Category Archives: Africa

Episode 329: Manatees and a Surprise Sloth

Posted on by

Podcast: Play in new window | Download (Duration: 13:19 — 14.8MB)

Subscribe: RSS | More

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 326: The Harpy Eagle and Friends

Posted on by

Podcast: Play in new window | Download (Duration: 12:55 — 14.4MB)

Subscribe: RSS | More

Thanks to Eva and Anbo for suggesting the harpy eagle!

Further reading:

Crested Eagle Feeding a Post-Fledged Young Harpy Eagle

Harpy eagle with a food [By http://www.birdphotos.com – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=3785263]:

The harpy eagle has great big feet and talons:

The harpy eagle with its feather crown raised [photo by Eric Kilby]:

The New Guinea harpy eagle looks similar to its South American cousin [By gailhampshire from Cradley, Malvern, U.K – New Guinea Harpy Eagle. Harpyopsis novaeguineae, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=86187611]:

Ruppell’s griffon vulture:

Show transcript:

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

We’ve been talking about a lot of mammals lately, so let’s have an episode about birds. Anbo suggested the harpy eagle not too long ago, and a much longer time ago Eva suggested the harpy eagle and other raptors.

The word raptor can be confusing because it refers to a type of small theropod dinosaur as well as a type of bird. When referring to a bird, the term raptor includes eagles, hawks, vultures, owls, and other birds of prey. And that includes the harpy eagle.

The harpy eagle lives throughout much of Central and South America, although not as far south as Patagonia. It has a wingspan up to about seven feet across, or over 2 meters, and like other raptors, females are larger than males. This isn’t an especially big wingspan for an eagle, but that’s because the harpy eagle hunts in forests and needs short, broad wings that allow it to maneuver through branches.

The harpy eagle is a beautiful bird. It has a light gray head and darker gray or black body, and is white underneath with delicate black stripes on its leg feathers, with broader stripes on its tail and wings. It has a black ring around its neck, huge yellow feet with enormous talons, and a black bill. Each talon, which is the term for a raptor’s claws, can be over 5 inches long, or 13 cm, while its feet in general are bigger than a grown man’s hand, even if the man has especially big hands.

Most striking of all is the harpy eagle’s crest, also sometimes referred to as a crown. The crown is made of long, rounded feathers and most of the time they don’t show very much. When a harpy eagle is alarmed, it raises the feather crown and poofs out the feathers on its face, which makes its head look bigger and sort of owl-shaped.

The harpy eagle mostly lives in lowland rainforests. It mates for life and doesn’t have babies every year. Every two or three years a harpy eagle pair will build a huge nest out of sticks in the top of the tallest tree they can find. The female lays two eggs, which the parents care for together. The female spends most of her time incubating the eggs while the male brings her food, although he will also take a turn incubating while she goes out to stretch her wings and do a bit of hunting herself. When the first egg hatches, the parents bring the baby lots of food and give it lots of attention–but they ignore the other egg at that point, which usually doesn’t hatch as a result. A harpy eagle chick is all white at first, and although it can fly at around 6 months old, its parents will keep feeding it for almost another year.

The harpy eagle is increasingly threatened due to habitat loss and poaching. Because it’s such a big bird, many people shoot it because they think it’s dangerous to livestock or children. But it mostly eats monkeys, sloths, kinkajous and coatis, iguanas, and other medium-sized animals. It’s rare that it attacks livestock since it mostly hunts within the tree canopy for arboreal animals. If your lambs and chickens are sitting on tree branches, you already have a bigger problem than harpy eagles eating them.

A captive breeding program has been started in various zoos around the world, while conservationists work to protect the harpy eagle’s natural habitat so that individuals can be released back into the wild.

We don’t actually know all that much about the harpy eagle, but we know even less about its close relation, the New Guinea harpy eagle. It resembles the harpy eagle but instead of being mostly gray and white, it’s mostly brown and cream in color. It has longer legs and tail but is smaller overall than the harpy eagle, with a wingspan closer to 5 feet across, or 1.5 meters. It has a smaller crest than the harpy eagle too.

Like its South American cousin, the New Guinea harpy eagle hunts in forests, especially rainforests, and spends most of its time perched in a tree, watching for small animals to happen by. Sometimes it will shake a branch to startle any animals in the area to run or fly away, at which point the eagle flies after them. It will even climb around in a tree and poke around in any potential hiding places it finds. It eats tree kangaroos, possums, and other small to medium-sized mammals, but it also eats a lot of birds and reptiles.

While it’s closely related to the harpy eagle, the New Guinea harpy eagle is placed in a different genus. This is also the case for another closely related bird, the crested eagle, which lives in parts of South America. It’s a little smaller than the harpy eagle of South America, with a wingspan of not quite 6 feet across, or 1.8 meters, with a black mask marking over its eyes and a black spot on its crest. Other than that it’s mostly gray.

The two species look enough alike that sometimes people confuse the crested eagle for a young harpy eagle where their ranges overlap. But in at least one documented case, the birds seemingly got confused too.

In early 2004, a team of scientists observing a harpy eagle nest noticed something odd. The nest had one baby in it that was about a month old when the scientists first observed it, and they noticed a crested eagle perched nearby. Every time the scientists visited the nest, the crested eagle seemed to be nearby, although the harpy eagle parents were also around and seemed just fine. The scientists observed the crested eagle adding branches to the nest and even bringing food to the harpy eagle baby. This continued for almost a year. The baby actively solicited food from the crested eagle and happily ate what it brought. At the same time, the harpy eagle parents allowed the crested eagle to approach, although generally the crested eagle didn’t come very close when the harpy eagle parents were around.

The scientists published a short paper about these observations in 2006, including a few hypotheses about the crested eagle’s behavior. They suggested that the crested eagle might have lost her own chick and transferred her maternal instincts to another eagle chick nearby, or she might have just been responding to the eagle chick’s requests for food. She might even have wanted to use that tree for her own nest, but when the bigger, stronger harpy eagles moved in, she abandoned her nest but hung around. A male crested eagle wasn’t observed, so it’s also possible she had lost her mate.

Sometimes different species of raptor do feed each other’s nestlings, although we don’t know why. It also occasionally happens with other types of birds, often male birds whose own nests are still being incubated by the female or by birds whose nest is very close to another nest with babies in it.

Another raptor that hunts animals that live in trees is the crane hawk, also from South America. It lives in forests that are near water and usually hunts by sitting in a tree and watching for potential prey. A lot of the time, though, it hunts like the New Guinea harpy eagle, climbing around in a tree and poking through any nooks and crannies to find animals that are hiding. In the case of the crane hawk, though, it actually has double-jointed legs that allow it to reach a foot into a little hole in a tree to grab prey. Most birds don’t have legs that are flexible enough to allow this behavior. The crane hawk eats a lot of nestling birds, bats, frogs, and other small animals that hide in tree cavities, including some larger invertebrates like cicadas and snails. The only other raptor known to both hunt like this and have double-jointed legs is a genus of African harrier-hawks that aren’t related to the crane hawk. Yes, it’s convergent evolution, at it again!

Let’s get out of the trees now and finish with another raptor Eva suggested. We talked about Ruppell’s griffon vulture in episode 159, but only very briefly.

Ruppell’s griffon vulture is a critically endangered vulture that lives in parts of central and eastern Africa. Unlike the raptors we’ve talked about so far in this episode, it spends a lot of its time soaring at high elevations, so it has really big wings. Its wingspan is as much as 8 and a half feet across, or 2.6 meters. It’s mostly brown and black and like other vultures, it doesn’t have feathers on its head, just a little bit of thin fluff. It will travel enormous distances to find the dead animals it eats, sometimes following herds of migrating animals to scavenge individuals that die of injury or illness. It doesn’t just eat the yummy soft parts of a carcass, it will also eat bones and even the hide of a dead animal. It has a long neck that helps it get to the best bits of its food, uh, from the inside of the carcass. It sometimes even climbs completely inside the rib cage of a dead animal to more easily get every scrap of food.

The way vultures eat is gross, which makes it fun for me to talk about, but vultures are incredibly important. They actually help stop the spread of diseases like rabies and anthrax by eating animals that died of the diseases. The vulture’s digestive tract is so effective that it kills off any viruses that caused the animals to die.

Ruppell’s vulture mates for life. It nests in cliffs, with hundreds of vulture pairs nesting very close together. The female lays one egg, and both parents take care of the baby when it hatches. Even after it can fly, the parents take care of their chick for almost a year while it learns how to find food on its own. Most vultures have relatively weak feet since they don’t use them to catch prey like other raptors, but Ruppell’s vulture has strong feet to help it perch on the cliffs where it nests.

Ruppell’s griffon vulture is one of the highest-flying birds known. It’s been recorded flying as high as 37,000 feet, or 11,300 meters, and we know it was flying at 37,000 feet because unfortunately it was sucked into a jet engine and killed. There’s so little oxygen at that height that a human would pass out pretty much instantly, but the vulture’s blood contains a variant type of hemoglobin that’s more efficient at carrying oxygen than ordinary hemoglobin.

As if all that weren’t enough for one bird, Ruppell’s vulture can also live to be 50 years old. That’s pretty good for an animal that mostly eats rotting and diseased meat.

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 320: More Elephants

Posted on by

Podcast: Play in new window | Download (Duration: 11:44 — 13.0MB)

Subscribe: RSS | More

Thanks to Connor and Pranav who suggested this week’s episode about elephants! It’s been too long since we had an elephant episode and there’s lots more to learn.

Further reading:

Asian elephants could be the maths kings of the jungle

Many wild animals ‘count’

A big difference between Asian and African elephants is diet

Study reveals ancient link between mammoth dung and pumpkin pie

The Asian elephant (left) and the African elephant (right):

The African bush elephant (left) and the African forest elephant (right) [photo taken from this page]:

The osage orange is not an orange and nothing wants to eat it these days:

Show transcript:

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

We haven’t talked about elephants since episode 200! It’s definitely time for some elephant updates, so thanks to Conner and Pranav for their suggestions!

