Episode 310: The Crab-Eating Fox

Thanks to Dean for this week’s suggestion, the crab-eating fox!

Further reading:

Jaguars could prevent a not-so-great American biotic exchange

The crab-eating fox is not actually a fox:

Show transcript:

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

I’m happy to report that I’m feeling healthy and testing negative for covid now. Even my lingering cough has pretty much cleared up! I hope you’re healthy too. Anyway, this week let’s learn about an unusual animal suggested by Dean, the crab-eating fox.

The crab-eating fox lives in parts of South America east of the Andes Mountains. It likes forests and open woodlands, and sometimes lives in savannas too although it prefers areas with a lot of tree cover and rivers. It’s a fairly small animal that rarely weighs more than 18 pounds, or 8 kg, and stands about 16 inches tall at the shoulder, or 40 cm. It has a thick coat that’s mostly gray or brown with reddish ears and paws, black markings on the ears, tail, and legs, and a black stripe down its spine. It also has a bushy tail and a relatively short muzzle.

There are two important questions we need to answer about the crab-eating fox. First, does it actually eat crabs? Second, is it actually a fox?

The crab-eating fox does indeed eat crabs, although it’s an omnivore and will eat pretty much anything it can find. This includes insects, eggs, fruit, carrion, and small animals of various kinds, especially rodents. But during the wet season, when it rains a whole lot and rivers flood and ebb repeatedly, the crab-eating fox eats a whole lot of crabs and other crustaceans.

The crab-eating fox is not, in fact, a fox. It’s definitely related to foxes, since it’s a canid and the family Canidae includes foxes as well as wolves, dogs, coyotes, and all their relations, and it looks like a fox. It’s the only member of its own genus, but it’s grouped together with some other South American canids that look like foxes but are more closely related to wolves. But they’re not all that closely related to either foxes or wolves. Another member of this group is the maned wolf, the one with super long legs, which we talked about most recently in episode 167.

Scientists think that the crab-eating fox’s closest relation is another South American canid called the short-eared dog, which we talked about in episode 195. Unlike the crab-eating fox, the short-eared dog likes heavy forests and lives in the Amazon rainforest. We know so little about it that researchers sometimes refer to it as the ghost dog.

The crab-eating fox is nocturnal and spends most of the daytime sleeping in a den. Sometimes it makes a den by burrowing into thick grass, sometimes it will dig a burrow, but it prefers to find a den made by another animal and move into it if it’s empty. It may have several dens in its territory, which it often shares with its mate. Both parents help take care of the babies, and a female may have two litters a year.

I’m happy to report that the crab-eating fox is not endangered. It’s doing just fine in most places. It’s an adaptable, intelligent animal, which helps it thrive in a changing environment the same way coyotes do in North America. In fact, it fills the same ecological niche in South America that the coyote fills in North America, and this has led to a really weird potential problem.

The crab-eating fox is native to South America, but it has been spreading northward into Central America. Likewise, the coyote is native to North America, but it has been spreading southward into Central America. Neither species likes thick forested areas, but as more rainforests are cleared for agriculture and housing, people have inadvertently made a sort of corridor for both species. Having people around doesn’t bother either the crab-eating fox or the coyote. Coyotes have made it as far south as Panama, almost to South America.

If this continues, with crab-eating foxes migrating north and coyotes migrating south in ever greater numbers, eventually they’ll start to compete with each other. This isn’t good for either of them.

The only thing stopping coyotes from migrating farther south at this point is a thick strip of tropical forest called Darien National Park in Panama, where jaguars live. Unlike coyotes and crab-eating foxes, jaguars are very shy of humans and need a lot of dense forest to live in. This is exactly the kind of place that coyotes and crab-eating foxes like least, not to mention that a jaguar would be more than happy to catch and eat either species of canid. So as long as the forest in the national park remains intact, it acts as a barrier to keep both canid species apart, and that’s good. It’s also good for the jaguars and lots of other animals. Hooray for protected forests!

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 303: Weird and Mysterious Animal Sounds

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

Further reading/watching:

The Story of Elk in the Great Smoky Mountains

Terrifying Sounds in the Forests of the Great Smoky Mountains

Evidence found of stingrays making noise

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

The wapiti [pic from article linked above]:

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

The tawny owl makes some weird sounds:

The fox says all kinds of things:

Show transcript:

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

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

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

[elk bugle]

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

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

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

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

[elk bugle]

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

[Stingray making clicking sounds]

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

[mouse song]

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

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

[Pelochelys bibron]

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

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

[Typhlonectes compressicauda]

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

[mystery sound]

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

[owl sounds]

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

[tawny owl alarm call]

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

[mystery sound]

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

[fox sound]

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

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

Thanks for listening!

BONUS! Two more Mongolian animals!

It’s a bonus episode because some people are too disturbed by the thought of diseases to listen to this week’s regular episode. I’m really sorry about that! To make it up to you, here are two adorable fluffy animals that live in Mongolia and other parts of Asia.

