Tag Archives: mice

Episode 171: The Animals of St. Kilda



Thanks to Emma for the suggestion! Let’s learn about some animals that live on the St. Kilda islands off the coast of Scotland!

St. Kilda:

Soay rams (kept on farms, not the feral sheep):

A small flock of Soay sheep (these are from a farm too):

A Boreray ram (on a farm):

A Boreray ewe with her babies (also on a farm, or at least I think so):

The St. Kilda wren (not a sheep):

The St. Kilda field mouse (also not a sheep) is the size of a hamster:

Show transcript:

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

This week’s episode is a suggestion from Emma, who long ago told me about the interesting history and unique animals of the island of St. Kilda in Scotland. I’ve been meaning to cover it ever since, so finally I’m getting around to it after only two years or so.

Emma says, “It’s an amazing little island and sort of a reverse of the usual ‘humans cause extinction’ story. The humans on the island went ‘extinct’, being evacuated from the island partly because increased mainland human contact was bringing illnesses they couldn’t fight without hospitals. Two lots of rad ancient sheep and some unique wrens and mice are happily living there to this day.”

St. Kilda is not one but a group of islands off the coast of Scotland, but the largest island and the only one where people once lived is called Hirta. In 1930, everyone who still lived there moved to the mainland, but by that time hardly anyone remained on St. Kilda anyway. The island probably never had more than a few hundred people in residence at any given time. In 1957 St Kilda was designated as a nature reserve and in 1986 as a World Heritage Site.

Since then, as Emma says, the animals of the islands have mostly been left alone. This includes two breeds of sheep that were left behind on two of the smaller islands when the last residents moved away.

One of these sheep breeds is the Soay, which originally lived on a tiny island called Soay, which actually means “sheep island.” The island of Soay is only about 250 acres in size, or 100 hectares, but that’s not the only place they used to be found. The breed has lived in northern Europe for probably 4,000 years, and was a popular sheep in Britain for centuries. When all the people moved away, 107 sheep living on Soay were moved to Hirta. The sheep on Hirta are feral and receive no care from humans, but they also have basically no predators on the island. They have been studied since 1955 by a small team of scientists and conservationists.

The Soay is a primitive breed of sheep that closely resembles its wild ancestor, the Asiatic mouflon. It’s brown, usually with lighter markings on the face and rump, and the rams often grow a short mane of hair in addition to wool. Rams have dark brown horns and ewes often grow smaller horns too. It also has a short tail. In late spring, Soay sheep shed their fleece naturally instead of needing to be shorn. This is the case with many primitive sheep breeds. Its wool is considered high quality and sought after by handcrafters.

Also like many primitive breeds, the Soay doesn’t have much of a flocking instinct. Soay sheep have been exported from the islands and are kept on farms in many areas for their wool, but if a sheep dog tries to herd a flock of Soay, the poor dog is going to be so frustrated. Soay scatter instead of flocking together. It can also be an aggressive sheep, especially the rams, but it’s also a small breed, with even a big ram rarely heavier than 70 lbs, or 32 kg. And these days, the feral Soay sheep are actually getting smaller overall and have been for the last twenty years. The research team that studies the sheep thinks it’s because climate change has led to shorter, warmer winters, which allows more of the sheep to survive, including smaller sheep that would ordinarily have trouble in cold weather. The smaller sheep breed and their offspring are more likely to be small too, and after twenty years of this the breed overall is smaller than it used to be.

While the Soay used to be a popular breed throughout much of Europe, it’s an at-risk rare breed these days. There are fewer than 1500 breeding ewes registered on farms, in addition to the feral flock on Hirta.

The other breed of St. Kilda sheep is called the Boreray, and it’s also a feral sheep on one of the St. Kilda islands. In this case it lives on the island of Boreray. It’s even rarer than the Soay sheep, the rarest sheep breed in the UK. In 1999 there were only 84 individuals known, but a conservation effort by the Rare Breeds Survival Trust has increased the number to nearly 900 breeding ewes as of 2018.

