Episode 337: Ghost Shrimp and Snapping Shrimp

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Thanks to Zachary and Anbo for their suggestions this week! Let’s learn about some shrimp!

Further reading:

This is why the pistol shrimp is immune to its own powerful shock waves

The Symbiotic Relationship Between Gobies and Pistol Shrimp

An eastern ghost shrimp:

A snapping shrimp:

A goby fish and its snapping shrimp buddy:

Show transcript:

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

This week we’re going to have an episode about a few different types of shrimp, with suggestions from Zachary and Ambo.

Let’s start with the ghost shrimp, since Zachary recently got an aquarium and has some ghost shrimp in it.

The name ghost shrimp refers to various species of freshwater shrimp in the genus Palaemon. One of the most popular species to keep as a pet is Palaemonetes paludosus. It’s sometimes called the glass shrimp since it’s mostly transparent, or the eastern ghost shrimp.

The eastern ghost shrimp can grow up to about an inch long, or 2.5 cm. It’s native to the southeastern United States, mostly east of the Appalachian Mountains, where it lives in lakes and eats plankton.

Even though the eastern ghost shrimp is mostly transparent, it can actually change its color to blend in with its background. Only one other species of ghost shrimp is known to do this, a very similar species that is only found in the Mississippi River.

There are dozens of species of ghost shrimp, though, and they live throughout the world. Some species are freshwater, others are marine. Most are at least partially transparent and rarely grow more than two inches long, or maybe 5 cm at most. In some cases people catch them to eat, although more often they’re caught to use as bait or fish food, and of course they’re eaten by a whole lot of wild animals.

We actually don’t know a whole lot about many species of ghost shrimp. Some have only recently been discovered, and some are endangered. For instance, the Florida cave shrimp is only found in a single sinkhole near Gainesville, Florida. It’s the only known species of ghost shrimp that lives in a cave, and it’s closely related to the eastern ghost shrimp.

The Florida cave shrimp grows a little over one inch long, or about 3 cm. It has eyes but doesn’t need them, so they don’t work anymore. It’s mostly transparent with some white spots. It was discovered in 1953 during a scientific exploration of a sinkhole in the Squirrel Chimney Cave and hasn’t been seen since 1973. It may even be extinct by now, but further explorations of the sinkhole have revealed that it connects with a much larger underwater cave system. Hopefully the little shrimp lives within this cave system, but it hasn’t been found anywhere else so far and we know almost nothing about it.

That’s pretty much all there is to know about the ghost shrimp, so congratulations to Zachary for keeping a mysterious little friend in your aquarium.

Next, Anbo wanted to learn about snapping shrimp. (Anbo also wanted to learn about the mantis shrimp, but it turns out that the mantis shrimp isn’t actually a shrimp, or a mantis, and it deserves its own episode one day.) We talked about the snapping shrimp before in episode 273, but there’s definitely more to learn about it. There are a whole lot of species–like, more than a thousand. They’re especially common in coral reefs and live in colonies that communicate with each other by snapping their claws. The sound is so loud that it can sound like a gunshot, which is why it’s sometimes called the pistol shrimp.

The snapping shrimp is about the same size as the ghost shrimp, about 2 inches long at most, or 5 cm. One of its claws is ordinary, but the other claw is much bigger, and it’s the large claw that makes the snapping sound. As we discussed in episode 273, the snapping shrimp will hide in a burrow or rock crevice with its antennae sticking out, and when a small animal like a fish happens by, the shrimp will emerge from its hiding place just far enough to get a good shot at the animal. It opens its big claw and snaps it shut so fast and so forcefully that it shoots tiny bubbles out at speeds of over 60mph, or 100 km/hour. The bubbles only travel a few millimeters in distance, but the shock wave is powerful enough at this short range to stun or outright kill a small animal.

Scientists figured out how the snapping shrimp’s snap worked in 2020, but it wasn’t until 2022 that they discovered why the shrimp doesn’t damage its tiny shrimp brain when it snaps. It turns out that its brain is protected by a translucent helmet called an orbital hood. It needs to be translucent because it covers the shrimp’s eyes as well as the rest of its head. The hood is an extension of the shrimp’s exoskeleton, and it has an opening at the back. Scientists think that when the shock wave of a snap meets the hood, the change in water pressure under the hood is expelled out the opening instead of affecting the brain.

Scientists want to learn how exactly the orbital hood works to redirect pressure waves, in hopes of being able to replicate it. That way we can make really effective armor for people who work with explosives, or for military personnel.

In episode 332 we talked about mutualism, and the snapping shrimp actually has a mutualistic relationship with the goby fish. Gobies are little fish that are usually even smaller than snapping shrimp, or not much bigger. The order Gobiiformes is one of the largest fish families, and we’ve talked about at least one type of goby before. That was back in episode 189 when we learned about the lumpsucker. Not all gobies are buddies with snapping shrimp, but about 130 species are, most of which live in the Pacific Ocean.

Snapping shrimp live in burrows, and the 20 species or so of snapping shrimp that partner with gobies will dig an extra-large burrow. That’s because it’s making room for its goby friend, or even more than one goby friend. The burrow can extend as much as two feet deep, or about 61 cm, with different chambers. While the shrimp is digging the burrow, the goby watches for danger. If a predator approaches, the fish warns the shrimp by moving its fins in a specific way, which signals that the shrimp should hide. If part of the burrow collapses and buries the fish, it just waits until the shrimp digs it out of the sand.

The shrimp and the goby live together in the burrow. They leave the burrow together so they can watch out for each other. The snapping shrimp doesn’t see very well so while it’s outside of the burrow, it will keep track of the goby with its long antennae. The goby watches out for danger and warns the shrimp if it needs to hide.

Both eat small animals, but the shrimp also likes eating some types of algae that grow on rocks. The shrimp will even bring pieces of algae to its burrow to snack on later, and at least one researcher has witnessed the goby help transport algae to the burrow.

During mating season, the goby brings its mate into the burrow, where the female lays eggs in the male’s chamber. Only the male takes care of the eggs, and he spends almost all of his time guarding them and swimming around them to keep them oxygenated. When he has to leave, he blocks the entrance with sand. The eggs hatch after a little over a week and the larvae swim out of the burrow immediately. The female shrimp carries her eggs around until they hatch, which they do in the burrow, and they too leave the burrow right away and float off on their own.

Both the goby eggs and the shrimp eggs hatch at night or sometimes early in the morning, which is important because those are times when both the goby and the shrimp are not active. In other words, that’s a time when the larva can safely leave the burrow without being eaten by its parent’s roommate. Having a buddy is great, but when it comes to your kids, it’s always safety first, even among fish and snapping shrimp.

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 336: The Turtle Ant and the Alien Butt Spider

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Thanks to Kari for suggesting this week’s topics! Definitely check out her book Butt or Face?, which is funny and has lots of animal information!

Further reading:

Butt or Face? by Kari Lavelle

GBIF: Araneus praesignis [the spider pictures below come from this site]

The turtle ant’s body is flattened and the soldier caste ants have specialized head shapes to block the nest entrances:

The alien butt spider has a butt that looks like an alien’s face!

The alien butt spider hides during the day in its leaf fort:

Show transcript:

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

This week we’re going to learn about two really weird invertebrates suggested by Kari. One of these two animals is her favorite and the other is a weird ant from a book she wrote. Kari’s full name is Kari Lavelle and her book is for kids, called Butt or Face? It actually releases tomorrow as this episode goes live, so if you’re listening to this episode on Monday, July 10, 2023, you still have time to preorder the book, or you can just wait a day and run out to your local bookstore or library to get a copy.

Kari was nice enough to send me a copy of the book and it’s really funny and interesting. It’s partly a game where you look at a picture and decide whether it shows an animal’s butt or its face. It’s a lot harder than you’d think! You make your guess and turn the page to find out if you’re right and learn about the animal. It’s very fun and I actually guessed wrong on one animal, but I’m not telling you which one. There’s a link in the show notes if you want to learn more about the book and maybe order a copy for yourself.

