Wet Dog Shake Sheds Light on Shedding Moisture
Willow Smith may have had the right idea with her "Whip My Hair" back and forth song hit a few years back. Now Scientists confirm that the wet-dog shake is actually a powerful adaptation to conserve heat and energy as wet mammals can face hypothermia if they do not shed moisture quickly.David Hu and his colleagues at the Georgia Institute of Technology in Atlanta studied several species including mice, dogs, tigers and bears using a video camera. Wet animals were able to fine tune their shaking speed to get as dry as possible while expending the least amount of energy.
Smaller mammals have to spin faster to make up for their smaller area of centrifugal force. Loose skin and jowls provides greater surface area to make the spin cycle particularly effective. In fact, a large dog can shed up to 70% of the water on their bodies in 4 seconds.
These findings may guide the production of water shedding features on man-made devices to incorporate elasticity to mimic the loose skin of mammals as they shake. This is vividly illustrated on the following video:
Photo courtesy of carterse.