Conner suggested we learn more about the Asian elephant, which was one we talked about way back in episode 200. The biggest Asian elephant ever reliably measured was a male who stood 11.3 feet tall, or 3.43 meters, although on average a male Asian elephant, also called a bull, stands about 9 feet tall, or 2.75 meters. Females, called cows, are smaller. For comparison, the official height of a basketball hoop is 10 feet, or 3 meters. An elephant could dunk the ball every single time, no problem.

The Asian elephant used to live throughout southern Asia but these days it’s endangered and its range is reduced to fragmented populations in southeast Asia. There are four living subspecies recognized today although there used to be more in ancient times.

Elephants are popular in zoos, but the sad fact is that zoo elephants often don’t live as long as wild elephants, even with the best care. The elephant is adapted to roam enormous areas in a family group, which isn’t possible in captivity. In the wild, though, the elephant is increasingly endangered due to habitat loss and poaching. Even though the Asian elephant is a protected species, people kill elephants because their tusks are valuable as ivory. Tusks are a modified form of really big tooth, and it’s valuable to some people because it can be carved into intricate pieces of art that can sell for a lot of money. That’s it. That’s the main reason why we may not have any elephants left in another hundred years at this rate, because rich people want carvings made in a dead animal’s tooth. People are weird, and not always the good kind of weird.

In happier Asian elephant news, though, a 2018 study conducted in Japan using zoo elephants replicated the results of previous studies that show Asian elephants have numeric competence that’s surprisingly similar to that in humans. That means they understand numbers at least up to ten, and can determine which group of items has more or less items than another group. That sounds simple because humans are really good at this, but most animals can only understand numbers up to three. It goes one, two, three, lots.

Many animals do have a good idea of numbers in a general way even if they can’t specifically count. Gray wolves, for instance, know how many wolves need to join the hunt to successfully bring down different prey animals. Even the humble frog will choose the larger group of food items when two groups are available. But the Asian elephant seems to have an actual grasp of numbers. I specify the Asian elephant because studies with African elephants haven’t found the same numeric ability.

Elephants make a lot of sounds, such as the iconic trumpeting that they make using the trunk. Way back in episode 8 we talked about the infrasonic sounds elephants also make with their vocal folds, sounds that are too low for humans to hear. But the Asian elephant also sometimes makes a high-pitched squeaking sound and until recently, no one was sure how it was produced. It turns out that the elephant makes this sound by buzzing its lips the same way a human does when playing a brass instrument. It’s the first time this particular method of sound production has been found outside of humans.

This is what a squeaking Asian elephant sounds like:

[elephant squeak]

Pranav suggested we learn more about the African forest and bush elephants. Those are the two species of African elephants that are still alive, and they’re also endangered due to habitat loss and poaching. The forest elephant is critically endangered. The forest elephant lives in forests, as you probably guessed, especially rainforests, while the bush elephant lives in grasslands and open forests. It’s sometimes called the savanna elephant since it’s well adapted to life on the savanna.

The forest elephant is only a little larger on average than the Asian elephant, while the bush elephant is much bigger on average. A big bull bush elephant can stand as much as 13 feet tall, or 4 meters, which means it might not dunk the basketball every time because the basketball hoop is awkwardly low.

The bush elephant lives in areas where it’s often extremely hot and dry. Since large animals retain heat, the bush elephant has many adaptations to stay cool. Its ears are really big, for instance, and have lots of blood vessels. This means the blood is close to the surface of the skin where it can shed heat into the air. In hot weather the elephant can flap its ears to help cool its blood faster. But one big adaptation has to do with its skin. The bush elephant’s skin is covered with what look like wrinkles but are actually crevices in the skin only a few micrometers wide. The crevices retain tiny amounts of water that help keep the elephant cool. Since elephants don’t have sweat glands the way people do, they have to bathe in water and mud to get moisture in the crevices in the first place.

Elephants are megaherbivores, meaning they eat mega amounts of plants. This has an impact on forest dynamics, but until recently the only studies on elephant diets and ecological effects were on African elephants. A 2017 study on Asian elephants in Malaysia found that instead of mostly eating sapling trees, the elephants preferred to eat bamboo, grasses, and especially palms.

In comparison, the African bush elephant eats plant parts that other animals can’t chew or digest, including tough stems, bark, and roots. It also eats grass, leaves, and fruit. The African forest elephant eats a lot more fruit and softer plant parts than the bush elephant, and in fact the forest elephant is incredibly important as a seed disperser. Seeds that pass through the forest elephant’s digestive system sprout a lot faster than seeds that don’t, and they also have the added benefit of sprouting in a pile of elephant dung. Instant fertilizer! At least 14 species of tree need the elephant to eat their fruit in order for the seeds to sprout at all. If the forest elephant goes extinct, the trees will too.

Around 11,000 years ago, when the North American mammoths went extinct, something similar happened. Mammoths and other megafauna co-evolved with many plants and trees to disperse their seeds, and in return the animals got to eat some yummy fruit. But when the mammoths went extinct, many plants seeds couldn’t germinate since there were no mammoths to eat the fruit and poop out the seeds. Some of these plants survive but have declined severely, like the osage orange. It produces giant yellowish-green fruits that look like round greenish brains, and although it’s related to the mulberry, you wouldn’t be able to guess that from the fruit. Nothing much eats the fruit these days, but mammoths and other megafauna loved it. The osage orange mostly survives today because the plant can clone itself by sending up fresh sprouts from old roots.

Another plant that nearly went extinct after the mammoth did is a surprising one. Wild ancestors of modern North American squash plants relied on mammoths to disperse their seeds and create the type of habitat where the plants thrived. Mammoths probably behaved a lot like modern elephants, pulling down tree limbs to eat and sometimes pushing entire trees over. This disturbed land is what wild squash plants loved, and if you’ve ever prepared a pumpkin or squash you’ll know that it’s full of seeds. The wild ancestors of these modern cultivated plants didn’t have delicious fruits, though, at least not to human taste buds. The fruit contained toxins that made them bitter, which kept small animals from eating them, because the small animals would chew up the seeds instead of swallowing them whole. But the mammoths weren’t bothered by the toxins and in fact probably couldn’t even taste the bitterness. They thought these wild squash were delicious and they ate a lot of them.

After the mammoth went extinct, the wild squash lost its main seed disperser. As forests grew thicker after mammoths weren’t around to keep the trees open, the squash also lost a lot of its preferred habitat. The main reason why we have pumpkins and summer squash is because of our ancient ancestors. They bred for squash that weren’t bitter, and they planted them and cared for the plants. So even though the main cause of the mammoth’s extinction was probably overhunting by ancient humans, at least we got pumpkin pies out of the whole situation. I mean, I personally would prefer to have both pumpkin pie AND mammoths, but no one asked me.

World Elephant Day is on August 12, and this episode is going live in late March. That means you have a little over four months to get your elephant celebration plans ready!

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 318: The Mysterious Malagasy Hippo

Posted on by

Podcast: Play in new window | Download (Duration: 15:41 — 17.8MB)

Subscribe: RSS | More

Thanks to the Tracing Owls podcast for this week’s suggestion. I’m a guest on that podcast so make sure to check it out (but while my episode is appropriate for younger listeners, most episodes are not, so be warned).

Further reading:

Huge Hippos Roamed Britain One Million Years Ago

Kenyan fossils show evolution of hippos

The Kilopilopitsofy, Kidoky, and Bokyboky: Accounts of Strange Animals from Belo-sur-mer, Madagascar, and the Megafaunal “Extinction Window”

A sort-of Malagasy hippo:

Actual hippo (not from Madagascar, By Muhammad Mahdi Karim – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=121282994):

A modern hippo skull. There’s a reason the hippo is more dangerous to humans than sharks are [By Raul654 – Darkened version of Image:Hippo skull.jpg, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=242785]:

A pygmy hippo and its calf!

Show transcript:

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

This week we’re going to learn about a topic suggested by the host of the podcast Tracing Owls, because I’m actually a guest on that podcast in an upcoming episode! I think the episode releases later this week. I’ll put a link in the show notes, but be aware that while the podcast is interesting and often very funny, with topics that focus on weird stuff related to science, most episodes are not appropriate for younger listeners. (I think my episode should be okay.)

Several years ago now there was a movie called Madagascar, which is about a group of zoo animals that end up shipwrecked on the island of Madagascar. I love this movie, especially the lemur King Julian, but one of my favorite characters is a hippopotamus named Gloria, voiced by Jada Pinkett Smith. The island country of Madagascar is off the southeastern coast of Africa, but as we talked about in episode 77, it’s been separated from the continent of Africa for millions of years and the animals of that country have mostly evolved separately from the animals of Africa. That’s part of why the movie Madagascar is so funny, since the main characters in the movie are all native to Africa—a lion, a zebra, a giraffe, and Gloria the hippo—and don’t know anything about the animals they encounter on Madagascar. Like this guy:

[King Julian clip]

But it turns out that hippos did once live on Madagascar, and that’s what we’re going to learn about today.

We’re not sure when the first humans visited Madagascar, but it was at least 2500 years ago and possibly as much as 9500 years ago or even earlier. By 1500 years ago people were definitely living on the island. 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.

Madagascar is a really big island, the fourth largest island in the world. It’s been separated from every other landmass for around 88 million years, and has been separated from Africa for about 165 million years. Many of the animals and plants that live on Madagascar are very different from the ones living anywhere else in the world as a result.

To put this into perspective, here’s your reminder that the closest living relative of the hippopotamus is the whale, and 60 million years ago the common ancestor of both hippos and whales was a small semi-aquatic animal. That was about 28 million years after Madagascar was on its own in the big wide ocean, and 105 million years after the landmass that we call Africa broke off from the supercontinent Gondwana and began moving very slowly into the position it’s in today. When Madagascar finally broke free of the landmass we now call India, dinosaurs were still the dominant land animal.