Super floof! Pallas’s cat, AKA the manol or manul (photo by Julie Larsen Maher, looks like):

I would deny you nothing, round boi:

we all died of cute right here:

The handsome corsac fox would break your heart in an instant if it felt like it:

Show transcript:

Hello, it’s a bonus episode of Strange Animals Podcast, because it turns out that some people couldn’t listen to this week’s episode because they get too creeped out about diseases. I feel terrible about that so I’ve put together a short bonus episode to make up for it. Let’s learn about two more Mongolian animals, because I am still completely obsessed with the Mongolian band The Hu and in fact I have tickets to see them live in May in Lexington! If you’re going to be there too, let me know so we can hang out.

Our first animal is called the manol or Pallas’s cat, a type of wildcat native to parts of central Asia. It’s about the size of a domestic cat with plush grayish-brown fur that gets very thick in winter. It has black spots and stripes, including a long ringed tail, and ears that are set low on the head. It is magnificently fluffy, especially in winter, with especially long fur on its belly.

In fact, it gets so fluffy that it looks a lot like a longhaired domestic cat. The zoologist Peter Pallas, who first described the manol in 1776, thought it must actually be the ancestor of the Persian breed of domestic cat, especially since the manol has a relatively short nose and flat face like Persian cats, and has a stocky build like Persians. But the manol is actually not very closely related to domestic cats, and is in its own genus instead of the genus Felis. For one thing, its pupils are round instead of vertical like a domestic cat’s pupils.

The manol is solitary and doesn’t get along well with other manols, not even family members. One zoo was concerned about a litter of manol kittens that had just been born, since it sounded like they were making little wheezing noises. But a closer inspection revealed that the kittens were just growling at each other.

The manol eats small animals, especially a small rabbit relative called a pika, but also gerbils, voles, insects, and other animals. It lives in the steppes of central Asia and often lives at high elevations. It mostly lives in dry habitats where there isn’t much snow, especially rocky areas or grassland. Because its rounded ears are set so low on its head, the cat can hide among rocks and among plants without its ears giving away its position by sticking up too far. If it feels threatened, it will flatten itself to the ground and freeze, where it looks kind of like a fluffy gray rock.

Our other Mongolian animal is the corsac fox, which lives in very similar habitats as the manol and which also grows a lovely fluffy coat in winter. In the summer its coat is much shorter. It’s yellowish-gray or pale gold in color, paler underneath and with a dark stripe down the back in winter.

The corsac fox isn’t very big, a little over two feet long, or 65 cm, not counting the tail, which adds another 14 inches, or 35 cm, to its length. Since it lives in areas where it’s usually dry, it doesn’t need to drink water very often. It gets most of its water from its diet, which is very similar to the manol’s diet—mostly small animals like hamsters, gerbils, and pikas, although it also eats insects, carrion, and fruit and other vegetation. Its teeth are small compared to other foxes.

Unlike many fox species, which are mostly solitary, the corsac fox usually lives in small packs. The pack lives in a series of shallow burrows that the foxes either dig themselves or take over from other animals. The burrows are usually connected to each other and have several entrances. The corsac fox is also a good climber because of its claws, which are more hook-shaped than most canid claws.

Both the corsac fox and the manol are threatened by habitat loss and poaching. People hunt both animals for their fur. But they’re both still doing well otherwise, with the corsac fox in particular given a conservation rating of least concern. The manol is considered near threatened, but it’s protected in most countries where it lives with a captive breeding program in place across a number of the world’s zoos.

That’s all for this bonus episode. Again, I apologize to anyone who had trouble with this week’s regular episode. I hope you feel better now thinking about these adorable fluffy animals!

Thanks for listening!

Episode 138: City Animals

This week we’re going to learn about some animals that have made their homes in cities alongside humans. Thanks to Corianne who suggested this amazing topic!

Further reading:

The BBC’s Urban Fox FAQ

Toronto vs. Raccoons

The urban fox has a favorite coffee shop and knows where to find parking downtown:

The urban raccoon’s apartment is really small but it’s in a great location:

The urban (rock) pigeon can walk to work in good weather:

Show transcript:

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

This week we’re going to look at animals that live in cities. This is a great suggestion by Corianne, who especially suggested the pigeon. But pigeons aren’t the only animals that live in cities alongside people. In fact, in 2018 a large-scale camera trap study of animals in Washington DC and Raleigh, NC concluded that just as many mammal species live in cities as live in the countryside. That’s only mammals, though. There aren’t as many species of other animals in cities.

Different animals hang out in cities in different parts of the world. In parts of Africa and Asia, local monkeys have moved into cities and cause mischief by stealing food from markets and tourists. Gulls are also thieves of food, sometimes getting so bold as to snatch a sandwich from a person’s hands while they’re eating it, even in cities nowhere near the ocean. City parks attract squirrels and deer, decorative fountains and ponds attract geese and ducks as well as alligators, peregrine falcons move in to feast on pigeons, rats, and other small animals, and some cities have to deal with the occasional bear or leopard, wild boars, even penguins. But today we’re going to focus on three really common city dwellers, both because they’re interesting and because there are so many misconceptions out there about them.

