Two scientists at MIT used YouTube videos to help supplement their research on how cats' tongues extract water or milk from a bowl. The videos helped prove their formula describing the unique way felines draw liquids into their mouths.
They observed that a cat's tongue changes into the shape of a capitol 'J' when it is about to touch the surface of a liquid. The tip of the tongue is flattened and draws the liquid up into a column shape, formed by inertia. The cat's jaw closes over the liquid just before gravity acts to pull the liquid back into the dish. The scientists also found that cats naturally lap at the optimal frequency, instinctively maximizing the efficiency of the drinking process.
The scientists used a mechanical analogue of a cat's tongue - a glass disk attached to a piston that they dipped into water - to test the process and get a better understanding of how cats use inertia to overcome gravity. (Interestingly, the project didn't cost the scientists anything. The disk was borrowed from a neighboring lab who had created it for an experiment aboard the International Space Station.)
Stocker and his colleagues then developed a mathematical theory to predict how lapping frequency would change with a feline's mass. Their theory predicted that a cat with greater mass would lap more slowly. To test their theory, the duo turned to Zoo New England who allowed them to film large cats, like lions, tigers and jaguars, as they drank. Stocker then realized that additional data was already freely available on the Internet in the form of YouTube videos of large African cats caught on film during safaris, for example.
To watch an interview of Stocker and colleague Pedro Reis talking about their study, click here. To read the original paper, click here.