Believe it or not, dogs can shake off 70% of moisture in 4 seconds! If you own a dog (or ever stood next to a shaking dog) you already know that.
The science of shaking off water is much more fascinating then you imagined:
“Let’s look at the actual mechanism. A dog’s backbone can’t really whip all the way around. In fact, Hu told me, it can can only move around 30 degrees in either direction. If you imagine a clock face with the backbone at 12 o’clock, the backbone is making it to the 11 and 1 marks.
But think about a dog’s skin. You know how loose it is? I had previously thought the main purpose of loose dog skin was so that they would look funny on UpsideDownDogs.com. But it turns out there is another more important reason. Because the skin is loose, it can whip around farther and faster than the backbone can. The skin, to which the fur is attached, travels at three times the speed of the backbone, which, according to the math, generates nine times as much force on the water droplets, helping fling them off. That’s the magic of the mammal shake. “
So basically the aim of the shake is to move the loose skin around, fast. That’s why it doesn’t work for humans by the way. Not that I ever tried.
Think of all the useful applications of this mechanism – imagine drying your mop by spinning it fast in the air… Eh, maybe not.