So why are there remains of small hippos on Madagascar? How did the hippos get to Madagascar and why aren’t they still around? Did the hippo originate in Africa or in some other place? So many questions!

The ancestors of modern cetaceans, which includes whales and dolphins and their close relations, are found in the fossil record about 52 million years ago, although it might have been 53 or even 54 million years ago depending on which scientist you ask. That’s when the whale side of the suborder Whippomorpha started developing separately from the hippo side. The “morpha” part of Whippomorpha just means “resembling,” and I’m happy to report that the “whippo” part is actually a combination of the words whale and hippo. Truly, it gave me great joy when I learned this fact, because I assumed “whippo” was something in Greek or Latin, or maybe referred to an animal with a whip-like tail. Nope, whale+hippo=whippo.

Anyway, while we know a fair amount about the evolution of cetaceans from their semi-aquatic ancestors, we don’t know much at all about the hippo’s evolution. There’s still a lot of controversy about whether hippos really are all that closely related to whales after all. They share a lot of similarities both physically and genetically, so they’re definitely relations, but whether they’re close cousins is less certain. The confusion is mainly due to not having enough fossils of hippopotamus ancestors.

The modern hippo, the one we’re familiar with today, usually called the common hippo, first appears in the fossil record about six million years ago. We have fossils of animals that were pretty obviously close relations to the common hippo, if not direct ancestors, that date back about 20 million years. But it’s the gap between the hypothesized shared ancestor of both hippos and cetaceans that lived around 60 million years ago, and the first ancestral hippos 20 million years ago, that is such a mystery.

What we do know, though, is that while the common hippo is native to Africa, its ancestors weren’t. Hippo relations once lived throughout Europe and Asia, and probably migrated to Africa around 35 million years ago. In fact, hippos were common throughout Eurasia until relatively recent times. In 2021, a fossilized hippopotamus tooth was found in a cave in Somerset, England that probably lived only one million years ago. That was well before humans migrated into the area, which was a good thing for the humans because this hippo was humongous. It probably weighed around 3 tons, or 3200 kg, while the common hippo is about half that on average.

This particular huge hippo, Hippopotamus antiquus, lived throughout Europe and only went extinct around 550,000 years ago as far as we know. This was during a time that Europe was a lot warmer than it is today and hippos migrated north from the Mediterranean as far as southern England. The common hippo, H. amphibius, the one still around today, also migrated back into Eurasia during this warm period and its fossilized remains have been found in parts of England too.

These days, there are only two living species of hippo, the common hippo and the pygmy hippo. We talked about the pygmy hippo briefly in episode 135, including the astonishing fact that it only grows around 3 feet tall, or 90 cm, and lives in deep forests in parts of west Africa. There also used to be some other small hippos that evolved on islands and exhibited island dwarfism, and which probably weren’t closely related to the pygmy hippo. These include the Cretan dwarf hippopotamus that lived on the Greek island of Crete until around 300,000 years ago and maybe much more recently, and the Cyprus dwarf hippopotamus that lived on the island of Cyprus until only around 10,000 years ago. The Cyprus hippo was the smallest hippo found so far, only about 2.5 feet tall, or 75 cm. There are dogs larger than that! But the small hippo we’re interested in is the Malagasy pygmy hippopotamus.

There actually wasn’t just one hippo species that lived on Madagascar. Scientists have identified three species, although this may change as more studies take place and as new remains are found. The different species probably didn’t all live on the island at the same time, and some researchers think they might have resulted from three different migrations of hippos to the island.

But how did they get to the island? Madagascar is 250 miles away from Africa, or 400 km, way too far for a hippo to swim. The Malagasy hippos were well established on the island, too, not just a few individuals who accidentally reached shore. That means there must have been some way for hippos to reach Madagascar fairly easily at different times.

The best hypothesis right now is that at times when the ocean was overall shallower than it is now, such as during the Pleistocene glaciations, there are enough small islands between Africa and Madagascar that hippos could travel between them pretty easily. Since those islands would be far underwater now, we don’t have any way to know for sure. We can’t exactly dive down and look for hippo fossils, unfortunately.

The really big question, of course, is whether any hippos still survive on Madagascar. We know they were around as recently as 1,000 years ago, because we have subfossil remains. (Just a reminder that subfossil means that the remains are either not fossilized, or only partially fossilized.) Not only that, the bones show butchering marks so we know people killed and ate the hippos. Right now scientists think the hippos were hunted to extinction by the humans who settled on Madagascar, but there’s some evidence that it happened much more recently than 1,000 years ago.

Over the last several hundred years, European colonizers of Madagascar collected stories from Malagasy natives about animals that resemble hippos. More recently, some stories have also been collected by scientists.

In 1995, a biologist named David Burney, who was studying recently extinct animals on Madagascar, interviewed some elderly residents in various villages. He wasn’t actually trying to learn about mystery animals, he was mostly just trying to find the paleontological sites scientists had found decades before. He figured the older residents would remember those scientists’ visits, and he was right. But the residents also had other stories to tell about the bones dug up by scientists. Some of them said those bones belonged to animals they had seen alive.

In one village, several different people told a story about a cow-sized animal that had occasionally entered the village at night. It was dark in color and made distinctive grunting sounds, and had large floppy ears. When some people approached it too closely, it ran back to the water and submerged.

Dr. Burney thought the residents might have seen pictures of an elephant and transferred some of its details to the mystery animal, especially the large size and floppy ears. But when he showed a picture of an elephant to them, they were clear that it wasn’t the same animal. They chose a picture of a hippo instead, but said the animal they’d seen had larger ears. Various witnesses also said the animal had a large mouth with really big teeth, that its feet were flat, and that it was the size of a cow but didn’t have horns. One man even imitated the animal’s call, which Burney reported sounded like a hippopotamus even though the man had never seen or heard a hippo.

Burney was cautious about publishing his findings, and in fact in his article he mentions that even at the time, he and his team of scientists were cautious about even pursuing information about living Malagasy hippos. They didn’t want to be seen as acting like cryptozoologists, which says a lot about how cryptozoologists conduct their research. Cryptozoology isn’t a scientific field of study despite its name. Biologists, paleontologists, and other experts research mystery animals all the time. That’s just part of their job; they don’t have to call themselves something special. It’s unfortunately common that people who call themselves cryptozoologists don’t have a scientific background and may not know how to conduct proper field research. Very often, cryptozoologists also don’t know very much about the animals that definitely exist, and how can you determine what a true mystery animal is if you don’t know about non-mystery animals?

Luckily, Dr. Burney and his team decided to pursue this particular mystery animal, along with some others they learned about. The last hippo-like animal sighting they could pin to a particular date happened in 1976. If the animal in question was a hippo, and it really was alive only about 50 years ago, it might have gone extinct since then. Or it might still be alive and hiding deep in the forests of Madagascar.

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!

This is what a hippo sounds like, and you hear it all the time on this podcast because I like it:

[hippo sound]

Episode 312: Little Bouncy Animals

Posted on by

Podcast: Play in new window | Download (Duration: 11:56 — 13.2MB)

Subscribe: RSS | More

Thanks to Zachary and Oran for this week’s topic, some little animals that bounce around like tiny kangaroos!

Further reading:

Evolution of Kangaroo-Like Jerboas Sheds Light on Limb Development

Supposedly extinct kangaroo rat resurfaces after 30 years

High-Speed Videos Show Kangaroo Rats Using Ninja-Style Kicks to Escape Snakes

Williams’s jerboa [picture by Mohammad Amin Ghaffari – https://www.inaturalist.org/photos/177950563, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=115769436]:

A drawing of a jerboa skeleton. LEGS FOR DAYS:

The San Quintin kangaroo rat lives! [photo from article linked above]

Show transcript:

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

This week we’re going to learn about two cute little animals suggested by Zachary and Oran! Both of these animals are rodents but although they look remarkably alike in some unusual ways, they’re not actually all that closely related.

First, Zachary suggested the jerboa. We talked about the pygmy jerboa in episode 136, but we haven’t talked about jerboas in general. It’s a small rodent that’s native to the deserts of Asia, north Africa, and the Middle East. It’s usually brown or tan with some darker shading on the back and tail. It looks sort of like a gerbil with long ears, long hind legs, and a tuft at the end of the tail. Its front legs are short and it has an adorable whiskery nose.

The reason the jerboa’s hind legs are so long while its front legs are really short is that it jumps around on its hind legs like a kangaroo. Not only can it jump really fast, up to 15 mph, or 24 km/h, it can change directions incredibly fast too. This helps it evade predators, because most animals are fastest when running in a straight line. The jerboa bounces in all sorts of directions, hopping or just running on its long hind legs, with its long tail held out for balance. It can also run on all fours with its short front legs helping it maneuver, but for the most part it’s a bipedal animal. It has tufts of stiff hairs under its toes that help it run through loose sand.

The jerboa eats plants, although sometimes if it finds a nice juicy insect it will eat it too. Mostly it just eats leaves, bulbs, roots, and some seeds. It gets all of the moisture it needs from its diet, which is good because it lives in the desert where there’s not much water available.

Some species of jerboa mainly eat insects and spiders, and some have short ears instead of long ears. This is the case for the thick-tailed pygmy jerboa that lives in parts of China, Mongolia, and Russia. Its head and body only measures about two inches long, or almost 5 cm, but its tail is twice that length. The reason it’s called a thick-tailed jerboa is because it stores fat at the base of its tail, which makes the tail look thick compared to many rodent tails.

The jerboa is mostly active at dawn and dusk, although some species are fully nocturnal. It spends the day in a burrow it digs in sand or dirt. A jerboa will usually have more than one burrow in its territory, with the entrances usually hidden under a bush or some other plant. Different burrows have different purposes. Some have numerous entrances and lots of side tunnels but are relatively shallow, which is useful if the jerboa lives in an area with a rainy season. A shallow burrow won’t flood if it rains a lot. Some burrows are temporary, which the jerboa may dig if it’s out and about during the day looking for food. A mother jerboa will dig a burrow with a roomy nesting chamber to raise her babies, and a jerboa’s winter burrow has a nesting chamber that’s deep underground to help it stay warm. Some species of jerboa construct unusual burrows, like the lesser Egyptian jerboa that has spiral-shaped burrows with storage chambers. Most jerboas are solitary animals, although sometimes a group will hibernate together in winter to help everyone stay warmer.

