where the water is barely warmer than the freezing point. It can grow up to 23 feet long, or 7 meters, with females being larger than males. Despite getting to such enormous sizes, it only grows one or two centimeters a year, and that was a clue for scientists to look into how old these sharks can get.

In 2016, a team of scientists published a study about how they determined the age of Greenland sharks that had been accidentally caught by fishing nets or that had otherwise been discovered already dead. The lenses inside vertebrate eyeballs don’t change throughout an animal’s life. They’re referred to as metabolically inactive tissue, which means they don’t grow or change as the animal grows. That means that if you can determine how old the lens is, you know when the animal was born, or hatched in the case of sharks.

In the past, scientists have been able to determine the age of dead whales using their eye lenses, but the Greenland shark was different. It turns out that the shark can live a whole lot longer than any whale studied, so the scientists had to use a type of carbon-14 dating ordinarily used by archaeologists.

The Greenland shark may be the oldest-living vertebrate known. Its life expectancy is at least 272 years, and probably closer to 500 years. Individual sharks can most likely live much longer than that. It’s not even mature enough to have babies until it’s about 16 feet long, or 5 meters, and scientists estimate it takes some 150 years to reach that length. Females may stay pregnant for at least 8 years, and maybe as long as 18 years. Babies hatch inside their mother and remain within her, growing slowly, until they’re ready to be born.

The Greenland shark is so big, so long-lived, and lives in such a remote part of the ocean that taking so long to reproduce isn’t a problem. Its body tissues contain chemical compounds that help keep it buoyant so it doesn’t have to use very much energy to swim, and which have a side effect of being toxic to most other animals. Nothing much wants to eat the Greenland shark. But it is caught by accident by commercial fishing boats, with an estimated 3,500 sharks killed that way every year. Scientists hope that by learning more about the Greenland shark, they can bring more attention to its plight and make sure it’s protected. There’s still a lot we don’t know about it.

At least one species of whale does live much longer than humans. In 2007, researchers studying a dead bowhead whale found a piece of harpoon embedded in its skin. It turned out to be a type of harpoon that was manufactured between 1879 and 1885. After that, scientists started testing other bowhead whales that were found dead. The oldest specimen studied was determined to be 211 years old when it died, and it’s estimated that the bowhead can probably live well past 250 years if no one harpoons it and it stays healthy. It may be the longest-lived mammal. It has a low metabolic rate compared to other whales, which may contribute to its longevity.

Most small fish don’t live very long even if nothing eats them. Rockfish, for instance, only live for about 10 years even if they’re really lucky. Well, most rockfish. There is one species, the rougheye rockfish, that lives much, much longer. Its lifespan is at least 200 years old.

The rougheye rockfish has a lot of other common names. Its scientific name is Sebastes aleutianus. It can grow over 3 feet long, or 97 cm, and is red or orangey-red. It lives in cold waters of the Pacific, where it usually stays near the sea floor. It eats other fish along with crustaceans.

Naturally, scientists are curious as to why the rougheye rockfish lives so long but its close relations don’t. In 2021 a team of scientists published results of a genetic study of the rougheye rockfish and 87 other species. They discovered a number of genes associated with longevity, along with genes controlling inflammation that may help the fish stay healthy for longer.

The rougheye rockfish only evolved as a separate species of rockfish about ten million years ago. Because the longest-living females lay the most eggs, the genes for longevity are more likely to be passed on to the next generation, which means that as time goes on, lifespans of the fish overall get longer and longer. The rougheye also isn’t the only species of rockfish that lives a long time, it’s just the one that lives longest. At least one other species can live over 150 years and quite a few live past 100 years.

Another animal that can easily outlive humans is the giant tortoise, which we talked about in episode 95. Giant tortoises are famous for their longevity, routinely living beyond age 100 and sometimes more than 200 years old. The oldest known tortoise is an Aldabra giant tortoise that may have been 255 years old when it died in 2006. The Aldabra giant tortoise is from the Aldabra Atoll in the Seychelles, a collection of 115 islands off the coast of East Africa.

Scientists studied the Aldabran tortoise’s genetic profile in 2018 and learned that in addition to genes controlling longevity, it also has genes that control DNA repair and other processes that keep it healthy for a long time.

Oz also suggested the infinite jellyfish, also called the immortal jellyfish. An adult immortal jelly that’s starving or injured can transform itself back into a polyp, its juvenile stage. We talked about it in episode 343 in some detail, which was recent enough that I won’t cover it again in this episode. Scientists are currently studying the jelly to learn more about how it accomplishes this transformation and how long it can really live.

So far all the animals we’ve talked about, except the immortal jellyfish, are vertebrates. It’s when we get to the invertebrates that we find animals with the longest lifespans. The ocean quahog, a type of clam that lives in the North Atlantic Ocean, grows very slowly compared to other clams, and populations that live in cold water can live a long time. Sort of like tree rings, the age of a clam can be determined by counting the growth rings on its shell, and a particular clam dredged up from the coast of Iceland in 2006 was discovered to be 507 years old. Its age was double-checked by carbon-14 dating of the shell, which verified that it was indeed just over 500 years old when it was caught and died. Researchers aren’t sure how long the quahog can live, but it’s a safe bet that there are some alive today that are older than 507 years, possibly a lot older.

