Dog Shaking With His Head

The body shakes at the same frequency as the skin but it cannot rotate as far. This means the skin twists further around the body and moves faster than the body and head causing a higher acceleration and higher water removal. On some animals the skin can move up to 90 degrees on either side of the spine.
Dogs that have a lot of hair/ fur often have loose skin that further assists the acceleration of the coat when the dog changes the direction of its shake.
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!