How do cats drink? Is the “wet dog shake” an effective drying mechanism? These may have fleetingly crossed your mind, but it took an engineer to get to the bottom of such creature curiosities.

The ability of felines to lap up an entire bowl of liquid may seem to defy gravity. But four engineers at MIT, Virginia Polytechnic Institute, and Princeton have proven that it’s not so. Their study was inspired by observing one of their cats, Cutta Cutta.

The team used high-speed photography to capture and analyze the mysterious cat lap’s fluid dynamics. Since a cat’s tongue is not large enough to create a ladle that can “scoop” water into its mouth, kitties lightly touch the tip of their tongue to the surface of the water, and then quickly dart it back, drawing a column of liquid into their mouths.

This method takes advantage of the physical properties of water and similar liquids, namely surface tension and the cohesion of molecules. Cats do this approximately four times a second (watch in slow motion below).

Putting their findings to the test, the engineers borrowed a small mechanism that mimics the tongue motion using a piston with a small glass circle at the end (watch how it works in the video below). With this device and a bowl of water, the team was able to calculate the optimal speed for cats to move their tongue in order to take the largest possible gulp. Turns out that cats already lap at this speed – perhaps they should be nominated as Nature’s Best Engineer(s)?

Or should the prize go to dogs? Researchers  looking into the physics behind the “wet dog shake” have found that it is a remarkably efficient way for canines and other mammals to dry themselves.

Like the cat team, engineers from the Georgia Institute of Technology used high-speed video to analyze the shake in slo-mo. Biologists already knew that mammals perform the maneuver to help regulate their body heat. But the new study determined why such an action is necessary and how fast mammals have to shimmy to dry off.

The Tech team discovered that size determines the speed of the shake: waterlogged mice may go back and forth as much as 30 times a second, but an average dog needs to shake only 5 times a second to rid itself of most of its water.

It sure seems to be raining cats and dogs research these days!

Let’s hear from you: Time to brainstorm some biomimicry. What sort of new (and old) technologies could the knowledge in these studies be applied to?

Images:
jonclegg/Flickr
smichal/Flickr

Filed under: e-News, Explore Engineering, Mechanical

Tags: Biomimicry, Mechanical