The real long-lived animals are very simple ones, especially sponges and corals. Some species of both can live for thousands of years. Various kinds of mollusks and at least one urchin can live for hundreds of years.

It’s probable that there are lots of other animals that routinely outlive humans, we just don’t know that they do. Scientists don’t always have a way to check an animal’s age, or they don’t think to do so while studying an organism. There are also plenty of animals that we just don’t know exist, especially ones that live in the ocean. For example, a species of tube worm named Escarpia laminata wasn’t even discovered until 1985, and it wasn’t until 2017 that scientists realized it lived for hundreds or even thousands of years.

The tube worm doesn’t have a common name, since it lives in the deepest parts of the Gulf of Mexico around what are called cold seeps, so no one ever needed to refer to it until it was discovered by scientists. A cold seep isn’t actually cold, it just isn’t as hot as a hydrothermal vent. In a cold seep, oil and methane are released into the ocean from fissures in the earth’s crust. Life forms live around these areas that live nowhere else in the world.

Many tube worms can grow quite long and can live over 250 years, with the giant tube worm growing almost 10 feet long, or 3 meters. Escarpia laminata is smaller, typically only growing about half that length. In a study published in 2017, a team of scientists estimated that it routinely lives for 250 to 300 years and potentially much, much longer. A tube worm doesn’t actually eat; instead, it forms a symbiotic relationship with bacteria that live in its body. The bacteria have a safe place to live and the tube worm receives energy from the bacteria as they oxidize sulfur released by the cold seeps. The tube worm, in other words, lives a stress-free life with a constant source of energy, and nothing much wants to eat it. The limit to its life may be the limit of the cold seeps where it lives. Cold seeps don’t last forever, although many of them remain active for thousands of years.

Humans are probably the longest-living terrestrial mammal. This may not seem too impressive compared to the animals we’ve talked about in this episode, but our lives are a whole lot more interesting than a tube worm’s.

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 359: The Antarctic Death Star(fish)!

Posted on by

Podcast: Play in new window | Download (Duration: 7:49 — 9.2MB)

Subscribe: RSS | More

Thanks to Morgan for suggesting this week’s topic, the Antarctic Death Star!

Further reading:

Giant Monster Starfish ALERT

Echinoderm Tube Feet Don’t Suck! They Stick!

Bodies of Starfish and Other Echinoderms Are Really Just Heads, New Research Suggests

The Antarctic death star [from first link listed above]:

The “beartrap” structures, magnified [from first link listed above]:

Show transcript:

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

It’s been way too long since we talked about an invertebrate, so this week we’ll look at one suggested by Morgan, the Antarctic death star.

It has a lot of other names too, including the Antarctic sun starfish and the wolftrap or beartrap starfish. Its scientific name is Labidiaster annulatus. I’m going to call it the death star because I think that’s hilarious.

As you may have guessed from its common names, the Antarctic death star is a starfish that lives in cold ocean waters near the Antarctic, AKA the south pole. But its common names also hint at how it gets its food, and this would be a good time to take a moment and be glad you’re not a copepod that also lives in the Antarctic Ocean.

The death star is reddish-brown on its dorsal side, white underneath. It’s a large starfish, up to two feet across, or 60 cm, and it also has a lot of legs, more properly called rays—up to 50 of them. The rays are long, narrow, and very flexible, and the undersides have rows of little structures called tube feet. All echinoderms, including starfish, have these tube feet and they’re used for several purposes. One important purpose is helping the animal stick to a hard surface, which allows it to climb around more easily and right itself if it gets flipped over.

For over 150 years scientists thought the tube feet acted like little suction cups, but that didn’t explain how a starfish or other echinoderm could stick to porous surfaces. It wasn’t until 2012 that a study was published explaining how the tube feet actually work. The tube feet exude tiny amounts of a sticky chemical that acts like glue.

The death star’s body also has little spines and bumps all over it, but it also has some structures that give the animal its other names, the wolftrap or beartrap starfish. The structures are called pedicellariae [PED-uh-suh-LAIR-ee-aye], which are also common in echinoderms. Most echinoderms seem to use them to keep algae and other organisms from settling on the body, although scientists aren’t completely sure. Pedicellariae have muscles and sensory receptors, and when something touches them, they snap shut like a trap. In the case of the Antarctic death star, its pedicellariae are extra big and really sharp. When a krill or other tiny animal brushes against one of these little traps, it grabs the animal and then the death star can eat it.

But that’s just part of what’s going on when the death star goes hunting, so let’s discuss it in more detail.

Most starfish spend almost all their time on the ocean floor, walking around looking for food. The death star does this too, but not all the time. Quite often a death star will climb on top of a rock or other large structure, and then it will extend some of its rays up and out into the water. It waves its rays around and if it touches a small animal, it will wrap the rays around it. The pedicellariae also snap shut. Then the death star can eat whatever it caught. Usually this is krill or amphipods, but it’s not a picky eater. Since it will eat animals it finds already dead, researchers aren’t completely sure if the death star ever catches fish. They’ve certainly found dead fish in death star stomachs, but the water it lives in is so cold that not many fish live there anyway. Fish don’t make up a big part of the death star’s diet, whether or not it’s catching them itself. The death star also eats other starfish, including smaller death stars.

