Category Archives: invertebrates

Episode 445: Salinella

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It’s a tiny mystery animal!

Further reading:

Salinella – what the crap was it?

Some of Frenzel’s drawings of Salinella:

Show transcript:

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

Johannes Frenzel was a German zoologist in the 19th century. He worked in Argentina for several years, studying microscopic and near-microscopic animals, and seemed to be a perfectly good scientist who did good work but didn’t make a real splash. But these days he’s remembered for a mystery animal that is still causing controversy in the scientific community.

Frenzel described a strange worm-like animal he named Salinella salve in 1892, and Salinella hasn’t been seen since. According to Frenzel’s description of it, Salinella is very different from every other animal known. It’s so different, in fact, that some scientists think Frenzel just made the whole thing up.

In 1890 or 1891, a colleague gave Frenzel a soil sample reportedly from the salt pans in Argentina. We don’t know exactly where it came from, just that it’s somewhere in the Río Cuarto region. Frenzel put the sample in an aquarium and added water, although apparently some iodine got mixed in too, either on purpose or maybe by accident. Then he forgot all about the sample for a few weeks. It wasn’t covered and Frenzel reported that some dead flies had fallen into the aquarium.

When Frenzel finally got around to examining the sample, he discovered something he had never seen before. No one else had either, before or since. He said it was a worm-like animal about 2 millimeters long, and there wasn’t just one of them. There were quite a few in the sample, some in the soil and some attached to the glass.

When he studied the tiny worms, he discovered they had a very basic, very unusual body plan. It was basically just a tube open at both ends, with a single layer of cells around the interior sac. Each cell was covered with cilia on both the exterior side of the animal and the interior side. Cilia are hair-like structures, and salinella used them to move around, a method of propulsion called ciliary gliding. It didn’t have any organs or even tissues—basically nothing you’d expect even in a very simple animal. It reproduced by splitting down the middle, called transverse fission.

Assuming Frenzel was describing a real animal, and was describing it accurately, this body plan is unlike any other animal known. It’s most similar to what scientists think the body plan was of the precursors to sea sponges. It’s also similar in some ways to a group of parasitic animals called Mesozoa, which are wormlike, very simple, only a few millimeters long at most, and which have an outer layer of ciliated cells. Mesozoans aren’t well understood and most scientists these days think the group is made up of animals that aren’t closely related to each other. Salinella has sometimes been considered a mesozoan, but it’s still not that close of a match.

Frenzel took detailed notes and made careful drawings of Salinella, and compared it to known animals like protozoans. His description of the animal is solid, and he described many other animals in his career that are well-known to scientists today. The main reason some scientists now think Frenzel made Salinella up is because it’s so weird and no one has been able to find it since. Frenzel died in 1897 without ever having the chance to look for more specimens.

In 1963 an American biologist placed Salinella in its own phylum, which he named Monoblastozoa. In the early 2010s, a team of German scientists visited various saline lakes in Argentina and Chile in hopes of finding Salinella specimens, but without luck. The area where the original soil sample came from has mostly been converted to farmland, so if Salinella was restricted to that one spot, it might well be extinct now.

So what happened to the type specimens that Frenzel collected? We don’t know. They vanished sometime between 1891 when Frenzel moved back to Germany from Argentina, and now. It might even be that he couldn’t preserve the specimens, since he reported that every time he tried to preserve one, it disintegrated.

While I was researching this episode, I wondered if Salinella actually came from the flies that reportedly fell into the aquarium. Many parasites evolve to become very simple, like Myxozoa that we talked about in episode 422. But Frenzel observed Salinella apparently eating organic matter in the soil, which isn’t something a fly parasite would or could do.

At this point, unless we can find a living Salinella specimen, there’s no way to know if the animal was real or a figment of Frenzel’s imagination. Some scientists even suggest that Frenzel was mistaken in his description and the real animal might actually be very different from what he described. Considering how detailed and careful Frenzel’s notes and drawings are, and how many other species he described without causing any controversy at all, I think Salinella was a real animal, just a weird one. Let’s hope that one day it’s discovered again so we can 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 444: Diskagma and Horodyskia

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It’s Invertebrate August! These creatures are the most invertebrate-y of all!

Further reading:

Dubious Diskagma

Horodyskia is among the oldest multicellular macroorganisms, finds study

A painting of diskagma, taken from the top link above:

Little brown jug flowers (not related to diskagma in any way!):

Show transcript:

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

This episode started out as the March 2025 Patreon episode, but there was more I wanted to add to it that I didn’t have time to cover in that one. Here’s the expanded version to kick off Invertebrate August, which also happens to be episode 444 and releasing on August 4th! It’s about two mystery fossils.

The first is named Diskagma, which means disc-shaped fragment, and it was only described in 2013. That’s partly because it’s so small, barely two millimeters long at most, and partly because of where it’s found. That would be fossilized in extremely old rocks.

When I saw the illustration accompanying the blog post where I learned about Diskagma, I thought it was a cluster of cup-like flowers, sort of like the flowers of the plant called little brown jug. I was ready to send the link to Meredith Hemphill of the Herbarium of the Bizarre podcast, which by the way you should be listening to. But then I saw how old Diskagma is.

It’s been dated to 2.2 billion years old. That’s older than any plant, probably by as much as a billion years.

Even more astounding, it lived on land.

As a reminder, the Cambrian explosion took place about half a billion years ago, when tiny marine animals diversified rapidly to fill new ecological niches. That happened in the water, though, mainly in shallow, warm oceans. If you go back to around 850 million years ago, that may have been roughly the time that land plants evolved from green algae that lived in fresh water. Plant-like algae, or possibly algae-like plants, might be as old as 1 billion years old. But before then, scientists don’t find evidence of anything except microbes living on land, and they were probably restricted to lakes and other bodies of fresh water. That’s because there wasn’t much soil, just broken-up rock that contained very few nutrients and couldn’t retain much water.

Diskagma was shaped like a tiny elongated cup, or an urn or vase, with what looks like a stem on one end and what looks like an opening at the other end. The opening contained structures that look like little filaments, but the filaments didn’t fill the whole cup. Most of the cup was diskagma’s body, so to speak, although we don’t know what it contained. We also don’t know what the filaments were for. We do know that the stem actually did connect diskagma to other cups, so that they lived in little groups. We don’t know if it was a single animal with multiple cuplike structures or if it was a colony, or really anything.

That’s the problem. We don’t know anything about diskagma except that it existed, and that it lived on land 2.2 billion years ago. Tiny as it was, though, it wasn’t microscopic, and it definitely appears more complex than would be expected that long ago, especially from something living on dry land.

One suggestion is that the main part of its body contained a symbiotic bacteria that could convert chemicals to nutrients. As in many modern animals, especially extremophiles, the bacteria would have had a safe place to live and the diskagma would have had nutrients that allowed it to live without needing to eat.

Diskagma lived at an interesting time in the earth’s history, called the great oxygenation event, also called the great oxidation event. We talked about it in episode 341 in conjunction with cyanobacteria, because cyanobacteria basically started the great oxygenation event. Cyanobacteria are still around, by the way, and are doing just fine. They’re usually called blue-green algae even though they’re not actually algae.

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, if you were wondering.

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.

Since Diskagma lived during the time of the great oxygenation event, some scientists suggest that it contained microbes that photosynthesized sunlight into nutrients diskagma could use. And, as in cyanobacteria, the side effect of photosynthesis is oxygen, so diskagma might have been contributing to the oxygen in the air that allows us to breathe these days. On the other hand, it might not have had anything to do with photosynthesis and the great oxygenation event might have driven diskagma to extinction. We have no way to know right now.

What we do know is that 700 million years after diskagma lived, something similar appears in the fossil record. It’s called Horodyskia and its fossils have been found in rocks dating between 1.5 billion years ago to 550 million years ago. Unlike diskagma, which has only been found in rocks from South Africa, horodyskia fossils have been found in Australia, China, and North America. That doesn’t mean diskagma wasn’t widespread, just that we haven’t found it anywhere else. There aren’t all that many rocks that are over two billion years old.

Horodyskia lived in the water, specifically at the bottom of the ocean, probably in shallow water. It’s been described as looking like a row of beads on a thread. The thread seemed to be buried in the sand, and growing up from it in intervals were little pear-shaped bulbs, each no larger than a millimeter long, that stuck up through the sand into the water. There may have been little root-like structures called holdfasts that grew from the bottom of the thread to help keep it in place.

