If you’ve even seen your cat chase a toy, prey or another cat you’ll know that they wiggle their bums just before they pounce. Why do they do that?
The short answer is: we’re not sure!
John Hutchinson, professor of evolutionary biomechanics at the Royal Veterinary College in London, says that this behaviour “has not been studied, to my knowledge, in an experimental context”.
However, he does have a few ideas that might explain why cats wiggle their bums. One possible reason is that bum wiggling may help press the hindlimbs into the ground to give cats added friction (traction) for pushing them forward in the pounce. It may also help a cat physically prepare for all the “rapid neural commands needed for the pounce”. Another physical reason cats may do this is that it probably stretches the muscles a bit which might help with pouncing.
But the best explanation? “We can’t exclude that it’s just fun for cats; they do it because they are excited by the thrill of the hunt [and] prey.”