Like other starfish, the death star can eat surprisingly large pieces of food because it can evert its stomach. This means it can actually push its stomach out through its mouth and engulf whatever large food it’s found or caught. The digestion process starts right away, which allows the starfish to eat food that can’t actually fit through its mouth. It doesn’t chew its food because it doesn’t have any kind of teeth or jaws, but who needs teeth and jaws if your stomach can just reach out and grab food?

While I was researching the death star, I came across a study published in November 2023 about echinoderms, so let’s learn something surprising about starfish and their relations in general.

Echinoderms demonstrate radial symmetry instead of bilateral symmetry. That’s why you can’t tell when a starfish or other echinoderm is facing forward, because it doesn’t actually have a forward. But it’s actually more complicated than it sounds, because the distant ancestor of echinoderms, which lived during the Cambrian almost half a billion years ago, did demonstrate bilateral symmetry, and the larvae of modern echinoderms do too. When a modern echinoderm larva develops into an adult, the left side of its body is the only part that grows. The right side of its body is absorbed and from then on the body develops radially. It actually shows pentaradial symmetry, with five sections around the central part of the body. That’s why so many starfish have five rays, although obviously not all of them. The death star starts out with five rays but adds more and more as it grows.

For a long time scientists have wondered if echinoderms technically have heads or if they’re just bodies. They don’t have eyes or nostrils or most other body parts that we associate with the head, just an oral opening in the middle of the underside of the disc. Starfish do have cells at the ends of their rays that act as eyespots, which are sensitive to light and dark but can’t actually see anything else. Instead of a brain, it has a nerve ring around its mouth and connected nerve nets in its rays, and its digestive system extends into its rays.

In other words, it sure seems like an echinoderm has no head and is basically just a weird body. But the new study came to a surprising conclusion. The study examined starfish genetics and discovered that the genes associated with head development were there. It was the genes associated with the development of a body and tail that were missing. In other words, the starfish, and echinoderms in general, are just really complicated heads.

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 343: Mystery Jellyfish

Posted on by

Podcast: Play in new window | Download (Duration: 10:37 — 12.7MB)

Subscribe: RSS | More

This week we finish out Invertebrate August with some mysterious jellyfish, including a suggestion by Siya!

Further reading:

Mystery giant jellyfish washes up in Australia

New jellyfish named after curious Australian schoolboy

Mysterious jellyfish found off the coast of Papua New Guinea intrigues researchers

Newly discovered jellyfish is a 24-eyed weirdo related to the world’s most venomous marine creature

Rare jellyfish with three tentacles spotted in Pacific Ocean

The Immortal Jellyfish

A mystery jellyfish washed up on an Australian beach [photo by Josie Lim]:

The tiny box jellyfish found in a pond in Hong Kong:

The very rare Chirodectes:

The mystery jelly that may be Chirodectes or a close relation:

A mystery deep-sea jelly with only three tentacles:

Bathykorus, a possible relation of the three-tentacled mystery jelly:

Show transcript:

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

It’s hard to believe Invertebrate August is already ending, so let’s finish the month out with some mystery jellyfish, including a recent suggestion from Siya!

When you visit the beach, it’s pretty common to find jellyfish washed ashore. They’re usually pretty small and obviously you don’t want to touch them, because many jellies can sting and the stings can activate even if the jelly is dead. Well, in February 2014, a family visiting the beach in Tasmania found a jelly washed ashore that was a little bit larger than normal. Okay, a lot larger than normal.

The jellyfish they found measured almost five feet across, or 1.5 meters. It had flattened out under its own weight but it was still impressive. The family was so surprised at how big it was that they sent pictures to the state’s wildlife organization, who sent scientists to look at it. The scientists had heard reports of a big pink and white jellyfish for years, and now they had one to examine. Dr. Lisa-ann Gershwin thought it might even be a new species of lion’s mane jelly.

New species of jellyfish are discovered all the time. Dr. Gershwin has described over 200 new species herself. One example is a jellyfish discovered by a nine-year-old.

In 2013, a nine-year-old boy in Queensland, Australia was fishing in a canal with his dad and a friend, when he noticed a jellyfish and scooped it up with a net. Its bell was only about an inch long, or 2.5 cm, and the boy thought it was really cute and interesting. He wanted to know what kind of jellyfish it was, so after some pestering on his part, his dad helped him send it to the Queensland Museum for identification.

Dr. Gershwin was the jellyfish expert at the museum at the time, and she was as surprised as the boy’s dad to discover that the jellyfish was new to science! The boy’s name was Saxon Thomas, and to thank him for being so persistent about getting his jellyfish looked at by a scientist, the jellyfish was named Chiropsella saxoni. It’s a type of box jellyfish, which can be deadly, but this one is so small that it’s probably not that dangerous to humans. You still wouldn’t want to be stung by one, though, I bet.

In 2022, a diver visiting Papua New Guinea got video of several really pretty jellyfish. He sent the video to Dr. Gershwin, who realized the jelly was either a very rare jelly called Chirodectes, or it was new to science.

Chirodectes was only discovered in 1997 and described in 2005. It’s a type of box jellyfish and only one specimen has ever been collected, caught off the coast of Queensland, Australia near the Great Barrier Reef after a cyclone. Its bell was about 6 inches long, or 15 cm, but if you include the tentacles it was almost 4 feet long, or 1.2 meters. It’s pale in color with darker rings and speckles on its bell.