Anyway, let’s talk about the ant first, because it’s actually one I’ve had on the list to talk about for a while. I was really excited to see it in Kari’s book. It’s called the turtle ant, sometimes called the “door head” ant. That gives you a clue as to whether its picture in the book features its butt or its face.

The turtle ant is any of the well over 100 species of ant in the genus Cephalotes, which are native to the Americas. Most live in Central and South America, especially in tropical and subtropical areas. Almost all species live in trees, nesting in cavities originally made by beetle larvae.

For the most part, turtle ants are pretty typical compared to other ant species. They have a generalized diet, eating pretty much anything they find. This includes plant material, dead insects and other animals they find, bird poop, nectar, and even pollen in some species. Each colony has a single queen that mates with multiple males and lays all the eggs for the colony. Worker ants tend the eggs and larvae, gather food, and keep the colony clean. But as in some other ants, many species of turtle ant have a soldier caste. These are worker ants who are specialized to defend the nest. We talked about army ants recently, in episode 328, and also back in episode 185, and army ant soldiers have massive sharp mandibles that can inflict painful bites. But the turtle ant soldiers don’t have sharp mandibles and aren’t aggressive. They have one job, and that job is to stand at the nest’s entrances and stop them up with their heads, only moving when another ant needs to get through.

As a result, turtle ant soldiers have weird-shaped heads. The head shape varies from species to species, with some looking more normal and some being heavily armored and strangely shaped. Well, they’re not strangely shaped except in comparison to an ordinary ant head. They’re shaped exactly right to do the job they’ve evolved to do, be a door. In some species, the top of the soldier’s head is completely round and flattened, just the right size and shape to block the entrance.

Turtle ants have another ability that they share with some other ants. If an ant falls from the twig or branch it’s climbing on, instead of just falling to the ground, it can glide back to the tree trunk. Turtle ants have flattened bodies, which helps catch the air like a tiny ant-shaped parachute. Unlike other ants that do this, which glide head-first, the turtle ant glides abdomen-first. It uses its legs and head to adjust which way it’s gliding, and most of the time it lands safely on the tree trunk.

There are undoubtedly more turtle ant species than we know about so far, and we actually don’t know very much about most of the species we have discovered. Most turtle ants live in trees, and that makes them hard to study.

There’s actually a spider called the ant-mimicking crab spider that eats turtle ants. It looks so much like a turtle ant worker that it can get close to the actual ants before it’s recognized as a predator, at which point it has a good chance of grabbing an ant to eat before the ant can run away. But that’s not actually the type of spider we’re talking about next.

The other animal we’re talking about today isn’t one from the book, it just happens to be one of Kari’s favorite animals *cough*sequel*cough*. It’s called the alien butt spider and it is completely awesome, as you can tell from the name.

The alien butt spider lives in Queensland, Australia, and it gets its name because—maybe you should just guess. I’ll wait.

Yes, you’re right! The abdomen of the spider has black or dark blue-green markings that look for all the world like the face of a tiny space alien from a movie. The spider itself is mostly green and very small, with a big female only growing about 8 mm long, although its legspan can be 20 mm across. Males are smaller, mostly because the male has a much smaller abdomen.

Its scientific name is Bijoaraneus praesignis, changed in December 2021 from Araneus praesignis. It’s also called the outstanding orbweaver or green orbweaver. Like many spiders, especially orbweavers, it’s mostly active at night. It spins a big round web that looks like the kind you see on Halloween decorations, because that’s the kind of web most orbweavers make, and at night it waits on or near the web for an insect to get stuck in it. During the day, though, the alien butt spider needs to hide. It makes what’s called a retreat in a leaf that’s partially closed or curled. The spider spins a thick layer of silk across the edges of the leaf that turns it into basically a little leaf fort, then crawls inside. The underside of the spider is plain greenish-yellow with no markings, so it’s hard to see against the leaf, especially through the layer of silk.

The spider’s abdomen is green with a yellow or white pattern on top, with black eye spots visible from the rear. The eye spots show up really well against the yellow or white pattern. But the spider also has black markings at the front of its abdomen, which also look like eyespots from some angles. The rest of its body is green, greeny-yellow, and brown, which helps it blend into leafy backgrounds.

Naturally, the alien butt spider is not actually trying to look like an alien. That’s something humans have decided it looks like because it’s green and the eyespots are so large. The spider just wants potential predators to see the eyespots and think, “Darn, that animal already saw me so I can’t sneak up on it. I won’t waste my energy trying to grab it.” Or maybe, “Uh oh, look at the size of that animal’s eyes! I must be looking at the head of a very large animal that might eat me, plus it’s looking right at me. I’d better run.”

Even though it looks kind of spooky, the alien butt spider is completely harmless to humans. We also don’t know much about it, so while it seems to be a common spider within its range, we don’t know for sure if it’s potentially endangered. It’s best to leave this little alien alone no matter how cute it is (and it is very 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. 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 335: Large Blue Butterfly vs Ants

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We’re kicking off July with a beautiful butterfly that does horrible things to ants!

Further reading:

UK Butterflies – Large Blue

The large blue butterfly (picture taken from page linked above):

Show transcript:

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

I recently realized that I have so many weird and interesting invertebrates saved up to feature for invertebrate August that I can’t fit them all into one month, so let’s kick off invertebrate August in July!

This week we’re going to learn about a beautiful butterfly called the large blue, because it is both large and blue. Well, sort of large. The butterfly has a wingspan of up to two inches, or about 5 cm. Its wings are a dusty blue with black spots, although there are a lot of regional differences. Some populations are almost black, some are more tan than blue, and some don’t have spots.

The large blue lives throughout much of Eurasia, although its numbers have decreased in many places in the last 50 years or so. In some places it’s even gone extinct, mainly due to habitat loss. It needs specific host plants for the caterpillars to eat, and it also needs a particular type of ant in order for the caterpillars to survive–because the large blue caterpillar is a brood parasite!

We’ve talked about brood parasites before in birds, where a bird will lay an egg in the nest of a different species of bird. In the case of the large blue butterfly, in summertime the female lays her eggs on wild thyme or marjoram plants near a colony of red ants in the genus Myrmica [meer-mee-kuh]. She usually only lays one egg on any given plant.

When the eggs hatch, the newly emerged caterpillars feed on plants at first, just like any other caterpillar, especially the flowers of the plant. If more than one large blue caterpillar is on a plant and they encounter each other, one of them will grab the other and eat it. Drama among the thyme plants! The caterpillar goes through three growth stages, called instars, as an ordinary caterpillar (except for the cannibalism thing), but once it reaches the fourth instar it starts acting very different.

The caterpillar drops to the ground and releases a chemical that mimics the smell of the Myrmica ant larvae. When an ant finds a caterpillar, the caterpillar will rear up so that it resembles an ant larva. The ant usually takes it back to its nest at this point, but sometimes the caterpillar will just follow an ant trail and enter the nest on its own. Either way, the ants will assume it’s a lost baby and take it to the nesting chamber, where they feed and take care of it.

The caterpillar is bigger than a usual ant larva, but it uses this to its advantage. It mimics the sounds made by a queen ant, which means the ants take extra good care of it. If the ants run out of regular food to feed the caterpillar, they will even start feeding it real ant larvae. But sometimes the caterpillar gets impatient, or maybe just hungry, and will just start eating the other pupating ant larvae.

The system isn’t perfect, because a lot of times the ants figure out that the caterpillar is an intruder and will kill and eat it. If the queen ant encounters the caterpillar, she recognizes that it isn’t an ant larva and will attack it. Sometimes the ants just up and abandon the nest, leaving the caterpillar behind. In that case, the caterpillar will either leave the nest itself and find another one, or it will wait for a new ant colony to find the nest and move in. This can actually happen repeatedly during the nine months or so that the caterpillar requires to finish growing, although during the winter the caterpillar is more or less dormant.

Around the end of spring, the caterpillar spins a cocoon and pupates right there in the ant nest. The ants continue to take care of it, making sure the pupa is clean. When it emerges as a new butterfly after a few weeks, it has to find its way out of the ant nest and to the surface, where it climbs a plant stem and rests while its wings inflate and dry. The adult butterflies only live for a few weeks, eating flower nectar, especially of the thyme plant.