We don’t know a lot about horodyskia either. It wasn’t a plant, since it also lived long before plants evolved. A 2023 study determined that it was a multicellular creature and that it was most likely a protist. Protists are related to animals, plants, and fungi, but aren’t any of those things, and they’re an incredibly diverse group. Most are single-celled and microscopic, but not always. They include algae, amoebas, slime molds, and lots more. Horodyskia’s bulbs might have been encased in a jelly-like substance, as is common in a lot of protists. Some horodyskia specimens found in younger rocks, the ones about 550 million years old, are much smaller than the earlier specimens, with each bulb barely a fraction of a millimeter in size.

We might not know much about these strange life forms, but knowing they existed tells us that even two billion years ago, life was a lot more varied than we used to think. And that’s the most exciting thing of all.

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 443: Ant Lions and the Horrible Seal Problem

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Thanks to Jayson and warblrwatchr for suggesting this week’s invertebrates!

Further reading:

Parasite of the Day: Orthohalarachne attenuata

Trap-jaw ants jump with their jaws to escape the antlion’s den

Get out of my noooooose:

An ant lion pit:

An ant lion larva:

A lovely adult antlion, Nannoleon, which lives in parts of Africa [photo by Alandmanson – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=58068259]:

Show transcript:

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

It’s almost August, and of course we’re doing invertebrate August again this year. Let’s get ready by talking about a few extra invertebrates this week, with suggestions from Jayson and warblrwatchr.

Before we get started, I have some quick housekeeping. First, a big shout-out to Nora who emailed me recently. I just wanted to say hi and I hope you’re having a good day. Next, I’m moving in just a few weeks to Atlanta, Georgia! I know I was talking forever about moving to Bloomington, Indiana, but I changed my mind. The next few episodes are already scheduled so I can concentrate on moving.

I’m about 75% packed at this point and have given away or sold a lot of stuff, including a lot of books. But I have a collection that a listener might be interested in. I offered it to the patrons last month but no one grabbed it, so I’ll offer it here.

I have every issue of the little magazine Flying Snake ever published, 30 in all. They’re a fun hodgepodge of articles, reprinted newspaper clippings, old photos, and other stuff more or less associated with cryptozoology and weirdness in general. I’ve decided they take up too much space on my shelves to take with me to Atlanta. If you’re interested in giving them a home, let me know and I’ll box them up and send them to you for free. The first person who says they’ll take them will get them, but the catch is that you have to take them all. I won’t just send you a few. I’ll also throw in all four volumes of the Journal of Cryptozoology. This offer stands until mid-August when I move, because if I have to move them to my new apartment, I’m just going to keep them.

Okay, now let’s learn about some invertebrates! First, Jayson wanted to learn about a tiny invertebrate called Orthohalarachne attenuata. It doesn’t have a common name because most people will never ever encounter it, or think about it, and I kind of wish I didn’t have to think about it because it’s gross. Thanks a lot, Jayson. It’s a mite that lives in the nasal passages of seals, sea lions, and walruses. It’s incredibly common and usually doesn’t bother the seal very much, although sometimes it can cause the seal to have difficulty breathing if the infestation is heavy.

The adult mite spends its whole life anchored in the seal’s nasal passages with sharp little claws, although it can move around if it wants to. Its larvae are more active. The mite is mainly spread by seals sneezing on each other, which spreads the larvae onto another seal, and the larvae crawl into the new seal’s nose and mouth.

Unless you’re a seal or other pinniped, this might sound gross but probably doesn’t bother you too much. But consider that in 1984, a man went to the doctor when one of his eyes started hurting. The doctor found a mite attached to his eyeball, and yes, it was Orthohalarachne attenuata. The man had visited Sea World two days before he started feeling pain in his eye, and happened to be close to some walruses that were sneezing.

Luckily for pinnipeds kept in captivity in zoos that give their animals proper care, mite infestations can be treated successfully by veterinarians.

Let’s move on quickly to an invertebrate that isn’t a parasite that can get in your eyes, the ant lion! It was suggested by warblrwatchr and I’ve been wanting to cover it for a while. When I was a kid, there was a strip of soft powdery dirt under the eaves of the school gym that always had ant lions in it, and I would squat down during recess and watch to see if any ants would fall in and get caught. Sometimes this did actually happen and the resulting battle between ant and ant lion was exciting and kind of horrible to witness.

The ant lion is actually the larva of antlion lacewing, which look like a small damselfly that is mainly active at dusk. Ant lions live throughout the world, with more than 2,000 species known. Some wait for prey while hidden in leaf litter, while some hide in rock crevices and become camouflaged by lichens growing on them. Many others dig little pits in sand or soft dirt. They’re also called the doodlebug in some places, because when they’re looking for a place to dig a little pit, they make a loopy pattern in the dirt as they’re walking around.

The ant lion’s body is robust and has little backwards-pointing bristles that help it dig itself into the dirt and stay there without moving until it needs to. It waits at the bottom of the pit, hidden underground with just its long, sharp jaws showing through the dirt, until an ant or other insect falls in. The ant can’t climb out because the sides of the pit are so sharply angled that they start to cave in, sending the ant down to the bottom of the pit. If that doesn’t work, the ant lion kicks dirt at the ant so that it falls. Then the ant lion grabs the ant in its fearsome jaws and injects venom and digestive enzymes into it, and that is the end of the ant. The jaws actually have little projections that are hollow and act like horrible little straws, so that the ant lion sucks the liquefied ant insides into its digestive system.

One species of ant, the trap-jaw ant, can sometimes escape the ant lion’s pit by using its own fearsome jaws as a spring to bounce itself to safety. There are many species of trap-jaw ant that live in tropical and subtropical areas throughout much of the world, including Africa, Asia, Australia, and much of the Americas. Its long jaws can snap closed extremely quickly and with a lot of force, allowing it to kill prey, bite pieces off of food, and lots of other activities. They can also jump with their jaws, and this improves their ability to bounce right out of the ant lion pit.

The ant lion can remain in its larval stage for years, maturing slowly. It has no anus but it doesn’t expel the waste products that it can’t digest, it just stores them in its body. When it does finally pupate, it uses a lot of the waste to produce silk for its cocoon. Whatever is left over it leaves behind when it emerges from its cocoon.

The cocoons are naturally hidden underground, and when the adult antlion lacewing emerges, it digs its way to the surface and rests while its wings open. Compared to the tough little larva, the adult is delicate and not very robust. It doesn’t live very long, usually no more than a few weeks, and most species eat pollen or nectar, or maybe tiny insects. It mainly just seeks out a mate, and the female lays her eggs in soft soil. When they hatch, they build their first tiny pits and the cycle starts again. And nobody gets into anybody’s eyeballs.

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 440: Trilobites!

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Thanks to Micah for suggesting this week’s topic, the trilobite!

Further reading:

The Largest Trilobites

Stunning 3D images show anatomy of 500 million-year-old Cambrian trilobites entombed in volcanic ash

Strange Symmetries #06: Trilobite Tridents

Trilobite Ventral Structures

A typical trilobite:

Isotelus rex, the largest trilobite ever found [photo from the first link above]:

Walliserops showing off its trident [picture by TheFossilTrade – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=133758014]:

Another Walliserops individual with four prongs on its trident [photo by Daderot, CC0, via Wikimedia Commons]:

Show transcript:

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

This week we’re going to learn about an ancient animal that was incredibly successful for millions of years, until it wasn’t. It’s a topic suggested by Micah: the trilobite.

Trilobites first appear in the fossil record in the Cambrian, about 520 million years ago. They evolved separately from other arthropods so early and left no living descendants, that they’re not actually very closely related to any animals alive today. They were arthropods, though, so they’re distantly related to all other arthropods, including insects, spiders, and crustaceans.

The word trilobite means “three lobes,” which describes its basic appearance. It had a head shield, often with elaborate spikes depending on the species, and a little tail shield. In between, its body was segmented like a pillbug’s or an armadillo’s, so that it could flex without cracking its exoskeleton. Its body was also divided into three lobes running from head to tail. Its head and tail were usually rounded so that the entire animal was roughly shaped like an oval, with the head part of the oval larger than the tail part. It had legs underneath that it used to crawl around on the sea floor, burrow into sand and mud, and swim. Some species could even roll up into a ball to protect its legs and softer underside, just like a pillbug.