We’ll start with urban foxes. We talked about foxes in episode 106, but while urban foxes are plain old red foxes and not a separate species or subspecies, they’ve adapted to city life easily since they’re omnivores and agile animals that can climb obstacles like fences.

Many cities throughout the world have urban foxes, but they’re especially common in the UK. They eat out of trash cans for some of their diet, but they also hunt rats and other small animals that live in cities too, along with earthworms, insects, and even plants. They especially like fruit and acorns. When a fox finds some food, it will often run off with it and bury it somewhere, then come back later to eat it.

Because an urban fox doesn’t have to worry about predators as much as ordinary countryside foxes do, it can grow larger on average than its country cousins. But it’s also in more danger of being hit by cars or infected with diseases common to dogs and other canids, like mange and distemper.

Urban foxes have a bad reputation for biting, attacking pets, and in general being a nuisance. But the fox is just being a fox and doing the best it can. In many parts of the world, the red fox’s natural habitat is fragmented more every year as cities grow larger and farmland and woodland is turned into houses. Besides, foxes have been reported in cities for a long time—over a century in London, England, where foxes are relatively common. They especially like areas with parks, or where people have gardens or lawns.

The biggest problem with urban foxes is people who treat them like they’re dogs. They’re wild animals, so while it’s okay to leave food out for them, don’t try to touch one or get too close to it. Foxes who get too used to people can become aggressive. Foxes usually don’t bother animals as large as cats, either, and they avoid dogs, but don’t leave small pets like guinea pigs or rabbits outside, especially at night, because that is just asking for trouble.

The urban fox doesn’t always live only in the city, though. One fox, nicknamed Fleet, was tagged by researchers in 2014 and tracked to see where he spent his time. To their surprise, Fleet lived up to his name and traveled from the city of Hove into the countryside across England. In 21 days he traveled 195 miles, or 314 km, and probably went farther but his GPS tracker stopped working so we don’t know how far.

This is what a fox sounds like:

[fox sound]

In the UK, foxes are frequent city animals, but in North America it’s much more common for raccoons to fill the same ecological niche. The raccoon is native to North and Central America although it’s been introduced in parts of Europe as a fur animal and briefly to Japan as a pet. The raccoon makes a really bad pet, by the way. It’s not domesticated and will tear your house up.

The raccoon is mostly gray or gray-brown with some lighter areas of fur, black rings on its bushy tail, and black markings over its eyes. It grows a little over two feet long, or around 70 cm, not counting its tail. Its legs are relatively short and it scurries instead of really running, although it can swim well. The raccoon is a great climber and can even climb down trees headfirst by turning its hind feet so that they point backwards, which gives it a better grip. It has sharp claws too, and dexterous hands although they don’t have opposable thumbs. The raccoon’s front paws have as many sensory receptors as human hands, which means it can learn a lot by just touching something. Like, for instance, how to unlock a trash bin.

The raccoon is well-known for getting into trash no matter what kind of bin it’s in. This is because raccoons are remarkably intelligent. By now you probably know that intelligence and social complexity are linked, but raccoons have a much different society than other intelligent animals. Groups of related females generally occupy the same territory and come together to eat and rest, while males usually live in small groups that are mostly separate from females.

Like the fox, the raccoon is an omnivore. It eats insects and worms, fruit and nuts as well as other plant material, bird and reptile eggs, frogs, fish, crustaceans, and other small animals. Raccoons in captivity are known to wash their food by dipping it in water, but this behavior hasn’t actually been documented in wild raccoons. Some researchers think the raccoons aren’t actually trying to clean the food, but are mimicking the motion of catching food in water, while others suggest the raccoons are stimulating the nerve endings in their hands with water to learn more about the food they’re touching.

Raccoons prefer open forests near water, since they like to catch fish and frogs. But they will eat pretty much anything, which means they raid trash bins. For years, the city of Toronto in Canada had trouble with raccoons getting into people’s trash bins. The bins were designed to be picked up and emptied by city trucks, but the raccoons had learned to break the locks. In 2015 the city redesigned the bins to be raccoon resistant, and in 2016 after extensive testing the new bins were distributed to residents. Before long the raccoons had figured out how to open them.

Researchers think that the daily puzzles urban raccoons solve to find food actually make them smarter. Since they’re pretty smart to start with, that’s kind of scary.

Like urban foxes, urban raccoons can get too used to humans. They’re rarely dangerous to people or pets, but they can cause a real mess if they get into your house and will bite if they feel threatened.

This is what a raccoon sounds like:

[raccoon sound]

We’ll finish with the ubiquitous city bird, the pigeon. It’s properly called the rock pigeon or rock dove and is native to parts of Eurasia and Africa. But these days it’s spread throughout much of the world, especially in cities.

Most people are familiar with the pigeon. It’s usually gray or brownish-gray with a white patch on its rump and two broad stripes of black on its wings. Both males and females have iridescent feathers on the neck that shine green and purple in sunlight, but the iridescence in males is much more pronounced. Pigeons with other markings are either feral domesticated pigeons or have feral domesticated pigeons in their ancestry. The domesticated pigeon was actually developed from the rock pigeon and it’s probable that most city pigeons are actually mostly feral domesticated pigeons.