Scientists have been studying the jerboa to learn how different animals have evolved radically different leg lengths. The jerboa’s incredibly long hind legs are very different from its very short front legs, but it evolved from animals that had four short legs. But jerboas are born with four short legs, and as the babies grow up their hind legs grow longer and longer.

The jerboa is an incredibly efficient runner. Some species can jump as far as six feet in a single bound, or 1.8 meters, and up to three feet, or 90 cm, straight up.

The jerboa isn’t the only rodent that hops on its hind legs like a kangaroo. The kangaroo rat does too, and it’s Oran’s suggestion. Oran pointed out that a long time ago, I think in the humans episode, I said that humans are the only fully bipedal mammal, meaning we only ever walk on our hind legs. (Crawling when you’re a baby or trying to find something under the couch don’t count.) I was wrong about that for sure, because the kangaroo rat, the jerboa, and a few other mammals are also bipedal.

The kangaroo rat is native to parts of western North America. It looks a lot like a jerboa, with long hind legs and a long tail, although its ears are smaller. But the kangaroo rat and the jerboa aren’t closely related, although both are rodents. Their similarities are due to convergent evolution, since both animals live in very similar environments with the same selective pressures.

The largest species of kangaroo rat, the giant kangaroo rat, grows around 6 inches long, or 15 cm, with a tail about 8 inches long, or 20 cm. It can jump even longer than the jerboa although it doesn’t move as fast on average.

Like the jerboa, the kangaroo rat can change directions quickly, and it’s also mostly nocturnal and spends the day in a burrow. Some species spend almost all the time in burrows, only emerging for about an hour a night to gather seeds. Since owls like to eat kangaroo rats, you can’t blame them for wanting to stay underground as much as possible.

Snakes also like to eat kangaroo rats, especially the sidewinder rattlesnake. It’s a fast predator with venom that can easily kill a little kangaroo rat, but the kangaroo rat isn’t helpless. A study published in 2019 filmed interactions in the wild between the desert kangaroo rat and the sidewinder, using high-speed cameras. They had to use high-speed cameras because the snakes can go from completely unmoving to a strike in under 100 milliseconds. That’s less time than it takes you to blink. But the kangaroo rat can react in even less time, as little as 38 milliseconds after the snake starts to move. A lot of time the kangaroo rat will completely leap out of range of the snake, but if it can’t manage that, it will kick the snake with its long hind legs, which are strong enough to knock the snake away. Little fuzzy ninjas.

Unlike the jerboa, the kangaroo rat mostly eats seeds. The jerboa’s teeth aren’t very strong so it can’t bite through hard seeds, but the kangaroo rat’s teeth are just fine with seeds. The kangaroo rat also has cheek pouches, and it will carry lots of seeds home to its burrow. It keeps extra seeds in special burrow chambers called larders.

The kangaroo rat sometimes lives in colonies that can number in the hundreds, but it’s still a mostly solitary animal. It has its own burrow that’s separate from the burrows of other members of its colony, and it doesn’t share food or interact very much with its neighbors. It will communicate with other kangaroo rats by drumming its hind feet on the ground, including warning its neighbors to stay away and alerting them to predators in the area.

The kangaroo rat is vulnerable to habitat loss, since it mostly lives in desert grassland and humans tend to view that kind of land as useless and in need of development. An example of this is the San Quintin kangaroo rat, which is only found in western Baja California in Mexico. Only two large colonies were known when it was discovered by science in 1925, although it used to be much more widespread. But in the decades since 1925, the land was developed for agriculture until by 1986 the two colonies were completely wiped out. Scientists worried the species had gone extinct. Then, in 2017, a colony was discovered in a nature preserve and everyone breathed a sigh of relief. Other colonies have been discovered on farmland that has been abandoned due to drought. Still, the San Quintin kangaroo rat is critically endangered.

The kangaroo rat is actually helpful for the environment. Because it stores seeds underground, and sometimes forgets where it put them, it helps native plants spread. Its burrows help increase soil fertility and the spread of water through the soil. This is similar to the jerboa, which also eats enough insects to help reduce the number of agricultural pests in some areas.

There are also two species of kangaroo mouse, which are closely related to kangaroo rats. They mostly live in the state of Nevada in North America. There are also jumping mice that look like ordinary mice but with long hind legs. It also has cheek pouches. While some jumping mice live in western North America, some live in northeastern North America and Canada and are adapted to cold weather and long winters. One species of jumping mouse lives in the mountains in parts of China. There’s also a larger jumping rodent called the springhare that lives in parts of Africa, and which is about the size of a squirrel or a small rabbit. Like all these other rodents, it’s bipedal and hops on its hind legs like a little kangaroo, using its long tail for balance and to prop itself up when it’s standing. It mostly eats plants but will sometimes eat insects, and it spends most of the day in burrows. There’s also a hopping mouse native to Australia, which is a rodent with long hind legs and a long tail and long ears. It’s not closely related to the jerboa or the kangaroo rat, but it looks a lot like both because of convergent evolution. It mostly eats seeds.

All these animals are rodents, but Australia also has another animal called the kultarr that looks a lot like the kangaroo rat and the jerboa. It’s not a rodent, though. It’s actually a marsupial that’s completely unrelated to rodents although it looks like a rodent. That’s definitely what you call convergent evolution.

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 301: Hairless Mammals

Posted on by

Podcast: Play in new window | Download (Duration: 8:25 — 9.5MB)

Subscribe: RSS | More

Thanks to Liesbet for this week’s suggestion, about two mammals that have evolved to be hairless!

Happy birthday this week to Declan and Shannon!

The hairless bat has a doglike face and a doglike tail but (and this is important) it is not a dog [photos from this site]:

The naked mole-rat’s mouth is behind its teeth instead of the usual “my teeth are in my mouth” kind of thing:

Show transcript:

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

This week we have a suggestion from Liesbet, who asked about furless animals. We’re going to learn about two mammals that don’t have fur, and they’re not ones you may be thinking of.

But first, we have two birthday shout-outs! Happy birthday to Declan and Shannon! I hope both your birthdays are so amazing that whatever town you live in finishes off the day by giving you the key to the city. What do you do with the key? I don’t know, but it sounds like something to brag about.

Mammals are famous for having hair, but not all mammals actually have hair. Cetaceans like whales and dolphins have lost all their hair during their evolution into marine animals, although before a baby whale is born it has a little bit of fuzzy hair on its head. Other mammals, like humans, pigs, walruses, and elephants, have evolved to only have a little hair. There are also domesticated mammals that have been bred to have no hair, like sphynx cats and Chinese crested dogs.

There are other domesticated hairless mammals, though, including two types of guinea pig. The skinny pig only has a little bit of fuzzy hair on its face and ears, while the baldwin pig only has a tuft of hair on its nose. But the animals we’re going to talk about today are hairless animals you may not have heard of.

For instance, the hairless bat, which lives in parts of Southeast Asia. Its dark gray body is almost completely hairless, although it does sometimes have little patches of fuzz on the head and tail, and longer bristles around the neck. It’s nocturnal and eats insects, but since it’s a fairly large bat, around 6 inches long, or 15 cm, it can eat fairly large insects. It especially likes grasshoppers, termites, and moths.

The hairless bat roosts in colonies of up to a thousand individuals, and it lives in caves, hollow trees, or rock crevices. Although it uses echolocation, it doesn’t have a nose leaf like many microbats have, but instead has a little doglike snout. Its tail is skinny like a little dog’s tail instead of being connected to the hind legs or body by patagia. It has a little throat pouch that secretes strong-smelling oil.

It also has a sort of pocket on either side of the body. Originally people thought that mother bats used these pouches to carry their babies, since hairless bats usually have two babies at a time. Instead, it turns out that mother bats leave their babies at home when they go out to hunt, and the pockets are used for something else. The pockets are formed by a fold of skin and the end of the wing fingers and membranes fit into them. The bat uses its hind feet to push the wings into the pockets, sort of like stuffing an umbrella into the little cover that it comes in when you first buy it. This allows the bat to run around on all fours without its wings getting in the way. Since most bats can’t walk on all fours at all, this is pretty amazing.

Our other hairless animal today is the naked mole-rat, which is not a mole or a rat. It is a type of rodent but it’s more closely related to porcupines than to rats. It lives in tropical grasslands in parts of East Africa and spends almost its entire life underground. It lives in colonies of up to 300 individuals, and the colony’s tunnels and nesting burrows are extensive, often covering up to 3 miles, or 5 km. It eats roots of plants and the colony carefully only eats part of each root so that they don’t kill the plant. The roots continue to grow, providing the colony with lots of food.

The naked mole-rat grows about 4 inches long, or 10 cm, although dominant females are larger. It has tiny eyes and doesn’t see very well, since most of the time it doesn’t need to see, and it has a chonky body but short, spindly legs. It pretty much has no hair except for whiskers and some tiny hairs between the toes, and its skin is so pale it’s almost translucent. It digs with its protruding front teeth, and these teeth are not in its mouth. They grow out through the skin and the animal’s mouth is actually behind the teeth. This way the mole-rat can dig without getting dirt in its mouth, but it sure looks weird to us.

But that’s not even close to the weirdest thing about the naked mole-rat. We haven’t even scratched the surface of weirdness!

The naked mole-rat lives underground in a part of the world where it’s always warm, and its tunnel system has no exits to the surface except for temporary exits when new tunnels are being excavated, because the dirt has to go somewhere. Its environment is so consistent in temperature that it doesn’t need to regulate its body temperature like every other mammal known. It’s ectothermic, which is sometimes called cold-blooded. Reptiles and amphibians are ectothermic but all other mammals known are endothermic. It’s kind of our thing. But the naked mole-rat is different. Its metabolism is extremely low, and as a result it can live for more than 30 years when most rodents the same size are lucky to live 2 or 3 years.