Because trilobites existed for at least 270 million years, there were a lot of species. Scientists have identified about 22,000 different species so far, and there were undoubtedly thousands more that we don’t know about yet. Most are about the size of a big stag beetle although some were tinier. The largest trilobite found so far lived in what is now North America, and it grew over two feet long, or more than 70 centimeters, and was 15 inches wide, or 40 cm. It’s named Isotelus rex.

I. rex had 26 pairs of legs, possibly more, and prominent eyes on the head shield. Scientists think it lived in warm, shallow ocean water like most other trilobites did, where it burrowed in the bottom and ate small animals like worms. There were probably other species of trilobite that were even bigger, we just haven’t found specimens yet that are more than fragments.

Because trilobites molted their exoskeletons the way modern crustaceans and other animals still do, we have a whole lot of fossilized exoskeletons. Fossilized legs, antennae, and other body parts are much rarer, and preserved soft body parts are the rarest of all. We know that some trilobite species had gills on the legs, some had hairlike structures on the legs, and many had compound eyes. A specimen with preserved eggs inside was also found recently.

Some incredibly detailed trilobite fossils have been found in Morocco, including details like the mouth and digestive tract. The detail comes from volcanic ash that fell into shallow coastal water around half a billion years ago. The water cooled the ash enough that when it fell onto the trilobites living in the water, it didn’t burn them. It did suffocate them, though, since so much ash fell that the ocean was more ash than water.

The ash was soft and as fine as powder, and it covered the trilobites and protected their bodies from potential damage, while also preserving the body details as they fossilized over millions of years. The fossils were discovered in 2015, about 509 million years after the trilobites died, and are still being studied.

Two species of trilobite have been found at this Morocco site, and the team is using non-invasive technology to study the preserved insides in one exceptionally preserved specimen. Its entire digestive system is intact, probably because the poor trilobite ended up swallowing a lot of ash before it died. The ash kept the soft tissues from decomposing.

Some trilobites had spines growing from their head shields and even from the rest of the exoskeleton. Scientists think these may have helped protect the animals from being eaten, but they might also have helped them navigate more easily in the water without getting flipped over by currents. One genus of trilobite, Walliserops, even had a structure sticking out from the front of its head called a trident.

The trident grew forward and slightly upward from the head, then split into three prongs. Scientists aren’t sure what it was for, but suggest that it acted as a nose spike like some modern beetles have, which allowed trilobites to fight each other for resources or mates. The tridents weren’t completely symmetrical, and one individual has even been found with a four-pronged trident. (I guess you would call that a quadrent.) Some species had long tridents, some short, but there’s no evidence that only males or only females had them.

Electron microscopes and other modern imaging technology have allowed scientists to learn more about what the trilobite looked like when it was alive. This includes some hints about different species’ coloration and markings. Most trilobites had good vision and were probably as colorful as modern crustaceans. Some rare trilobite fossils show microscopic traces of spots and stripes. One species studied may have had a brown stripe that faded to white along the edges of the body.

All trilobites went extinct at the end of the Permian, about 250 million years ago, during the extinction event called the Great Dying. We talked about it in detail in episode 227 so I won’t go over its causes and effects again except to say that an estimated 95% of all marine animals went extinct during that event. The Great Dying ended the trilobite’s successful 270 million year run on this amazing planet.

When I was little, I found trilobites fascinating. They were so common for so long, and then they were gone. I’ve always wondered if some trilobites survived the Great Dying and were still alive in the deep sea. I’m not the only one who’s wondered that, so let’s talk a little more about why the trilobites went extinct and how some of them might have survived.

Almost all trilobites we know of lived in shallow coastal water. We have trilobite tracks of an ancient low tide shore, which tells us that at least some species could leave the water and venture onto land occasionally, possibly the first animals on earth to do so. Coastal water is well oxygenated and we know trilobites had trouble surviving anoxic events, when the water where they lived had much less oxygen than usual. Anoxic events are actually what led to the Great Dying, but it wasn’t the first time the world’s oceans became less oxygenated. It happened in earlier extinction events too during the Devonian, around 372 and 359 million years ago, and each time many species and genera of trilobites went extinct. The trilobite was already in decline when the Great Dying occurred, with only a handful of genera left, and the extinction event finished them off once and for all according to the fossil record.

But we do know of a few species of trilobite that were adapted to the deep sea. Deep-sea animals have to evolve to be tolerant of low-oxygen conditions. The deep sea is also very little known by humans. It’s possible, even if it’s unlikely, that deep-sea trilobites survived the Great Dying and that their descendants are still around, unknown to science.

One interesting note, and an ongoing mystery about trilobites, is that while we know they were arthropods, we don’t actually know which branch of the phylum Arthropoda they’re most related to. That’s because there are no ancestral versions of the trilobite that have ever been found. When they appear in the fossil record, they’re already recognizably trilobites. It’s possible that the ancestral forms didn’t have exoskeletons that were likely to fossilize, or that we just haven’t found the right fossil bed yet. Until we learn more, it’ll remain a mystery.

You can find Strange Animals Podcast at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. 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 437: Updates 8 and the Nutria

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Thanks to Nicholas, Måns, Warblrwatchr, Llewelly, and Emerson this week, in our yearly updates episode!

Further reading:

An Early Cretaceous Tribosphenic Mammal and Metatherian Evolution

Guam’s invasive tree snakes loop themselves into lassos to reach their feathered prey

Rhythmically trained sea lion returns for an encore — and performs as well as humans

Scientists Solve Mystery of Brown Giant Pandas

Elephant turns a hose into a sophisticated showering tool

New name for one of the world’s rarest rhinoceroses

Antarctica’s only native insect’s unique survival mechanism

Komodo dragons have iron-coated teeth to rip apart their prey

The nutria has really orange teeth:

Show transcript:

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

This week is our annual updates episode, and we’ll also learn about an animal suggested by Emerson. But first, we have some corrections!

Nicholas shared a paper with me that indicates that marsupials actually evolved in what is now Asia, with marsupial ancestors discovered in China. They spread into North America later. So I’ve been getting that wrong over many episodes, over several years.

Måns shared a correction from an older episode where I mentioned that humans can’t get pregnant while breastfeeding a baby. I’ve heard this all my life but it turns out it’s not true. It is true that a woman’s fertility cycle is suppressed after giving birth, but it’s not related to breastfeeding. Some women can become pregnant again only a few months after giving birth, while others can’t get pregnant again for a few years. It depends on the individual. That’s important, since the myth is so widespread that many women get pregnant by accident thinking they can’t since they’re still feeding a baby.

Warblrwatchr commented on the ultraviolet episode and mentioned that cats can see ultraviolet, which is useful to them because mouse urine glows in UV light.

Finally, Llewelly pointed out that in episode 416, I didn’t mention that fire ant venom isn’t delivered when the ant bites someone. The ant bites with its mandibles to hold on, then uses the stinger on its back end to sting repeatedly.

Now, let’s dive into some updates about animals we’ve talked about in past episodes. As usual, I don’t try to give an update on every single animal, because we’d be here all week if I did. I just chose interesting studies that caught my eye.

In episode 402, we talked about snakes that travel in unusual ways, like sidewinders. Even though I had a note to myself to talk about the brown tree snake in that episode, I completely forgot. The brown tree snake is native to parts of coastal Australia and many islands around Indonesia and Papua New Guinea. It’s not native to Guam, which is an island in the western Pacific, way far away from the brown tree snake’s home. But in the late 1940s, some brown tree snakes made their way to Guam in cargo ships and have become invasive since then.

The brown tree snake can grow up to six and a half feet long, or 2 meters, and is nocturnal, aggressive, and venomous. It’s not typically a danger to adults, but its venom can be dangerous to children and pets. The government employs trained dogs to find the snakes so they can be removed, and this has worked so well that brown tree snake population is declining rapidly on the island. But that hasn’t stopped the snake from driving many native animals to extinction in the last 75 years, especially birds.

One of the things scientists did in Guam to try and protect the native birds was to place smooth poles around the island so birds could nest on top but snakes couldn’t climb up to eat the eggs and chicks. But before long, the snakes had figured out a way to climb the poles, a method never before documented in any snake.

