Dog Shaking With His Head

The study also found that smaller dogs must shake much faster than larger dogs because their hair and skin is much closer to their central axis. The only way to generate sufficient acceleration of the fur, and to flick the water off their body, is to shake much faster. They have measured some of the smallest animals experiencing up to 20 g’s of acceleration at their hairs end. A G force is the equivalent of feeling the force experience of earth gravity. And so 20 Gs is equivalent of 20 times the force of gravity (where force = mass x gravity). One of the smallest creatures measured was a mouse that was found to shake itself at around 27 Hz, or 27 back and forth shakes per second!
To put the G force effect into perspective, on the fastest roller-coasters you may experience a maximum of up to 4G. And if you were to be in a jet and you are not a pilot (or wearing a G-force suit), most people usually black out between 4 and 6 G’s.
At the opposite end of the scale, the largest dogs and large mammals such as bears shake as slow as 4 hertz or four complete shakes per second.