The pigeon is a fairly large bird, up to 15 inches long, or 37 cm, with a wingspan over two feet, or 72 cm. It mostly eats seeds and other plant material, but will also eat small insects. City pigeons will eat bread and other foods too, but they would be happier with whole grains. Like many other birds, the pigeon stores food in its crop after swallowing it, which allows it to eat more food than it would otherwise be able to hold. The crop is a chamber at the bottom of the esophagus.

Not only do pigeons have a crop, which not all birds have, pigeon parents produce a food called crop milk or pigeon milk that they feed to babies. It’s not milk at all, of course, but the nutrient-rich lining of the crop that it sheds and regurgitates to feed its babies, which are called squabs. Both parents produce crop milk, which sort of looks like cottage cheese. The babies can’t digest anything except crop milk for the first week of life, so the parents may actually not eat anything during the first days after the eggs hatch to make sure there aren’t any seeds mixed in with the crop milk. After a few days the parents mix in food that’s been softened in the crop.

Pigeons and doves are almost the only birds that produce crop milk. The flamingo and the male emperor penguin do too, even though they aren’t related to pigeons. But that’s it, as far as we know. So if anyone asks you what the flamingo, the emperor penguin, and the pigeon have in common, now you know. Also, they’re all birds.

Pigeons live in flocks, although the flock may break up into smaller groups or pairs during part of the day. At night the birds usually roost together except for pairs who have eggs or babies in a nest. Pigeons mate for life and both parents take care of the eggs and squabs. Flock leaders find food and lead the rest of the birds to it, whether the food comes from plants growing in a park or from a person scattering birdseed.

Pigeons are actually clean animals when they have access to water. They like to bathe and preen to keep their feathers clean. If you’ve ever watched a typical bird drink water, maybe at a puddle or a birdbath, you might have noticed that the bird dips some water into its beak, then tilts its head back so the water runs down its throat. This is because most birds can’t actually swallow water the way most mammals can. I mean, if you had to you could drink water while you were upside down, although you might choke or get it in your sinuses. But some of the water at least would get into your stomach. Birds couldn’t. Except for the pigeon, which can actually drink like a mammal, keeping its head down as it swallows. The pigeon and its close relatives are the only birds known who can do this.

No one thinks of pigeons as especially smart birds, but guess what. They’re actually pretty bright. Pigeons can easily memorize images, even hundreds of them, and retain those memories for years. They not only recognize individual humans, they can learn to understand what human expressions mean. They also have keen vision and can differentiate between very similar items or pictures, which leads to pigeons being trained to do something unexpected. Wait for it. You’re not going to believe this. Pigeons can learn to identify malignant breast tissue in mammograms at least as well as humans can. Researchers train birds to identify the differences in mammogram slides, then use four birds in a team. The team can be 99% accurate in identifying malignancies that need to be treated. So pigeons can save human lives!

Not only that, but researchers can find sources of lead pollution by taking blood samples from sick or dead pigeons found in cities. Since city pigeons generally have small territories that only encompass a few blocks, researchers can measure the level of lead found in birds and know roughly where the lead exposure occurred. That helps the city find and clean up sources of lead pollution.

Pigeons are actually quite healthy birds, despite their reputation as diseased. They’re surprisingly resistant to a lot of bird diseases, including bird flu. Many people think of pigeons as dirty scavengers, but like other urban animals, they’re just living out their lives in an environment humans made. And if they’re scavengers, just think about where that food is coming from. People are dropping it on the ground, that’s where. Maybe people are the dirty ones, throwing food around. Pigeons are just cleaning it up for us.

This is what a pigeon sounds like:

[pigeon sound]

You can find Strange Animals Podcast online at strangeanimalspodcast.blubrry.net. That’s blueberry without any E’s. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 106: Domestication with and without foxes

Thanks to M Is for Awesome, who suggested the topic of domestication! This week we look mainly at foxes and how they relate to the domestication of dogs. Also, chickens.

Unlocked Patreon episode about chicken development and domestication: https://www.patreon.com/posts/21433845

A red fox:

Domestic foxes want pets and cuddles also coffee:

The fennec fox with toy I JUST DIED:

The raccoon dog is actually a species of fox:

Show transcript:

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

Back in episode 80, about mystery dogs and other canids, I said I was going to leave foxes for another episode. And here it is! But as I researched, it turned out that while there are lots of interesting foxes, they’re all pretty similar overall. So while we will learn about some of the more unusual foxes this week, I’m mostly going to talk about how animals are domesticated by humans. This is a suggestion from M Is for Awesome, who suggested domestication “and how it changes domesticated creatures from their wild cousins.” You may not know how this relates to foxes, in which case, I’m about to blow your mind.

But first, we should learn about how scientists think other canids became domesticated. You know, how dogs became dogs instead of wolves.