To climb a pole, the snake wraps its body around it, with the head overlapping the tail. Then it sort of scoots itself up the pole with tiny motions of its spine, a slow, difficult process that takes a lot of energy. Tests of captured brown tree snakes afterwards showed that not all snakes are willing or able to climb poles this way. Scientists think the brown tree snake evolved this method of movement to climb smooth-trunked trees in its native habitat. They also suspect some other species of snake can do the same.

Way back in episode 23 we talked about musical animals, including how some species can recognize and react to a rhythmic beat while most can’t. Sea lions are really good at it, especially a sea lion named Ronan.

Ronan was rescued in 2009 when she was a young sea lion suffering from malnutrition, wandering down a highway in California. She was determined to be non-releasable after she recovered, so she’s been a member of the Pinniped Lab in the University of California – Santa Cruz ever since, where she participates in activities that help scientists study sea lions. The rhythm studies are only one of the things she does, and only occasionally. The scientists put on a metronome and she bobs her head to the beat while they film her in ultra-slow motion.

The latest study was published in May of 2025. Ronan is 16 years old now and in her prime, so it’s not surprising that she performed even better than her last tests when she was still quite young. The study determined that not only does Ronan hit the beat right on time, she’s actually better at it than a human a lot of the time. She hits the beat within 15 milliseconds. When you blink your eye, it takes 150 milliseconds. If only she had hands, she’d be the best drummer ever!

The greatest thing about this process is that Ronan enjoys it. She’s rewarded with fish after a training session, and if she doesn’t feel like doing an activity, she doesn’t have to.

Back in episode 220, we talked about the giant panda, especially the mysterious Qinling panda that’s brown and tan instead of black and white. A study published in March of 2024 looked into the genetics of this unusual coat color and determined that it was a natural genetic mutation that doesn’t make the animals unhealthy, meaning it probably isn’t a result of inbreeding.

We talk occasionally about tool use in animals, especially in birds like crows and parrots, and in primates like chimpanzees. But a study published in November of 2024 detailed an elephant in the Berlin Zoo that uses a water hose to shower.

You may not think that’s a big deal, but the elephant in question, named Mary, uses the hose the way a human would to shower off. She holds the hose with her trunk just behind the nozzle, then moves it around and shifts her body to make sure she gets water everywhere she wants. She has to sling the hose backwards to clean her back, and when researchers gave her a heavier hose that she couldn’t move around as easily, she didn’t bother with it but just used her own trunk to spray water on herself.

Even more interesting, another elephant, named Anchali, who doesn’t get along with Mary, will interfere with the hose while Mary is using it. She lifts part of the hose to kink it and stop the water from flowing. Sometimes she even steps on the hose to stop the water, something the elephants have been trained not to do since zookeepers use hoses to clean out the enclosures. Anchali only steps on a hose if Mary is using it.

This is the first time researchers have studied a water hose as tool use, but it makes sense for elephants to understand how to use a hose, since they have a built-in hose on their faces.

We talked about the rhinoceros in episode 346, and more recently in the narwhals and unicorns episode. A study published in March of 2025 suggested that the Javan rhino should be classified as a new species of rhino in its own genus. The Javan rhino is incredibly rare, with only about 60 individuals alive in the world, all of them living in the wild in one part of Java. The Javan rhino is also called the Sundaic rhinoceros, and it’s been considered a close relation of the Indian rhinoceros. It’s smaller than the Indian rhino and most Javan rhino females either don’t have a horn at all or only have a big bump on the nose instead of a real horn.

The Javan rhino is so rare that we don’t really know much about it. The new study determined that there are big enough differences between the Javan rhino and the Indian rhino, in their skeletons, skin, diet, behavior, and fossil remains, that they should be placed in separate genera. The proposed new name for the Javan rhino is Eurhinoceros sondaicus instead of Rhinoceros sondaicus.

The only insect native to Antarctica is the Antarctic midge, which we mentioned in episode 221 but haven’t really talked about. It’s a flightless insect that can grow up to 6 mm long, and it’s the only insect that lives year-round in Antarctica. It’s only been found on the peninsula on the northwestern side of the continent.

Every animal that lives in Antarctica is considered an extremophile, and this little midge has some remarkable adaptations to its harsh environment. Its body contains compounds that minimize the amount of ice that forms in its body when the temperature plunges. It’s so well adapted to cold weather that it actually can’t survive if the temperature gets much above freezing. It eats decaying vegetation, algae, microorganisms, and other tiny food in its larval stages, but doesn’t eat at all as an adult.

The midge spends most of its life as a larva, only metamorphosing into its adult form after two winters. During its first winter it enters a dormant phase called quiescence, but as soon as the weather warms, it can resume development. It enters another dormant phase called obligate diapause for its second winter, where it pupates as soon as the weather gets cold. When summer arrives, all the midges emerge as adults at the same time, which allows them to find mates and lay eggs before dying a few days later.

The female midge lays her eggs and deposits a jelly-like protein on top of them. The jelly acts as antifreeze and keeps the eggs from drying out, and when the eggs hatch, the babies can eat the jelly.

In episode 384, we talked about the Komodo dragon, and only a month or so after that, and right after the 2024 updates episode, a new study was released about Komodo dragon teeth. It turns out that the Komodo dragon has teeth that are tipped with iron, which helps keep them incredibly sharp but also strong. As if Komodo dragons weren’t already scary enough, now we know they have metal teeth!

Many animals incorporate iron in their teeth, especially rodents, which causes some animals to have orange or partially orange teeth. In the Komodo dragon, the iron is incorporated into the tooth’s enamel coating, but only on the tips of the teeth. Since Komodo dragons have serrated teeth, that’s a lot of very sharp points.

There’s no way currently to test fossilized teeth to see if they once contained iron, especially since the iron would most likely be deposited in the tooth coating, the way it is for animals living today, not in the tooth itself. But because the Komodo dragon has teeth that are very similar in many ways to the teeth of meat-eating dinosaurs, scientists think some dinosaurs may have had iron in their teeth too.

And that brings us to the nutria, an animal suggested by Emerson. Emerson likes the nutria because of its orange teeth, and hopefully you can guess why its teeth are orange.

The nutria is also called the coypu, and it’s a rodent native to South America. In Spanish the word nutria means otter, so in South America it’s almost exclusively called the coypu, and the name coypu is becoming more popular in other languages too. It’s been introduced to other parts of the world as a fur animal, and it has become invasive in parts of Europe, Japan, New Zealand, and the United States.

The nutria is a semi-aquatic rodent that looks like a muskrat but is much bigger, up to two feet long, or 64 cm, not counting its tail. It also kind of looks like a beaver but is smaller. If you’re not sure which of these three animals you’re looking at, since they’re so similar, the easiest way to tell them apart is to look at their tails. The beaver has a famously flattened paddle-like tail, the muskrat’s tail is flattened side to side to act as a rudder, and the nutria’s tail is just plain old round. The nutria also has a white muzzle and chin, and magnificent white whiskers.

The nutria mostly eats water plants and is mostly active in the twilight. While it usually lives around slow-moving streams and shallow lakes, it will also tolerate saltwater wetlands. Wild nutrias are generally dark brown, but ones bred for their fur are often blond or even white.

The nutria digs large dens with the entrance usually underwater, but the nesting chamber inside is dry. It also digs for roots. This can cause a lot of damage to levees and riverbanks, which is why the nutria is so destructive as an invasive animal. It will also eat people’s gardens and commercial crops like rice and alfalfa.

One interesting thing about the nutria is that the female has teats that are high up on her sides, which allows her babies to nurse even when they’re all in the water.

The nutria’s big incisor teeth are bright orange, as we mentioned before. This is indeed because of the iron in the enamel that strengthens the teeth. Like other rodents, the nutria’s incisors grow throughout its life and are continually worn down as it chews tough plants. A nutria eats about 25% of its weight in plants every single day. That’s almost as much as me and pizza.

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 432: The Fossa and Other Animals of Madagascar

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This week we learn about the fossa and a few other animals of Madagascar, a suggestion by Pranav!

Further reading:

The stories people tell, and how they can contribute to our understanding of megafaunal decline and extinction in Madagascar

The fossa!

