Visitors Now:
Total Visits:
Total Stories:

By Alton Parrish (Reporter)
Contributor profile | More stories

Story Views
Now:
Last Hour:
Last 24 Hours:
Total:

Shake It Baby Shake It: How Wet Dogs Instantly Dry Themselves

Friday, December 7, 2012 0:42

% of readers think this story is Fact. Add your two cents.

(Before It's News)

Why do mammals shake when wet? The simple answer, as you may guess, is to dry. Perhaps a better question is why an animal wants to be dry. According to calculations, a wet animal could spend 20% or more of it’s daily food energy to evaporate water in its fur, if it cannot shake.

A Georgia Tech study found the largest mammals such as bears, tigers, and large dogs shake about 4 times per second while small mice shake at more than 30 times per second!

Mammals shaking is very effective. A shaking mammal can remove about 70% of the water trapped in its fur in few seconds, when fully wet. The remaining moisture content (RMC) in the fur is about 30%. When comparing the accelerations generated by animals to data gathered on our “wet-dog simulator” (see Methods below), we note that animals shake in the region where drying tapers off.

We found shaking longer or faster does not contribute to further drying. Therefore, mammals “tune” their shaking to achieve maximal dryness with the least effort.

Why study the proverbial wet-dog shake? Shaking when wet is a commonality among many furry mammals. Such a study provides insight into mammal survival, adaptation, and fluid mechanical phenomena which links numerous species.

Drop ejection from spinning disks is well-studied, but are the first to look at dripping from long fibers under accelerations higher than that of gravity.

The kangaroo does not display the ability to shake the entire body. We believe this occurs due to the largest of the hind quarters and shape of the spine. Additionally, kangaroos reside in hot and dry climates where shaking is of less priority.