Domestication of wolves took place possibly as much as 40,000 years ago, but certainly at least 14,000 years ago. Gray wolves are the closest living relative of the domestic dog, but the gray wolf isn’t the dog’s ancestor. Another species of wolf lived throughout Europe and Asia, possibly two species, and domestication of these wolves occurred at least four different times in different places, according to DNA studies of ancient dog remains.

One of the oldest dog remains ever found dates to 33,000 years ago, found in a cave in Russia. Researchers think it wasn’t fully domesticated, but was probably connected with the people who had been using the cave as shelter. A 2017 study concluded that it isn’t related to any modern dogs and apparently was related to a species of wolf that has since gone extinct.

Many researchers think that wolves actually started the domestication process. Wolves hunt but they also scavenge, so they may have gotten into the habit of following bands of humans around to find scraps of food. Back in the hunter-gatherer days before we started growing crops, humans were nomadic, moving from place to place to find food. Wolves would have been attracted to the bones and other parts of dead animals humans left behind. If a wolf got too close to a campfire where humans were sitting around eating, two things might happen. If it was an aggressive wolf, the humans would chase it away or even kill it. But if it wasn’t aggressive, maybe because it was scared or young, a human might have tossed it a little bit of meat or a bone. That wolf would definitely hang around more, hoping for more food. If the humans grew used to it, it might even have started to consider itself part of the human’s pack. And if another predator approached, the wolf might growl at it and warn the humans, who would reward the wolf with more food. Over the generations, the wolves who got along best with humans would receive the most food and therefore be more likely to have babies that also got along with humans. It’s a lot easier to act as a camp guard and be given food and pets than it is to go out and try to kill ice age megafauna with your teeth.

Remains of a puppy dated to 14,000 years ago was found recently in a prehistoric grave in Germany. A test of its DNA indicates that it is related to modern dogs. The puppy was fully domesticated, well cared for, and had been buried with a man and a woman. Researchers can even tell that the puppy died of distemper, which leaves telltale marks on the teeth. The puppy had survived until the disease was well advanced, and it could only have done so with special care from humans. Even today distemper is a terrible disease among dogs. I had a puppy that died of it when I was little. Obviously, even 14,000 years ago dogs were already more than working animals or camp scavengers. Someone loved that puppy and tried to help it get better.

An interesting thing happens with domestication. Certain physical traits come along with the behavioral traits of reduced aggression and willingness to treat humans as surrogate parents. In the case of dogs, these often include a puppy-like appearance, including floppy ears, curled tail, smaller adult size, and a rounder head with smaller jaws. This isn’t the case with all dog breeds, of course, but the changes seem to be genetically linked to behavior. It’s called domestication syndrome.

So this is interesting, but how does it apply to foxes? Foxes are canids, but they aren’t all that closely related to dogs.

Well, in 1959 a Russian zoologist named Dmitry Belyaev decided to see if he could domesticate foxes. Taming and domestication are different things. A wild animal that has become used to certain humans can be considered tame, but a domesticated animal is one that is genetically predisposed to treat humans as caregivers. Belyaev didn’t just want to tame a few foxes, he wanted to try actually domesticating them.

He started his project by going to a fur farm that bred foxes to kill for their furs, which were then made into coats and other clothing. These were red foxes, which are common throughout much of the world, but because they were bred for their fur, they weren’t red. They were a darker color called silver, a color mutation, but other than that they were regular foxes. Belyaev chose foxes by how well they tolerated people, the ones that were less likely to bite.

He bred these foxes and when the babies grew up, he chose the least aggressive ones to breed. Then he chose the least aggressive babies from those parents, and so on. And after only six generations, he started to see results. Some of the foxes in the sixth generation actively sought out humans. They licked their hands, whined for attention, and even wagged their tails.

Something else happened too. The foxes started showing physical differences. Some had fur with white patches or various other color variations, some had floppy ears, some carried their tails so that the tip pointed up. All these traits are common in dogs, but pretty much never seen in wild foxes. Recent research shows that the changes are genetic and linked to lower adrenaline production. One color of fox, called Georgian white, has never been seen except in Belyaev’s domesticated foxes. It’s a lovely white all over with black ears and black or gray markings on the face and paws.

In case you’re wondering how much of the behavioral differences are due to increased human contact, the study also breeds the least tame foxes. They continue to look and act like wild foxes.

The breeding project has continued even though Belyaev died in 1985. These days almost all the foxes are as tame as dogs. Belyaev also conducted domestication projects with rats and American mink, both of which succeeded as well as the fox project. But if you want a pet fox, you’re out of luck. The foxes are occasionally for sale, but they’re extremely expensive and some parts of the world don’t allow foxes to be kept as pets at all, even these domesticated foxes. Occasionally someone will pop up online claiming to have some of the domesticated foxes for sale, but they always disappear after taking people’s money and never deliver any foxes.

