7 Fierce Facts About Weasels


Weasels may look cute and cuddly, but trust us: you don't want to get too close to these little beasts. Here are seven things you might not know about the fierce furballs.

1. They’re Killing Machines

They might have cute little faces, but weasels are also bloodthirsty. It’s a matter of necessity: they have super-fast metabolisms and need to kill and eat about half their body weight every day. As a result, they’ve become fearsome hunters. The weasel corners and grabs its prey, wraps its muscular body around the animal to immobilize it and then delivers a single killing bite to the back of the head, puncturing the skull or spinal cord. You know what other animal kills like that? The jaguar

The weasel’s bloodlust is instinctual and triggered by movement. Even on a full belly, a weasel will kill anything that moves and looks like prey. And to the tenacious weasel, pretty much everything looks like prey. Tiny weasels have been seen killing and carrying off animals twice, four times, and even 10 times their size

2. They Save Their Leftovers

When prey is plentiful, a frenzied weasel will often kill much more than it can eat. This is no problem; the leftovers will keep. Weasels evolved in cold climates, and learned to use this to their advantage. They dig little underground caches near their den entrances and keep them stocked with leftovers. In the winter, when it’s too cold to go outside, a weasel can just go to the fridge and pull out yesterday’s vole or that extra mouse from last week.

Like any refrigerator, the caches can occasionally get out of control. Scientists found one cache in Greenland stuffed with the carcasses of almost 150 lemmings

3. They Do a War Dance

Weasels, stoats, and even domesticated ferrets all perform a hilarious “weasel war dance” when they’ve got their prey cornered. Scientists aren’t totally sure why they do this. One theory is that the weasel’s wacky twisting, hopping, and darting around distracts, confuses, or even hypnotizes prey animals. In one case, researchers concluded that a number of rabbits killed by stoats had actually “died of fright” after being subjected to the weasel war dance. 

But sometimes there’s no prey in sight, and a weasel’s just dancing on its own. With no audience and no chance to kill anything, weasels may dance for the same reason we do—because it’s fun. 

4. They’re Not Afraid to Fly

Remember that viral picture of the weasel “riding” a woodpecker? That “ride” was probably more like a hijacking. There’s a long, rich history of weasels attacking birds, including kiwis, magpies, owls, herons, and even birds of prey, as Dr. Carolyn M. King observed in her article “Weasel Roulette”:

 [A] British observer named Anderson witnessed a buzzard, or European hawk, swoop down, pick up a weasel from the ground, and then fly off to its usual feeding perch. But within seconds the buzzard's smooth flight turned into an ungainly struggle, and it eventually fell to the ground. Anderson ran to where it fell, and there was the buzzard lying dead on the ground, its underparts bloody, and the weasel still gripping its breast with meshed teeth. 

Naturally, these gambits do not always work out in the weasel’s favor, hence the term “roulette.” (On a related note, a weasel's lifespan is a mere 1 to 2 years in the wild, for obvious reasons.) But when they do? Watch out. 

5. They Deploy Stink Bombs

By now, you’ve probably realized that it’s a bad idea to cross a weasel. On the off chance you aren’t totally sure, consider the following: a cornered weasel can blast its opponent in the face with a thick, oily, yellowish fluid that positively reeks. Like its cousin the skunk, the weasel brews up tablespoons of this special “musk” in little pouches under its tail, then shoots it out on special occasions. Do not stick around during one of those occasions.  

6. They’re Legendary Monster Slayers

The Algonquian-speaking peoples of Canada and the U.S. tell stories of the windigo (also spelled wendigo and witiko), an enormous, man-eating monster. According to legend, the windigo is cursed with an insatiable hunger. Eating does not satiate the beast; instead, with every meal, the monster grows in size and becomes even hungrier. The windigo stalks from village to village, devouring the inhabitants and wanderers along the road. No man can destroy him. 

One day, the windigo captures a traveler. He sends the terrified man out to find sticks for his own cook fire. Along the way, the man encounters a weasel and begs it desperately for help. The man returns to the monster with the weasel hidden in his clothing. As they approach, the weasel rushes at the windigo and climbs into his anus. The windigo begins to look quite ill, and soon falls down dead: the tiny, brave weasel has eaten his heart from within. 

