CLOSE
Universal Images Group via Getty Images
Universal Images Group via Getty Images

The Sound of Running Water Puts Beavers in the Mood to Build

Universal Images Group via Getty Images
Universal Images Group via Getty Images

From the outside, a beaver dam looks like a heap of sticks, but a closer look reveals the insane amount of effort and detail that goes into building each structure. At a rate of five feet per day, beavers use mud, sticks, and rocks to construct the multi-chamber, watertight dams that hold their families and store their food. 

In the 1960s, Swedish biologist Lars Wilsson wanted to know if this industrious behavior was learned or innate. He decided to capture four adult beavers with the intention of raising them in different habitats. Some were kept in an outdoor enclosure and others in a glass-walled terrarium indoors. 

When a new generation of beavers was born, he chose a few of them to raise in isolation in order to study which of their behaviors were instinctual. He discovered that when released into running water, the young beavers built near perfect examples of dams on their first try. Wilsson then tried a different experiment where he placed the beavers in still or very slow-moving water. The subjects responded by burying themselves in the mud and making no attempts to build. 

It was only when Wilsson played them the sounds of running water through a speaker that their instincts kicked in. Suddenly the beavers were compelled to start building over the speaker, convinced that it was the source of the leak. When the sound was played for them through a loudspeaker on concrete, the beavers still built their dam over the dry floor. Even when presented with a clear pipe that showed water (silently) escaping through their dam and a speaker that played them the sound of running water, they chose to build over the speaker and ignore the clearly visible leak. 

This instinctive quirk makes beavers easy for people to manipulate. Instead of demolishing the dams that overflow river banks and damage property, a special, silent outflow pipe can be installed that diverts the water under the beavers’ radar. If blocking the sound of the pipe is impossible, people will sometimes make small holes in the dam around the pipe, which the beavers will innately plug up instead. For some reason, all those wicked dam-building skills now seem a lot less intimidating. 

[h/t: io9]

nextArticle.image_alt|e
iStock
arrow
Big Questions
Why Do Cats 'Blep'?
iStock
iStock

As pet owners are well aware, cats are inscrutable creatures. They hiss at bare walls. They invite petting and then answer with scratching ingratitude. Their eyes are wandering globes of murky motivations.

Sometimes, you may catch your cat staring off into the abyss with his or her tongue lolling out of their mouth. This cartoonish expression, which is atypical of a cat’s normally regal air, has been identified as a “blep” by internet cat photo connoisseurs. An example:

Cunning as they are, cats probably don’t have the self-awareness to realize how charming this is. So why do cats really blep?

In a piece for Inverse, cat consultant Amy Shojai expressed the belief that a blep could be associated with the Flehmen response, which describes the act of a cat “smelling” their environment with their tongue. As a cat pants with his or her mouth open, pheromones are collected and passed along to the vomeronasal organ on the roof of their mouth. This typically happens when cats want to learn more about other cats or intriguing scents, like your dirty socks.

While the Flehmen response might precede a blep, it is not precisely a blep. That involves the cat’s mouth being closed while the tongue hangs out listlessly.

Ingrid Johnson, a certified cat behavior consultant through the International Association of Animal Behavior Consultants and the owner of Fundamentally Feline, tells Mental Floss that cat bleps may have several other plausible explanations. “It’s likely they don’t feel it or even realize they’re doing it,” she says. “One reason for that might be that they’re on medication that causes relaxation. Something for anxiety or stress or a muscle relaxer would do it.”

A photo of a cat sticking its tongue out
iStock

If the cat isn’t sedated and unfurling their tongue because they’re high, then it’s possible that an anatomic cause is behind a blep: Johnson says she’s seen several cats display their tongues after having teeth extracted for health reasons. “Canine teeth help keep the tongue in place, so this would be a more common behavior for cats missing teeth, particularly on the bottom.”

A blep might even be breed-specific. Persians, which have been bred to have flat faces, might dangle their tongues because they lack the real estate to store it. “I see it a lot with Persians because there’s just no room to tuck it back in,” Johnson says. A cat may also simply have a Gene Simmons-sized tongue that gets caught on their incisors during a grooming session, leading to repeated bleps.

Whatever the origin, bleps are generally no cause for concern unless they’re doing it on a regular basis. That could be sign of an oral problem with their gums or teeth, prompting an evaluation by a veterinarian. Otherwise, a blep can either be admired—or retracted with a gentle prod of the tongue (provided your cat puts up with that kind of nonsense). “They might put up with touching their tongue, or they may bite or swipe at you,” Johnson says. “It depends on the temperament of the cat.” Considering the possible wrath involved, it may be best to let them blep in peace.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

nextArticle.image_alt|e
iStock
arrow
Animals
Why Crows Hold Noisy Funerals for Their Fallen Friends
iStock
iStock

The next time you hear a murder of crows cackling for no apparent reason, show a little respect: You may have stumbled onto a crow funeral. Crows are among the few animals that exhibit a social response to a dead member of their species. Though their caws may sound like heartbroken cries, such funerals aren't so much about mourning their fallen friends as they are about learning from their mistakes.

In the video below from the PBS series Deep Look, Kaeli Swift, a researcher at the University of Washington's Avian Conservation Lab, investigates this unusual phenomenon firsthand. She familiarized herself with a group of crows in a Seattle park by feeding them peanuts in the same spot for a few days. After the crows got used to her visits, she returned to the site holding a dead, taxidermied crow and wearing a mask and wig to hide her identity. The crows immediately started their ritual by gathering in the trees and crying in her direction. According to Swift, this behavior is a way for crows to observe whatever might have killed the dead bird and learn to avoid the same fate. Flocking into a large, noisy group provides them protection from the threat if it's still around.

She tested her theory by returning to the same spot the next week without her mask or the stuffed crow. She offered the crows peanuts just as she had done before, only this time the birds were skittish and hesitant to take them from her. The idea that crows remember and learn from their funerals was further supported when she returned wearing the mask and wig. Though she didn't have the dead bird with her this time, the crows were still able to recognize her and squawked at her presence. Even birds that weren't at the funeral learned from the other birds' reactions and joined in the ruckus.

Swift was lucky this group of crows wasn't particularly vengeful. Crows have been known to nurse and spread grudges, sometimes dive-bombing people that have harmed one of their own.

[h/t Deep Look]

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios