The scoop on how your cat's sandpapery tongue cleans deeply

Cat lovers know when kittens are grooming, their tongue is pretty irritating. Using high-tech scanners and other tips, scientists are learning how these sandpapery languages ​​help cats stay clean and stay cool.

The secret: tiny hooks that spurt out on the tongue – with built-in spoons to carry saliva deep into the fur.

A team of mechanical engineers reported the results Monday and said that they are more than a curiosity. They could lead to inventions for animals and people.

"Their tongue could help us apply fluids, clean carpets or apply medications" on hairy skin, said Georgia Tech senior researcher Alexis Noel, who is seeking a patent for a 3D-inspired brush inspired by language.

Cats are tedious and devote up to a quarter of their waking hours to grooming. Christmas's interest was stung when her cat, Murphy, found herself stuck in a fluffy blanket. Scientists have long believed that the cat's tongue was studded with tiny cone-shaped bumps. Noel, working in a laboratory known for his animal-inspired engineering, wondered why.

First of all, CT scans showed that they were not covered with full cones but claw-shaped hooks. They are lying flat and facing backwards, apart until, with a muscular contraction of the tongue, the little spines stand up, she explained.

The big surprise: these spines contain hollow scoops, find Noel. Speaking to zoos and taxidermists for preserved languages, she discovered that leopards, cougars, snow leopards, even lions and tigers share this trait.

When Noel touched the tips of the preserved spines – called taste buds – with drops of food coloring, they diluted the liquid. Nearly 300 household taste buds contain a small amount of saliva that is released as the tongue presses on the fur and then retains even more.

The surface of the tongue is wetter. But Noel saw evidence that thorns were the key to deep cleansing.

The taste buds were only slightly longer in lions than housewives, although the largest feline languages ​​contain hundreds more, reported David L. Hu, associate professor at Georgia Tech, in Proceedings of the National Academy of Sciences.

Next, Noel measured the cat fur, which contains a lot of air to be insulated like a down jacket. Indeed, compress this fur and in many types of cat, the distance to the skin corresponds to the length of the spines of the tongue, she found. An exception: Persian cats with their very long fur that veterinarians warn must be brushed every day to avoid carpets.

A machine that imitated grooming a cat found that saliva from the surface of the tongue simply could not penetrate as deeply. And a thermal camera showed as they were grooming, evaporating saliva cooled cats.

Explore further:
Cat languages ​​are even more "practical" than you think

More information:
Alexis C. Noel et al. Cats use hollow taste buds to absorb fur saliva, Proceedings of the National Academy of Sciences (2018). DOI: 10.1073 / pnas.1809544115