The Boreray is a little smaller than the Soay and shares characteristics with that breed, including a short tail and its fleece shedding naturally in late spring. It’s usually gray or white, although sometimes brown, often with a speckled black face. Its wool is much coarser than the Soay’s and was traditionally used to make tweed fabric or carpets.

But sheep are domesticated animals, feral or not. What about some of the other animals of St. Kilda?

The St. Kilda wren is a subspecies of Eurasian wren that’s found nowhere else in the world. Like other wrens it’s a tiny songbird, brown and gray with a short tail. It was only recognized as a separate subspecies in 1884, and as happened a lot in those days, museum collectors killed so many of them to stuff and mount that the bird nearly went extinct. Fortunately, early conservationists realized the danger in time, and a special Act of Parliament in 1904 protected the bird. After all the people were evacuated from Hirta, a small team of scientists studied the wren. In 1931 68 nesting pairs were counted, and in 2002 230 breeding pairs were counted. That’s still a low population, but since the wren has almost no predators on St. Kilda, that’s a decent number for such a small habitat.

The St. Kilda wren eats insects, spiders, and other small invertebrates. The male builds the nest out of dead grass and other plants, moss, and seabird feathers.

This is what the St. Kilda wren sounds like:

[St Kilda wren singing]

Another animal found nowhere else in the world is the St. Kilda field mouse, a subspecies of wood mouse. There used to be another mouse subspecies found only on St. Kilda, the St. Kilda house mouse. Both mice were described in 1899, and both are larger than mainland mice. But because the house mouse is dependent on humans, once everyone evacuated the islands the St. Kilda house mouse went extinct within two years.

But the field mouse was fine, and is common throughout the island of Hirta and at least one other island. It actually moved into the abandoned buildings after the house mice went extinct, since houses are full of little nooks and crannies that mice can use as homes. Researchers think the mouse may have been on the islands for something like a thousand years, arriving with Viking settlers.

The St. Kilda field mouse is twice as large and heavy as mainland mice, probably because it basically has no predators. It’s an omnivore like most other mice, and eats seeds, moss, insects and other small animals, and even scavenges meat from dead sheep and birds.

Many sea birds nest on St. Kilda, including Atlantic puffins and northern gannets. The grey seal started breeding on Hirta after everyone left. But except for the sheep, the mice, and the gray seals coming ashore during breeding season, there are no other mammals living on St. Kilda. There are also no trees, no bees, and a limited number of plants and animals, all due to how remote the islands are. They’re 41 miles, or 66 km, away from the Outer Hebrides, a series of much larger islands off the Scottish coast.

Humans have probably lived on Hirta for two thousand years, maybe longer, and have visited the St. Kilda islands as long as 5,000 years ago. But now that the people are gone, the mice and sheep and birds are free to live their quiet lives. As long as they don’t mind a few curious scientists keeping an eye on them.

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!


Episode 054: Regenerating Animals



This week we’re going to learn about animals that can regenerate parts of their body. What animals can do it, how does it work, and can humans figure out how to make it work for us too?

Thanks to Maxwell of the awesome Relic: The Lost Treasure podcast for suggesting this week’s topic!

The planarian, not exciting to look at but you can get a lot of them easily:

A starfish leg growing a new starfish, or possibly a slightly gross magic wand. Ping! You’ve been turned into a magical starfish:

The adorable axolotl:

The almost as adorable African spiny mouse:

A hydra. Not really very adorable except possibly to other hydras but kind of pretty:

Show transcript:

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

This week’s episode was going to be about lungfish, but I had to postpone it because I ran across some conflicting information about a mystery lungfish, which required me to order a book that probably won’t arrive for a week or two. So when I tweeted about needing a new topic quick, Maxwell of the Relic: The Lost Treasure podcast suggested animals that can regenerate parts of their bodies.