The votsotsa is a rodent, not a rabbit! [photo by Andrey Giljov – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=113271739]:

The golden mantella frog is sometimes golden, but sometimes red:

The nano-chameleon may be the smallest reptile in the world:

Show transcript:

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

This week we have a very old Pranav suggestion, animals of Madagascar!

The island country of Madagascar is off the southeastern coast of Africa. About 88 million years ago, it broke off from every other landmass in the world, specifically the supercontinent Gondwana. The continent we now call Africa separated from Gondwana even earlier, around 165 million years ago. Madagascar is the fourth largest island in the world and even though it’s relatively close to Africa these days, many of its animals and plants are much different from those in Africa and other parts of the world because they’ve been evolving separately for 88 million years.

But at various times in the past, some animals from Africa were able to reach Madagascar. We’re still not completely sure how this happened. Madagascar is 250 miles away from Africa, or 400 kilometers, and these days the prevailing ocean currents push floating debris away from the island. In the past, though, the currents might have been different and some animals could have arrived on floating debris washed out to sea during storms. During times when the ocean levels were overall lower, islands that are underwater now might have been above the surface and allowed animals to travel from island to island until they reached Madagascar.

We’re not sure when the first humans visited Madagascar, but it was at least 2,500 years ago and possibly as much as 9,500 years ago or even earlier. It’s likely that hunting parties would travel to Madagascar and stay there for a while, then return home with lots of food, but eventually people decided it would be a nice place to live. By 1,500 years ago people were definitely living on the island.

Let’s start with the fossa, an animal we’ve only talked about on the podcast once before, and then only in passing. It resembles a type of cat about the size of a cougar, although its legs are short in comparison to a similarly-sized cat. Its tail is almost as long as its body, and if you include its tail, it can grow around five feet long, or 1.5 meters. It’s reddish-brown with a paler belly. Its head is small with a short muzzle, rounded ears, and big eyes.

But the fossa isn’t a felid. It resembles a really big mustelid in many ways, especially a mongoose, and some studies suggest it’s most closely related to the mongoose. Really, though, it’s not closely related to anything living today. It spends a lot of time in trees, where it uses its long tail to help it balance. It even has semi-retractable claws. It eats lemurs and other mammals, birds, insects, crabs, lizards, and even fruit.

There used to be an even bigger fossa called the giant fossa, although we don’t know much about it. We only know about it from some subfossil remains found in caves. We’re not sure how big it was compared to the fossa living today, but it was definitely bigger and stronger and might have grown 7 feet long including its tail, or a little over 2 meters. There used to be much bigger lemurs living on Madagascar that have also gone extinct, so the giant fossa probably evolved to prey on them.

Most scientists estimate that the giant fossa went extinct at least 700 years ago, but some think it might have survived in remote areas of Madagascar until much more recently. There are even modern sightings of unusually large fossas, sometimes reported as twice the size of a regular fossa.

One interesting thing about the fossa is that its anus is hidden most of the time by a little fold of skin called an anal pouch, sort of like built-in underwear.

One animal most people outside of Madagascar have never heard of is the votsotsa, also called the Malagascar giant rat or the giant jumping rat since it’s a rodent that is especially known for its ability to jump. It actually looks a lot like a rabbit in size and shape, including its long ears, but it has a long tail. It’s gray or brown in color and grows about a foot long, or 30 cm, with a tail that can be up to 10 inches long, or 25 cm.

The votsotsa mates for life and both parents raise the single baby the mother gives birth to once or twice a year. It’s a nocturnal animal that spends the day in its burrow, which can be as much as 16 feet long, or 5 meters, with multiple exits. It eats nuts and seeds, fruit, leaves, and other plant material, along with insects and other small animals.

Lots of bats live on Madagascar, including the Madagascar flying fox. It’s a fruit-eating bat that’s brown or golden-brown in color with gray or black wings, and it’s the biggest bat native to the island. It has a wingspan of more than four feet across, or 125 cm. Like other species of flying fox, it lives in colonies of up to a thousand individuals that roost together in trees during the day. It mostly forages in the evenings, searching for fruit like figs. It eats flowers and sometimes leaves as well as fruit, and it may even be a pollinator for the kapok tree’s flowers.

Naturally, Madagascar also has a lot of reptiles, amphibians, and other non-mammalian animals. For instance, the golden mantella frog. It’s a little frog that’s only found in a few small areas, and measures around 20 millimeters long snout to vent. Some individuals are golden yellow while others are bright orange or red. As you may remember from our many previous episodes about frogs, such bright colors act as a warning to potential predators, to let them know that the frog is toxic. It absorbs toxins from some of the insects it eats. It’s active during the day in summertime, and in winter it spends most of the time hiding and doing nothing, which is the best way to spend the winter.

There are also lots of chameleons on Madagascar, including one called the nano-chameleon. It gets its name from its size, which is extremely small. It’s the smallest chameleon in the world, only 29 mm long at the very most, which is barely more than an inch long. Males are smaller than females, usually around 22 mm. It was described in 2021 and is brownish-grey with pale yellow or yellow-brown markings. Chameleons are famous for changing color, but the nano-chameleon doesn’t. It also mostly lives on the ground, where it hunts tiny insects and other invertebrates. Some scientists think it may be the smallest reptile in the world.

The female Darwin’s bark spider is about the same size as the female nano-chameleon, if you don’t count the spider’s legs. Males are much smaller. Darwin’s bark spider is a type of orb-weaver, which is the kind of spider that spins large webs that look like Halloween decorations. It was described in 2010 after first being discovered by scientists in 2009, which is surprising because it builds the largest orb webs known. Some webs can be over 30 square feet in size, or 2.8 square meters.

The silk is the strongest biological material ever studied, twice as strong as any other spider silk studied. The spider builds its web over water, because it eats a lot of mayflies and other insects that are attracted to water. It also eats a lot of dragonflies, and dragonflies are quite large and strong insects that don’t usually get caught in spiderwebs.

The people of Madagascar are considered very poor compared to other countries, after almost a century of French colonization and the resulting instability after it regained independence in 1960. A lot of animals that were once considered to be forbidden to bother, for religious and cultural reasons, now end up killed so people can eat them instead of starving. Mining and slash-and-burn agriculture has also contributed to pollution, habitat loss, and other factors that aren’t good for the animals of Madagascar or its people. Luckily, eco-tourism, where people visit the island to experience its beauty and see animals and plants found nowhere else on earth, is becoming more common. Hopefully that will help improve conditions for the people who live there and for the animals too.

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 427: The Other Cephalopods

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Further reading:

Reconstructing fossil cephalopods: Endoceras

Retro vs Modern #17: Ammonites

Hammering Away at Hamites

An endocerid [picture by Entelognathus – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=111981757]:

An ammonite fossil:

A hamite ammonoid that looks a lot like a paperclip [picture by Hectonichus – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=34882102]:

Show transcript:

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

When you think about cephalopods, if that’s a word you know, you probably think of octopuses and squid, maybe cuttlefish. But those aren’t the only cephalopods, and in particular in the past, there used to be even more cephalopods that are even weirder than the ones we have today.

Cephalopods are in the family Mollusca along with snails and clams, and many other animals. The first ancestral cephalopods date back to the Cambrian, and naturally we don’t know a whole lot about them since that was around 500 million years ago. We have fossilized shells that were only a few centimeters long at most, although none of the specimens we’ve found are complete. By about 475 million years ago, these early cephalopod ancestors had mostly died out but had given rise to some amazing animals called Endocerids.

Endocerids had shells that were mostly cone-shaped, like one of those pointy-ended ice cream cones but mostly larger and not as tasty. Most were pretty small, usually only a few feet long, or less than a meter, but some were really big. The largest Endoceras giganteum fossil we have is just under 10 feet long, or 3 meters, and it isn’t complete. Some scientists estimate that it might have been almost 19 feet long, or about 5.75 meters, when it was alive.

But that’s just the long, conical shell. What did the animal that lived in the shell look like? We don’t know, but scientists speculate that it had a squid-like body. The head and arms were outside of the shell’s opening, while the main part of the body was protected by the front part of the shell. We know it had arms because we have arm impressions in sections of fossilized sea floor that show ten arms that are all about the same length. We don’t know if the arms had suckers the way many modern cephalopods do, and some scientists suggest it had ridges on the undersides of the arms that helped it grab prey, the way modern nautiluses do. It also had a hood-shaped structure on top of its head called an operculum, which is also seen in nautiluses. This probably allowed Endoceras giganteum to pull its head and arms into its shell and use the operculum to block the shell’s entrance.

