Cats strike delicate balance between gravity and inertia when lapping milk

US researchers unveiled the secret of how cats lap water or milk with such elegance, a phenomenon that happens so fast it cannot be followed by human eyes. A cat lapping milk strikes a delicate balance between gravity and inertia, the research finds.

Unlike dogs, which use their tongues to scoop water into their mouths, a cat uses the tip of its tongue to pull water upward, closing its jaws before gravity pulls the column of liquid back toward earth.

The method requires cats to lap at just the right speed to balance the inertial force that keeps the water moving upward with the gravitational force pulling the water back down, CBS reports.

An average house cat, the team found, can make four of these mini-streams per second.

"What we found is that the cat uses fluid dynamics and physics in a way to absolutely optimize tongue lapping and water collection," said Jeffrey Aristoff, now at Princeton University but who was one of the four researchers who began the study out of curiosity at the Massachusetts Institute of Technology.

"Nobody had ever studied it before, so nobody knew how the water went from the bowl into the cat's mouth," he said. Not surprisingly, they found that cats lap at precisely the rate that would get them the most water for the effort expended, Washington Post informs.