We’ve touched on regenerative abilities before in one or two episodes. Some lizards can drop their tail if threatened, which then regrows later—but a lizard can only do that once. The fish-scaled gecko from episode 20 can lose its scales and regenerate them repeatedly. But other animals can regenerate not just bits and pieces, but entire organs and even their brains. The sea lamprey can even regenerate spinal cord cells. You better believe researchers are trying to figure out how regeneration works and if it can be adapted for human application.

A lot of worms can regenerate lost pieces, including earthworms. Whenever I’m gardening and accidentally cut an earthworm in half with the shovel, I reassure myself that the worm will regenerate the end I cut off. Some species can even grow back from both cut pieces, effectively turning one earthworm into two, depending on where it is severed, although that’s rare. Some species of worm can only regrow the tail, but some can regrow the head. And some, of course, can’t regrow anything. Leeches are a type of worm but they can’t regenerate at all.

Planarians are flatworms. Some species live in water, some in damp areas on land, but they can all regenerate. If you cut a planarian in two, each half will regenerate into a new planarian. If you cut a planarian in three, you’ll get three planarians. Cut one into four, you get four planarians, and so on and on. Researchers with a lot of time and patience have determined that you can cut a planarian into as many as 277 pieces and you will get 277 planarians after a few weeks. But I guess if you cut a planarian into 278 or more pieces, some of the extra pieces won’t do anything.

Starfish are well-known to regenerate lost or injured legs, and may even drop a leg to escape from predators the way some lizards drop their tails. Some species of starfish can regrow an entire starfish from a single limb. That’s oddly creepy. I don’t know why I find it so creepy. I don’t find the planarians creepy. It’s like if I was run over by a motorboat that chopped my arms and legs off, and instead of dying I not only regrew my arms and legs, my severed arms and legs each grew a new me. I don’t think I’d like that. Although I’m not going to get in the water so I doubt I’ll be run over by a motorboat, and also if I was, sharks would probably eat me before we could see if any parts regrew.

Many starfish relations, such as sea urchins and sea cucumbers, can also regenerate body parts. When the sea cucumber is threatened, it can and will eject its internal organs. They’re sticky and full of toxins, which deters predators, and the sea cucumber just regenerates them.

Most crustaceans, such as crabs and krill, can regenerate legs. So can spiders, which may drop legs to escape from predators. That’s called autotomy, by the way, when an animal detaches a body part to escape from a predator. Spiders molt their exoskeletons every so often as they grow, and lost limbs grow back after molting. Sometimes it takes a few molts for the leg to be the same size as the other legs. Spiders can also regenerate other lost or damaged parts, including mouthparts and spinnerets.

Salamanders and newts can regenerate limbs, tail, some organs, jaws, even parts of their eyes. Frogs and other amphibians can’t. Likewise, some fish can regenerate injured tissue, such as the zebrafish which can regrow fins and eye retinas, and some species of sharks that can regenerate skin tissue, while others can’t. The axolotl, which is an adorable rare salamander found in Mexico, can regrow just about any part of its body, including its spinal cord and up to half of its brain.

So what about mammals? Do any mammals have regenerative capabilities? As a matter of fact, yes. The African spiny mouse is the big regenerator among mammals. It’s actually more closely related to gerbils, and it has stiff guard hairs all over its body that stick out and make it look fuzzy but which act as spines to help ward off predators. But if a predator attacks anyway, three species of the spiny mouse can autotomically drop off part of its skin, which later grows back. Some species of spiny mouse are kept as pets, even though they don’t do very well in captivity. The pet species don’t have regeneration abilities, incidentally. However, they do have delicate tails that are easily injured, which they then lose, and the tail does not grow back.

Those three species of African spiny mouse can also regenerate ear tissue. If a spiny mouse’s ear is damaged, even if it has a hole as big as four mm across, it can regenerate the ear as good as new rather than heal it with scar tissue. A number of mammals can regenerate small injuries to ear cartilage under the right circumstances, including cats. Rabbits can also regrow damaged ear tissue, and have some other regenerative abilities too.