The 2022 video appears to show a jellyfish without speckles or other markings, and it’s also larger than the single known Chirodectes specimen. Its bell appears to be about the size of a soccer ball, or a football if you live in most of the world. However, Dr. Gershwin and other experts who have studied the video say that it’s similar in many ways to Chirodectes and may be a close relation. Since all we have is the video, there’s no way to tell for sure if it’s a species new to science.

Most box jellies live around Australia and New Guinea, but in 2020 scientists in Hong Kong studying organisms living in an intertidal shrimp pond noticed a jellyfish they didn’t recognize. It was tiny, even smaller than Saxon’s little box jelly, with a bell barely half an inch long, or about 15 mm. There were hundreds of the little jellies in the pond, which connects to the ocean with a narrow tidal channel, and they appeared to be eating the tiny shrimp living in the pond. Close study of the jelly determined that it was indeed a new species.

The box jelly gets its name from its bell shape, which is shaped sort of like a cube. Most species are transparent to some degree, with tentacles that hang down from the corners of its cube-shaped bell. Most box jellies are fast swimmers, able to use jet propulsion to move around. Some species, including the newly discovered Tripedalia maipoensis from Hong Kong, even have paddle-like structures at the end of their tentacles to help them swim. Tripedalia probably isn’t dangerous to humans, but the scientists who studied it don’t know for sure because no one wanted to volunteer to be stung by it.

In 2015, the Ocean Exploration Trust was conducting an expedition in the Pacific Ocean, pretty much as far away from land as it’s possible to get, when they saw a mysterious little jellyfish. It was brown in color, but it only had three tentacles—and those tentacles emerge from the top of its bell, not from underneath. Then, in June 2023, another Ocean Exploration Trust expedition spotted the same type of jelly. It’s only the second time it’s been seen, and we know almost nothing about it.

The mystery jelly swims with its tentacles pointing forward, and scientists think that it hunts other jellies and small animals. When its tentacles touch an animal, it grabs it. But that’s pretty much all we know about it so far. Researchers think it might be related to the deep-sea hydrozoan Bathykorus, which was only described in 2010.

Bathykorus is sometimes called the Darth Vader jellyfish, because the shape of its bell kind of resembles Darth Vader’s helmet. Unlike Darth Vader, though, Bathykorus is mostly transparent and has eight tentacles. Four grow from the top of its bell, four grow from the bottom, and it holds the top tentacles up while it swims. It’s been found as deep as 8,200 feet below the surface of the Arctic Ocean, or 2,500 meters. And that’s pretty much all we know about this jelly, even though scientists have been able to carefully capture a few specimens and keep them alive for a few days in specially constructed tanks that mimic conditions found in the deep sea.

Let’s finish with a suggestion from Siya, the immortal jellyfish. It’s tiny, barely more than 4 mm across as an adult, and lives throughout much of the world’s oceans, especially where it’s warm. It eats tiny food, including plankton and fish eggs, which it grabs with its tiny tentacles. Small as it is, the immortal jellyfish has stinging cells in its tentacles. It’s mostly transparent, although its stomach is red and an adult jelly has up to 90 white tentacles.

The immortal jellyfish starts life as a larva called a planula, which can swim, but when it finds a place it likes, it sticks itself to a rock or shell, or just the sea floor. There it develops into a polyp colony, and this colony buds new polyps that are clones of the original. These polyps swim away and grow into jellyfish, which spawn and develop eggs, and those eggs hatch into new planulae.

Polyps can live for years, while adult jellies, called medusae, usually only live a few months. But if an adult immortal jellyfish is injured, starving, sick, or otherwise under stress, it can transform back into a polyp. It forms a new polyp colony and buds clones of itself that then grow into adult jellies.

This is all really interesting, and scientists are studying the immortal jellyfish to learn more about how it manages this incredible feat. It’s the only organism known that can revert to an earlier stage of life after reaching sexual maturity. But only an individual at the adult stage, called the medusa stage, can revert to an earlier stage of development, and an individual can only achieve the medusa stage once after it buds from the polyp colony. If it reverts to the polyp stage, it will remain a polyp until it eventually dies. However, it will bud off clones of itself that develop into medusae.

In other words, an immortal jellyfish isn’t technically immortal, but it can certainly prolong its life in an extraordinary way. It’s also really cute.

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 342: Giant Snails and Giant Crabs

Posted on by

Podcast: Play in new window | Download (Duration: 10:32 — 12.7MB)

Subscribe: RSS | More

Thanks to Tobey and Anbo for their suggestions this week! We’re going to learn about some giant invertebrates!

Further reading:

The Invasive Giant African Land Snail Has Been Spotted in Florida

A very big shell:

The giant African snail is pretty darn giant [photo from article linked above]:

The largest giant spider crab ever measured, and a person:

Show transcript:

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

This week we’re going to learn about some giant invertebrates, suggested by Tobey and Anbo. Maybe they’re not as big as dinosaurs or whales, but they’re surprisingly big compared to most invertebrates.

Let’s start with Tobey’s suggestion, about a big gastropod. Gastropods include slugs and snails, and while Tobey suggested the African trumpet snail specifically, I couldn’t figure out which species of snail it is. But it did lead me to learning a lot about some really big snails.