Besides, even though Belyaev’s foxes are domesticated, they aren’t dogs. They don’t always behave in ways that make sense to humans. Humans and dogs have been buddies for untold thousands of years and we’ve basically evolved together, while foxes have only been domesticated for basically one human lifetime. One zoologist whose institute has several of the domesticated foxes for study and outreach says that she has to watch her coffee cup because if she doesn’t, one of the foxes might pee in her coffee. As soon as I read that, my desire to own a pet fox diminished. They’re really cute, but so are dogs, and while I have had a dog that would steal and eat sticks of butter off the counter, I never had to worry about him peeing in my coffee. Besides, the domestic foxes are also hard to house-train and still retain a wild fox’s musky odor.

The fennec fox is the smallest canid, and it’s sometimes kept as a pet, but it’s not domesticated. If the babies are taken from their mother very early, they grow up fairly tame, but they’re still wild animals and can be aggressive.

I have seen a fennec fox at the Helsinki Zoo! It was adorable. I definitely can see why people want one as a pet, but honestly, cats are about the same size and shape but are a lot less likely to bite. Also, cats purr. The fennec fox lives in northern Africa and parts of Asia and its fur is a pale sandy color with a black tip to the tail. Its eyes are dark and its ears are large. It stands only about 8 inches tall at the shoulder, or 20 cm, but its ears can be six inches long, or 15 cm. It eats rodents, birds and their eggs, insects, and other small animals, as well as fruit. It can jump really far, some four feet in one bound, or 120 cm. Because it lives in desert areas, it rarely needs to drink water. It gets most of its water through the food it eats, and researchers think it may also lap dew that gathers in the burrow where it spends the day.

The most common species of fox is the red fox. Foxes are canids related to dogs and wolves, and just to be confusing, male foxes are sometimes called dogs. Female foxes are vixens and baby foxes are cubs or kits. But the red fox isn’t the only species out there, not by a long shot.

For instance, the grey fox lives throughout North and Central America. It can look a lot like a red fox but its legs are always reddish or tan, unlike the red fox, which always has black legs. Instead of a white tip to its tail like red foxes have, the grey fox has a black tipped tail. It’s also not that closely related to the red fox or any other foxes, for that matter. Its pupils are rounded like a dog’s instead of slit like other foxes, which have eyes that resemble cats’ eyes.

The grey fox also has hooked claws that allow it to climb trees. That’s right. I said it can and does climb trees just like a cat. It’s nocturnal and omnivorous, which means it eats pretty much anything. It especially likes rabbits and rodents, but it also eats lots of fruit and insects.

The only other canid that can climb trees is the raccoon dog, which is neither a raccoon nor a dog. It’s actually a type of fox, but it does look a lot like a raccoon at first glance. It has grizzled brown-gray fur, a black mask over the eyes and cheeks, and a short muzzle and rounded ears. And, of course, it also climbs trees like a raccoon. But it’s larger and bulkier than a raccoon with much longer legs, and its tail isn’t ringed like a raccoon’s tail.

The raccoon dog is native to parts of Asia, but it was introduced to parts of western Russia in the early 20th century as a fur animal and is now widespread throughout much of Europe. It’s an omnivore too; pretty much all foxes are omnivores. It eats rodents, frogs and toads, birds, fish, fruit and plant bulbs, some grains, and insects. You know, pretty much anything. It even eats toads that are toxic to other animals, diluting the toxins with massive amounts of saliva. And in cold areas, the raccoon dog hibernates. It’s the only canid that does.

Several months ago, I released a Patreon episode about chicken teeth that also talked about the domestication of chickens. It wasn’t my best episode but it’s relevant here so I went ahead and unlocked it for anyone to listen to. There’s a link in the show notes so you can click through and listen in your browser without needing a Patreon login or anything. Anyway, let’s finish up today with some information I just learned about the domestication of chickens. Specifically, a breeding project similar to the Belyaev foxes but with the wild birds that are the ancestors of domesticated chickens.

The bird is called the red jungle fowl, which lives in Asia and looks like a chicken, but is smaller than domesticated chickens. It was domesticated as long as 8,000 years ago but the wild bird still exists. A Swedish research team tried replicating Belyaev’s domesticated fox experiment with some of the wild birds. Like the foxes, the researchers bred a population of birds that were just ordinary wild jungle fowl and not selected for tameness, and a population of birds that were chosen because they tolerated humans a little more than usual. As each of the baby birds grew up, they were tested by having a human walk into the pen and try to touch it. The human wasn’t told whether the bird was from the tame group or the wild group. But after a couple of generations, it was obvious which was which. The tame birds became so tame that they didn’t mind the human at all.

And like the foxes, although the only trait the researchers selected for was tameness, the chickens began to change in other ways too. They became bigger and the hens laid more and larger eggs. This happened within only a few generations, which suggests that domestication is a much faster process than researchers once assumed.

And thanks to recent study, we’re pretty sure we know why these physical changes happen along with the behavioral changes. Selecting for tameness alters the genes that controls what are called the neural crest cells. When the embryo is developing, the neural crest cells migrate to different parts of the body. They affect the coat or feather coloring and some other physical developments, but they also affect the development of many other traits, including the fight-or-flight response. In other words, if you select for an animal that tends to be calm instead of fighty or flighty, you’re also accidentally selecting for differences in physical traits. Follow-up studies confirm that neural crest cells migrate differently in domestic animals than they do in their wild counterparts.