It’s all well and good to point out that a whole lot of animals can regenerate lost or damaged body parts. But how does it work? And more to the point, why can’t humans do it?

Technically, humans and other animals are regenerating certain cells all the time, especially skin cells and blood cells. Small cuts and scrapes heal up without scarring and we don’t think about it at all. Fingertips will grow back after injury and the liver can regenerate. The endometrium, which is the lining of the uterus, is partially reabsorbed into the body and partially expelled from the body every month during menstruation, then regrows. Toenails and fingernails regrow after injury. We just don’t think about all these things because they seem normal to us, whereas we can’t regrow a whole finger if it’s been chopped off, for instance.

I won’t go too deeply into how regeneration works, mostly because it’s complicated and I don’t want to screw it up too badly. There are also different types of regenerative abilities with different processes. Basically, though, as an example, when a salamander loses a leg, the cells surrounding the wound dedifferentiate, basically turning from regular skin cells or what have you into stem cells that can grow into anything the body needs. These cells form what’s called a blastema, which is just the fancy name for a bundle of dedifferentiated cells. Then the blastemal cells start differentiating again, this time into the cells needed to regrow the leg, just as stem cells grew legs when the salamander was developing in its egg.

It sounds pretty simple, put like that. I mean, that’s how we all develop in the first place, from a fertilized egg into a person who can make podcasts and eat cupcakes. The main problem is figuring out how to get human cells to dedifferentiate into a blastema. Because it’s not just injuries that could be helped if scientists figure this out, it’s all sorts of problems. People who have lost their sight due to retinal diseases could regrow new retinas. People born with birth defects could have the nonstandard parts regrown so that they work the way they’re supposed to.

Researchers are working hard to figure all this out. Stem cell research is a big part of regenerative research. Unfortunately, at some point the rumor started that all stem cells come from babies, specifically embryonic stem cells. When a human egg is fertilized, after a couple of days a blastocyst is formed from the cells, which is similar to a blastema but made of cells that have never differentiated into anything else. They’re brand new cells with the capacity to make a brand new human. Naturally, people are squiffy about taking cells that might make a baby and using them for something else. But amniotic fluid, the fluid that surrounds the baby as it’s growing in its mother, also contains stem cells, and they can be harvested without hurting the baby or the mother. You can also get stem cells from the umbilical cord right after a baby is born, and the umbilical cord is just cut off and thrown away anyway so you might as well give it a little extra use. But most stem cells used in research and treatment these days come from bone marrow, lipid cells in fat tissue, and blood, all of which can be extracted without harming the person. They’re not as powerful as embryonic and amniotic stem cells, but they have the benefit of being from the patient’s own body, so no immunosuppression is required to make sure the body accepts them in stem cell treatment.

That was a lot of confusing medical information, so let’s talk about one more animal that can regenerate, the hydra. We’ve talked about the hydra before in the jellyfish episode, which for a long time was our most popular episode. It’s now our second-most downloaded episode, with our first episode inexplicably in the top spot. The hydra is a freshwater animal related to jellies that can regenerate so completely it’s essentially immortal.

The hydra is related to the so-called immortal jellyfish we talked about in episode 19. It can regenerate just about any injury, and like the planarian it can regenerate into more than one copy of itself if it’s cut up into tiny pieces. It’s only a few millimeters long but its tiny body is full of stem cells, and as long as stem cells are present in the body part that was cut off, an entirely new hydra can grow from it. Because of its amazing regenerative abilities, some admittedly controversial studies suggest the hydra doesn’t age. That’s a neat trick, if you can manage it.

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. If you like the podcast and want to help us out, leave us a rating and review on Apple Podcasts or whatever platform you listen on. We also have a Patreon if you’d like to support us that way.