The very biggest snail known to be alive today is called the Australian trumpet snail, Syrinx aruanus. This isn’t the kind of snail you’d find in your garden, though. It’s a sea snail that lives in shallow water off the coast of northern Australia, around Papua New Guinea, and other nearby areas. It has a coiled shell that’s referred to as spindle-shaped, because the coils form a point like the spindle of a tower. It’s a pretty common shape for sea snails and you’ve undoubtedly seen this kind of seashell before if you’ve spent any time on the beach. But unless you live in the places where the Australian trumpet lives, you probably haven’t seen a seashell this size. The Australian trumpet’s shell can grow up to three feet long, or 91 cm. Not only is this a huge shell, the snail itself is really heavy. It can weigh as much as 31 lbs, or 14 kg, which is as heavy as a good-sized dog.

The snail eats worms, but not just any old worms. If you remember episode 289, you might remember that Australia is home to the giant beach worm, a polychaete worm that burrows in the sand between high and low tide marks. It can grow as much as 8 feet long, or 2.4 meters, and probably longer. Well, that’s the type of worm the Australian trumpet likes to eat, along with other worms. The snail extends a proboscis into the worm’s burrow to reach the worm, but although I’ve tried to find out how it actually captures the worm in order to eat it, this seems to be a mystery. Like other gastropods, the Australian trumpet eats by scraping pieces of food into its mouth using a radula. That’s a tongue-like structure studded with tiny sharp teeth, and the Australian trumpet has a formidable radula. Some other sea snails, especially cone snails, are able to paralyze or outright kill prey by injecting it with venom via a proboscis, so it’s possible the Australian trumpet does too. The Australian trumpet is related to cone snails, although not very closely.

Obviously, we know very little about the Australian trumpet, even though it’s not hard to find. The trouble is that its an edible snail to humans and humans also really like those big shells and will pay a lot for them. In some areas people have hunted the snail to extinction, but we don’t even know how common it is overall to know if it’s endangered or not.

Tobey may have been referring to the giant African snail, which is probably the largest living land snail known. There are several snails that share the name “giant African snail,” and they’re all big, but the biggest is Lissachatina fulica. It can grow more than 8 inches long, or 20 cm, and its conical shell is usually brown and white with pretty banding in some of the whorls. It looks more like the shell of a sea snail than a land snail, but the shell is incredibly tough.

The giant African snail is an invasive species in many areas. Not only will it eat plants down to nothing, it will also eat stucco and concrete for the minerals they contain. It even eats sand, cardboard, certain rocks, bones, and sometimes other African giant snails, presumably when it runs out of trees and houses to eat. It can spread diseases to plants, animals, and humans, which is a problem since it’s also edible.

Like many snails, the African giant snail is a simultaneous hermaphrodite, meaning it can produce both sperm and eggs. It can’t self-fertilize its own eggs, but after mating a snail can keep any unused sperm alive in its body for up to two years, using it to fertilize eggs during that whole time, and it can lay up to 200 eggs five or six times a year. In other words, it only takes a single snail to produce a wasteland of invasive snails in a very short amount of time.

In June 2023, some African giant snails were found near Miami, Florida and officials placed the whole area under agricultural quarantine. That means no one can move any soil or plants out of the area without permission, since that could cause the snails to spread to other places. Meanwhile, officials are working to eradicate the snails. Other parts of Florida are also under the same quarantine after the snails were found the year before. Sometimes when people go on vacation in the Caribbean they bring back garden plants, without realizing that the soil in the pot contains giant African snail eggs, because the giant African snail is also an invasive species throughout the Caribbean.

Next, Anbo wanted to learn about the giant spider crab, also called the Japanese spider crab because it lives in the Pacific Ocean around Japan. It is indeed a type of crab, which is a crustacean, which is an arthropod, and it has the largest legspan of any arthropod known. Its body can grow 16 inches across, or 40 cm, and it can weigh as much as 42 pounds, or 19 kg, which is almost as big as the biggest lobster. But its legs are really really really long. Really long! It can have a legspan of 12 feet across, or 3.7 meters! That includes the claws at the end of its front legs. Most individual crabs are much smaller, but since crustaceans continue to grow throughout their lives, and the giant spider crab can probably live to be 100 years old, there’s no reason why some crabs couldn’t be even bigger than 12 feet across. Its long legs are delicate, though, and it’s rare to find an old crab that hasn’t had an injury to at least one leg.

The giant spider crab is orange with white spots, sort of like a koi fish but in crab form. Its carapace is also bumpy and spiky. You wouldn’t think a crab this size would need to worry about predators, but it’s actually eaten by large octopuses. The crab sticks small organisms like sponges and kelp to its carapace to help camouflage it.

The giant spider crab is considered a delicacy in some places, which has led to overfishing. It’s now protected in Japan, where people are only allowed to catch the crabs during part of the year. This allows the crabs to safely mate and lay eggs.

There’s another species called the European spider crab that has long legs, but it’s nowhere near the size of the giant spider crab. Its carapace width is barely 8 ½ inches across, or 22 cm, and its legs are about the same length. Remember that the giant spider crab’s legs can be up to six feet long each, or 1.8 meters. While the European spider crab does resemble the giant spider crab in many ways, it’s actually not closely related to it. They two species belong to separate families.