Research into domestication is a hot area of study right now, now that DNA and molecular genetics studies are more sophisticated. You know, in case anyone out there is considering a career in science.

You can find Strange Animals Podcast online at strangeanimalspodcast.com. We’re on Twitter at strangebeasties and have a facebook page at facebook.com/strangeanimalspodcast. If you have questions, comments, or suggestions for future episodes, email us at strangeanimalspodcast@gmail.com. We also have a Patreon if you’d like to support us that way.

Thanks for listening!

Episode 008: The Loneliest Whale and Other Strange Recordings

This week’s episode is a collection of strange animal sounds, some unknown, others identified. We start with “the loneliest whale.”

A blue whale. Not the loneliest whale, as far as anyone knows.

A tarsier:

This fox can see into your soul and does not like you:

Show transcript:

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

One of the great things about making my own podcast is that I’m the one who gets to decide what topics to cover. I love podcasts about unexplained sounds captured on audio, so this week’s episode is just that.

With one or two exceptions, I’ve tried to keep to sounds that are definitely or probably made by animals. I’ve also tried to dig a little deeper to explore some sounds that I haven’t heard covered in other podcasts. I waded through a million pop-up ads so you don’t have to.

First, let’s talk about a whale you’ve probably heard of. It’s frequently called the loneliest whale. The story goes that this whale is lonely because its voice is too high to be heard or understood by other whales. It calls but never gets a response.

But that’s actually not the case. Its voice is higher than other blue whales, fin whales, and humpback whales, but they can certainly hear it, and for all we know, they answer. Since the individual whale hasn’t actually been spotted, we don’t know if it travels alone or with other whales.

The loneliest whale was first detected in 1989 by the US Navy listening for submarines in the North Pacific, then again in 1990 and 1991. At that time the recordings were classified due to the cold war, but in 1992, some were partially declassified, and word about the whale got out. The calls vary but are similar to blue whale calls. The main difference is the voice’s pitch. The loneliest whale calls at 52 hertz. That’s slightly higher than the lowest notes on a piano or tuba. Blue whale songs are typically around 10 to 40 hertz. The whale’s voice has deepened over the years to around 49 hertz, suggesting that it has matured.

Suggestions as to why this whale has a different call include the possibility that the whale is deaf, that it’s malformed in some way, or that it’s a hybrid of two different species of whale. Fin whales and blue whales do interbreed occasionally, but no one has successfully recorded a hybrid’s calls.

Whale researchers think the recordings seem to be of one individual whale, but in 2010, sensors off the coast of California picked up lonely whale type calls that might have been made by more than one whale at the same time. One suggestion is that blue and fin whale hybrids might be common enough that they band together. This seems a little far-fetched to me, but I’m not a whale expert.

The loneliest whale’s migratory patterns suggest it’s a blue whale. So do its call patterns, if not its actual voice, but no one has recorded the whale’s song since 2004.

A documentary called “52: The Search for the Loneliest Whale” is currently in production. There aren’t any dates listed on the official site, 52thesearch.com, but it’s supposed to be released some time this year, 2017. [Note from 2020: it doesn’t appear that this has ever been released.] The film’s expedition has concluded, although we don’t know yet whether the scientific and film teams actually identified the loneliest whale or recorded it.

Here is the call of the loneliest whale. This recording has been sped up 10x to make it easier to hear. The original recording is barely more than a rumble, depending on how good your hearing is and how good your speakers are.

[whale call]

And just for fun, here’s a recording of an ordinary blue whale, also sped up:

[another whale call]

Now let’s go from the largest mammal alive to one of the largest land mammals alive, the elephant. In 1984, biologist Katy Payne, a pioneer in the field of bioacoutics, was at a zoo in Portland, Oregon to give a talk about whale songs. While she was there, she visited the elephant exhibit and noticed that every so often she felt what she called a throbbing in the air. She got some recording equipment and came back to the zoo, recorded the elephants, and sped up her recording. Sure enough, the elephants were making sounds below 20 hertz.

She pursued the finding with wild elephants in Africa. It turns out that elephants communicate not only with the familiar trumpets and squeaks, but in infrasound—that is, sounds below the lower limits of human hearing.

Infrasound can travel a long distance, especially useful in forested areas with limited visibility, and at dusk and dawn when atmospheric conditions help propagate the sound waves so they can travel as far as six miles away [9.6 km]. Females in estrus make a special call to bull elephants, for instance, attracting potential mates from a long way away.

Here’s a recording of elephant rumbles—again, sped up so we can hear it:

[elephant sounds]

Other animals communicate in infrasound, generally large animals like rhinos, hippos, giraffes, and of course whales. Many more communicate in ultrasounds, sounds above the top hearing range of humans, about 20 kilohertz. Bat radar navigation and sonar navigation sounds made by many species of dolphins and toothed whales register in the ultrasonic range, as do many insect calls. But there are other much more surprising animals that communicate in ultrasound.