One of the places where the large blue butterfly went extinct was in the British Isles, where it was last seen in 1979. Before that, though, scientists already recognized that the species was in danger in Britain. They knew that the butterflies needed wild thyme and Myrmica ants, and made sure to plant lots of the thyme in areas with lots of Myrmica ant colonies. But the butterflies still declined until none were left in Britain. It turns out that the large blue butterfly requires a particular species of Myrmica ant, Myrmica sabuleti, and if the caterpillars are adopted by other ant species, they aren’t usually successful in surviving to grow up.

Fortunately, a few years later, scientists re-introduced large blue butterflies to Britain from Sweden, and this time it worked. Not only are there still large blue butterflies in Britain again, they’re now more common in Britain than anywhere else throughout its range.

Other butterflies closely related to the large blue also act as brood parasites to Myrmica ants, but to different species. There are probably more butterflies that do this than we know, since it takes a lot of very careful observation of the butterflies, caterpillars, and ants to determine what exactly is going on. Considering that even the ants don’t really know what’s going on, it’s no surprise that scientists have trouble figuring it out 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. 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 334: Piranha!

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Thanks to David for this week’s suggestion, the piranha!

Further reading:

Florida wildlife officer’s fish seizure nibbles at illegal piranha sales

How Teddy Roosevelt Turned Piranhas into Ferocious Maneaters

The beautiful butterfly peacock bass (not a piranha):

The red-bellied piranha (By H. Zell – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=82557603):

Chompy chompy teeth:

Show transcript:

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

This week we’re covering a type of fish that I absolutely cannot believe we haven’t talked about before. It’s the piranha! Thanks to David for telling me on Mastodon about a piranha incident that led to me realizing we don’t have an episode about it yet.

David’s incident is something that happened in Florida in 2009. In October of that year, a 14-year-old boy named Jake was fishing in a retention pond in West Palm Beach, Florida, which he did a lot. He’d caught all kinds of unusual fish in the pond, including a butterfly peacock bass, which is yellow, green, or even orange in color with three black stripes on its back. It can grow well over two feet long, or 74 cm. The peacock bass is native to tropical areas of South America but was deliberately introduced to Florida in 1984 to prey on other invasive species. This actually worked, and because the fish can’t survive if the water gets too cold, it can’t spread very far.

But on this particular October day in 2009, Jake caught a fish that no one wanted to find in Florida, a red-bellied piranha! The teenager took the fish to his dad, who called the Florida Fish and Wildlife Conservation Commission. A wildlife biologist investigated and caught another piranha in the same pond the following week.

That was enough of a problem that wildlife officials decided to poison the entire 4-acre pond rather than risk having piranhas become naturalized in Florida. The poison killed every single fish in the pond, including at least one other piranha, although it was a poison that quickly broke down into nontoxic compounds. The pond was later restocked with bluegills and other native fish.

The reason that Florida wildlife officials would rather kill all the fish in a big pond rather than let any piranhas live is that Florida is very similar to the piranha’s native habitat in South America. Florida already has enough issues with invasive species like the Burmese python, cane toad, lionfish, and giant land snail without adding another fish that’s famous for its sharp teeth and voracious appetite. If the piranha became established in Florida, it could drive all kinds of native fish and other animals to extinction very quickly.

This has actually happened in parts of China, where red-bellied piranha were first found in the wild in 1990 and have since spread throughout much of South China. In some waterways, up to half of the native fish have disappeared after piranha and other invasive species became established.

But wait, you may be thinking, what about the danger to humans? Aren’t piranhas incredibly dangerous to swimmers?

The red-bellied piranha is the species that most people think is dangerous to people. We’ve all heard the stories and maybe seen movies where a pack of piranha attack someone swimming along, and within minutes all that’s left of them is a skeleton. But it may not surprise you to learn that those stories are fake, but they’re widespread for an unusual reason.

Back in 1913, the former U.S. President Teddy Roosevelt, who we talked about in episode 284 about the teddy bear, took part in an expedition to the Amazon basin in South America. The expedition was arranged by the Brazilian government, who invited Roosevelt along.

The expedition planned to explore the headwaters of the Amazon and it did, at great peril. Three people died and almost everyone got sick from malaria or some other disease, including Roosevelt, who got a cut on his leg that became badly infected. One of the three people who died was murdered by another expedition member, and instead of taking the murderer home to face justice, they just…left him in the jungle, a looooooooong way from anywhere or anyone.

Anyway, one of the things Roosevelt saw early on in the trip was something he told everyone about later, in gruesome detail. You’ve probably heard about it too. The local dignitaries took Roosevelt and the other expedition members on a tour of their town, showing things off, as people do all over the world when they have important visitors. They also showed how ferocious the local piranhas were by driving a cow into the water. A pack of piranhas attacked the cow, and within minutes it was nothing but a skeleton, just like in the movies!

But wait, you’re probably thinking again, I just said that was all fake! Did it really happen? It did, but not the way it sounds. The whole cruel spectacle was arranged ahead of time by the local dignitaries. They had people capture piranhas from miles away and bring them to one section of the river, where they were penned in with a net and not given any food for days. By the time the cow was driven into the makeshift pen, the piranhas were starving and desperate. Under normal circumstances, they would have never attacked the cow.

The red-bellied piranha and its relations are actually mild-mannered fish who only want to eat small fish, snails, insects, and other tiny animals, along with fruit and leaves. It will also sometimes eat dead animals it finds, which has led to people assuming piranhas killed someone swimming in the water when actually the person drowned and the piranhas just, you know, cleaned things up a little.

The red-bellied piranha can grow up to 20 inches long, or 50 cm, and is usually silvery-gray in color with black markings and a reddish belly. It does have big sharp teeth, but so do lots of other fish. Most importantly, the piranha doesn’t hunt in packs. It hunts individually most of the time, but it may stay in a school with other piranhas to help it avoid predators. If a caiman or something decides it wants a piranha snack, any given individual fish in a school is likely to escape the caiman, whereas a fish by itself has a much higher chance of being grabbed and eaten.

The piranha communicates with other piranha by sound. Fish aren’t usually famous for making noise, but the piranha can use its swim bladder as a resonant chamber. It uses special muscles to make a low-pitched drumming sound, usually to warn another piranha away from whatever food it’s found.

Aquarium enthusiasts sometimes keep piranha as pets, but they need special care. A piranha won’t eat meat that’s going bad, so it has to have fresh meat or live animals it can catch, and some animals can make the piranha sick, like goldfish. It’s also a messy eater, so its water will get yucky very quickly and has to be continually changed. And, of course, in some places people aren’t allowed to own piranha at all. You know, places like Florida.

The red-bellied piranha is the largest living species, but 8 to 10 million years ago a species named Megapiranha could grow as much as four feet long, or 1.27 meters. If you’d lived back then, you might have needed to be a little more careful where you swam.

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 333: Robins and Ravens

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Thanks to Liesbet, Simon, and Thea for their suggestions this week! Let’s learn about some birds!

Further reading:

Blue Tits and Milk Bottle Tops

Ravens parallel great apes in flexible planning for tool-use and bartering

Further watching:

A Raven Calling [this is a great video of a raven making all sorts of interesting sounds–I only used a tiny clip of it in the episode but it’s worth watching the whole thing]

The European robin:

The American robin and a worm that is having a very bad day:

A blue tit [photo By © Francis C. Franklin / CC-BY-SA-3.0, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=37675470]:

A blue tit about to get the cap off that milk bottle [photo from link above]:

The Eastern bluebird:

A raven:

An American crow:

Show transcript:

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

This week we have suggestions from Liesbet, Simon, and Thea, who suggested some relatively common birds that you may already think you know all about, but there’s lots to learn about them!

We’ll start with Liesbet’s suggestion, about the European robin and bluebird, and while we’re at it we’ll learn about the American robin and bluebird. The European and American birds are completely different species. The reason they have the same names is because when Europeans first started paying attention to the birds of North America, they needed names for the birds. The native peoples had names for them, of course, but the Europeans wanted names in a language they understood, so in a lot of cases they just borrowed names already in use at home.