We don’t know what colors the shells were, but some specimens seem to show a mottled or spotted pattern. The interior of Endoceras giganteum’s shell was made up of chambers, some of which were filled with calcium deposits that helped balance the body weight, so the animal didn’t have trouble dragging it around.

3D models of the shells show that they could easily stick straight up in the water, but we also have trace fossils that show drag marks of the shell through sediment. Scientists think Endoceras was mainly an ambush predator, sitting quietly until a small animal got too close. Then it would grab it with its arms. It could also crawl around to find a better spot to hunt, and younger individuals that had smaller shells were probably a lot more active.

We talked about ammonites way back in episode 86. Ammonites were really common in the fossil record for hundreds of millions of years, only going extinct at the same time as the dinosaurs. Some ammonites lived at the bottom of the ocean in shallow water, but many swam or floated throughout the ocean. Many ammonite fossils look like snail shells, but the shell contains sections inside called chambers. The largest chamber, at the end of the shell, was for the ammonite’s body, except for a thin tube that extended through the smaller inner chambers, which allowed the animal to pump water or air into and out of the chambers in order to make itself more or less buoyant in the water.

While many ammonites were no larger than modern snails, many others were bigger than your hand, sometimes twice the size of your hand even if you have really big hands. But during the Jurassic and part of the Cretaceous, some ammonites got even bigger. One species grew almost two feet across, or 53 cm. Another grew some 4 ½ feet across, or 137 cm, and one species grew as much as 6 ½ feet across, or 2 meters. It was found in Germany in 1895 and dates to about 78 million years ago–and it wasn’t actually a complete fossil. Researchers estimate that in life it would have been something like 8 and a half feet across, or 2.55 meters.

Ammonites look a lot like a modern cephalopod called the nautilus, so much so that I thought for a long time that they were the same animal and they were all extinct. Imagine my surprise when I started researching episode 86! But although nautiluses look similar, it turns out they’re not all that closely related to ammonites. Ammonites were probably more closely related to squid, octopuses, and cuttlefish than to modern nautiluses.

Until very recently, we had no idea what the ammonite’s body looked like, just its shell. Scientists hypothesized that they had ten arms. Then, in 2021, three years after episode 86 because I have been making this podcast for a really long time, scientists found a partial fossil of an ammonite’s body. That was followed by two more discoveries of ammonite bodies, so we know a lot more about it now. We now know that ammonites resembled squid with shells a lot more than they resembled nautiluses. We still don’t know how many arms they had, but they do appear to have had two feeding tentacles like squid have, with hook-like structures that would help the ammonite hold onto wiggly prey.

Not all ammonoids had shells that resembled a snail’s spiral shell. Heteromorph ammonites had a wide variety of shell shapes. They were extremely common starting around 200 million years ago, so common that they’re used as index fossils to help scientists determine how old a particular segment of rock is. Some of the shells look a lot like ram horns, loosely coiled with ribs on the upper surface, while others were almost straight.

Baculites are a genus of ammonoid that had straight or only gently curved shells, sort of like Endocerids but living about 300 million years later and only very distantly related to them. The longest baculite shell found so far was about 6 and a half feet long, or 2 meters. Nipponites were a more complicated shape, as though a ram’s horn somehow got twisted up and crumpled into a lopsided ball. Turrilites grew in a tight spiral but with the coils on top of each other like a spiral staircase. But the best to my mind are the hamites, because some of them had shells shaped like paper clips.

We don’t know much about heteromorph ammonites, and scientists aren’t even sure how they moved around and found food. Their shell shapes would have made them slow swimmers. Many scientists now think they floated around in the water and caught tiny food as they encountered it. They even survived the end-cretaceous extinction event, although they only lived for about half a million years afterwards.

Let’s finish with a living animal, the Dana octopus squid. It’s a squid but as an adult it doesn’t have the two feeding tentacles that most squid have. It just has eight arms, which is why it’s called the octopus squid. The Dana octopus squid is a deep-sea animal that can grow quite large, although it doesn’t have very long arms. The largest specimen measured was 7 and a half feet long including its arms, or 2.3 meters, but most of that length was the mantle. The arms are only about two feet long, or 61 cm.

Because it lives in deep water, we don’t know very much about the Dana octopus squid. We know it’s eaten by sperm whales, sharks, and other large animals, and occasionally part of a dead one will wash ashore. In 2005 a team of Japanese researchers filmed a living Dana octopus squid in deep water and discovered something surprising. The undersides of the squid’s arms contain photophores that can emit light, which is pretty common in deep-sea animals. The squid’s photophores are the largest known, and now we know why.

The video showed the squid attacking the bait, and before it did, its photophores flashed extremely bright. It was so bright that the scientists think the light disorients the squid’s prey as well as allowing the squid to get a good look at where its prey is. Even better, young Dana octopus squid have been observed flashing their photophores at large predators and swimming toward them in a mock attack, startling and even scaring away a much larger animal.

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 426 Lots of Little Birds

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Thanks to Murilo, Alexandra, and Joel for their suggestions this week!

The bird sounds in this episode come from xeno-canto, a great resource for lots of animal sounds!

A cactus wren [picture by Mike & Chris – Cactus WrenUploaded by snowmanradio, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=15876953]:

The sultan tit [photo by By Dibyendu Ash – CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=72070998]:

A female scarlet tanager [photo by Félix Uribe, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=81340425]. The male is red with black wings:

The Northern cardinal:

The yellow grosbeak [photo by Arjan Haverkamp – originally posted to Flickr as 2008-08-23-15h00m37.IMG_4747l, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=9596644]:

The purple martin isn’t actually purple [photo by JJ Cadiz, Cajay – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=4255626]:

The dusky thrush [photo by Jerry Gunner from Lincoln, UK Uploaded by snowmanradio, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=20762838]:

The European rose chafer, not a bird [photo by I, Chrumps, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2521547]:

Show transcript:

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

This week we’re going to learn about a lot of little birds that deserve more attention, because they’re cute and interesting. Thanks to Murilo, Alexandra, and Joel for their little bird suggestions!

All the birds we’ll talk about today are called passerines, because they belong to the order Passeriformes. They’re also sometimes referred to as perching birds or songbirds, even though not all passerines sing. Passerines are common throughout the world, with more than 6,500 species identified. I’ve seen about 150 of those species, so clearly I need to work harder as a birdwatcher.

Passerines are referred to as perching birds because of their feet. A passerine bird has three toes that point forward and another toe pointing backwards, which allows it to wrap its toes securely around a twig or branch to sit. Its legs are also adapted so that the toes automatically curl up tight when the leg is bent. That’s why a sleeping bird doesn’t fall off its branch.

Let’s start with one of Murilo’s suggestions, the wren. Wrens are birds in the family Troglodytidae, and are usually very small with a short tail, a pointy bill that turns slightly downward at the tip, and brown plumage. It mainly eats insects and larvae that it finds in nooks and crannies of trees, and many species will investigate dark places like hollow logs, the openings to caves, or your apartment if you leave the back door open on a warm day. Many sing beautiful songs and have very loud voices for such little bitty birds.

Most wrens are native to the Americas, including the canyon wren that’s native to western North America in desert areas. It’s cinnamon-brown with a white throat and an especially long bill, which it uses to find insects in rock crevices. It lives in canyons and has a more flattened skull than other wrens, which means it can get its head into crevices without hurting itself. No one has ever seen a canyon wren drink water, and scientists think it probably gets all the water it needs from the insects it eats. Where do the insects get the water they need? That’s an episode for another day.

This is what a canyon wren sounds like:

[bird sound]

Not every bird that’s called a wren is actually in the family Troglodytidae. Some just resemble wrens, like an unusual bird that Murilo brought to my attention. It’s called Lyall’s wren but it’s actually in the family Acanthisittidae, and it was once widespread throughout New Zealand. By the time it was scientifically identified and described in 1894, it was restricted to a single island in Cook Strait.