Thanks for listening!


Episode 039: The Devil’s Footprints



Happy Halloween, everyone! This week’s episode is about a spooky occurrence in 1855, where people in Devon woke to find small hoofprints all over the place, even on roofs. Join us in an attempt to figure out just what animal might have made the devil’s footprints!

The footprints as drawn by the Rev. Ellacombe from newspaper accounts:

The h*ckin adorable wood mouse:

Link to lots of pictures of jumping wood mice omg

Wood mouse prints from jumping, from Leutscher via Dash (see further reading, below):

Mystery print from 2009:

Further reading:

The Devil’s Hoofmarks: Source Material on the Great Devon Mystery of 1855 edited by Mike Dash

HALLOWEEN BONUS AW YISS! I’ve unlocked the following Patreon bonus episodes so everyone can listen. You should be able to open them in your browser without needing a Patreon login:

Animals That Glow

The Beast of Busco

Weird Teeth

Carnivorous Plants

Also thank you for buying a lot of copies of my book Skytown:

Amazon USA

Amazon UK

Show transcript:

Welcome to Strange Animals Podcast Halloween episode for 2017. I’m your host, Kate Shaw. This is the best time of the year if you like candy, ghost stories, monsters, wearing spooky costumes, and buying all the bat decorations in Target. I have so many bat decorations. I’ve stopped taking them down after Halloween and my room looks like a bat cave.

Before we get started, a quick heads-up that I’ve unlocked a few of the older Patreon bonus episodes so that anyone can listen to them. They won’t show up in your feed but I have links to the specific episodes in this week’s show notes so you can go listen to them in your browser if you’re interested. You don’t even need a Patreon login. I hope you enjoy them as an extra Halloween treat.

Another reminder that I have a novel available through Fox Spirit Books. It’s called Skytown and it’s a fun steampunk adventure story. I’ll put a link in the shownotes if you want to learn more.

Oh, and if you want a Strange Animals Podcast sticker, just send me your mailing address at strangeanimalspodcast@gmail.com and I’ll mail you one!

Now, on with the spooky Halloween episode!

This week’s episode is something that has baffled me since I read about it as a kid. It’s baffled everyone for more than 150 years. I’ll tell you now that while I make one suggestion that seems plausible to me, it’s by no means a perfect match for the creature that made…the devil’s footprints.

/reverb reverb reverb

The winter of 1855 was especially bitter in England. Around Devon, the rivers froze solid and temperatures stayed below freezing almost every day and night from January to March. On the night of February 8 it snowed, but towards dawn a brief thaw turned the falling snow to rain before the temperature dropped again and a frost fell. When residents of Devon woke on the morning of February 9, they found some 4” of snow on the ground, or 10 cm. They also found small hoofprints everywhere.

These weren’t ordinary hoofprints. A donkey or pony hadn’t gotten loose during the night and wandered around. Some of the prints did look like a donkey’s, but some appeared cloven, more like a large goat’s hoof. And the stride was short, only about 8” between most prints, or a little over 20 cm, sometimes about double that. Besides, the prints appeared in places where a donkey couldn’t possibly have left prints: on rooftops, inside gardens with tall walls and locked gates. Even a nimble goat couldn’t have managed that without someone hearing a goat bounding around. Sometimes a line of prints would walk right up to an obstacle, like a haystack or hedge, and continue on the other side as though the obstacle didn’t exist. Tracks began or ended abruptly as though the animal had dropped from or flown into the sky.

And there were untold thousands of the prints. Some villages had prints in almost every yard. They appeared in churchyards among gravestones, in gardens and on doorsteps, in fields and roads. They meandered from place to place or sometimes continued in a straight line. And they appeared to be made not by a four-footed animal but by something walking on its hind legs, placing one hoof nearly in front of the other.

People tracked some of the prints for miles without coming across any clue as to what had made them. A few forward thinkers made sketches of the prints and jotted down notes. By February 13, reports of the strange footprints had made it into the local newspapers.

