Why Your Cat's Tongue Is Nature's Perfect Hairbrush

iStock.com/takashikiji
iStock.com/takashikiji

A lick from a cat is a mixed blessing. On the one hand, cats don’t dole out affection to just anyone, so it’s a true compliment when they try to groom you. On the other hand, their tongues feel like sandpaper wrapped in barbed wire. Those sharp tongues are actually incredible tools, according to a new study published in Proceedings of the National Academy of Sciences. Their unique structure is very efficient at depositing saliva on cats' fur to help them clean themselves and keep cool. Researchers from Georgia Tech made the discovery using high-speed video, CT scans, and “grooming force measurements.”

Cats aren't just prettying themselves up when they spend all day grooming themselves, the study shows. (That’s not an exaggeration—house cats can spend up to a quarter of their waking lives grooming.) As they lick themselves, their tongues remove debris, fleas, and excess heat from their fur thanks to those sharp, curved spines—called filiform papillae—that are so unpleasant to feel on your skin.

A close-up image of a cat's tongue
Alexis Noel

These keratin-based filiform papillae have U-shaped hollows at their tips that allow cats to wick saliva from their mouths onto their fur, helping them regulate body temperature and cool down. Each of these papillae can carry one-tenth of an eyedropper’s worth of spit, half of which gets deposited on the fur. The papillae spread the saliva along the roots of each hair, allowing it to penetrate cats’ fur so that it can cool their skin. Saliva alone can provide 25 percent of a cat’s cooling needs, according to the study.

This useful adaptation isn’t limited to domestic cats. Researchers looked at tongue tissue from six different species—bobcat, cougar, snow leopard, tiger, and lion, in addition to house cats—and found similar structures.

As part of the study, the researchers also created a flexible “tongue-inspired grooming" (TIGR) brush with the help of 3D models of a house cat’s papillae. They found it was easier to clean than a typical human hairbrush—hair could be removed from it in one swipe, without the tweezers or other tools you need to get hair out of the stiff bristles of the typical hairbrush. (The wavy ridges on the roofs of cats’ mouths may do this job in the animals themselves.)

The brush has several potential uses. Because of its papillae-inspired structure, it could be used to apply liquids to cats’ skin. That could be helpful for applying topical medication, but it might also be a way to wash off some of the allergens they produce that bother humans. Potentially, there could be human uses for a papillae-like hairbrush in the future, too. You could imagine using it to brush styling products evenly through your hair, for instance. The researchers suggest the structure "may provide inspiration to soft robotics and biologically inspired technologies for sorting, cleaning, and depositing fluids into fur and arrays of flexible filaments."

Why Are There No Snakes in Ireland?

iStock
iStock

Legend tells of St. Patrick using the power of his faith to drive all of Ireland’s snakes into the sea. It’s an impressive image, but there’s no way it could have happened.

There never were any snakes in Ireland, partly for the same reason that there are no snakes in Hawaii, Iceland, New Zealand, Greenland, or Antarctica: the Emerald Isle is, well, an island.

Eightofnine via Wikimedia Commons // Public Domain

Once upon a time, Ireland was connected to a larger landmass. But that time was an ice age that kept the land far too chilly for cold-blooded reptiles. As the ice age ended around 10,000 years ago, glaciers melted, pouring even more cold water into the now-impassable expanse between Ireland and its neighbors.

Other animals, like wild boars, lynx, and brown bears, managed to make it across—as did a single reptile: the common lizard. Snakes, however, missed their chance.

The country’s serpent-free reputation has, somewhat perversely, turned snake ownership into a status symbol. There have been numerous reports of large pet snakes escaping or being released. As of yet, no species has managed to take hold in the wild—a small miracle in itself.

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

Intense Staring Contest Between a Squirrel and a Bald Eagle Caught on Camera

iStock.com/StefanoVenturi
iStock.com/StefanoVenturi

Wildlife photographers have an eye for the majestic beauty of life on planet Earth, but they also know that nature has a silly side. This picture, captured by Maine photographer Roger Stevens Jr., shows a bald eagle and a gray squirrel locked in an epic staring match.

As WMTW Portland reports, the image has been shared more than 8000 times since Stevens posted it on his Facebook page. According to the post, the photo was taken behind a Rite Aid store in Lincoln, Maine. "I couldn't have made this up!!" Stevens wrote.

Bald eagles eat small rodents like squirrels, which is likely why the creatures were so interested in one another. But the staring contest didn't end with the bird getting his meal; after the photo was snapped, the squirrel escaped down a hole in the tree to safety.

What was a life-or-death moment for the animals made for an entertaining picture. The photograph has over 400 comments, with Facebook users praising the photographer's timing and the squirrel's apparent bravery.

Funny nature photos are common enough that there's an entire contest devoted to them. Here are some of past winners of the Comedy Wildlife Photography Awards.

[h/t WMTW]

SECTIONS

arrow
LIVE SMARTER