Lyall’s wren was flightless, and only five passerines are flightless as far as we know. All five were island birds who have since gone extinct, which is unfortunately the case with Lyall’s wren too. It was greenish-brown with a yellow eye stripe and its tail was just a little short nub. We don’t know much about it because between 1894 when a lighthouse was built and some families moved to the island to work at the lighthouse, bringing their housecats, and 1925 when the feral cat colony on the island was finally killed off, all the remaining Lyall’s wrens were eaten by cats or killed by people to sell as museum specimens. To be clear, it’s entirely the fault of people that the bird went extinct, because they brought the cats to the island and let them run loose. The bird probably actually went extinct in 1895, just one year after cats were introduced to the island.

Murilo also suggested some little birds called chickadees and tits, which belong to the family Paridae. They’re very small, often brightly colored or with bright white markings, with short bills that help them crack seeds open. They also eat insects. They’re not found in South America or Australia, but they’re very common in North America, Eurasia, and most of sub-Saharan Africa. Many species love to visit bird feeders, and since they’re cute and active little birds, people are happy to have them around.

Some species in this family have crests, which makes them even cuter. The tufted titmouse, which is found in eastern North America, has a little tufted crest on its head, for instance. It’s a soft gray-blue in color with patches of rusty-red under its wings, and white underneath. The gray crested tit lives in western Europe and also has a fluffy crest on its head. It’s gray-brown with a thin black and white ring around its neck and a buff-colored underside. The yellow tit lives only in forests in central Taiwan and is a gorgeous dark blue with bright yellow underneath and on its face, with a darker crest. It’s so beautiful that it’s becoming rare, since people trap the birds to sell to disreputable collectors. The sultan tit is even more spectacular, if that’s possible, since the male is black with bright yellow underparts and a bright yellow crest. It lives in parts of south Asia and some subspecies have a black crest instead.

This is what a sultan tit sounds like:

[bird sound]

Another spectacular bird is one Alexandra suggested, the summer tanager. It’s a common summer visitor in the eastern and southwestern United States that winters in Central and northern South America. The male is a bright, cheerful red all over while the female is yellow. The western tanager is a close relation that lives in western North America, wintering in Mexico. The male has a mostly black back with a yellow rump and yellow underneath, with red and orange on his face. Females are yellowy-green and gray. The scarlet tanager is also similar, although the male is red with black wings and the female is yellowy-green and gray. They eat insects and fruit, and spend a lot of time in the very tops of trees.

This is what a scarlet tanager sounds like:

[bird sound]

Despite their names, all three of these tanagers aren’t actually tanagers. Tanagers are members of the family Thraupidae and are native to central and South America. Many of them are brightly colored and absolutely gorgeous, like the red-legged honeycreeper that’s common in Central and parts of South America. The male has a black back and tail and is bright blue on the rest of his body, except for a black mask over his eyes. His long curved bill is also black, but his legs are bright red. The female has red legs but she’s mostly greeny-yellow.

The North American tanagers are actually more closely related to the cardinal than to other tanagers, and are placed in the family Cardinalidae. The family is named after the northern cardinal, which is common throughout most of the United States and parts of Mexico. The male is bright red with black around his bill, while the female is more of a rosy brown color. Both have red bills and tufted crests. In North America, the cardinal appears on a lot of Christmas cards because its bright red plumage against a snowy background is so cheerful in winter.

This is what a northern cardinal sounds like:

[bird sound]

Alexandra also suggested the blue grosbeak, while Joel suggested the yellow grosbeak. Both are also members of the family Cardinalidae. The blue grosbeak lives in much of the United States in summer and spends the winter in Mexico and Central America. The male is blue with black and rufous markings and a silvery-gray beak, while the female is rufous-brown and gray. The yellow grosbeak lives along the Pacific slope of Mexico and may be the same as the golden grosbeak that lives in western South America, or a very close relation. Scientists aren’t sure yet. The male is a bright golden yellow with black and white wings and a black bill, while females are a less conspicuous green-yellow. The yellow grosbeak is larger than the blue but they’re both pretty big and robust. They eat insects and lots of other small animals like snails and spiders, along with fruit and seeds. Sometimes a yellow grosbeak will show up farther north, in the United States, and birdwatchers lose their minds with excitement.

This is what a yellow grosbeak sounds like:

[bird sound]

Joel also suggested the purple martin, a type of swallow that’s common throughout the Americas. It’s not purple but it is a dark blue-black color with iridescence that reflects light. This makes the bird look anywhere from dark purple to blue depending on the angle of the light. The male is much darker than the female, who is more gray-blue in color. It spends the summer in North America, raising babies and eating lots of insects, then migrates to South America to spend the winter.

This is what a purple martin sounds like:

[bird sound]

Another Joel suggestion is the dusky thrush, which is another passerine that migrates a long distance. It spends the summer in Siberia and nearby areas to nest, then flies south to spend the winter in southern China, Japan, India, Vietnam, Korea, and other nearby areas. It’s mostly brown on its back and white underneath with lots of speckles, and a light stripe over its eye. Males and females look very similar. It eats insects, spiders, worms, seeds, and berries and spends a lot of its time on the ground. Every so often a dusky thrush will get lost during migration and end up in western Europe or Alaska, and again, birdwatchers in those areas go nuts trying to catch a glimpse of it.

This is what a dusky thrush sounds like:

[bird sound]

Let’s finish this episode with another of Joel’s suggestions, the European rose chafer. You may be wondering what kind of bird this is, and that is exactly what I was wondering. It sounds very pretty! Then I looked it up, and it’s not a bird at all, it’s a type of beetle!

The rose chafer is a big metallic-green beetle related to scarabs that grows up to 20 mm long. It’s common in Europe and some parts of southeast Asia, and is often found on rose bushes in summer. It eats flowers, including the petals, nectar, and pollen, and really likes roses.

The female rose chafer lays her eggs in the ground and the larvae eat decaying vegetation. There’s also a related beetle called the rose chafer that lives in parts of North America, but it’s sort of a muddy tan color, and while it likes to eat roses and other flowers, it also likes to eat fruit like peaches and grapes. Its larvae eat roots and can damage plants.

Since the European rose chafer is such attractive beetle, with an iridescent bronze shimmer to its emerald-green carapace, you’d think people who grow roses would like to have them on their rose bushes, but this isn’t actually the case. I guess people who grow roses want to see the roses without them being all chewed up by beetles. To bring it back to birds, birds don’t eat the rose chafer because the beetle contains toxins that make it taste awful. But they’re still really pretty.

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 422: Two Tiny, Tiny Animals

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Thanks to Tim and Mia who suggested one of this week’s animals!

Further reading:

Genomic insights into the evolutionary origin of Myxozoa within Cnidaria

A tardigrade, photo taken with an electron microscope because these little guys are incredibly tiny:

Show transcript:

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

This week we’re going to talk about two microscopic or almost microscopic animals, one suggested by Mia and Tim, the other one I just learned about myself.

We’ll start with Mia and Tim’s suggestion, the water bear, also known as the tardigrade. We’ve talked about it before but there’s always more to learn about an animal.

The water bear isn’t a bear at all but a tiny eight-legged animal that barely ever grows larger than 1.5 millimeters. Some species are microscopic. There are about 1,300 known species of water bear and they all look pretty similar. It looks for all the world like a plump eight-legged stuffed animal made out of couch upholstery. It uses six of its fat little legs for walking and the hind two to cling to the moss and other plant material where it lives. Each leg has four to eight long hooked claws. It has a tubular mouth that looks a little like a pig’s snout.

An extremophile is an organism adapted to live in a particular environment that’s considered extreme, like undersea volcanic vents or inside rocks deep below the ocean floor. Tardigrades aren’t technically extremophiles, but they are incredibly tough. Researchers have found tardigrades in environments such as the gloppy ooze at the bottom of the ocean and the icy peaks of the Himalayas. It can survive massive amounts of radiation, dehydration for up to five years, pressures even more intense than at the bottom of the Mariana Trench, temperatures as low as -450 Fahrenheit, or -270 Celsius, heat up to 300 degrees Fahrenheit, or 150 Celsius, and even outer space. It’s survived on Earth for at least half a billion years. Mostly, though, it just lives in moss.

Not every tardigrade is able to do everything we just talked about. They’re tough, but they’re not invulnerable, and different species of tardigrade are good at withstanding different extreme environments. Many species can withstand incredible heat, but only for half an hour or less. Long-term temperature increases, even if only a little warmer than what it’s used to, can cause the tardigrade to die.