Beyond the often maddeningly vague newspaper accounts, most of what we know about the hoofprints comes from the Reverend H.T. Ellacombe, who was vicar of the parish of Clyst St George from 1850 to 1885. He collected letters and sketches and made his own notes about the event, since some of the prints appeared in his own rectory grounds. Local historian Major Antony Gibbs discovered Ellacombe’s bundle of notes and letters in 1952, tucked away in a church office gathering dust.

But a series of letters published in 1855 by the Illustrated London News has been more influential than Ellacombe’s information. The letters were written by someone who signed himself “South Devon,” and we know from Ellacombe that South Devon was a 19-year-old local man whom Ellacombe called “young D’Urban.”

William D’Urban’s letters were exciting, to say the least. If you’ve heard anything about the devil’s footprints before, it was probably mostly details from D’Urban’s account. According to him, all the prints were identical in size, the stride likewise did not vary, and the prints were one unbroken trail at least 40 miles and as much as 100 miles in length, or 64 to 160 kilometers. This has sometimes been garbled in later retellings as a perfectly straight trail 100 miles long. D’Urban was also the one who claimed the prints continued from one side of the River Exe to the other side, two miles distant. It’s not clear if the river was frozen at this point, although it was frozen so solid by late February that an enterprising stove manufacturer ran pipes from the gas main onto the river ice and cooked an entire dinner for 30 on it while people skated all around him and probably tripped over the gas pipes. Moreover, the river is an estuary of the sea so has tides, and at low tide it’s barely a few hundred yards wide in some areas, or say 200 meters, and barely four feet deep, or about 1.2 meters.

Even at the time, D’Urban’s account was refuted by other locals, whose letters responding to South Devon’s letters were printed in follow-up issues of the paper. Apparently newspapers back then were like really slow social media. People wrote letters in response to other letters they’d seen in the newspaper, and other people wrote letters in response to those letters. Old timey people really needed Facebook. And cameras, because we don’t have very many sketches of the footprints and the ones we do have aren’t very detailed.

So what did the tracks really look like? As far as we know, most of the tracks were about 4 inches long, or 10 cm, and 2.75 inches across, or 7 cm. They did vary in size and shape from place to place, which argues that more than one animal made them and that hoaxers weren’t involved, since hoaxers would leave identical prints. I’ll put Ellacombe’s drawings of the prints, which he copied from newspaper reports, in the show notes to give you an idea of what they looked like. When you hear the word hoofprint it’s easy to think of a crisp, well-marked round hoof, maybe even with a horseshoe, but these prints were kind of wobbly in shape—not unexpected since they were all somewhat distorted by the night’s thaw and refreeze.

One of the people who wrote in to denounce some of D’Urban’s details was a Reverend G.M. Musgrave, vicar of Exmouth, and one of the things Musgrave also mentions is that he himself had suggested to his parishioners that the tracks were made by kangaroos escaped from a private menagerie. But, he admits, he didn’t actually believe this, he was only trying to stop his parishioners from believing that the devil had walked through their town.

The devil only started getting blamed for the footprints once it was clear no one really knew what had caused them. Lots of animals were suggested as culprits, most of which were about as likely as Musgrave’s kangaroos. Among the suggestions were badgers, rats or mice, hares, wolves, cats, monkeys, toads, or various birds. One anonymous letter-writer said that a friend had examined the tracks, noted that some of them showed claw marks, and suggested the animal might be an otter—mostly as a way to explain how the trail passed under low branches without disturbing them and through a six-inch, or 15 cm, pipe.

Other suggestions were even more outlandish, like the runaway balloon trailing a rope theory. Or the complex and largely irrational theory proposed in 1973 that seven Romany tribes conspired to lay the tracks in one night using stilts made from stepladders, in an attempt to scare some other tribes away. Or the 1972 theory that UFOs were measuring…something…with lasers and the tracks were left as a result, by lasers. Measuring things.

