Physicist Andrew Dickerson, from the Georgia Institute of Technology in Atlanta (USA), has calculated the optimal speed at which dogs and other furry mammals should shake themselves to remove water after a bath and remain completely dry .
In their calculations, Dickerson and his colleagues, who compare the forces involved in shaking a wet mammal with those in spinning in a washing machine , took into account the balance of centripetal forces and surface tension in water droplets. And they obtained a simple formula, R 0.75 , where R is the radius of the animal's body. According to this formula, the smaller an animal is, the faster it must move to generate enough force for the water to fly out.
To test their model, the physicists filmed wet dogs and other animals of varying size, from mice to bears, as they dried off. Using the video recordings, along with particle tracking techniques and X-ray cinematography, they calculated that a Labrador retriever dries at a frequency of 4.3 Hz , cats dry at 6 Hz, and mice at 27 Hz . For a bulkier grizzly bear , the frequency required for drying is reduced to 4 Hz .