The giant spider crab spends most of its time in deep water, although in mating season it will come into shallower water. It uses its long legs to walk around on the sea floor, searching for food. It’s an omnivore that eats pretty much anything it can find, including plants, dead animals, and algae, but it will also use its claws to open mollusk shells and eat the animals inside. It prefers rocky areas of the sea floor, since its bumpy carapace blends in well among rocks.

Scientists report that the giant spider crab is mostly good-natured, even though it looks scary. Some big aquariums keep giant spider crabs, and the aquarium workers say the same thing. But it does have strong claws, and if it feels threatened it can seriously injure divers. I shouldn’t need to remind you not to pester a crab with a 12-foot legspan.

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 341: The Leaf Sheep and the Mold Pig

Posted on by

Podcast: Play in new window | Download (Duration: 9:20 — 10.4MB)

Subscribe: RSS | More

Thanks to Murilo and an anonymous listener for their suggestions this week!

Further reading:

The ‘sheep’ that can photosynthesize

Meet the ‘mold pigs,’ a new group of invertebrates from 30 million years ago

A leaf sheep:

Shaun the sheep:

A mold pig:

Show transcript:

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

This week let’s learn about two animals that sound like you’d find them on a farm, but they’re much different than their names imply. Thanks to Murilo for suggesting the leaf sheep, which is where we’ll start.

The leaf sheep isn’t a sheep or a leaf. It’s actually a type of sea slug that lives in tropical waters near Japan and throughout much of coastal south Asia. The reason it’s called a leaf sheep is because it actually looks a lot like a tiny cartoon sheep covered with green leaves instead of wool.

Back in episode 215 we talked about the sea bunny, which is another type of sea slug although it’s not closely related to the leaf sheep. The leaf sheep is even smaller than the sea bunny, which can grow up to an inch long, or about 25 mm. The leaf sheep only grows about 10 mm long at most, which explains why it wasn’t discovered until 1993. No one noticed it.

The leaf sheep’s face is white or pale yellow with two tiny black dots for eyes set close together, which kind of makes it look like Shaun the Sheep. It also has two black-tipped protuberances that look like ears, although they’re actually chemoreceptors called rhinophores. The rest of its body is covered with leaf-shaped spines called cerata, which are green and often tipped with pink, white, or black. This helps disguise it as a plant, but there’s another reason why it’s green.

The leaf sheep eats a particular kind of algae called Avrainvillea, which looks like moss or fuzzy carpet. While algae aren’t exactly plants or animals, many do photosynthesize like plants. In other words, they transform sunlight into energy to keep them alive. In order to photosynthesize, a plant or algae uses a special pigment called chlorophyll that makes up part of a chloroplast in its cells, which happens to be green.

The leaf sheep eats the algae, but it doesn’t digest the chloroplasts. Instead, it absorbs them into its own body and uses them for photosynthesis. That way it gets nutrients from eating and digesting algae and it gets extra energy from sunlight. This is a trait shared by other sea slugs in the superorder Sacoglossa. Because they need sunlight for photosynthesis, they live in shallow water, often near coral reefs.

When the leaf sheep’s eggs hatch, the larvae have shells, but as they mature they shed their shells.

This is a good place to talk about cyanobacteria, which was requested ages ago by an anonymous listener. Cyanobacteria mostly live in water and are also called blue-green algae, even though they’re not actually classified as algae. They’re considered bacteria, although not every scientist agrees. Some are unicellular, meaning they just consist of one cell, while others are multicellular like plants and animals, which means they have multiple cells specialized for different functions. Some other cyanobacteria group together in colonies. So basically, cyanobacteria looked at the chart of possible life forms and said, “yes, thanks, we’ll take some of everything.” That’s why it’s so hard to classify them.

Cyanobacteria photosynthesize, and they’ve been doing so for far longer than plants–possibly as much as 2.7 billion years, although scientists think cyanobacteria originally evolved around 3.5 billion years ago. The earth is about 4.5 billion years old and plants didn’t evolve until about 700 million years ago.

Like most plants also do, cyanobacteria produce oxygen as part of the photosynthetic process, and when they started doing so around 2.7 billion years ago, they changed the entire world. Before then, earth’s atmosphere hardly contained any oxygen. If you had a time machine and went back to more than two billion years ago, and you forgot to bring an oxygen tank, you’d instantly suffocate trying to breathe the air. But back then, even though animals and plants didn’t yet exist, the world contained a whole lot of microbial life, and none of it wanted anything to do with oxygen. Oxygen was toxic to the lifeforms that lived then, but cyanobacteria just kept producing it.

Cyanobacteria are tiny, but there were a lot of them. Over the course of about 700 million years, the oxygen added up until other lifeforms started to go extinct, poisoned by all that oxygen in the oceans and air. By two billion years ago, pretty much every lifeform that couldn’t evolve to use or at least tolerate oxygen had gone extinct. So take a deep breath of life-giving oxygen and thank cyanobacteria, which by the way are still around and still producing oxygen. However, they’re still up to their old tricks because they also produce what are called cyanotoxins, which can be deadly.