The naked mole-rat’s skin isn’t just hairless, it also lacks neurotransmitters. This means its skin doesn’t feel pain. The animal also lives in an environment that’s remarkably low in oxygen, and scientists think this contributes to the fact that the mole-rat never shows evidence of cancer except in captivity where its environment is higher in oxygen.

The naked mole-rat’s colony is led by a dominant female, called a queen, and she’s the only female in the colony that has babies. When a female achieves dominance, either by founding a new colony, taking over after the current queen dies, or defeating the current queen in a fight, she then grows larger and becomes able to reproduce. Only a few males in the colony mate with her. All the other members of the colony are unable to reproduce. They’re considered workers and help take care of the queen’s babies, maintain tunnels, forage for food, or act as soldiers to keep snakes and other predators out. If this sounds like the way some insect colonies are structured, especially bees and ants, you’re right. It’s called eusociality and the mole-rat is the only type of mammal known with this sort of social structure. There’s another type of mole-rat from southern Africa that’s also eusocial, but it has fur.

All that is so weird that I almost forgot the mole-rat is hairless. That now seems like the most normal thing 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. 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 292: The Kunga

Posted on by

Podcast: Play in new window | Download (Duration: 7:52 — 9.1MB)

Subscribe: RSS | More

This week let’s learn about a mystery that was solved by science!

Happy birthday to Zoe!

Further reading:

Let’s all do the kunga!

The kunga, as depicted in a 4500-year-old mosaic:

The Syrian wild ass as depicted in a 1915 photograph (note the size of the animal compared to the man standing behind it):

Domestic donkeys:

Show transcript:

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

As this episode goes live, I should be on my way home from Dragon Con, ready to finish moving into my new apartment! It’s been an extremely busy week, so we’re just going to have a short episode about a historical mystery that was recently solved by science.

But first, we have another birthday shout-out! Happy birthday to Zoe, and I hope you have the most sparkly and exciting birthday ever, unless you’d rather have a chill and low-key birthday, which is just as good depending on your mood.

This week we’re going to learn about an animal called the kunga, which I learned about on Dr. Karl Shuker’s blog. There’s a link in the show notes if you’d like to read his original post.

The mystery of the kunga goes back thousands of years, to the fertile crescent in the Middle East. We’ve talked about this area before in episode 177, about the sirrush, specifically Mesopotamia. I’ll quote from that episode to give you some background:

“These days the countries of Iraq and Kuwait, parts of Turkey and Syria, and a little sliver of Iran are all within what was once called Mesopotamia. It’s part of what’s sometimes referred to as the Fertile Crescent in the Middle East. The known history of this region goes back five thousand years in written history, but people have lived there much, much longer. Some 50,000 years ago humans migrated from Africa into the area, found it a really nice place to live, and settled there.

“Parts of it are marshy but it’s overall a semi-arid climate, with desert to the north. People developed agriculture in the Fertile Crescent, including irrigation, but many cultures specialized in fishing or nomadic grazing of animals they domesticated, including sheep, goats, and camels. As the centuries passed, the cultures of the area became more and more sophisticated, with big cities, elaborate trade routes, and stupendous artwork.”

The domestic horse wasn’t introduced to this area until about 4,000 years ago, although donkeys were common. The domestic donkey is still around today, of course, and is descended from the African wild ass. Researchers estimate it was domesticated 5- or 6,000 years ago by the ancient nomadic peoples of Nubia, and quickly spread throughout the Middle East and into southern Asia and Europe.

But although horses weren’t known in the Middle East 4,500 years ago, we have artwork that shows an animal that looks like a really big donkey, much larger than the donkeys known at the time. It was called the kunga and was highly prized as a beast of burden since it was larger and stronger than an ordinary donkey. It was also rare, bred only in Syria and exported at high prices. No one outside of Syria knew what kind of animal the kunga really was, but we have writings that suggest it was a hybrid animal of some kind. This explains why its breeding was such a secret and why it couldn’t be bred elsewhere. Many hybrid animals are infertile and can’t have babies.

If the artwork was from later times, we could assume it showed mules, the offspring of a horse and a donkey. But horses definitely weren’t known in the Middle East or nearby areas at this time, so it can’t have been a mule.

The kunga was used as a beast of burden to pull plows and wagons, but the largest individuals were used to pull the chariots of kings. Fortunately, the kunga was so highly prized that it was sometimes sacrificed and buried with important people as part of their grave goods. Archaeologists have found a number of kunga skeletons, together with ceremonial harnesses. Unfortunately, it’s actually difficult to tell the difference between the skeletons of various equids, including horses, donkeys, zebras, and various hybrid offspring like mules. All scientists could determine is that the kunga most closely resembled various species and subspecies of donkey.

In January 2022, the mystery was finally solved. A genetic study of kunga remains was published that determined that the kunga was the offspring of a female domesticated donkey and a male Syrian wild ass.

The Syrian wild ass was native to many parts of western Asia. It was barely more than three feet tall at the shoulder, or about a meter, and while it was admired as a strong, beautiful animal that was sometimes hunted for its meat and skin, it couldn’t be tamed.

Because the Syrian wild ass was a different species of equid from the domesticated donkey, and because it couldn’t be tamed and was hard to catch, breeding kungas would be difficult. Male wild asses had to be captured, probably when young, and kept with female donkeys in hopes that they would mate eventually and offspring would result. Obviously the kunga showed what’s called hybrid vigor, where a hybrid is stronger than either of its parents, but because it was also infertile, the largest and strongest kungas couldn’t be bred together. Each kunga had to be bred from a pairing of wild ass and domestic donkey. No wonder it was expensive!

When the horse was introduced to the Middle East, it took the place of the kunga quickly and before long everyone had forgotten what the kunga even was.

Sadly, we can’t try to breed a kunga today to see what it was really like, because the Syrian wild ass went extinct in 1927. But the endangered Persian wild ass was introduced to parts of the Middle East starting in 2003, including Saudi Arabia, Iran, and Israel, to take the place of its extinct Syrian relation, and its numbers are increasing.

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 291: The Ediacaran Biota

Posted on by

Podcast: Play in new window | Download (Duration: 16:04 — 18.3MB)

Subscribe: RSS | More

This week let’s find out what lived before the Cambrian explosion!

A very happy birthday to Isaac!

Further reading:

Some of Earth’s first animals–including a mysterious, alien-looking creature–are spilling out of Canadian rocks

Say Hello to Dickinsonia, the Animal Kingdom’s Newest (and Oldest) Member

Charnia looks like a leaf or feather:

Kimberella looks like a lost earring:

Dickinsonia looks like one of those astronaut footprints on the moon:

Spriggina looks like a centipede no a trilobite no a polychaete worm no a

Glide reflection is hard to describe unless you look at pictures:

Trilobozoans look like the Manx flag or a cloverleaf roll:

Cochleatina looked like a snail:

Show transcript:

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

It’s the last week of August 2022, so let’s close out invertebrate August with a whole slew of mystery fossils, all invertebrates.

But first, we have a birthday shoutout! A humongous happy birthday to Isaac! Whatever your favorite thing is, I hope it happens on your birthday, unless your favorite thing is a kaiju attack.

We’ve talked about the Cambrian explosion before, especially in episode 69 about some of the Burgess shale animals. “Cambrian explosion” is the term for a time starting around 540 million years ago, when diverse and often bizarre-looking animals suddenly appear in the fossil record. But we haven’t talked much about what lived before the Cambrian explosion, so let’s talk specifically about the Ediacaran (eedee-ACK-eron) biota!

I was halfway through researching this episode when I remembered I’d done a Patreon episode about it in 2021. Patrons may recognize that I used part of the Patreon episode in this one. You’d think that would save me time but surprise, it did not.

The word Ediacara comes from a range of hills in South Australia, where in 1946 a geologist noticed what he thought were fossilized impressions of jellyfish in the rocks. At the time the rocks were dated to the early Cambrian period, and this was long before the Cambrian explosion was recognized as a thing at all, much less such an important thing. But since then, geologists and paleontologists have reevaluated the hills and determined that they’re much older than the Cambrian, dating to between 635 to 539 million years ago. That’s as much as 100 million years before the Cambrian. The Ediacaran period was formally designated in 2004 to mark this entire period of time, although fossils of Ediacaran animals generally start appearing about 580 million years ago.

Here’s something interesting, by the way. During the Ediacaran period, every day was only 22 hours long instead of 24, and there were about 400 days in a year instead of 365. The moon was closer to the earth too. And life on earth was still sorting out the details.

Fossils from the Ediacaran period have been discovered in other places besides Australia, including Namibia in southern Africa, Newfoundland in eastern Canada, England, northwestern Russia, and southern China. Once the first well-preserved fossils started being found, in Newfoundland in 1967, paleontologists started to really take notice, because they turned out to be extremely weird. The fossils, not the paleontologists.

Many organisms that lived during this time lived on, in, or under microbial mats on the sea floor or at the bottoms of rivers. Microbial mats are colonies of microorganisms like bacteria that grow on surfaces that are either submerged or just tend to stay damp. Microbial mats are still around today, usually growing in extreme environments like hot springs and hypersaline lakes. But 580 million years ago, they were everywhere.

One problem with the Ediacaran biota, and I should explain that biota just means all the animals and plants that live in a particular place, is that it’s not always clear if a fossil is actually an animal. Many Ediacaran fossils look sort of plant-like. At this stage, the blurry line between animals and plants was even more blurry than it is now, with the added confusion that sometimes non-organic materials can resemble fossils, and vice versa.