Most species of tardigrade eat plant material or bacteria, but a few eat smaller species of tardigrade. It has no lungs since it just absorbs air directly into its body by gas exchange. It has a teeny brain, teeny eyes, and teeny sensory bristles on its body. Its legs have no joints. Its tubular mouth contains tube-like structures called stylets that are secreted from glands on either side of the mouth. Every time the tardigrade molts its cuticle, or body covering, it loses the stylets too and has to regrow them. In some species, the only time the tardigrade poops is when it molts. The poop is left behind in the molted cuticle.

The tardigrade’s success is largely due to its ability to suspend its metabolism, during which time the water in its body is replaced with a type of protein that protects its cells from damage. It retracts its legs and rearranges its internal organs so it can curl up into a teeny barrel shape, at which point it’s called a tun. It needs a moist environment, and if its environment dries out too much, the water bear will automatically go into this suspended state, called cryptobiosis.

Tests in 2007 and 2011 that exposed tardigrades to outer space led to some speculation that tardigrades might actually be from outer space, and that they, or organisms that gave rise to them, might have hitched a ride on a comet or some other heavenly body and ended up on earth. But this isn’t actually the case, since genetic studies show that tardigrades fit neatly into what we know of animal development and evolution. In other words, tardigrades are weird, but they’re Earth weird.

Our other tiny animal today is one that lacks pretty much everything animals usually have. Myxozoa are parasites that can’t live outside of the host’s body, a condition called obligate parasitism. They’re found in both freshwater and ocean water animals but evolved from an animal similar to a jellyfish that would have just swum around happily in the ocean. Now they’re microscopic parasites with the smallest genomes of any animals studied. Most only measure 300 micrometers at most, or 1/3 of a millimeter, although the largest known grows a humongous 2 mm long.

Different myxozoa have different life cycles, some of them complex. Because they’re so small, we naturally don’t know that much about them, and there are undoubtedly a whole lot of species that haven’t been discovered by science. They’re so numerous, and so different from other animals, that they’ve been placed into their own subphylum, classified in the Phylum Cnidaria. Cnidarians include jellyfish, corals, sea anemones, and many other aquatic invertebrates that show radial symmetry–but not comb jellies which have their own phylum.

In general, this is how a myxozoan spreads to a new host. A myxozoan secretes tiny capsules called myxospores that contain polar filaments. The myxopores are eaten by worms, at which point the capsule opens and the polar filaments uncoil and attach to the worm’s gut, where it develops into a sporoplasm and eventually detaches from the worm. The sporoplasm floats around in the water until it touches a fish, especially a fish’s gills, at which point it digs into the fish’s body and continues to develop.

When scientists identified the first myxozoans, they were classified as protozoans, single-celled animals. Many protozoans are parasitic. But as genetic testing became more refined and easier to do, and some myxozoans had their DNA sequenced, it became obvious that they were something else. Scientists just weren’t sure what. Finally scientists realized that they were similar genetically to jellyfish and their close relations, although they estimate it’s been about 600 million years since they shared a common ancestor.

Many myxozoans no longer have genes that allow communication between cells, multicellular development, body coordination, or even respiration in some species. Most are only a few cells in size and the most complex cell is the one that contains what’s called a polar capsule. This probably developed from its ancestor’s nematocysts, which are the cells that sting you if you touch a jellyfish, which is why you should never touch a jellyfish no matter how pretty it is.

Most myxozoa infect fish, but they’ve also been discovered in other animals. This includes a few frogs, turtles, aquatic birds, and octopuses. But they’ve also been discovered in two mammals, both of them shrews. Even though we already know about more than 2,000 species of myxozoa, scientists think there are probably hundreds, if not thousands more, but no one’s noticed them yet because they’re so small.

If you remember the Dr. Seuss book Horton Hears a Who, consider that the Whos might have actually been tardigrades. But probably not myxozoa, which wouldn’t have been able to build a Who city.

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 420: The Sea Bunny

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Thanks to Sam for suggesting this week’s topic, the sea bunny!

My plush sea bunny, with one of my cats, Dracula, who does not like it:

Show transcript:

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

This week we’re going to revisit an animal we haven’t talked about in a few years! Thanks to Sam for suggesting it, and for sending a whole list of questions after listening to episode 215. Episode 215 was about the cutest invertebrates, and we talked about a lot of them. This week it’s all about the sea bunny.

Before we answer Sam’s questions, let’s go over what we learned in episode 215, in case you haven’t listened to it since it came out in March of 2021. The sea bunny, or sea rabbit, is a type of nudribranch [noodi-bronk] that lives along the coastline of the Indo-Pacific Ocean, especially in tropical waters. Nudibranchs are a type of mollusk that are sometimes called sea slugs. Many are brightly colored with beautiful patterns.

Compared to some sea slugs, the sea bunny is a little on the plain side. It’s usually orange or yellow, sometimes white or even green, with tiny brown or black speckles. It looks fuzzy because it’s covered in little protuberances that it uses to sense the world around it, as well as longer, thinner fibers called spicules. It also has two larger black-tipped protuberances that look for all the world like little bunny ears, although they’re actually chemoreceptors called rhinophores. It has a flower-shaped structure on its rear end that looks kind of like a bunny tail, but it’s actually gills. It really is amazing how much the sea bunny actually resembles a little white bunny with dark speckles.

Like other nudibranchs, the sea bunny is a hermaphrodite, which means it produces both eggs and sperm, although it can’t fertilize its own eggs. When it finds a potential mate, they both perform a little courtship dance to decide if they like each other. After mating, both lay strings of eggs in a spiral pattern. The eggs hatch into larvae that are free-swimming, although the adults crawl along the ocean floor looking for food. Some nudibranch larvae have small coiled shells like snails, which they shed when they metamorphose into an adult, but the sea bunny hatches into a teeny-tiny miniature sea bunny.

One of Sam’s questions was what the sea bunny eats. It mainly eats sea sponges. The toxins present in many sponges don’t bother the sea bunny. Instead, the sea bunny absorbs the sponge’s toxins and keeps them in its body. I don’t usually bother with Reddit posts while researching episodes, but I saw one where people were discussing how toxic the sea bunny is. Someone pointed out that small as they are, it’s not a good idea to pick up a sea bunny because they are so toxic, and someone replied, “That’s good for them, because I’m going to assume they taste like Marshmallows.”

That brings us to Sam’s next question, does anything eat the sea bunny? That’s mainly a no, because they are so incredibly toxic. An animal the size of a big shark or something like that probably wouldn’t be affected by the sea bunny’s toxins, but it also wouldn’t bother with such a tiny snack. A fish or other animal small enough for the sea bunny to seem like a meal probably wouldn’t survive its toxins.

Sam also wants to know if the sea bunny travels in groups, and that doesn’t seem to be the case. It’s a mostly solitary animal most of the time. If it did gather in a group, say if a bunch of sea bunnies were munching on the same sponge at the same time, maybe we could call it a fluffle of sea bunnies, or a school of sea bunnies.

Sam also wants a better idea of how small the sea bunny is. It’s easy enough to say, oh, it’s a little less than an inch, or around 2 ½ cm, but most of us have a hard time picturing that. So here’s a comparison that will help you visualize it. If you have an ordinary paperclip, not one of the jumbo ones, it’s usually around 2.5 cm long, maybe just a bit bigger. So a big sea bunny is just barely the length of an ordinary paperclip.

Sam’s last question is one of the most important ones, and I bet at least some of our listeners are wondering the same thing. Can you keep a sea bunny as a pet?

The answer is no, sorry! Aside from the sea bunny being really toxic and not safe for your other aquarium pets or you, it would need care that’s hard for a home aquarium keeper to provide. Some experienced saltwater aquarium keepers do have some types of sea slugs, but not typically sea bunnies, not even big professional aquariums.

Fortunately for all of us, sea bunnies are popular enough these days that you can get a sea bunny plushie. I know because I have one—and I found it just two days ago as this episode goes live! I was looking through the half-priced Valentine’s Day stuff on February 15 when I found a stuffy that looked just like a sea bunny. I picked it up and sure enough, it was a sea bunny, and it was on sale! There’s a picture of it in the show notes. It’s a lot bigger than a real life sea bunny, but it’s also not toxic.

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!