By Linda Cole
I’m one of “those” people who can sit and watch my cats for hours, observing what they do, how they move, how their whiskers quiver when watching a bird and other interesting things about them. Cats have a unique way of drinking that has actual science behind it. If you’ve ever watched closely as your cat drinks, you can see how they defy gravity every time they take a drink.
In 1940, a documentary called Quicker ‘n a Wink was shot using stroboscopic photography that slowed down movements which were too fast for us to see with the naked eye. Some of the subjects of the slow motion film were a cat drinking, the beating wings of a hovering hummingbird, and the point of impact on a football by a kicker. The film was a huge success, and it won an Academy Award in 1941. For many people, seeing for the first time how a cat drinks was fascinating. When a cat laps up a liquid, she curls her tongue backwards to form a “J”, but she doesn’t just lap it up, she lets physics do the work for her.
A biophysicist at the Massachusetts Institute of Technology in Cambridge wanted to find out how his cat drank, and with the help of colleagues decided to film cats drinking with a high speed camera to answer the mystery of how cats drink. You can watch a slow motion video here.
When you casually watch a cat drink, you might assume she’s using her tongue like a ladle to “scoop up” what she’s drinking, which is how dogs drink. But what is really happening can only be explained as a force of nature. Cats brush their tongue along the surface of a liquid and let inertia do the rest. Inertia is the concept that something in motion tends to continue in the same direction unless it’s broken by other forces. Our feline friends drink by initiating a delicate balance between inertia and gravity.
The process of drinking begins when the cat gently touches the tip of her tongue along the surface of a liquid without breaking it. As she lifts her tongue, liquid sticks to the tip and is drawn upward in a column. The tongue is lifted in a rapid motion, and the stream of liquid grows because of inertia. When she pulls her tongue into her mouth, the column thins out as gravity begins to pull it back down, and she quickly traps the water in her mouth. She swallows every three to 17 laps. Each lap contains about a tenth of a milliliter.