Let’s start with the robin, which we also talked about way back in episode 81.

The European robin is a little bitty bird, only around 5 inches long, or 13 cm, with a brown back, streaked gray or buff belly, and orange face and breast. It has a short black bill and round black eyes. It eats insects, worms, berries, and seeds. The eggs are pale brown with reddish speckles.

It lives throughout much of Eurasia, but robins in Britain tend to be fairly tame, probably because they were traditionally considered beneficial in Britain and Ireland, so farmers and gardeners wouldn’t hurt them. In other parts of Europe they were hunted and are much more shy. European robins are also common on Christmas cards in Britain and Ireland, possibly because in the olden days, postmen used to wear red jackets. The postmen started to be called robins as a result, and since postmen bring Christmas cards, the bird robin became linked with card delivery and finally just ended up on the Christmas cards. Plus, their orange markings are cheerful in winter.

This is what the European robin sounds like:

[robin song]

The American robin is a type of thrush. It lives year-round in most of the United States and parts of Mexico, spends summers in much of Canada, and winters in parts of Mexico. It’s very different from the European robin. The European robin is tiny and round and adorable, while the American robin is big and always looks kind of angry. It grows around 10 inches long, or 25 cm. It’s dark gray on its back, with a rusty red breast, white undertail coverts, and a long yellow bill. It also has white markings around its eyes. Young birds are speckled. It mostly eats insects, worms, and berries.

If you see a bird on the ground, running quickly and then stopping, it’s probably a robin. Mostly the robin hunts bugs by sight, but it has good hearing and can actually hear worms moving around underground. You can sometimes see a robin with its head cocked, listening for a worm, before pouncing and pulling it out of the ground, just like in a cartoon.

American robin eggs are a light teal blue, so common and well-known that robin’s-egg-blue is a typical description of that particular color. In the spring after eggs hatch, the mother robin will carry the eggshells away from the nest to drop them, so predators won’t see the shells and know there’s a nest nearby. That’s why you’ll sometimes see half a robin eggshell on the sidewalk. It doesn’t mean something bad happened to the baby, just that the mother bird is doing her job. Both parents feed the chicks, and the parents also carry off the babies’ droppings to scatter them away from the nest.

This is what an American robin’s song sounds like.

[robin song]

Liesbet also wanted to learn about the European bluebird, more commonly called the Eurasian blue tit. We haven’t talked about it or the American bluebird before, even though they’re both beautiful birds.

The blue tit lives throughout Europe and parts of western Asia. It grows around 4 and a half inches long, or 12 cm, and has a bright blue crown on its head with blue on its wings, tail, and back. Its face is mostly white but it has a black streak that crosses its eye and a black ring around its neck. In fact, if you’re familiar with the blue jay of North America, the blue tit looks a lot like a miniature blue jay. It even has a little bit of a crest that it can raise and lower.

Because it eats a lot of insects and other small invertebrates, along with some seeds, the blue tit is an acrobatic bird. It will hang upside down from a twig to reach a caterpillar on the underside of a leaf, that sort of thing. It will also peel bits of bark away from a tree trunk to find tiny insects and spiders hiding underneath it. This habit leads it to sometimes peel bits off of people’s houses, like the putty that holds windowpanes in place. It also once led to the blue tit learning a surprising way to find food, and to learn about that, we have to learn a little bit about how people in the olden days got their milk if they didn’t own cows.

Back in the early 20th century, people used to get milk delivered every morning by a milkman. Refrigerators and ice boxes weren’t common like they are today, and most people didn’t have a way to keep milk cold. That meant it would go bad very quickly, so people would just order how much milk they needed in one day and when they got up in the morning, the milkman would have left the milk and other dairy products on the doorstep for the family.

The milk was always whole milk, also called full-fat, and as it sat in its bottles on the doorstep waiting for the family to wake up and bring the milk in, the cream would separate and rise to the top of the milk. Cream is just the fattiest, richest part of the milk. These days milk is processed differently so even if you buy whole milk, the cream won’t separate from it, and most milk sold today has already had most of the cream separated out. That’s why skim milk is called that, because the cream has been skimmed off the top. It’s sold separately as heavy whipping cream or mixed with milk as half-and-half. But back in the olden days, if you wanted to make whipped cream or clotted cream or some other recipe that calls for cream, you’d just skim the cream off yourself to use it.

The problem is, cream is so rich and full of protein that other animals learned to rob milk bottles, especially the blue tit. Birds can’t digest milk, naturally, since only mammals produce milk and are adapted to digest it, and even most adult mammals have trouble digesting milk. But cream contains a lot less lactose than the milk itself, and lactose is the type of sugar in milk that can cause stomach upset in adults. Blue tits learned that if they peeled the little foil cap off a milk bottle, they could get at the cream, and it became such a widespread behavior that each generation of blue tits became more adapted to digest cream.

These days, of course, most people buy their milk at the grocery store. The blue tits have had to go back to eating bugs and seeds.

This is what a blue tit sounds like:

[blue tit song]

The bluebird is a North American bird that also eats insects and other small invertebrates, along with berries and seeds. It grows around 7 inches long, or 18 cm. There are three species, the eastern bluebird and western bluebird, which look similar with bright blue above and white underneath with rusty red breast, and the mountain bluebird, which is blue almost all over and lives in mountainous areas of western North America. The bluebird is a type of thrush, meaning that it’s actually related to the American robin and used to be called the blue robin.

The bluebird spends a lot of its time sitting on a branch and watching for insects in the grass below. When it spots a grasshopper or beetle or spider or even a snail, it will drop down from its branch to grab it. It prefers open grasslands with trees or brush it can perch in, so it’s common around farmland. The mountain bluebird hunts like this too, but it doesn’t always bother to perch and will just hover above the ground until it spots a bug.

This is what an eastern bluebird sounds like:

[bluebird song]

Next, Simon and Thea wanted to learn about crows and ravens. The raven is another bird we covered a long time ago, in episode 112. I had a really bad cold the week of that episode and not only did I sound awful, I didn’t do a very good job with my research. I’m glad to revisit the topic and correct a few mistakes.

Crows and ravens look similar and are closely related, with both belonging to the genus Corvus. There are lots of species and subspecies of both, but let’s talk specifically about the American crow since it’s closely related to the hooded crow and the carrion crow found throughout Europe and Asia. Likewise, we’ll talk about the common raven since it’s found throughout much of the northern hemisphere.

The American crow can grow up to about 20 inches long, or 50 cm, with a wingspan over 3 feet across, or about a meter. Meanwhile, the common raven has a wingspan of up to 5 feet across, or 1.5 meters, and can grow up to 26 inches long, or 67 cm. Both are glossy black all over with large, heavy bills and long legs.

Crows and ravens both mate for life. Crows in particular are devoted family birds, with the grown young of a pair often staying to help their parents raise the next nest.

Both crows and ravens are omnivores, which means they eat pretty much anything. They will eat roadkill and other carrion, fruit and grain, insects, small animals, other birds, and eggs. They’re also extremely smart, which means a crow or raven can figure out how to get into trash cans and other containers to find food that humans think is secure.

Both also sometimes make and use tools, especially sticks that they use to dig out insects in places where their beaks can’t reach. But ravens in particular show a lot of tool use. Ravens sometimes throw pinecones or rocks at people who approach too close to their nests, and will even use sticks to stab at attacking owls. A few ravens have been observed to hold big pieces of bark in their feet while flying in strong winds, and they use the bark as a sort of rudder to help them maneuver. Other cognitive studies of ravens show that they have sophisticated and flexible problem-solving abilities where they can plan at least one step ahead, similar to great apes. Other corvids show similar abilities.

The raven can imitate other animals and birds, even machinery, in addition to making all sorts of calls. It can even imitate human speech. If a raven finds a dead animal but isn’t strong enough to open the carcass to get at the meat, it may imitate a wolf or fox to attract the animal to the carcass. The wolf or fox will open the carcass, and even after it eats as much as it wants, there’s plenty left for the raven.

Ravens also communicate non-vocally with other ravens. A raven will use its beak to point with, the way humans will point with a finger. They’ll also hold something and wave it to get another raven’s attention, which hasn’t been observed in any other animal besides apes.

