High-speed videos reveal the strange technique and delicate balance of physical forces cats use to lap milk from a bowl.
Unlike dogs, who use their tongues as ladles to scoop water into their jaws, cats pull columns of liquid up to their mouths using only the very tips of their tongues.
"Cats are just smarter than dogs from the point of view of fluid mechanics," said civil engineer
Roman Stocker of MIT.
Cats' tongues operate more like octopus tentacles or elephant trunks, Stocker found. The study's results could have implications for designing soft, flexible robots.
Stocker grew curious about how cats lap about three years ago while watching his housecat, Cutta Cutta, eating breakfast.
"I started to think, there had to be something interesting about the mechanisms of how the cat was getting the water or milk into the mouth, because it had to overcome gravity," he said.
Cutta Cutta's tongue flicked in and out of his mouth too quickly for Stocker to study with his naked eye. So he borrowed a high-speed video camera from a colleague at MIT.
Stocker and his colleagues filmed Cutta Cutta drinking a bowl of water mixed with a little bit of yogurt ("for visual contrast and palatability") at 120 frames per second. The results appeared Nov. 11 in
Science.
Video: Pedro M. Reis, Sunghwan Jung, Jeffrey M. Aristoff and Roman Stocker