7. They Glow Purple Under a Black Light (Allegedly)

Weasels were plentiful in Pennsylvania in the early 1950s, but they weren’t welcome. After the Pennyslvania Game Commission offered a bounty for every weasel pelt, they found themselves inundated with fur. The region was home to three weasel species, but once the weasel's tail had been removed, the pelts all looked pretty much the same. So how could they figure out which species a pelt belonged to?

One employee thought he had the answer. In 1953, Roger M. Latham wrote a letter to the Journal of Mammalogy [PDF], announcing a “Simple Method for Identification of Least Weasel.”

“It was discovered,” he wrote, “that the fur of the least weasel would fluoresce under ultra-violet light, producing a vivid lavender color. The fur of the other two species remained a dull brown … Thus, identification is positively and simply made, immediately.” 

Latham’s glow-in-the-dark-weasel trick thereby entered the canon of weasel facts. Even today, you can find numerous sources claiming that least weasels glow under UV light. There’s just one problem: his method has never been validated. Nobody has ever reproduced his attempts. Still, it’s possible that Mustela nivalis glows in the dark. Given everything else we know about weasels, it wouldn’t be surprising.

iStock // Heinrich Hoffmann/Keystone Features/Getty Images // collage by Jen Pinkowski
When German Scientists Tried to Rename Bats and Shrews, Hitler Threatened to Send Them to War
iStock // Heinrich Hoffmann/Keystone Features/Getty Images // collage by Jen Pinkowski
iStock // Heinrich Hoffmann/Keystone Features/Getty Images // collage by Jen Pinkowski

In The Art of Naming (The MIT Press), Michael Ohl, a biologist at the Natural History Museum of Berlin, delves into the art, science, language, and history of taxonomy. There are some 1.8 million known species—and scientists estimate that 100 million more await discovery. Every one will need a name. How does the process work? 

Ohl takes us into the field with the explorers and scientists at the forefront of naming the natural world, including Father Armand David, a French priest who was the first to describe the panda to the Western world; American paleontologists Edward Dinker Cope and Othniel Charles Marsh, who bitterly battled in the Bone Wars; and Polish biologist Benedykt Dybowski, whose unique naming system for crustaceans called gammarids (a.k.a. "scuds") resulted in tongue-twisters such as Cancelloidokytodermogammarus (Loveninsuskytodermogammarus) loveni.

In the excerpt below, Ohl tells the story of one of the little-known footnotes to World War II: When Adolf Hitler threatened the German biologists who wanted to rename bats and shrews. And, read on for the best bat nickname of all time: "bacon mouse."

—Jen Pinkowski


On March 3, 1942, a brief item with a rather peculiar headline appeared tucked away in the Berliner Morgenpost newspaper. "Fledermaus No Longer!" the bold letters proclaimed. The following short text was printed underneath:

"At its 15th General Assembly, the German Society for Mammalogy passed a resolution to change the zoologically misleading names 'Spitzmaus' [shrew] and 'Fledermaus' [bat] to 'Spitzer' and 'Fleder.' Fleder is an old form for Flatterer [one that flutters]. The Spitzmaus, as it happens, has borne a variety of names: Spitzer [one that is pointed], Spitzlein, Spitzwicht, Spitzling. Over the course of the conference, several important lectures were held in the auditorium of the Zoologisches Museum […]."

To this day, despite the problems announced by Germany's leading specialists on mammals on the pages of one of the capital's daily papers, fledermaus and spitzmaus remain the common German names for bats and shrews. Neither dictionaries nor specialized nature guides contain entries for fleder or spitzer (provided one disregards the primary definition of spitzer, which is a "small implement used for the sharpening of pencils").

Indeed, a swift response to the item in question arrived from an unexpected source. Martin Bormann, Adolf Hitler's private secretary, sent a message on March 4, 1942, to Hans Heinrich Lammers, head of the Reich Chancellery. The missive contained remarkably unambiguous instructions from Hitler:

"In yesterday's newspapers, the Führer read an item regarding the changes of name ratified by the German Society for Mammalogy on the occasion of its 15th General Assembly. The Führer subsequently instructed me to communicate to the responsible parties, in no uncertain terms, that these changes of name are to be reversed immediately. Should members of the Society for Mammalogy have nothing more essential to the war effort or smarter to do, perhaps an extended stint in the construction battalion on the Russian front could be arranged. Should such asinine renamings occur once more, the Führer will unquestionably take appropriate measures; under no circumstance should terms that have become established over the course of many years be altered in this fashion."