For instance, the fossil Charnia, named after Charnwood Forest in England where it was first discovered. In 1957, a boy named Roger, who was rock-climbing in the forest, found a fossil that looked like a leaf or feather. He took a rubbing of the fossil and showed his father, who showed it to a geologist. The year before, in 1956, a 15-year-old girl named Tina saw the same fossil and told her teacher, who said those rocks dated to before the Cambrian and no animals lived before the Cambrian, so obviously what she’d found wasn’t a fossil.

Tina’s teacher was wrong about that, of course, although he was correct that the rocks dated to before the Cambrian, specifically to about 560 million years ago. But while Charnia looks like a leaf, it’s not a plant. This was about 200 million years before plants evolved leaves, and anyway Charnia lived in water too deep for plants to survive. It anchored itself to the sea floor on one end while the rest of the body stuck up into the water, and some specimens have been found that were over two feet long, or 66 cm. Some researchers think it was a filter feeder, but we have very little evidence one way or another.

One common animal found in Australia and Russia is called Kimberella, which lived around 555 million years ago and might have been related to modern mollusks or to gastropods like slugs. It might have looked kind of like a slug, at least superficially. It grew up to 6 inches long, or 15 cm, 3 inches wide, or 7 cm, and an inch and a half high, or 4 cm, which was actually quite large for most animals that lived back then. It was shaped roughly like an oval, with one thin end that stuck out, potentially showing where its front end was, although it didn’t have a head the way we think of it today. The upper surface of its body was protected by a shell, but not the type of shell you’d find on the seashore today. This was a flexible, non-mineralized shell, basically just thick, toughened tissue with what may be mineralized nodules called sclerites embedded in it. All around its body was a frill that might have acted as a gill. The underside of Kimberella was a flat foot like that of a slug.

We know Kimberella lived on microbial mats on the sea floor, and it might have had a feeding structure similar to a radula. That’s because it’s often found associated with little scratches on its microbial mat that resemble the scratches made by a radula when a slug or related animal is feeding on a surface. The radula is a tongue-like organ studded with hard, sharp structures that the animal uses to scrape tiny food particles from a surface.

Kimberella displays bilateralism, meaning it’s the same side to side. That’s the case with a lot of modern animals, including all vertebrates and a lot of invertebrates too, like insects and arachnids. But other Ediacarans showed radically different body plans. Charnia, for instance, exhibits glide reflection, where both sides are the same as in bilateralism, but the sides aren’t exactly opposite each other. If you walk along a beach and make footprints in the sand, your trail of footprints actually demonstrates glide reflection. If you stand on the sand and jump forward with both feet together, your footprints demonstrate bilateralism since the prints are side by side. (This is confusing to describe, sorry.) Pretty much the only living animals with this body pattern are some sea pens, which get their name because they resemble old-fashioned quill pens. Many sea pens look like plants, and for a long time researchers thought Charnia might be an ancient relation to the sea pen. These days most researchers are less certain about the relationship.

A similar-looking animal that lived around the same time as Charnia was Dickinsonia. It looks sort of like a leaf too, but a more broad oval-shaped leaf instead of a long thin one like Charnia. It’s also not a leaf. Some are only a few millimeters long, but some are over 4 1/2 feet long, or 1.4 meters.

Dickinsonia may be related to modern placozoans, a simple squishy creature only about one millimeter across. It travels very slowly across the sea floor and absorbs nutrients from whatever organic materials it encounters. But we don’t know if Dickinsonia was like that or if it was something radically different. Until a few years ago a lot of paleontologists thought Dickinsonia might be some kind of early plant or algae. Then, in 2016, a graduate student discovered some Dickinsonia fossils that were so well preserved that researchers were able to identify molecular information from them. They found cholesteroids in the preserved cells, and since only animals produce cholesteroids, Dickinsonia was definitely an animal. But that’s still about all we know about it so far.

Spriggina is another animal that at first glance looks like a leaf or feather. Then it sort of resembles a trilobite, or a segmented worm, or a possible relation to Dickinsonia. It looks like all sorts of animals but doesn’t really fit with anything known. It grew up to two inches long, or 5 cm, and had what’s referred to as a head shield although we don’t know for sure if it was actually its head. The head shield might have had eyes and might have had some kind of antennae, and some fossils seem to show a round mouth in the middle of the head, but it’s hard to tell. The rest of its body was segmented in rings. What Spriggina didn’t have was legs, or at least none of the fossils found so far show any kind of legs. Some species of Spriggina show a glide reflection body plan, while others appear to show a more ordinary bilateral body plan.

Three Ediacaran animals have such a weird body plan that they’ve been placed in their own phylum, Trilobozoa, meaning three-lobed animals. They show tri-radial symmetry, meaning that they have three sections that are identical radiating out from the center. They lived on microbial mats and were only about 40 mm across at most, which is about an inch and a half. Tribrachidium was roughly round in shape although its relations looked more like tiny cloverleaf rolls. Cloverleaf rolls are made by putting three little round pieces of dough together and baking them so that the roll has three lobes, although Trilobozoans probably didn’t taste as good. Also, Trilobozoans were covered with little grooves from center to edge and had three curved ridges, one on each lobe. The ridges were originally interpreted as arms or tentacles, but they seem to have just been ridges. Researchers think the little grooves directed water over the body’s surface and the ridges acted as tiny dams that slowed the water down just enough that particles of food carried in the water would fall onto the body so that the animal could absorb the nutrients, although we don’t know how that worked.

Many other Ediacaran animals had radial symmetry like modern echinoderms and jellyfish, including the ancestors of jellyfish. Some Ediacaran animals even had shells of various kinds, and they’re generally referred to as small shelly fossils. They were rarely more than a few millimeters across at most and are sometimes found mixed in with microbial mats. Cochleatina, for instance, is less than a millimeter across and all we know about it is that it had a ribbon-like spiral shell like a really simple snail’s shell. It wasn’t a snail, though. We don’t even know if it was an animal. It might have been some kind of algae or it might have been something else. Unlike most small shelly fossils, Cochleatina survived into the Cambrian period.

We’re also not sure why most Ediacaran organisms went extinct at the beginning of the Cambrian, but it’s probable that most were outcompeted by newly evolved animals. There may also have been a change in the chemical makeup of the ocean and atmosphere that caused an extinction event of old forms and allowed the rapid expansion of new animal forms that we call the Cambrian explosion.

We can also learn a lot about what we don’t find in the Ediacaran rocks. Pre-Cambrian animals didn’t appear to burrow into the sea floor, or at least we haven’t found any burrows, just tracks on the surface. Most Ediacaran animals also didn’t have armored bodies or claws or so forth. Researchers think that predation was actually pretty rare back then, with most animals acting as passive filter feeders to gather nutrients from the water, or they ate the microbial mats. It wasn’t until the Cambrian explosion that we see evidence that some animals evolved to kill and eat other animals exclusively.

With every new Ediacaran fossil that’s found and studied, we learn more about this long-ago time when multi-cellular life was brand new.

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 289: Weird Worms

Posted on by

Podcast: Play in new window | Download (Duration: 14:20 — 16.4MB)

Subscribe: RSS | More

This week we learn about some weird worms!

Further reading:

Otherworldly Worms with Three Sexes Discovered in Mono Lake

Bizarre sea worm with regenerative butts named after Godzilla’s monstrous nemesis

Underground giant glows in the dark but is rarely seen

Giant Gippsland earthworm (you can listen to one gurgling through its burrow here too)

Further watching:

A giant Gippsland earthworm

Glowing earthworms (photo by Milton Cormier):

This sea worm’s head is on the left, its many “butts” on the right [photo from article linked to above]:

A North Auckland worm [photo from article linked to above]:

A giant beach worm:

Show transcript:

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

This week we continue Invertebrate August with a topic I almost saved for monster month in October. Let’s learn about some weird worms!

We’ll start with a newly discovered worm that’s very tiny, and we’ll work our way up to larger worms.

Mono Lake in California is a salty inland lake that probably started forming after a massive volcanic eruption about 760,000 years ago. The eruption left behind a crater called a caldera that slowly filled with water from rain and several creeks. But there’s no outlet from the lake—no river or even stream that carries water from the lake down to the ocean. As a result, the water stays where it is and over the centuries a lot of salts and other minerals have dissolved into the lake from the surrounding rocks. The water is three times as salty as the ocean and very alkaline.

No fish live in the lake, but some extremophiles do. There’s a type of algae that often turns the water bright green, brine shrimp that eat the algae, some unusual flies that dive into the water encased in bubbles, birds that visit the lake and eat the brine shrimp and flies, and eight species of worms that have only been discovered recently. All the worms are weird, but one of them is really weird. It hasn’t been described yet so at the moment is just going by the name Auanema, since the research team thinks it probably belongs in that genus.

Auanema is microscopic and lives throughout the lake, which is unusual because the lake contains high levels of arsenic. You know, a DEADLY POISON. But the arsenic and the salt and the other factors that make the lake inhospitable to most life don’t bother the worms.

Auanema produces offspring that can have one of three sexes: hermaphrodites that can self-fertilize, and males and females that need each other to fertilize eggs. Researchers think that the males and females of the species help maintain genetic diversity while the hermaphrodites are able to colonize new environments, since they don’t need a mate to reproduce.

When some of the worms were brought to the laboratory for further study, they did just fine in normal lab conditions, without extreme levels of arsenic and so forth. That’s unusual, because generally extremophiles are so well adapted for their extreme environments that they can’t live anywhere else. But Auanema is just fine in a non-harsh environment. Not only that, but the team tested other species in the Auanema genus that aren’t extremophiles and discovered that even though they don’t live in water high in arsenic, they tolerate arsenic just as well as the newly discovered species.

The team’s plan is to sequence Auanema’s genome to see if they can determine the genetic factors that confer such high resistance to arsenic.

Next, we go up in size from a teensy worm to another newly discovered worm, this one only about 4 inches long at most, or 10 cm. It’s a marine polychaete worm that lives inside sea sponges, although we don’t know yet if it’s parasitizing the sponge or if it confers some benefit to the sponge that makes this a symbiotic relationship. The worm was only discovered in 2019 near Japan and described in early 2022 as Ramisyllis kingghidorahi.