The raven is much larger and heavier than a crow, and you can also distinguish a crow from a raven by their calls. This is what an American crow sounds like:

[crow call]

And this is what a raven sounds like:

[raven call]

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 332: Hunting Partners and Mutualism

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Thanks to Vaughn and Jan for their suggestions this week! We’re going to learn about mutualism of various types.

Further reading:

The odd couple: spider-frog mutualism in the Amazon rainforest

What Birds, Coyotes, and Badgers Know About Teamwork

Octopuses punch fishes during collaborative interspecific hunting events

An Emotional Support Dog Is the Only Thing That Chills Out a Cheetah

Buddies [picture from the first link above]:

The honeyguide bird:

Cheetahs and dogs can be friends:

Show transcript:

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

This week we’re going to learn about a topic that I’ve been wanting to cover for a long time, mutualism. It’s a broad topic so we won’t try to cover everything about it in this episode, just give an overview with some examples. Vaughn suggested symbiotic behavior ages ago, and Jan gave me a great example of this, also ages ago, so thanks to both of them!

Mutualism is similar to other terms, including symbiosis, often referred to as “a symbiotic relationship.” I’m using mutualism as a general term, but if you want to learn more you’ll quickly find that there are lots of terms referring to different interspecies relationships. Basically we’re talking about two unrelated organisms interacting in a way that’s beneficial to both. This is different from commensalism, where one organism benefits and the other doesn’t but also isn’t harmed, and parasitism, where one organism benefits and the other is harmed.

We’ll start with the suggestion from Jan, who alerted me to this awesome pair of animals. Many different species have developed this relationship, but we’ll take as our specific example the dotted humming frog that lives in parts of western South America.

The dotted humming frog is a tiny nocturnal frog that barely grows more than half an inch long from snout to vent, or about 2 cm. It lives in swamps and lowland forests and spends most of the day in a burrow underground. It comes out at night to hunt insects, especially ants. It really loves ants and is considered an ant specialist. That may be why the dotted humming frog has a commensal relationship with a spider, the Colombian lesserblack tarantula.

The tarantula is a lot bigger than the frog, with its body alone almost 3 inches long, or 7 cm. Its legspan can be as much as 8 and a half inches across, or 22 cm. It’s also nocturnal and spends the day in its burrow, coming out at night to hunt insects and other small animals, although not ants. It’s after bigger prey, including small frogs. But it doesn’t eat the dotted humming frog. One or even more of the frogs actually lives in the same burrow as the tarantula and they come out to hunt in the evenings at the same time as their spider roommate.

So what’s going on? Obviously the frog gains protection from predators by buddying up with a tarantula, but why doesn’t the tarantula just eat the frog? Scientists aren’t sure, but the best guess is that the frog protects the spider’s eggs from ants. Ants like to eat invertebrate eggs, but the dotted humming frog likes to eat ants, and as it happens the female Colombian lesserblack tarantula is especially maternal. She lays about 100 eggs and carries them around in an egg sac. When the babies hatch, they live with their mother for up to a year, sharing food and burrow space.

This particular tarantula also gets along with another species of frog that also eats a lot of ants. Researchers think the spiders distinguish the frogs by smell. The ant-eating frogs apparently smell like friends, or at least useful roommates, while all other frogs smell like food. Or, of course, it’s possible that the ant-eating frogs smell and taste bad to the spider. Either way, both the frogs and the tarantulas benefit from the relationship–and this pairing of tiny frogs and big spiders is one that’s actually quite common throughout the world.

Mutualism is everywhere, from insects gathering nectar to eat while pollenating flowers at the same time, to cleaner fish eating parasites from bigger fish, to birds eating fruit and pooping out seeds that then germinate with a little extra fertilizer. Many mutualistic relationships aren’t obvious to us as humans until we’ve done a lot of careful observations, which is why it’s so important to protect not just a particular species of animal but its entire ecosystem. We don’t always know what other animals and plants that animal depends on to survive, and vice versa.

Sometimes an individual animal will work together with an individual of another species to find food. This may not happen all the time, just when circumstances are right. Sometimes, for example, a coyote will pair up with a badger to hunt. The coyote is closely related to wolves and can run really fast, while the American badger can dig really fast. Both are native to North America. They also both really like to eat prairie dogs, a type of rodent that can run really fast and lives in a burrow. Some prairie dog tunnels can extend more than 30 feet, or 10 meters, with multiple exits. The badger can dig into the burrow and if the prairie dog leaves through one of the exits, the coyote chases after it. When one of the predators catches the prairie dog, they don’t share the meal but they will often continue to hunt together until both are able to eat.

Other animals hunt together too. Moray eels will sometime pair up with a fish called the grouper in a similar way as the coyote and badger. The grouper is a fast swimmer while the eel can wriggle into crevices in rocks or coral. The grouper will swim up to the eel and shake its head rapidly to initiate a hunt, and if the grouper has seen a prey item disappear into a crevice, it will lead the eel to the crevice and shake its head at it again.

Groupers also sometimes pair up with octopuses to hunt together, as will some other species of fish. Like the eel, the octopus can enter crevices to chase an animal that’s trying to hide. But the octopus isn’t always a good hunting partner, because if the grouper catches a fish, sometimes the octopus will punch the grouper and steal its fish. Not cool, octopus.

Birds have mutualistic relationships too, including the honeyguide that lives in parts of Africa and Asia. It’s a little perching bird that’s mostly gray and white or brown and white, with the males of some species having yellow markings. It eats insects, spiders, and other invertebrates, and it especially likes bee larvae. But it’s just a little bird and can’t break open wild honeybee hives by itself.

Some species of honeyguide that live in Africa have figured out that humans can break open beehives. When the honeyguide bird finds a beehive, it will fly around until it hears the local people’s hunting calls. The bird will then respond with a distinct call of its own, alerting the people, and will guide them to the beehive. This has been going on for thousands of years. The humans gather the honey, the honeyguide feasts on the bee larvae and wax, and everyone has a good day except the bees.

The honeyguide is also supposed to guide the honey badger to beehives, but there’s no definitive evidence that this actually happens. Honey badgers do like to eat honey and bee larvae, though, and when a honey badger breaks open a beehive, honeyguides and other birds will wait until it’s eaten what it wants and will then pick through the wreckage for any food the badger missed. But the honeyguide might lead the honey badger to the hive, we just don’t know for sure.

Humans sometimes even help other animals into a commensal relationship. Vaughn gave me an example of a cheetah in a zoo who became best friends with a dog. This hasn’t just happened once, it’s happened lots of times because zookeepers have found that it helps cheetahs kept in captivity. Cheetahs are social animals but sometimes a zoo doesn’t have a good companion for a cheetah cub. The cub could be in danger from older, unrelated cheetahs, but a cheetah all on its own is prone to anxiety. It’s so important for a cheetah to have a sibling that if a mother cheetah only has one cub, or if all but one cub dies, a lot of times she’ll abandon the single cub. If this happens in the wild, it’s sad, but if it happens in captivity the zoo needs to help the cub.

To do this, the zoo will pair the cub with a puppy of a sociable, large breed of dog, such as a Labrador or golden retriever. The cub and the puppy grow up together. The cheetah has a mellow friend who helps alleviate its anxiety, and the dog has a friend who’s really good at playing chase.

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 just tell a friend. We also have a Patreon at patreon.com/strangeanimalspodcast if you’d like to support us that way.

Thanks for listening!

Episode 331: Ompax, the Mystery Fish

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This week we have a mystery fish from Australia, the ompax!

Main source consulted:

Whitley, G. P. (1933). Ompax spatuloides Castelnau, a Mythical Australian Fish. The American Naturalist, 67(713), 563–567. http://www.jstor.org/stable/2456813

The fateful Ompax drawing:

The freshwater longtom (picture by Barry Hutchins):

Show transcript:

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

For the Patreon episode this month, we had a bird mystery from Queensland, Australia. While I was researching it I came across this mystery fish, also from Queensland.

