Why Does Your Cat's Tongue Feel Like Sandpaper

Cats are obsessed with staying clean.

They can spend up to half their waking hours grooming.

Their tongue is covered in tiny spines.

They're what make the tongue feel so sandpapery.

These spines, called papillae, are made of keratin, just like their claws and our fingernails.

The papillae even look like miniature cat claws.

They do an impeccable job of detangling their fur.

Researchers at Georgia Tech made a 3D model of a cat's tongue… to test how it works.

See how the fur just peels off?

It's because the spines are all angled in the same direction.

With a typical hairbrush, you'd have to pick the fur out from between the bristles.

So why are cats so preoccupied with grooming?

For them, it's about more than just vanity.

For one thing, it's a way to show affection, to build bonds.

That's why they appreciate us petting them.

And it spreads out oils produced by the cat's skin that gives their fur some water resistance.

But when it really comes down to it, for cats, staying clean is a matter of life and death.

Cats are carnivores ambush predators.

They hide and sneak up on their unsuspecting prey.

One whiff of the wrong odor could give the cat away.

But when they pounce, it's their bite that finishes the job.

Cats have extra-wide mouths so they can get their teeth around their prey's neck.

It would be like having the corners of your mouth go all the way back by your ears.

But there's a tradeoff that comes with that big bite.

Those wide mouths mean their lips can't come together to form a good seal.

They can't create suction to drink the way we do.

So, they flick the surface of the water with the tip of their tongue.

Researchers at MIT made a model using a glass disc, to show how cats get a drink by just barely touching the water's surface.

The water sticks to the disc and to itself.

Lift the disc at the right speed and it pulls the water up into a column.

Then, the cat bites it at precisely the right moment to get as much water as possible.

And all of this happens four times per second!

It's a complicated way to take a drink,

but it's just one of the prices cats pay to be the expert predators they are…