That brings us to another animal in our imaginary farm, the mold pig. It’s not a pig or a mold, and unlike the leaf sheep and cyanobacteria, it’s extinct. At least, we think it’s extinct.

The mold pig is a microinvertebrate only discovered in 2019. The only reason we know about it at all is because of amber found in the Dominican Republic, on an island in the Caribbean Sea. As we’ve discussed in past episodes, especially episode 108, amber is the fossilized resin of certain types of tree, and sometimes the remains of small animals are found inside. Often these animals are insects, but sometimes even tinier creatures are preserved that we would otherwise probably never know about.

The mold pig was about 100 micrometers long, or .1 millimeter. You’ve probably heard of the tardigrade, or water bear, which we talked about in episode 234, and if so you might think the mold pig was a type of tardigrade just from looking at it, since it looks similar. It had four pairs of legs like tardigrades do, but while scientists think they were related, and that the mold pig was probably also related to mites, it was different enough that it’s been classified in its own genus and may need to belong to its own phylum. Its official name is Sialomorpha.

The mold pig probably ate mold, fungus, and microscopic invertebrates. It lived around 30 million years ago, and right now that’s about all we know about it. There’s a good chance that it still survives somewhere in the world, but it’s so tiny that it’s even easier to overlook than the leaf sheep. Maybe you will be the person who rediscovers its living descendants.

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 340: Whale Lice and Sea Lice

Posted on by

Podcast: Play in new window | Download (Duration: 13:25 — 16.1MB)

Subscribe: RSS | More

Thanks to Eilee for suggesting the sea louse this week!

Further reading:

Secrets of the Whale Riders: Crablike ‘Whale Lice’ Show How Endangered Cetaceans Evolved

Parasite of the Day: Neocyamus physeteris

A whale louse [By © Hans Hillewaert, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=19259257]:

The salmon sea louse [By Thomas Bjørkan – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=7524020]:

Show transcript:

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

It’s now officially August, so we’re officially kicking off Invertebrate August with two invertebrates with the word louse in their names, even though neither of them are technically lice. Thanks to Eilee for suggesting sea lice, and thanks to our patrons because I used some information from an old Patreon episode for the first part of this episode.

That would be the whale louse. The whale louse isn’t actually a louse, although it is a parasite. Lice are insects adapted for a parasitic lifestyle on the bodies of their hosts, but whale lice are crustaceans—specifically, amphipods specialized to live on whales, dolphins, and porpoises.

There are many species of whale louse, with some only living on a particular species of whale. In the case of the sperm whale, one species of whale louse lives on the male sperm whale while a totally different species of whale louse lives on the female sperm whale and on calves. This was a fact I found on Wikipedia and included in the Patreon episode, but at the time I couldn’t find out more. It’s puzzled me ever since, which is one of the reasons I wanted to revisit this topic. I couldn’t figure out how the male calves ended up with male sperm whale lice, and I couldn’t figure out why males and females would have different species of lice. I’m happy to report that I now know the answers to both questions, or at least I can report what experts hypothesize.

Male sperm whales spend more time in polar waters while females spend more time in warmer waters to raise their calves. Sperm whales are actually host to three different whale lice species, but one species prefers colder water and is much more likely to live on males, while another species prefers warmer water and is much more likely to live on females and calves. Any sperm whale might have lice from any of the three species, though, and whale lice are spread when whales rub against each other. This happens when the whales mate, but it also happens when males fight or when whales are just being friendly.

The whale louse has a flattened body and legs that end in claws that help it cling to the whale. Different species are different sizes, from only five millimeters up to an inch long, or about 25 mm. Typically the lice cling to areas where water currents won’t sweep them away, including around the eyes and genital folds, ventral pleats, blowholes, and in wounds. Barnacles also grow on some whales and the lice live around the barnacles. But even though all that sounds horrible, the lice don’t actually harm the whales. They eat dead skin cells and algae, which helps keep wounds clean and reduces the risk of infection.

The right whale is a baleen whale that can grow up to 65 feet long, or almost 20 meters. Right whales have callosities on their heads, which are raised patches of thickened, bumpy skin. Every whale has a different pattern of callosities. Right whales are dark in color, but while the callosities are generally paler than the surrounding skin, they appear white because that’s where the whale lice live, and the lice are white. This allows whales to identify other whales by sight. It’s gross but it works for the whales. Right whales also usually host one or two other species of louse that don’t live on the callosities.

Dolphins typically have very few lice, since most dolphins are much faster and more streamlined than whales and the lice have a harder time not getting washed off. Some dolphins studied have no lice at all, and others have less than a dozen. Almost all whales have lice.

Scientists study whale lice to learn more about whales, including how populations of whales overlap during migration. Studies of the lice on right whales helped researchers determine when the whales split into three species. But sometimes what researchers learn from the lice is puzzling. In 2004 researchers found a dead southern right whale calf and examined it, and were surprised to find it had humpback whale lice, not southern right whale lice. Researchers hypothesize that something had happened to the calf’s birth mother and it was adopted by a humpback whale mother. Another study determined that a single southern right whale crossed the equator between one and two million years ago and joined up with right whales in the North Pacific. Ordinarily right whales can’t cross the equator, since their blubber is too thick and they overheat in warm water. Researchers suggest that the right whale in question was an adventurous juvenile who crossed in an unusually cool year. The lice that whale carried interbred with lice the North Pacific whales carried, leaving a genetic marker to tell us about the whale’s successful adventure.