Almost all worms known are shaped, well, like worms. They have a mouth at one end, an anus at the other, and in between they’re basically just a tube. Ramisyllis is one of only three worms known that have branched bodies, which is why they’re called branching sea worms. In this case, Ramisyllis has a single head, which stays in the sponge, but its other end branches into multiple tail ends that occasionally break off and swim away. The tails are specialized structures called stolons. When a stolon breaks off, it swims away and releases the eggs or sperm it contains into the water before dying. The worm then regenerates another stolon in its place.

Ramisyllis’s branches are asymmetrical and the worms found so far can have dozens of branches. Its close relation, a species that lives in sponges off the coast of northern Australia, can have up to 100 branches. Researchers suspect that there are a lot more species of branching sea worms that haven’t been discovered yet.

Next, let’s head back to land to learn about a regular-sized earthworm. There are quite a few species across three different earthworm families that exhibit a particular trait, found in North and South America, Australia and New Zealand, and parts of Africa. A few species have been introduced to parts of Europe too. What’s the trait that links all these earthworms? THEY CAN GLOW IN THE DARK.

Bioluminescent earthworms don’t glow all the time. Most of the time they’re just regular earthworms of various sizes, depending on the species. But if they feel threatened, they exude a special slime that glows blue or green in the dark, or sometimes yellowish like firefly light. The glow is caused by proteins and enzymes in the slime that react chemically with oxygen.

Researchers think that the light may startle predators or even scare them away, since predators that live and hunt underground tend to avoid light. The glow may also signal to predators that the worm could taste bad or contain toxins. The light usually looks dim to human eyes but to an animal with eyes adapted for very low light, it would appear incredibly bright.

One bioluminescent earthworm is called the New Zealand earthworm. It can grow up to a foot long, or 30 cm, although it’s only about 10 mm thick at most, and while it’s mostly pink, it has a purplish streak along the top of its body (like a racing stripe).

Like other earthworms, the New Zealand earthworm spends most of its time burrowing through the soil to find decaying organic matter, mostly plant material, and it burrows quite deep, over 16 feet deep, or 5 meters. If a person tried to dig a hole that deep, without special materials to keep the hole from collapsing, it would fall in and squish the person. Dirt and sand are really heavy. The earthworm has the same problem, which it solves by exuding mucus from its body that sticks to the dirt and hardens, forming a lining that keeps the burrow from collapsing. This is a different kind of mucus than the bioluminescent kind, and all earthworms do this. Not only does the burrow lining keep the worm safe from being squished by cave-ins, it also contains a toxin that kills bacteria in the soil that could harm the worm.

Worms that burrow as deep as the New Zealand earthworm does are called subsoil worms, as opposed to topsoil worms that live closer to the surface. Topsoil contains a lot more organic material than subsoil, but it’s also easier for surface predators to reach. That’s why topsoil worms tend to move pretty fast compared to subsoil worms.

The New Zealand earthworm glows bright orange-yellow if it feels threatened, so bright that the Maori people used the worm as bait when fishing since it’s basically the best fish lure ever.

Another New Zealand earthworm is called the North Auckland worm, and while it looks like a regular earthworm that’s mostly pink or greenish, it’s also extremely large. Like, at least four and a half feet long, or 1.4 meters, and potentially much longer. It typically lives deep underground in undisturbed forests, so there aren’t usually very many people around on the rare occasion when heavy rain forces it to the surface. Since earthworms of all kinds absorb oxygen through the skin, instead of having lungs or gills, they can’t survive for long in water and have to surface if their burrow completely floods.

We don’t actually know that much about the North Auckland worm. Like the New Zealand earthworm, it’s a subsoil worm that mostly eats dead plant roots. Some people report that it glows bright yellow, although this hasn’t been studied and it’s not clear if this is a defensive reaction like in the New Zealand earthworm. It’s possible that people get large individual New Zealand earthworms confused with smaller North Auckland worm individuals. Then again, there’s no reason why both worms can’t bioluminesce.

An even bigger worm is the giant beach worm. It’s a polychaete worm, not an earthworm, and like other polychaete worms, including the branching sea worm we talked about earlier, it has a segmented body with setae that look a little like legs, although they’re just bristles. The giant beach worm’s setae help it move around through and over the sand. It hides in a burrow it digs in the sand between the high and low tide marks, but it comes out to eat dead fish and other animals, seaweed, and anything else it can find. It has strong jaws and usually will poke its head out of its burrow just far enough to grab a piece of food. It has a really good sense of smell but can’t see at all.

There are two species of giant beach worm that live in parts of Australia, especially the eastern and southeastern coasts, where people dig them up to use as fish bait. The largest species can grow up to 8 feet long, or 2.4 meters, and possibly even longer. There are also two species that live in Central and South America, although we don’t know much about them.

Another huge Australian worm is the endangered Giant Gippsland earthworm that lives in Victoria, Australia. It’s also a subsoil worm and is about 8 inches long, or 20 cm…when it’s first hatched. It can grow almost ten feet long, or 3 meters. It’s mostly bluish-gray but you can tell which end is its head because it’s darker in color, almost purple. It lives beneath grasslands, usually near streams, and is so big that if you happen to be in the right place at the right time on a quiet day and listen closely, you might actually hear one of the giant worms moving around underground. When it moves quickly, its body makes a gurgling sound as it passes through the moist soil in its burrow.

The Giant Gippsland earthworm is increasingly endangered due to habitat loss. It also reproduces slowly and takes as much as five years to reach maturity. Conservationists are working to protect it and its remaining habitat in Gippsland. The city of Korumburra used to have a giant worm festival, but it doesn’t look like that’s been held for a while, which is too bad because there aren’t enough giant worm festivals in the world.

To finish us off, let’s learn what the longest worm ever reliably measured is. It was found on a road in South Africa in 1967 and identified as Microchaetus rappi, or the African giant earthworm. It’s mostly dark greenish-brown in color and it looks like an earthworm, because it is an earthworm. On average, this species typically grows around 6 feet long, or 1.8 meters, which is pretty darn big, but this particular individual was 21 feet long, or 6.7 meters. It’s listed in the Guinness Book of World Records as the longest worm ever measured. Beat that, other worms. I don’t think you can.

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 288: Mystery Invertebrates

Posted on by

Podcast: Play in new window | Download (Duration: 19:58 — 22.9MB)

Subscribe: RSS | More

Thanks to Joel for suggesting this week’s topic!

Happy birthday to Fern this week!

Further reading:

Small, rare crayfish thought extinct is rediscovered in cave in Huntsville city limits

Hundreds of three-eyed ‘dinosaur shrimp’ emerge after Arizona monsoon

An invertebrate mystery track in South Africa

The case of the mysterious holes in the sea floor

Contemplating the Con Rit

The Shelton Cave crayfish, rediscovered:

The three-eyed “tadpole shrimp” or “dinosaur shrimp,” triops [photo from article linked above]:

A leech track in South Africa [photo from article linked above]:

A track, or at least a series of holes, discovered in the deep seafloor [photos from article linked above]:

Show transcript:

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

Thanks to Joel who suggested we do an episode about mystery invertebrates! It took me a while, but I think you’re really going to like this episode. Some of the mysteries are solved and some are not, but they’re all fun.

Before we get to the mystery animals, though, we have a birthday shout-out! A great big happy birthday to Fern! I hope you have your favorite type of birthday cake or other treat and get to enjoy it with your loved ones.

Our first mystery starts in a cave near Huntsville, Alabama in the southern United States, which is in North America. Shelta Cave is a relatively small cave system, only about 2,500 feet long, or 760 meters. That’s about half a mile. It’s a nature preserve now but in the early 1900s it was used as an underground dance hall with a bar and everything.

Biologist John Cooper studied the cave’s aquatic ecosystem in the 1960s when he was doing his dissertation work. His wife Martha helped him since they were both active cavers. At the time, the cave ecosystem was incredibly diverse, including three species of crayfish. One was called the Shelta Cave crayfish, which was only a few inches long, or about 5 cm, mostly translucent or white since it didn’t have any pigment in its body, and with long, thin pincers.

It was rarer than the cave’s other two crayfish species, and unlike them it had only ever been found in Shelta Cave. From 1963 to 1975, only 115 individuals had been confirmed in repeated studies of the cave’s ecosystem.

Then, in the 1970s, several things happened that caused a serious decline in the diversity of life in the cave.

The first was development of the land around the cave into subdivisions, which meant that more pesticides were used on lawns and flower beds, which made its way into the groundwater that entered the cave. It also meant more people discovering the cave and going in to explore, which was disturbing a population of gray bats who also lived in the cave. To help the bats and keep people out, the park service put a gate over the entrance, but the initial gate’s design wasn’t a very good one. It kept people out but it also made it harder for the bats to go in and out, and eventually the bats gave up and moved out of the cave completely. This really impacted the cave’s ecosystem, since bats bring a lot of nutrients into a cave with their droppings and the occasional bat who dies and falls to the cave floor.

The gate has since been replaced with a much more bat-friendly one, but studies afterwards showed that a lot of the animals found in the cave had become rare. The Shelta Cave crayfish had disappeared completely. One was spotted in 1988 but after that, nothing, and the biologists studying the cave worried that it had gone extinct.

Then, in 2019, a team of scientists and students surveying life in the cave spotted a little white crayfish with long, thin pincers in the water. The team leader dived down and scooped it up with his net to examine more closely. The crayfish turned out to be a female Shelta Cave crayfish with eggs, which made everyone excited, and after taking a tiny tissue sample for DNA testing, and lots of photographs, they released her back into the water. The following year they found a second Shelta Cave crayfish.

The Shelta Cave crayfish is so little known that we don’t even know what it eats or how it survives in the same environment with two larger crayfish species. Biologist Dr. Matthew Niemiller is continuing Dr. Cooper’s initial studies of the cave and will hopefully be able to learn more about the crayfish and its environment.

