Thursday, November 11, 2010

We always knew they were beautiful, but now we also know how they drink

We Always Knew They Were Beautiful, But Now We Know How They Drink
Have you ever wondered how cats drink? I sure have. It was always a mystery. A dog will roll up its big tongue into more or less the shape of a cup, and then slurp that up (noisily). Cats don't do that. They just make that discreet little lappity-lap sound, and it's hard to see what they're really doing. They almost seem to ingest water through osmosis.

Until recently, nobody knew. Now science has provided the answer. And it's amazing. The NYT reports that a group of engineers published a paper today that clears up the mystery.
Writing in Thursday’s issue of Science, the four engineers report that the cat’s lapping method depends on its instinctive ability to calculate the balance between opposing gravitational and inertial forces.

What happens is that the cat darts out its tongue, curving the upper side downward so that the tip lightly touches the surface of the water. The tongue is then pulled upward at high speed, drawing a column of water up behind it. Just at the moment that gravity finally overcomes the upward rush of the water and starts to pull the column down — snap! The cat’s jaws have closed over the jet of water and swallowed it.

The cat laps four times a second — too fast for the human eye to see but a blur — and its tongue moves at a speed of one meter per second.
For a high-speed video of how this works, check out the NYT's story. The video also contains an interview with the researchers.

The researchers developed a formula that predicts how fast a cat, depending on body size, should lap to get the maximum amount of water. They then observed felines of various sizes. Lions, leopards, jaguars and ocelots all lapped at the predicted speeds for maximizing their water intake. It's a complex problem -- and one that that evolution figured out long before human science did.

1 comment:

Becca said...

I've also read that a cat will use its paw to "drink" water if it can't properly judge the distance to the water's surface. How neat!