In 1872, a man named Karl Staiger visited the town of Gayndah as part of his job. He was a chemist, but he also had an interest in nature and years later he worked for the Queensland Museum. One morning in Gayndah he went to breakfast and was served a strange-looking fish—so strange-looking that he asked what it was. He was told it was a very rare fish found in the nearby Burnett River.

Staiger was interested enough that he asked the road inspector, presumably one of his coworkers, to draw the fish for him. But the drawing wasn’t made until after Staiger ate the fish. It was his breakfast and he was hungry and, as he wrote later, he didn’t know he should have at least saved the head for study. Presumably he also didn’t want his breakfast to get cold while the drawing was being made.

The road inspector was a careful artist although he wasn’t a naturalist himself, so he did what he could to draw the fish accurately from the remains of Staiger’s meal. According to the drawing, the fish had a long, flattened rostrum that looked a little like a very long, thin duckbill, big scales on its body, and a fin that went all the way around the edges of the tail starting about halfway down the back, which appeared to be connected dorsal, caudal, and ventral fins. Its pectoral fins were small, and its eyes were also small and near the top of its head. The fish was brown in color and about 18 inches long, or 46 cm.

Staiger eventually wrote to a French naturalist and sent him the drawing. The French naturalist has about 500 names and titles, usually shortened to something like Francis de Laporte de Castelnau. I’m going to call him Francis because obviously I can’t pronounce any of those names properly.

Francis saw at a glance that the fish was unlike anything he’d ever seen before. He suspected it didn’t just deserve its own genus but its own family. Staiger had reported what he’d been told, that the fish was known from a particular part of the Burnett River, and he’d also mentioned that it lived in the same area as another strange fish, the Australian lungfish.

The Australian lungfish had only been described a few years before, in 1870, and it’s a very big fish. It can grow up to 5 feet long, or 1.5 meters, and is greenish in color. It has big overlapping scales on its body and four strong fins that look more like flippers than ordinary fish fins, which it uses to stand and walk on the bottom of the river. Its tail comes to a single rounded point and it has tooth plates instead of regular teeth, which it uses to crush the small animals it eats. It also has a single lung in addition to gills, and like other lungfish it comes to the surface every so often to replace the air in its lung. When it’s especially active it will breathe at the surface more often. The ability to breathe air allows it to survive in water with low oxygen.

Francis noted that there were some similarities between the new fish and the Australian lungfish, but he thought it was more likely to be related to the alligator gar of North America. It had the same type of scales as the alligator gar. He also noted that its duckbill rostrum resembled the rostrum of the American paddlefish, which is similarly shaped but even longer than the new fish’s, but that the rest of the new fish was very different from the paddlefish.

Francis described the new fish in 1879 and gave it the name Ompax spatuloides, but as early as 1881 some fish experts wondered if the original drawing was misleading. They pointed out that the fish wasn’t drawn by someone with a knowledge of fish and that it had already been cooked and eaten, so the details might be completely wrong.

As it happens, the details were completely wrong, but not in a way anyone expected.

There’s actually some confusion as to whether the drawing of the fish was made before or after Staiger ate it, but it doesn’t actually matter after all. In 1930, an article in the Sydney Bulletin claimed that Ompax was a hoax to fool Staiger, made up of a lungfish head, a mullet body, and an eel tail.

The 1930 article isn’t available online, but one published in 1933 is, and it quotes the 1930 article. The 1933 article appears in a periodical called The American Naturalist and discusses the history of Ompax from start to finish, which is where most of our information comes from. The article finishes by pointing out that the Ompax’s head can’t have been made from a lungfish head unless a platypus bill or something like that was added, and suggests that the head might actually have been that of a fish of the family Belonidae. These are commonly called needlefish because they have long thin rostrums lined with teeth.

Needlefish are long, slender fish that resemble gars, although gars are native to North America and mostly live in freshwater. Needlefish live throughout much of the world’s oceans although some do live in brackish or freshwater. The needlefish swims near the surface of the water and will leap out of the water at high speed to jump obstacles like floating logs or boats. Since needlefish rostrums really do have a sharp point like a needle, it sometimes badly injures or even kills people who are fishing in boats by accidentally stabbing them.

One species, the freshwater longtom, is not only found in Australian rivers, it’s found in Queensland and occasionally even in the Burnett River. Its rostrum is the right size and shape to be the Ompax’s rostrum, while the platypus’s so-called duckbill is much too large to match the drawing. The freshwater longtom can grow almost three feet long, or about 85 cm, but is usually much smaller than that.

Like most needlefish, the freshwater longtom eats small fish, insects, and crustaceans. Also like other needlefish, it has no stomach. It swallows its prey whole and instead of the food going into its stomach, it just goes directly into its intestines, which excrete an enzyme called trypsin that breaks down proteins so they can be absorbed. This isn’t as efficient as stomach acids, but it also takes less energy to digest food this way.

The freshwater longtom’s dorsal and anal fins are long but fairly low and set well back on its body. Its pectoral fins are very small. While it does have an ordinary-looking tail fin, this might easily appear different after being cooked. And the longtom is edible, although it has a lot of thin bones that make it difficult to eat. Its bones are also green in color, which can be offputting to some people. Some needlefish also have greenish meat.

Staiger didn’t recount any details about the edibility and taste and texture of the fish he ate, so we don’t know if he actually ate a mullet that had a needlefish head and an eel tail stuck to it. The sea mullet and the sand mullet are both common fish around Australia and considered excellent eating fish. But if there really was that much of an eel’s tail stuck onto the fish’s body, you’d think Staiger would have noticed the difference in meat texture. The eels found in Australia are edible and considered a delicacy, but they wouldn’t look or taste the same as the rest of the fish.

The only reason we know the Ompax fish was a hoax is because of the 1930 article written by someone who called himself Waranbini. Waranbini’s article was published 58 years after the fish was served to Staiger for his breakfast.

I think the only hoax here was the 1930 article. I think Waranbini, whoever he was, looked at the picture, thought, “That looks like someone stuck three different types of animal together,” and wrote his article.

I think Staiger was actually served a freshwater longtom, and I think the people who served it to him were sincere that it was a rare fish. It is rare in the Burnett River. Staiger wasn’t an ichthyologist, nor was the man who drew the fish. They did the best they could, and Francis did the best he could to decipher from Staiger’s notes and the drawing what the fish was.

So from this we can learn three important things: Don’t use a drawing of a cooked and possibly mostly eaten fish to describe a new species, don’t assume people in the olden days were stupid, and don’t trust anonymous newspaper articles with no sources listed.

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 330: Vintana and Tiarajudens

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Thanks to Lorenzo for suggesting Tiarajudens! We’ll learn about it this week along with another extinct animal, Vintana.

Further reading:

Funky facial flanges [the skull picture below comes from this site]

First Postcranial Fossils of Rare Gondwanatherian Mammal Unearthed in Madagascar

The Earliest Saberteeth Were for Fighting, Not Biting [the skeleton picture below comes from this site]

Vintana’s skull had weird jugal flanges:

Tiarajudens had saber teeth as well as palatal teeth:

Show transcript:

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

Just last month we had an episode about the tenrec and an extinct animal called Adalatherium. At the end of that episode, I said something I say a lot, that we don’t know very much about it or the other ancient mammals that lived at the time, and that I hoped we would find some new fossils soon. Well, guess what! A paper about a newly discovered Gondwanathere fossil was published just a few days ago as this episode goes live. Rather than save it for the updates episode later this summer, let’s learn about an animal named Vintana sertichi, along with a suggestion from Lorenzo for another extinct animal.

As you may remember from episode 324, Adalatherium is a member of a group of animals called Gondwanatheria, which arose in the southern hemisphere around the time that the supercontinent Gondwana was breaking apart. We only have a few fossils of these animals so paleontologists still don’t know how they’re related, although we do know they’re not related to the mammals living today. Every new specimen found of these rare mammals helps scientists fill the gaps in our knowledge. That’s what happened with Vintana.

Vintana lived at the end of the Cretaceous, until the asteroid strike about 66 million years ago that killed off the non-avian dinosaurs and a whole lot of other animals, probably including Vintana. The first fossilized specimen was a skull found in Madagascar and described in 2014. It was really well preserved, which allowed scientists to learn a lot about the animal.