Some animals do eat whale lice, including a little fish called topsmelt. Topsmelt live in shallow water along the Pacific coast of North America. It grows up to around 14 inches long, or 37 cm, and has tiny sharp teeth that it uses to eat zooplankton. But in mid-winter through spring, gray whales arrive in the warm, shallow waters where the topsmelt live to give birth. Then schools of topsmelt will gather around the whales, eating lice and barnacles from the whale’s skin. Good for those little fish. That makes me feel better for the whales.

Eilee suggested the sea louse a while back, and when I looked it up initially I was horrified. Sea lice is another name for a skin condition called seabather’s eruption that consists of intense itching and welts on the skin, that occurs after someone has been swimming in some parts of the world. That includes around parts of New Zealand, off the coast of Queensland, Australia, off the eastern coast of Africa, parts of south Asia, the Caribbean and Gulf of Mexico, and many other places. It usually shows up a few hours after a swimmer gets out of the water, and since it almost always shows up in people who keep wearing their bathing suit for a while after swimming, or wear their suit into a shower to rinse off, people used to think the itching was due to a type of louse that got caught in the suit. They were half-right, because it is due to a microscopic animal that gets trapped against a person’s skin by their bathing suit. It isn’t a louse, though, but the larvae of some species of jellyfish. The larvae aren’t dangerous to humans or anything else, but they do each have a single undeveloped nematocyst. That’s a stinging cell, the same kind that adult jellyfish have. In the case of the larvae, the sting only activates when a larva dies, and it dies if it dries out or gets soaked in fresh water. Fortunately, seabather’s eruption isn’t a very common occurrence and while it’s uncomfortable for a few days, it’s not dangerous and can be treated with anti-itch cream.

There is a type of animal called the sea louse, of course, but it doesn’t want anything to do with humans and wouldn’t bite a human even if it could. It’s a parasitic crustacean like the whale louse, but it only lives on fish. It’s also not related to the whale louse and doesn’t look anything like the whale louse. The whale louse looks kind of like a flattened shrimp without a tail, while the sea louse is hard to describe. It has a flattened shield at the front, with a thinner tail-like section behind, although it’s actually not a tail but the louse’s abdomen. Its legs are underneath its body and are short and hooked so it can keep hold of its host fish, although the shape of its shield acts as a sort of suction cup that also helps it remain attached.

Like the whale louse, different species of sea louse live on different species of fish. It’s usually quite small, less than 10 mm long, although at least one species can grow twice that length. Males are much smaller than females. It eats the mucus, skin, and blood of its host fish, and its mouthparts form a sharp cone that it uses to stab the fish and suck fluids out. Naturally, this isn’t good for the fish.

Most of the time a fish only has a few sea lice, if any, but sometimes when conditions are right a fish can have a much heavier infestation. This can lead to the fish dying in really bad cases, sometimes due to diseases spread by the lice, infected wounds caused by the lice, or just from anemia if the lice drink too much of the fish’s blood.

Conditions are right to spread sea lice when fish are crowded in a small space, and this happens a lot in farmed fish. It’s especially bad in salmon, so while we don’t know a lot about most sea lice, we know a whole lot about the species of sea louse that parasitizes salmon. It’s called Lepeophtheirus salmonis and it’s the sea louse that grows bigger than most others. Salmon are big fish, with the largest growing over 6 ½ feet long, or 2 meters.

The salmon sea louse has a complicated life cycle and only lives on fish part of the time, which is probably true of all sea lice. The female louse develops a pair of egg strings that hang down from the rear of her body, and each string has around 150 eggs. The eggs hatch into tiny larvae that mostly just drift along through the water, although they can swim. A larva molts its exoskeleton every few days as it transforms into new stages of development, and all the time it’s looking for a host fish.

Once it finds a salmon, the sea louse grabs hold and stays put until it molts again and reaches the next stage of its development, which doesn’t take long. Then it’s able to walk around on the fish and it can swim too if it needs to.

The sea louse can’t survive very long in fresh water, but that’s weird if you know anything about salmon. Salmon are famous for migrating from the ocean into rivers to spawn, and after spawning, most adult salmon die. Some Atlantic salmon will survive and return to the ocean, but most salmon die within a few days or weeks of spawning. Because all the sea lice die once the salmon enter fresh water, the new generation of salmon don’t get sea lice until they make their way into the ocean.

That’s a natural way that sea lice populations are kept under control. The salmon sea louse will also live on a few other species of fish, including the sea trout. But people like eating salmon, and farming salmon is an important industry. Unfortunately, as I mentioned earlier, having lots of fish in one place means the sea louse can also increase in numbers easily.

Salmon farmers have tried all kinds of things to get rid of sea lice, from underwater lasers that zap the lice to kill them, to putting cleaner fish among the salmon to eat the lice. Scientists are even trying to breed a variety of salmon that’s much more resistant to sea lice infestation, although this is controversial since it makes use of genetic modification. Not all countries allow genetically modified fish to be sold as human food.

For the most part, though, wild fish generally don’t have a lot of sea lice—and if they do, they can just visit a cleaner fish. Thank goodness for cleaner fish!

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!