Leaving aside the theories that are clearly farfetched, like animals escaped from menageries and UFOs, and going with the assumption that whatever left the tracks was likely a real animal native to England, what might have left the devil’s footprints? I’m going out on a limb and suggesting maybe it wasn’t the devil.

Badgers, otters, and wolves leave tracks much too large to fit the bill. Toads are cold-blooded and would not be active in the snow. Birds do not leave miles of prints in snow at night, not even owls hunting mice on the ground, as they sometimes do. The tracks of deer would probably be recognized no matter how distorted the melting snow might have made them, and there are no reports of dew claw marks that deer prints show.

What about cats? Cats leave small neat footprints in snow with prints nearly in front of each other. With the brief thaw, feral cats might be out hunting for mice and other animals around houses and gardens, exactly where many prints were found. Cats can climb well, and a small cat might be able to accomplish some of the astonishing feats reported, like getting through dense hedges or larger pipes. And we do have a witness whose report is interesting. A tenant of Aller Farm in Dawlish, the only person we know to have been outside during the night in question, said that his cat had left tracks in the snow, and that the thaw and rain melted them, after which they froze again into small hoof-like shapes. So it’s possible that at least some of the prints were made by cats.

Rats sometimes hop through snow on all four feet, leaving deeper impressions that do look remarkably like the hoofprints seen. Rats can also get through quite small spaces and climb well. The main drawbacks of this theory are that hopping rats leave clear tail prints and rats don’t hop for miles. Rats also usually leave prints larger than the ones found. But again, it’s possible that at least some of the prints were made by rats.

Finally, what about mice? When I was a kid, this argument seemed ridiculously weak. I had pet mice. I knew there was no way a mouse could leave a horseshoe shaped print in the snow. But I was only familiar with pet white mice and house mice. There’s a type of mouse common throughout Europe that I think might be our culprit. Let’s find out why, and learn about the wood mouse.

The wood mouse, also called the long-tailed field mouse, is as adorable as the otter but won’t kill you. It’s a cute little rodent with a long tail, sandy-brown or orangey fur, white or gray belly and legs, and big ears. Not counting its tail, it’s about 6 to 15 cm long, or 2 ½ to 6 inches long, and its tail can be as long as its body. It mostly eats seeds and nuts, although it will also eat roots, shoots, berries and other fruit, moss, fungi, snails, and insects when seeds aren’t available.

Like many rodents, it discovered a long time ago that humans are useful nuisances, so it frequently lives around houses and barns, although not usually in houses. It generally lives in burrows it digs in fields, gardens, or among the roots of trees, although sometimes it will make its nest in birdhouses, hollow logs, or in thick vegetation. The nesting chamber of a mouse’s burrow is lined with leaves, grass, and moss, and it may also dig chambers where it stores extra food.

In warm weather wood mice aren’t very social, but in winter they will sleep in pairs or groups to stay warm. They don’t hibernate, but in especially cold weather they become torpid. They’re nocturnal animals, good climbers, jumpers, and swimmers.

While it forages, a wood mouse will pick up small items like leaves and twigs and place them in conspicuous locations to mark certain areas. As far as researchers know, wood mice and humans are the only animals to mark trails with items, known as way-marking. A mouse’s typical winter territory is around 2000 square meters, or half an acre.

All this is interesting, but why do I think the devil’s footprints were mostly made by wood mice? Well, wood mice flee from predators by hopping on all four legs. They’re built like tiny kangaroos, with long hind legs and comparatively short forelegs. I had a hard time finding information about wood mice jumping, just references to their ability to jump sometimes quite long distances. Then I found an awesome site by a photographer with lots of action shots of the wood mice around their garden. I’ll put a link in the show notes. Unfortunately the page hasn’t been updated for a while, but it’s full of photos of mice in mid-leap. The photographer puts food out and apparently sets up cameras that react to movement—like mini trail cams. It’s clear just from these shots that wood mice can and do jump a lot.