Vintana was an active animal that ate plants. It had large eyes and a good sense of smell and hearing, so its ears might have been fairly large too. Its face probably looked a lot like a big rodent’s face, but the skull itself had a weird feature. The cheekbones extended downward on each side next to the jaw, and these extensions are called jugal flanges. They would have allowed for the attachment of really big jaw muscles. That suggests that Vintana could probably give you a nasty bite, not that you need to worry about that unless you find a time machine. It might also mean that Vintana ate tough plants that required a lot of chewing.

Vintana probably looked a lot like a groundhog, or marmot, which we talked about recently in episode 327. It wasn’t related to the groundhog, though, and was bigger too. Scientists estimate it weighed about 20 lbs, or 9 kg.

The fossil specimen of Adalatherium that we talked about in episode 324 was discovered in Madagascar in 2020. When a tail vertebra from another mammal was found in the same area, researchers scanned and compared it to Adalatherium’s vertebrae. They were similar but not an exact match, plus the new bone was almost twice as large as the same bone in Adalatherium’s spine. It matched the size of Vintana and was assigned to that species. Vintana was probably related to Adalatherium but was bigger and had a shorter, wider tail. And as of right now, that’s just about all we know about it.

Next, let’s learn about another extinct animal, this one suggested by Lorenzo. Lorenzo gave me a bunch of great suggestions and I picked this one to pair with Vintana, because otherwise this episode would have been really short. Vintana lived at the end of the dinosaurs, but Tiarajudens lived long before the dinosaurs evolved, around 260 million years ago.

Tiarajudens was a therapsid, a group that eventually gave rise to mammals although it’s not a direct ancestor of mammals. Technically it’s an anomodont. We don’t have a complete skeleton so we don’t know for sure how big it was, but we do have a skull and some leg bones so we know it was about the same size or a little bigger than a big dog. There are only two species known, one from what is now South America and one from what is now Africa, but 260 million years ago those two landmasses were connected and were part of the supercontinent Gondwana.

Tiarajudens had weird teeth even compared to other anomodonts. It had a pair of saber teeth that resembled the tusks found in later anomodonts, but they weren’t really tusks. They were big fangs that grew from the upper jaw and jutted down out of the mouth well past the bottom of the jaw. Later anomodonts probably used their tusks to dig up plants, but there aren’t wear marks on Tiarajudens’s saber teeth that would indicate it used them for digging. Many paleontologists think it used them for defense and to fight other Tiarajudenses over mates or territory. We don’t know if the saber teeth were present in all individuals, since we’ve only found a few specimens.

Tiarajudens also had palatal teeth. These days palatal teeth are mostly found in amphibians, especially frogs. Palatal teeth grow down from the roof of the mouth and Tiarajudens’s were flat like molars. We haven’t found a lower jaw yet so we don’t know what the bottom teeth looked like, but from the wear marks on the upper teeth, it was clear that Tiarajudens was actually chewing its food. That was really unusual among all animals at the time, and in fact Tiarajudens is one of the first animals to really chew its food instead of giving it a chomp or two and swallowing it mostly whole. It ate plants, probably tough ones that required a lot of chewing.

So what did Tiarajudens look like beyond its teeth? It probably resembled a bulky four-legged dinosaur with a short tail, but it may have had whiskers. That’s as much as we know right now, because Tiarajudens was not only an early therapsid, it was different in many ways from most other therapsids known. For instance, it had what are called gastralia, or belly ribs, which were once common in tetrapods. Some dinosaurs had gastralia, including T. rex, but most therapsids didn’t. These days crocodiles and their relations still have gastralia, and so does the tuatara, but most animals don’t.

Both Tiarajudens and Vintana were unusual animals that we just don’t know much about. Let’s hope that changes soon and scientists find more fossils of both. I’ll keep you updated.

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 329: Manatees and a Surprise Sloth

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Thanks to Alexandra and Pranav for their suggestions this week! Let’s learn about manatees and sloths, including a surprising extinct sloth.

Further reading:

Sloths in the Water

A West Indian manatee:

A three-toed sloth:

Show transcript:

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

This week we have a suggestion from Alexandra and Pranav, who wanted an episode about manatees. We’ll also talk about another marine mammal, a weird extinct one you may never have heard of.

The manatee is also called the sea cow, because it sort of slightly resembles a cow and it grazes on plants that grow underwater. It’s a member of the order Sirenia, which includes the dugong, and sirenians are probably most closely related to the elephant. This sounds ridiculous at first, but there are a lot of physical similarities between the manatee and the elephant. Their teeth are very similar, for instance, even if the manatee doesn’t grow tusks. The elephant has a pair of big chewing teeth on each side of its mouth that look more like the bottoms of running shoes than ordinary teeth. Every so many years, the four molars in an elephant’s mouth start to get pushed out by four new molars. The new teeth grow in at the back of the mouth and start moving forward, pushing the old molars farther forward until they fall out. The manatee has this same type of tooth replacement, although its teeth aren’t as gigantic as the elephant’s teeth. The manatee also has hard ridged pads on the roof of its mouth that help it chew its food.

Female manatees are larger than males on average, and a really big female manatee can grow over 15 feet long, or 4.6 meters. Most manatees are between 9 and 10 feet long, or a little less than 3 meters. Its body is elongated like a whale, but unlike a whale it’s slow, usually only swimming about as fast as a human can swim. Its skin is gray or brown although often it has algae growing on it that helps camouflage it. The end of the manatee’s tail looks like a rounded paddle, and it has front flippers but no rear limbs. Its face is rounded with a prehensile upper lip covered with bristly whiskers, which it uses to find and gather water plants.

Every so often a manatee will eat a little fish, apparently on purpose. Since most herbivorous animals will eat meat every so often, this isn’t unusual. Mostly, though, the manatee spends almost all of its time awake eating plants, often from the bottom of the waterway where it lives. It lives in shallow water and will use its flippers to walk itself along the bottom, and also uses its flippers to dig up plants. Its upper lip is divided in two like the upper lips of many animals, which you can see in a dog or cat as that little line connecting the bottom of the nose to the upper lip. In the manatee, though, both sides of the lips have a lot of muscles and can move independently.

There are three species of manatee alive today: the West Indian manatee that lives in the Gulf of Mexico down to the eastern coast of northern South America, the Amazonian manatee that lives exclusively in fresh water in the Amazon basin, and the West African manatee that lives in brackish and fresh water. Sometimes the West Indian manatee will also move into river systems to find food.

Back in episode 153 we talked about the Florida manatee, which is a subspecies of West Indian manatee. In the winter it mostly lives around Florida but in summer many individuals travel widely. It’s sometimes found as far north as Massachusetts along the Atlantic coast, and as far west as Texas in the Gulf of Mexico, but despite its size, the manatee doesn’t have a lot of blubber or fat to keep it warm. The farther away it travels from warm water, the more likely it is to die of cold.

In the 1970s there were only a few hundred Florida manatees alive and it nearly went extinct. It was listed as an endangered species and after a lot of effort by a lot of different conservation groups, it’s now only considered threatened, but it’s still vulnerable to habitat loss, injuries from boats, and getting tangled in fishing gear and drowning. Occasionally a crocodile will eat a young manatee, but for the most part it’s so big, and lives in such shallow water, that most predators won’t bother it. It basically only has to worry about humans, and unfortunately humans still cause a lot of manatee deaths every year with boats.

A lot of times, a manatee that’s hit by a boat is only injured. There are several rehabilitation centers in the United States, where an injured manatee can be treated by veterinarians until it’s healed and can be reintroduced into the wild.

One other detail that makes the manatee similar to the elephant is its flippers, which is probably not what you expected me to say. Most manatees have toenails on their flippers that closely resemble the nails on elephant feet. The exception is the Amazonian manatee that doesn’t have toenails at all.

A lot of the food the Amazonian manatee eats actually floats on the surface of the rivers where it lives, and it will also eat fruit that drops into the water. Because the Amazon basin is subject to a dry season where there’s not a lot of food, the manatee eats a lot when it can to build up fat reserves for later. During the dry season, it usually moves to the biggest lakes in the area as the rivers and shallower lakes dry up or get too shallow for the manatee to swim in. Since the manatee has a low metabolic rate, it can live off its fat reserves until the dry season is over.