There's no question that the "responsible parties" understood and responded to the injunction, which could hardly have been misinterpreted. On July 1, 1942, at least, a notice was printed in the Zoologischer Anzeiger—at that time, the "organ of the German Zoological Society"—that comprised a scant five lines. The notice has no byline and can most likely be attributed to the journal's publishers:

"Regarding the discussion [in earlier issues of the Zoologischer Anzeiger] about potential changes to the names 'Fledermaus' and 'Spitzmaus,' the Editors wish to make public that terms that have become established over the course of many years are not to be altered, following an announcement by the Reich Minister of Science, Education, and National Culture, as per the Führer's directive."

It's conceivable that Lammers forwarded Hitler's instructions (which had reached him by way of Bormann) to Bernhard Rust, the Reich Minister of Science, Education, and National Culture. Rust will then likely have ordered one of the "parties responsible" for the unpopular initiative to publish the retraction in the appropriate platform. The Zoologischer Anzeiger fit the bill, considering the fact that by 1941 it had already featured two articles debating whether the name spitzmaus should be changed.

What is the problem, though, that veteran scientists have with spitzmaus and fledermaus, those innocuous terms for the shrew and the bat? And how could it come to pass that Adolf Hitler—preoccupied as he was in 1942— should personally join in the campaign for the correct classification of these small mammals?


The common thread in these two unremarkable and familiar terms is of course the second word component, maus, or "mouse."

Fledermaus and spitzmaus … are (linguistically) first and foremost mice. By referencing certain characteristics in these compound words (fleder comes from flattern, "to flap"; spitz, or "point," refers to the shrew's pointy nose or rather head shape), it becomes possible to provide a clear name—or almost clear, at least, because there are many bat and shrew species, but more on that later.

Both names, of course, imply affiliation with mice, and that's the sticking point. In zoological terms, mice are a group of rodents known at the higher level of classification as Muroidea, "muroids" or the "mouse-like." The group includes quite the mix of animal groups, with occasionally curious names like zokor, blind mole-rat, spiny tree mouse, and Chinese pygmy dormouse, not to mention our pet hamsters and those domestic but unwelcome mice and rats. Common to all muroids are sundry and complex structural features in the skull, coupled of course with the oversized, continually growing incisors typical of rodents. Beyond that, although endless evolutionary gimmickry can revolve around this mouse theme (long or short legs, different fur colors and tail lengths, and much more), and even without biological expertise, most muroids tend to be identifiable as mice, if only vaguely.

Zoologically speaking, a mere mouse-like appearance is insufficient to denote a muroid. Instead, the specific anatomical features of the skull must be in evidence.

Field, house, and deer mice are familiar to many North Americans, although they typically live hidden away, and we don't often encounter them. These animals with the "mouse" base in their name are truly mice in the zoological sense.

The same cannot exactly be said for the bat and shrew—the fledermaus and spitzmaus—despite their names. Neither of them is even a rodent or, consequently, a muroid. Then what are they?

In the classification of mammals, a whole series of groupings is traditionally distinguished, usually assigned the rank of order within the class of mammals. Depending on scientific opinion, there are 25 to 30 of these orders of mammals. Rodents comprise one of these orders, to which muroids and several other groups of mammals belong.

Bats, meanwhile, are typical representatives of the order of flying mammals. Their scientific name is Chiroptera, from the Greek words chiros (hand) and pteros (wings). Chiroptera, then, means "hand-flier," which is a fitting name for bats and their closest relatives, flying foxes.

The systematic placement of the shrew, or spitzmaus, is determined in much the same way. They, too, fail to possess the mouse characteristics in question, although they do share traits with moles and hedgehogs, as well as with the solenodon (meaning "slotted tooth"), which is a venomous critter native exclusively to the Caribbean islands. They are now situated under the wondrous designation Eulipotyphla, but only since 1999. How they are related—along with ties to an array of other mammal families, such as tenrecs, desmans, and golden moles—has not been conclusively explained.