Next let’s travel from a cool, damp, flooded cave in Alabama to northern Arizona. Arizona is in the western United States and this particular part of the state has desert-like conditions most of the year. Almost a thousand years ago, people built what is now called Wupatki Pueblo, a 100-room building with a ballcourt out front and a big community room. It was basically a really nice apartment building. Wupatki means “tall house” in the Hopi language, and while the pueblo people who built it are long gone, Wupatki is still an important place for the Hopi and other Native American tribes in the area. It’s also a national monument that has been studied and restored by archaeologists and is open to the public.

In late July 2021, torrential rain fell over the area, so much rain that it pooled into a shallow temporary lake around Wupatki, including flooding the ballcourt. The ballcourt is 105 feet across, or 32 meters, and surrounded by a low wall. One day while the ballcourt was still flooded, a tourist came up to the lead ranger, Lauren Carter. The visitor said there were tadpoles in the ballcourt.

There are toads in the area that live in burrows and only come out during the wet season when there’s rain, and Carter thought the tadpoles might be from the toads. She went to investigate, saw what looked like tadpoles swimming around, and scooped one up in her hands to take a closer look. But the tadpoles were definitely not larval toads. In fact, they kind of looked like teensy horseshoe crabs, with a rounded shield over the front of the body and a segmented abdomen and tail sticking out from behind, with two long, thin spines at the very end that are called caudal extensions. It had two pairs of antennae and lots of small legs underneath, some adapted for swimming. The largest of the creatures were about two inches long, or 5 cm.

What on earth were they, and where did they come from? This area is basically a desert. Carter stared at the weird little things and remembered hearing about something similar when she worked at the Petrified Forest National Park, also in Arizona. She looked the animal up and discovered what it was.

It’s called Triops and is in the order Notostraca. Notostracans are small crustaceans shaped sort of like tadpoles, which is why it’s sometimes called the tadpole shrimp, but it’s not a shrimp. It has two eyes on the top of its head visible through its flattened, smooth carapace. Species in the genus Triops also have a so-called third eye between the two ordinary eyes, although it’s a very simple eye that probably only detects light and dark. Many crustaceans have these third eyes in their larval forms but very few retain them into adulthood.

Notostracans have been around for about 365 million years, and haven’t changed much in the last 250 million years. It’s an omnivore that mostly lives on the bottom of freshwater pools and shallow lakes, often temporary ones like the flooded ballcourt, although some species live in brackish water and saline pools, or permanent waterways like peat bogs.

Triops eggs are able to tolerate high temperatures and dry conditions, with the eggs remaining viable for years or even decades in the sediment of dried-up ponds. When enough water collects, the eggs hatch and within 24 hours are miniature versions of the adult Triops. They grow up quickly, lay lots of eggs, and die within a few months or when the water dries up again.

Triops eggs are even sold as aquarium pets, since they’re so unusual looking and are easy to care for. They basically eat anything. They especially like mosquito larvae, so if you see some in your local pond or other waterway, give them a tiny high-five.

In 1996, some workers near Indianapolis, Indiana were servicing a tank full of chemical byproducts from making plastic auto parts when they noticed movement in the toxic goo. They investigated and saw several squid-like creatures swimming around. They were red-brown and about 8 inches long, or 20 cm, including their arms or tentacles, but were only about an inch wide, or 2.5 cm.

The workers managed to capture one and put it in a jar, which they stuck in the break room refrigerator. By the time someone in management arranged to have it examined by a scientist, the jar had been thrown out. If you’ve ever tried to keep food in a break room fridge, you’ll know that there’s always someone who will throw out everything in the fridge that isn’t theirs, no matter whether it’s labeled or brand new or not. I have had my day’s lunch thrown out that had only been in the fridge a few hours. Anyway, when the tank was cleaned out the following year, no one found any creatures in it at all.

This sounds really interesting, but there’s precious little information to go on. The story appeared in a few newspapers but we have no names of the people who reportedly saw the creatures, no follow-up information. It has all the hallmarks of a hoax or urban legend. The creatures’ size also seems quite large for extremophiles in a small, closed environment. What would they find to eat to get so big?

Next let’s talk about some mysterious tracks made by invertebrates, as far as we know. We’ll start with a track on land that was a mystery at first, but was solved. A man in the Kruger National Park in South Africa named Rudi Hulshof came across a weird track in the sandy dirt that he didn’t recognize. It was maybe 10 mm wide and kind of looked like a series of connected rectangles, as though a tiny person was moving a tiny cardboard box by rolling it over and over, but there weren’t any footprints, just the body track.

Curious, Hulshof followed the track to find what had made it, and finally discovered the culprit. It was a leech! Most leeches live in water, whether it’s the ocean, a pond or swamp, a river, or just flooded ground. Most species are parasitic worms that attach to other animals with suckers, then pierce the animal’s skin and suck its blood. The leech stays on the animal until it’s full, then drops off. Some leeches are terrestrial, but it appears that this one was a freshwater leech that had attached to an animal passing through the water, then dropped off onto land. It had crawled as far as it could trying to find a better environment, but when Hulshof found it it was dead, so it had not had a good day.

The leech moves on land by stretching the front of its body forward, then dragging its tail end up in a bunch kind of like a worm (it is a kind of worm), so that’s why its track was so unusual-looking. It’s a good thing Hulshof found the leech before something ate it, or else he’d probably still be wondering what had made that track.

We have photographs of other tracks that are still mysterious. You may have heard about one that’s been in the news lately. This one was found by a deep-sea rover in July 2022, more than a mile and a half deep, or 2500 meters, in the north Atlantic Ocean.

The track may or may not actually be a track, although it looks like one at first glance. It consists of a line of little holes in the seafloor, one after the other, although they’re not all the same distance apart. The rover saw them on two separate dives in different locations, so it wasn’t just one track, but although the scientists operating the rover remotely tried to look into the holes, they couldn’t get a good enough view. It does look like there’s sediment piled up next to the holes, so researchers think something might actually be digging the holes, either digging down from the surface to find food hidden in the sediment, or digging up from inside the sediment to find food in the water. The rover did manage to get a sample of sediment from next to one of the holes and a water sample from just above it, and eventually those samples will be tested for possible environmental DNA that might help solve the mystery.

This wasn’t the first time these holes have been seen in the area, though. An expedition in 2004 saw them and hypothesized that the holes are made by an invertebrate with a feeding appendage of some kind that it uses to dig for food. Not only that, we have similar-looking fossil holes in rocks formed from deep marine sediments millions of years ago.

Other deep-sea tracks have a known cause, and humans are responsible. In the 1970s and 1980s, ships with deep-sea dredging equipment traveled through parts of the Pacific Ocean, testing the ocean floor to see whether the minerals in and beneath the sediment were valuable for mining. A few years ago scientists revisited the same areas to see how the ecosystems impacted by test mining had responded.

The answer is, not well. Even after 40 years or so since the deep-sea mining equipment sampled the sea floor, the marks remain. The deep sea is a fragile ecosystem to start with, and any disturbance takes a long, long time to recover—possibly thousands of years. So while the holes discovered in 2022 were almost certainly made by an animal or animals, they might be quite old.

Let’s finish with a mystery animal we’ve talked about before, but a really long time ago—way back in episode 6. It’s definitely time to revisit it.

In 1883 when he was 18 years old, a Vietnamese man named Tran Van Con had seen the body of an enormous creature washed up on shore at Hongay in Vietnam. Van Con said it was probably 60 feet long, or 18 meters, but less than three wide wide, or 90 cm. It had dark brown plates on its back with long spines sticking out from them to either side, and the segment at its tail end had two more spines pointing straight back. It didn’t have a head, which had presumably already rotted off, or something bit it off before the animal washed ashore. It had been dead for a long time considering the smell. In fact, it smelled so terrible that locals finally towed it out to sea to get rid of it. It sank and that was the last anyone ever saw of it. The locals referred to it as a con rit, which means “millipede,” since the armor plates made it look like the segmented body of an immense millipede.

Lots of people have made suggestions as to what the con rit could be, but nothing really fits. It was the length of a whale, but it doesn’t sound like any kind of whale known. The armored plates supposedly rang like metal when hit with a stick. Even if this was an exaggeration, it probably meant the armor plates were really hard, not just the skin of a dead whale that had hardened in the sun. It also implies that the plates had empty space under them, allowing them to echo when hit. Zoologist Dr. Karl Shuker suggests that the plates might have been the exoskeleton of a crustacean of some kind, which makes a lot more sense than a whale, but the sheer size of the carcass is far larger than any crustacean, or even any arthropod, ever known.

There’s also some doubt that the story is accurate. It might even be a hoax. We only know about the con rit at all because the director of Indochina’s Oceanographic and Fisheries service, Dr. A. Krempf, talked to Tran Van Con about it in 1921. That was 38 years after Van Con said he saw the creature, so he might have misremembered details. Not only that, Krempf translated the story from Vietnamese, and there’s no way of knowing how accurate his translation was.

The con rit is also a monster from Vietnamese folktales, a sort of sea serpent that had lots of feet. It was supposed to attack fishing boats to eat the sailors, until a king caught it and chopped it up into pieces. A local mountain was supposedly formed from its head, and the other pieces of its body turned into the unusual stones found on a nearby island.

There’s always the possibility that Tran Van Con actually told Krempf this folktale, but that Krempf misunderstood and thought he was telling him something he actually witnessed. Then again, there are eight reports from ships in the area between 1893 and 1915 of creatures that might have been a con rit. One account from 1899 was a sighting of a creature estimated as being 135 feet long, or 41 meters, which was rowing itself along at the surface by means of multiple fins along its sides.

Whatever the con rit was, there haven’t been any sightings since 1915. That doesn’t mean there isn’t a population of incredibly long invertebrates living in the deep ocean in southeast Asia. If it does exist, maybe one day a deep-sea rover will spot one. Maybe it dug those little holes, who knows?

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!