One interesting thing about the manatee is that it only has six vertebrae in its neck. Almost all other mammals have seven, even giraffes. The exception is the two-toed sloth, which also has six, and the three-toed sloth, which has a varying number of neck vertebrae, up to nine in some species!

Pranav also wanted to learn about sloths, so let’s talk about them next. All sloths are native to Central and South America. The sloths living today live in forests, especially rainforests, and spend almost all their time in trees.

A sloth makes the manatee look like a speed demon. It spends most of its time hanging from its long claws beneath branches, eating leaves and other plant material, but when it does move, it does so extremely slowly. This helps it stay camouflaged from predators, because its fur contains algae that makes it look green, so a barely-moving green-furred sloth hanging from a tree just looks like a bunch of leaves. It does move from one tree to another to find fresh leaves, and once a week it climbs down from its tree to defecate and urinate on the ground. Yes, it only relieves itself once a week.

The sloth’s digestive tract is also extremely slow, which allows it to extract as much nutrition as possible from each leaf. It takes about a month for a sloth to fully digest one mouthful of food.

The three-toed sloth is about the size of a large cat while the two-toed sloth is slightly larger, maybe the size of a small to medium-sized dog. The two-toed sloth is nocturnal while the three-toed sloth is mostly diurnal. Even though they look and act very similar, the two types of sloth are not very closely related. Both have long curved claws and strong pulling muscles, although their pushing muscles are weak. This is why a sloth can’t walk like other animals; the muscles that would allow it to do so aren’t strong enough to support its own weight. And yet, it can hang from a branch and walk along it for as long as it needs to. I don’t think I could hang from a branch by my fingers for five minutes without having to let go.

Surprisingly, the sloth can also swim quite well, which allows it to find new trees even if there are streams or rivers in the way. But a few million years ago, a different type of sloth lived off the coast of western South America and did a whole lot of swimming. In fact, later species of Thalassocnus were probably fully marine mammals.

We talked about Thalassocnus briefly way back in episode 22. It was related to the giant ground sloths that were themselves related to the living three-toed sloths. The earliest Thalassocnus fossils are of semi-aquatic animals that grazed in shallow water. Fossils from more recent species show increasing adaptations to deeper water, including increased weight of the skeleton to help it stay underwater instead of bobbing up to the surface.

Thalassocnus eventually evolved a stiff, partially fused spine, which reflects the unusual way it moved around underwater. Instead of swimming the way a whale does, or even the way a dog or person does, it moved more like a hippopotamus. Hippos sort of bounce along underwater, using their feet to push off from the bottom. Thalassocnus probably did this too and used its long tail to help it maneuver.

Thalassocnus was a lot bigger than modern sloths. Even the smallest known species were the size of a big human, and the biggest species grew up to 11 feet long, or 3.3 meters. That biggest species was the one that lived most recently, up to about 1.5 million years ago, and researchers think it was fully aquatic. Its nostrils were on the top of its snout and it had prehensile lips to help it find plants underwater. Some researchers even think it could have had a short trunk something like a tapir. It had seven neck vertebrae, as in most other mammals.

There’s still a lot we don’t know about Thalassocnus, but because we have fossils of five different species that lived at different times, scientists are able to determine a lot about how it developed from a mostly terrestrial animal to a mostly or fully marine animal. The youngest species had smaller, weaker legs than the earlier ones, which suggests it didn’t use its legs to walk on land. It probably lived a lot like modern manatees, finding sea grasses and other plants on the sea floor in shallow water, but not able to swim very fast.

One last thing about the manatee is that it spends about half of its time asleep, and it sleeps underwater. It comes up for a breath every 15 minutes or so. Modern sloths sleep a lot too, around 15 hours a day. Chill sleepy friends.

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 328: Giant Ants

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Thanks to Richard from NC for suggesting Titanomyrma!

Further reading:

‘Giant’ ant fossil raises questions about ancient Arctic migrations

A fossilized queen Titanomyrma ant with a rufous hummingbird (stuffed) for scale:

Show transcript:

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

This week we have a suggestion from Richard from North Carolina, who sent me an article about an extinct giant ant called Titanomyrma. This episode is short, but I think you’ll find it interesting.

We’ve talked about ants in previous episodes, most recently episode 185. Most ant colonies consist of a single queen ant who lays all the eggs for her colony, seasonally hatched males with wings who fly off as soon as they’re grown, and worker ants. The worker ants are all female but don’t lay eggs. Army ants have another caste, the soldier ant, which are much larger than the worker ants and have big heads and strong, sharp mandibles. In many species of ant, the worker ants are further divided into castes that are specialized for specific tasks.

The biggest species of ant alive today is probably the giant Amazonian ant. The workers can grow over 1.2 inches long, or more than 3 cm, which is huge for an ant. It lives in South America in small colonies, usually containing less than 100 workers, and unlike most ants it doesn’t have a queen. Instead, one of the workers mates with a male and lays eggs for the colony. The giant Amazonian ant can sting and its sting contains venom that causes intense pain for up to two days. Fortunately, you will probably never encounter these giant ants, and even if you do they’re not very aggressive.

Another contender for the biggest species of ant alive today is the Dorylus genus of army ants, also called driver ants, which we talked about in episode 185. It lives in Africa in colonies that have millions of members, and the queen is the largest ant known. A queen army ant can measure 2.4 inches long, or 63 millimeters, but worker ants are much smaller.

Around 50 million years ago, giant ants related to modern driver ants lived in both Europe and North America. The genus is Titanomyrma and three species are known so far, found in Germany, England, Canada, and the American states of Tennessee and Wyoming.

The Wyoming ant fossil was discovered years ago and donated to the Denver Museum of Nature and Science, where it was stored in a drawer and forgotten about. In 2011 a curator found it and showed it to a paleoentomologist named Bruce Archibald. Dr. Archibald recognized it immediately as a fossilized queen ant even though it was the size of a hummingbird. He also realized it was very similar to a type of giant ant that once lived in Germany.

The German discovery was the first Titanomyrma species discovered, and it’s also the biggest known so far. The queen Titanomyrma gigantea grew up to 2.8 inches long, or 7 centimeters. Males grew up to 1.2 inches long, or 3 cm. The fossilized queen ants found have wings, with a wingspan of over 6 inches, or 16 cm. The other two known species are generally smaller, although still pretty darn big for ants.While they’re not that much bigger than the living Dorylus queens, most of the size of a queen Dorylus ant comes from her enlarged abdomen. Titanomyrma ants were just plain big all over.

Titanomyrma didn’t have a stinger, so it’s possible it used its mandibles to inflict bites, the way modern army ants do. It might also have sprayed formic acid at potential predators, as some ants do today.

The biggest ants alive today all live in tropical areas, so researchers thought Titanomyrma probably did too. During the Eocene, the world was overall quite warm and parts of Europe were tropical. The northern hemisphere supercontinent Laurasia was in the process of breaking up, but Europe and North America were still connected by the Arctic. Even though the Arctic was a lot warmer 50 million years ago than it is now, it was still too cold for a tropical ant. If Titanomyrma couldn’t survive in cold weather, how did it spread from one continent to another when it had to go through the Arctic?

There were warming periods during the Eocene that lasted a few hundred thousand years at a time, so researchers thought the ants probably migrated through the Arctic while it was warmer than usual. Then, in early 2023, a fossilized Titanomyrma queen ant was discovered in Canada. Because the rock it was preserved in has been distorted over the years, we can’t be certain how big the ant actually was. What we do know, though, is that the ant lived in a mountainous area that could get quite chilly, very different from the tropical climate scientists thought the giant ants needed.

As a result of the new finding, researchers are reconsidering whether the giant ants that lived 50 million years ago were really all that similar to modern giant ants. Just because the biggest ants alive today require tropical climates doesn’t mean that ancient giant ants did.

Hopefully more giant ant fossils will turn up soon, so we can learn more about where they lived, how they lived, and precisely how big they could get.

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!