Experts have known for a long time—since Linnaeus's Systema Naturae at the latest—that neither bats nor shrews are related to mice, to which common parlance pays no heed. The fledermaus and spitzmaus comfortably maintain their spots in the lexicon.


One of the first mammal biologists to campaign for the standardization of German mammal names was Hermann Pohle. Born in Berlin in 1892, Pohle remained faithful to the city until his death and spent a large part of his life working at the natural history museum there. His career as a mammal biologist started early, when as a university student he worked as an unpaid hireling in the museum's famed mammal collection. Through diligence, endurance, and scientific acumen, he worked his way up to head curator of mammals. He thus held one of the most influential positions, of both national and international significance, in the field of systematic mammal research.

In 1926, Pohle—along with Ludwig Heck, the former director of the Berlin Zoo, and a number of other colleagues—founded the German Society for Mammalogy, of which he was the first head. Pohle thus had his finger on the pulse of mammal research, as it were, and he followed the history of the society over the next five decades "with keen interest," as one biographer noted.

In addition to his work as a researcher and curator of the mammal collection at Berlin's Museum für Naturkunde (Museum of Natural History), Pohle's interests also lay with German mammal names. Not only did he push for standardization of names, Pohle also campaigned to have existing names assessed for scientific plausibility and changed, should they not pass (his) zoological muster.

In 1942, Pohle published a summary article addressing the question, "How many species of mammals live in Germany?" He appended a comprehensive list of all German mammals, each with its correct "technical name," as Pohle called it, as well as its corresponding German name. When it came to the various species of spitzmaus (of which the Germans have eight, incidentally, despite the long-standing impression that there is "the" one and only shrew) and the 16 species of bats that have the base word "fledermaus" in their name, Pohle consistently uses alternative terms. The eight shrew species thus became waldspitzer, zwergspitzer, alpenspitzer, wasserspitzer, mittelspitzer, feldspitzer, gartenspitzer, and hausspitzer. For the bats, the base of their compound name was changed to fleder: teichfleder, langfußfleder, wasserfleder, and so on, all the way to a term of particular elegance, wimperfleder.

Pohle's article, which predates the society's 15th General Assembly and Hitler's emotional veto by more than a year, is a particularly interesting source because he also shares his actual motivations for the suggested changes. His emphatic objective is to see "the term 'Maus' disappear, responsible as it is for laypersons' wont to lump the animals together with actual mice."

In the estimation of these laypersons, mice are something "ugly and destructive that must be fought, or ideally exterminated." Shrews and bats, harmless as they are to humans, are thus subject to the same brutal fate. Pohle hopes for a "shift in perspective" to occur, once the endangered animals are no longer referred to as mice.

What to do, then? Pohle would prefer the term spitz for spitzmaus, but it's already been assigned to a dog breed. Rüssler could also work, only it already applies to some other insectivore. That leaves spitzer, a name that emphasizes the pointy head as a distinguishing characteristic and is still available.

Pohle wants a name for bats without "maus" but happily with a nod to the animals' flying ability. Most names of this kind are already employed for birds, and "flatterer" or "flutterer" could only logically be used for a certain population of bats, namely, those bad at flying. "Flieger" or "flyer," another hot candidate, is also in use by various other animal groups.

But why, Pohle asks the reader, would one even need to say "fledermaus," when "fleder" actually makes perfect sense? Pohle mentions that the original meaning of "fleder" was different, but few people were aware of this fact anymore.

On the off chance that he was correct in this assessment, let it be noted that fledermaus can be traced back to the 10th century, to the Old High German "vledern" or "flattern" (the infinitive form of "flatterer"). The image of the bat as a "fluttering mouse" has existed since this time in many languages, including "flittermouse" in English. A number of other German terms exist for bats. In some regions of Germany, such as Rhineland-Palatinate and Southern Hesse, the Old High German "fledarmus" is said to have been used to describe nocturnal creatures, such as moths. There, bats were apparently called "speckmaus," instead of fledermaus, because while hibernating, they could be seen hanging like pieces of bacon (speck) in the smoke.

