Cat lovers know when kittens take care of their skin, their tongues are rather scratchy. Using high-tech scans and a few other tricks, scientists are learning how these slashing tongues help cats to get clean and stay cool.
The Secret: Tiny hooks that pop open on the tongue ̵
A team of mechanical engineers reported the results on Monday, saying they were more than a curiosity. They could lead to inventions for pets and humans.
"Your tongue could help us apply fluids or clean carpets or apply medicine to hairy skin," said Georgia Tech's lead researcher Alexis Noel, who is seeking a patent for a 3D patent. printed, tongue-inspired brush.
Cats are demanding and spend up to a quarter of their wake-up time nursing. Noel's interest was aroused when her cat, Murphy, stuck his tongue in a fluffy blanket. Scientists had long believed that cat tongues were covered with tiny cone-shaped elevations. Noel, who worked in a laboratory known to animal-loving engineers, wondered why.
First, CT scans of the cats' tongues showed that they were covered with claw-shaped hooks rather than fixed cones. They lie flat and out of the way to the rear, until with a twitch of the tongue muscle the small spines jump straight ahead, she explained.
The big surprise: These spikes contain hollow blades, Noel thought. She visited zoos and zookeepers to study conserved tongues, and discovered that Bobcatats, pumas, snow leopards, even lions and tigers share this trait.
When Noel touched the tips of the preserved spines – called papillae – they came down with drops of food coloring absorbing the liquid. The almost 300 papillae of a domestic cat contain a small amount of saliva, which is released when the tongue presses on the coat, and then transported a little more.
The surface of the tongue is moister. However, Noel saw evidence that the spikes were the key to deep cleansing.
Papillae were only slightly longer in lions than householders, although larger tongues of larger cats hold many hundreds more, reported David L. Hu, professor of Georgia Tech Proceedings of the National Academy of Sciences .
Next, Noel measured cat fur, which contains a lot of air to insulate like a down jacket. Sure enough, compress the fur and in many cat types, the distance to the skin is the length of the tongue back, she found. An exception: Persian cats with their super-long coat, which must be brushed daily by veterinarians to avoid tangles.
A machine that mimics the movements of a cat grooming can penetrate only so deeply into the tongue. And a thermal imaging camera showed them how to cool the cats with boiling, evaporating saliva.
Cat tongues are even more "handy" than you imagined
Alexis C. Noel et al. Cats use hollow papillae to bring saliva into their fur Proceedings of the National Academy of Sciences (2018). DOI: 10.1073 / pnas.1809544115