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."

Pet Obesity is Causing Big Health Problems, According to a New Report

iStock/dennisvdw
iStock/dennisvdw

If you’ve recently picked up your cat and felt your back give out, your furry friend may be among the 60 percent of the feline population that’s overweight. Dogs are also getting chubbier: about 56 percent of pet pooches are obese.

According to Banfield Pet Hospital, America's largest general veterinary practice with more than 1000 hospitals nationwide, those fat cats and chunky puppies are at risk for chronic health issues. In a new report, the hospital finds that osteoarthritis (OA) in pets is on the rise, with a 66 percent increase in dogs and a 150 percent increase in cats over the past 10 years.

Osteoarthritis is a kind of arthritis caused by inflammation or damage in joint tissue. Genetics, injury, or bone abnormalities can all be factors. The disease is chronic and degenerative and can make it difficult for pets to move around as they get older.

Excess weight can both precede OA and make it worse. When a pet is overweight, they can develop chronic pain that leads to stress on joints. If they already have OA, that joint discomfort can prevent them from being active, leading to weight gain. That worsens the condition, and the cycle continues.

A dog is 2.3 times more likely to be diagnosed with OA if it's obese, while cats are 1.2 times more likely. Dogs suffering from the condition tend to display symptoms like putting their weight off to one side when sitting, avoiding stairs, or appearing uninterested in playing. Cats might have loose or matted hair because they can't maneuver to groom certain parts of their body.

Although OA can be seen at any age, it’s often mistaken for old age and a pet slowing down naturally. If you notice your pet is either soft around the middle or moving more slowly, it’s best to see a veterinarian. Pets who are overweight or suffering from OA—or both—can benefit from treatments like special diets.

There Are 2373 Squirrels in New York's Central Park, Census Finds

iStock/maximkabb
iStock/maximkabb

Central Park in New York City is home to starlings, raccoons, and exotic zoo animals, but perhaps the most visible fauna in the area are the eastern gray squirrels. Thanks to a team of citizen scientists, we now know exactly how many of the rodents occupy the space—approximately 2373 of them, according to a census reported by Smithsonian.

In October 2018, a group called the Squirrel Census—with help from the Explorers Club, the NYU Department of Environmental Studies, Macaulay Honors College, the Central Park Conservancy, and the New York City Department of Parks & Recreation—organized a squirrel survey across all 840 acres of Central Park. For 11 days, more than 300 volunteers staked out their sections of the park twice a day—at dawn and dusk when the crepuscular animals are most active—and noted each squirrel they spotted. They also recorded how the squirrels looked, vocalized, behaved, and reacted to humans.

The research was analyzed and presented at an Explorers Club event in New York City on June 20. All the non-peer-reviewed findings—which includes a printed report, an audio report on a vinyl 45, 37 pages of data, collectible squirrel cards, and large maps of the park and the squirrel locations—are available to purchase for $75 from the Squirrel Census website.

This isn't the first time a massive census has been conducted of a public park's squirrel population. In 2011, the Squirrel Census launched with its first survey of Atlanta's Inman Park. They've conducted satellite squirrel counts at other parks, but Central Park is just the second park the organization has investigated in person.

[h/t Smithsonian]

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