Pohle's dedication to promoting the protection of bats and shrews through a bold name change reached its temporary culmination a year later, when—at the 15th General Assembly of the German Society for Mammalogy in Berlin—a resolution was passed on a universal and binding adoption of the spitzer- and fleder-based names Pohle had suggested. The results are known: Hitler was not amused.


We can only guess at what Hitler's actual motive was in issuing such drastic threats to prevent the name alterations proposed by the German Society for Mammalogy. It could have been his outrage that in 1942—hard times because of the war—leading German intellectuals were concerned with something so unimportant and banal as the appropriateness of animal names. Perhaps this anecdote is just a further example of Hitler's hostility toward intellectuals.

It is ultimately unclear, even, to what extent Hitler was the driving force behind this directive or whether this is a case of subordinates "working towards the Führer," as historian Ian Kershaw describes it. Conceivably, after reading the Berliner Morgenpost, Hitler may have remarked negatively regarding the zoologists' plans. His circle—in this case, Bormann—may have immediately interpreted this as "the Führer's will" and sprung to action accordingly. As for Pohle and his colleagues, it can't have mattered much whether the "invitation" to the Eastern Front came directly from Hitler or was communicated in an act of premature obedience.

Whatever the case may be, Pohle's suggested name changes did not fail because of Hitler's intervention, which presumably resonated as little with the German-speaking public as the original notice. Pohle failed because he wanted to take the basic idea of a standardized naming system out of the scientific context and transfer it into the realm of vernacular. Everyday German is not formally and officially regulated, and like every other vernacular, it follows different rules than scientific speech. It is shaped by a multitude of factors and influences that have their own unpredictable dynamic, which leads to some word usages changing while others stabilize.

In kindergarten, we learn that small, furry four-legged animals with a tail are "mice." This act of naming fulfills the exact function expected of it. It "tags" specific linguistic content—a meaning—that is generally understood. The difference between muroids and insectivores, which is important to zoologists, has no application in everyday confrontations with "mouse-like" animals and makes no difference to most people. A mouse is a mouse, whether a striped field mouse or a shrew.

Tony Karumba, AFP/Getty Images
The World's Last Male Northern White Rhino Has Died, But Could He Still Help Save the Species?
Tony Karumba, AFP/Getty Images
Tony Karumba, AFP/Getty Images

Following age-related complications, Sudan the northern white rhinoceros was euthanized by a team of vets in Kenya at 45 years old, CNN reports. He was one of only three northern white rhinos left on earth and the last male of his subspecies. For years, Sudan had represented the final hope for the survival of his kind, but now scientists have a back-up plan: Using Sudan's sperm, they may be able to continue his genetic line even after his death.

Northern white rhino numbers dwindled from 2000 in 1960 to only three in recent years. Those last survivors, Sudan, his daughter Najin, and granddaughter Fatu, lived together at the Ol Pejeta Conservancy in Kenya. Each animal had physical issues making it difficult for them to breed, and now with Sudan gone, a new generation of northern white rhinos looks even less likely.

But there is one way the story of these animals doesn't end in extinction. Before Sudan died, researchers were able to save some of his genetic material, which means it's still possible for him to father offspring. Scientists may either use the sperm to artificially inseminate one of the surviving females (even though they're related) or, due to their age and ailments, fertilize one of their eggs and implant the embryo into a female of a similar subspecies, like the southern white rhino, using in vitro fertilization.

"We must take advantage of the unique situation in which cellular technologies are utilized for conservation of critically endangered species," Jan Stejskal, an official at the Dvur Kralove Zoo in the Czech Republic where Sudan lived until 2009, told AFP. "It may sound unbelievable, but thanks to the newly developed techniques even Sudan could still have an offspring."

Poaching has been a major contributor to the northern white rhino's decline over the past century. Rhinos are often hunted for their horns, which are believed to have medicinal properties in some Asian cultures. (Other people just view the horn as a sign of wealth and status.) Procreating is the biggest issue threatening the northern white rhinoceros at the moment. If such poaching continues, other rhino species in the wild could end up in the same situation.

[h/t CNN]


More from mental floss studios