The Philippine tarsier is a tiny primate only about five inches tall [13 cm], a big-eyed nocturnal fluffball with long fingers. Researchers studying the tarsiers wondered why the animals frequently opened their mouths as though to make calls but produced no sound. Sure enough, they’re communicating at ranges far too high for humans to detect—higher, in fact, than has been discovered for any terrestrial mammal.

The Philippine tarsier most often communicates at 70 kHz and can hear sounds up to 90 kHz. Researchers think the tarsier uses its ultrasonic hearing to track insects, and communicates in frequencies too high for predators to hear. Here’s a tarsier call, slowed down so we can hear it. I’ll keep it short because it’s super annoying.

[tarsier call]

Another animal that uses ultrasound is the cat. Domestic cats can hear sounds up to 85 kHz. Some kitten calls fall in the ultrasonic range, so the mother cat can hear her babies but many predators can’t. Cats have evolved to hear such high sounds because many rodents communicate in ultrasound. Male mice, for instance, sing like birds to attract mates. Here’s an example, slowed down so we can hear it:

[mouse singing]

But so far these are all known animals, or in the case of the loneliest whale, probably known. What about truly mysterious sounds?

Probably the most famous mystery sound is the bloop. It was recorded by NOAA in 1997 off the tip of South America. It’s an incredibly loud sound, much louder than the loudest animal ever recorded, the blue whale, and for a long time, people speculated that it might be an enormous unknown animal. Unfortunately, or maybe fortunately because no one wants to awaken Cthulhu, NOAA has identified the bloop as the sound of an icequake. That is, massive iceburgs breaking apart. Here’s a clip of the bloop, sped up so we can hear it:

[the bloop]

Another solved mystery sound has been dubbed “bioduck,” since it sounds sort of like a robotic duck. It’s been recorded since the 1960s, when it was first reported by submarine operators in the southern ocean off the Antarctic. It’s common, heard almost year-round near Antarctica and Australia, and was not from any known human-made source. Then, in 2013, whale researchers attached suction-cup tags to two Antarctic minke whales. While the tags remained in place, they recorded not only where the whales went, but the sounds they made. And to the research team’s astonishment, both whales made bioduck calls. This finding is important, not just because it cleared up a longstanding mystery, but because it tells us a lot about the Antarctic minke whale that wasn’t known. Researchers thought the whales only lived in Antarctic waters part of the year. Now they know that some whales remain year-round while some migrate near Australia. They can also make better estimates of whale populations now that they can identify this distinctive call.

The Antarctic minke whale is a baleen whale that grows to around 40 feet [12 m], but usually much smaller. It’s gray with white belly and mostly eats krill. This is what they sound like:

[minke whale call]

In our sea monster episode a couple of weeks ago, I shared another baleen whale call, this one from an unidentified species. It’s been dubbed the bio-twang and has been recorded in the Mariana trench in the western Pacific year-round in 2014 and 2015. Researchers suspect the dwarf minke whale, but they don’t know yet.

[mystery whale call]

To get out of the water for a moment, in 2012 a supposed bigfoot recorded started going around the internet. It was supposedly recorded on a cell phone in the Umatilla Indian Reservation near Pendleton, Oregon. It’s more likely to be nothing more exotic than a red fox.

Here’s the unknown scream:

[creepy animal sound]

And here’s a recording of a red fox:

[equally creepy red fox sound]

To me the sounds are very similar. If you want to know how I know the red fox scream is actually a red fox screaming, google “red fox scream.” The first hit is a YouTube clip of a fox screaming. I pulled the audio from that one.

In 2014, an unknown animal was recorded in Lake Champlain in Vermont. Dennis Hall, who claimed to have spotted the lake monster known as Champ in 1985, and Katy Elizabeth, who runs an organization known as Champ Search, made the recording and thought it might be from a beluga whale.

But while Lake Champlain is connected to the ocean, a whale would have a hard time reaching the lake due to canals, and would most likely have been spotted either on its way to the lake or once it arrived. Certainly it would have been spotted once it died from trying to live in fresh water.

Other recordings of clicking and squeaking sounds like those of beluga whales have been recorded in the lake in the past, including by a Discovery Channel team researching Champ. In 2013, Dr. Lance Barret Lennard from the Vancouver Aquarium Marine Science Center, and an expert on whale acoustics, examined some of the echolocation patterns. He determined that not only are the recordings not of beluga whales, they’re not from any kind of whale. They’re probably not mammalian in origin.

Some turtles have been found to produce underwater signals that may be a form of echolocation, and many fish make clicking and drumming sounds. But we don’t know what’s making the sounds recorded in Lake Champlain.

Here’s the 2014 recording:

[Lake Champlain sounds]

Finally, here’s a sound that’s not mysterious, I just really like it. It’s the song of the veery, an attractive but rather plain thrush. I’ve heard it in person while hiking at high elevations in the Smoky Mountains, and it’s completely ethereal.

If you listen closely, you can hear that the veery is actually making two sounds at the same time. The avian vocal mechanism, called a syrinx, is much different from a mammal’s larynx, and allows a bird to product more than one tone at a time.

[veery call]

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

Thanks for listening!