Unlike a rat, a jumping wood mouse doesn’t leave much of a tail mark in snow. It can also keep up this hopping gait for a long time, which it would do since it’s a more efficient way to travel through snow taller than the animal is high. It jumps with its feet together so the print it leaves behind roughly resembles a V shape where the two sides of the V don’t connect. Any amount of thawing and refreezing can turn that print into a cloven hoof print or a donkey-like hoof print.

Moreover, mice can get through extremely small holes and pipes, can burrow straight through haystacks, can hop across roofs without making noise. Where people reported finding prints that vanish in the middle of open fields, the mouse could have disappeared into a burrow, been picked off by an owl, or just stopped hopping and started walking, leaving footprints so small and shallow they likely didn’t survive the thaw.

But why were there so many prints on this particular night? Remember, the winter had been harsh but that particular night there was a brief thaw. It’s very possible that even slightly warmer weather would bring hungry mice out in droves to forage. The unusual weather conditions distorting otherwise barely noticeable tracks into hoofprints, and human nature, did the rest.

But if that’s the case, why haven’t people reported seeing the same mysterious prints at other times? Actually, they have, both before and after 1855.

The earliest account anyone has found in the papers was an 1840 report in the London Times of strange prints in Scotland. Other accounts date from the 1850s, 1890, the 1920s, the 1950s, and so on until 2009.

Some of these accounts are of much larger prints, some don’t match up with the hoofprints seen in 1855, but some sound similar. In 1957, for instance, when Lynda Hanson in Hull was a child, a line of cloven hoofprints 4” long and 12” apart appeared in her family’s garden in about an inch of snow that had fallen overnight. They vanished in the middle of the garden. Ms. Hanson notes that the family dog didn’t bark. He probably would have barked at the devil. Just saying.

Another interesting report comes from a sighting in late 1962 or early 1963. Zoologist Alfred Leutscher, writing in the April 20, 1965 edition of Animals and expanding on a talk he gave to the Zoological Society of London about the sighting, explains some tracks he found in Epping Forest. I’ll quote from his description. “It was during a search for snow tracks in Epping Forest, in the severe winter of 1962-3, that I came across dozens of trails of the wood mouse, each consisting of small ‘V-shaped’ marks regularly spaced out and conforming to the measurements which were given a hundred years ago. When I found them I was totally unaware of their significance.”

There are problems with this, of course. While the account says the tracks were identical to those reported in 1855, they’re described as V-shaped rather than hooflike. I have no doubt Leutscher’s prints were from wood mice, but whether they were the same type of thing seen in 1855 in Devon, we can’t know for sure since the reports from the 1855 sighting are so unclear.

Like I said, while the wood mouse is a good candidate for what caused the devil’s footprints, it’s not perfect. Why would mice be hopping around on snow-covered roofs, for instance? But nothing else fits the evidence we have as well as the wood mouse does.

In 2009, Jill Wade of North Devon woke up to snow and found a line of hoof-like prints across her garden. A zoologist who examined the prints suggested they might be those of a rabbit or hare, although since the prints were only 5” long, or 12.5 cm, that would have to be a little baby bunny. But the great thing in this case is we have photographs. Good ones. I’ll put one in the show notes. It definitely looks like a hoofprint—and it also looks like little animal legs made it.

One interesting thing. The wide part of a wood mouse’s print, the one that would make the rear of a hoofprint, is actually at the animal’s front. So anyone following the devil’s tracks in 1855 was following them backwards. Assuming the culprit really was a horde of hungry wood mice, and not the actual devil.

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. If you like the podcast and want to help us out, leave us a rating and review on iTunes or whatever platform you listen on. We also have a Patreon if you’d like to support us that way. Rewards include stickers and twice-monthly bonus episodes.

Thanks for listening, and Happy Halloween!

 


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. 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!