Sally: Grandma's Hairless Cat

You may or may not have a cat as a pet, but you have most likely seen one. While you were at your grandma's house observing her hairless cat, did you take the time to look at the magic of how he or she drinks? A recent paper has gone into detail of the wonderful complexity of just exactly how cats go about drinking. After reading those first sentences, you may be wondering what I could possibly be talking about. In your mind, you've most likely thought that cats drink in a simple manner. They form a ladle with their tongue and scoop the liquid into their mouth. Wrong. The method I just described is used by dogs, but cats employ a completely different method. Cats, being the intelligent creatures they are, take advantage of the liquid's inertia. Inertia is the laziness of an object, in simple terms. Inertia is the unwillingness of an object to change unless it is manipulated by another force. In this case, we will make the liquid milk and the manipulator gravity. As your grandma's hairless cat stealthily approaches the milk filled bowl (while wearing kitten mittens), he prepares to take full advantage of the inertia of the milk. Your grandma's cat, henceforth known as Sally, dips her tongue, which is the same color as her fur (or lack thereof), into the milk. Almost as quickly as the tongue enters the milk, she pulls it, yanking the milk up into the air. For a split second, the inertia of the milk suspends it in the air, and in this moment, Sally surrounds the milk with her mouth and swallows it. After that split second of suspension, gravity, the manipulator, kicks in, snapping the milk back down into the bowl. Still thirsty, Sally repeats the complex and intricate process again until her thirst is quenched.

The intricacy of this seemingly simple process was discovered by a team of scientists led by Pedro Reis. The team went about observing this by using high speed cameras, as cats dip their tongues down into the liquid an astounding three and a half times per second. Even more astoundingly, when the tongue shoots back into the mouth, it moves at a speed of seventy-eight centimeters per second. When Reis first began the experiment, he and his team figured that the roughness of the cat's tongue would play a role; a prediction that was drastically wrong. In actuality, the tip of the tongue that penetrates the surface of the liquid is smooth, and the smoothness is actually very good for lapping up the milk or water. Throughout the research, Reis and his team found that the viscosity of the liquid, and least between the bounds of what a cat would logically drink, did not affect the process. Rather, the determining factors were the inertia and gravitational pull. One may think that this is an odd thing to research or that somebody must have done it before, but as Rebecca Z. German of Johns Hopkins School of Medicine says, "What we know about mammalian feeding is woefully incomplete."

Here are some videos, one of a cat lapping up milk in slo-mo, and the other of a simulator demonstrating the inertia of water.


FAST LAPS from Science News on Vimeo.


TONGUE SUBSTITUTE from Science News on Vimeo.


So now you know, and next time you see your grandma's hairless feline lapping up some milk, you can explain to all your friends what Sally is really doing.

Source:

http://www.sciencenews.org/view/generic/id/65379/title/Cats_drink_using_lap-and-gulp_trick
http://www.dailymail.co.uk/news/article-481062/Puss-Hood-Hairless-Sphynx-cat-keeps-warm.html