When my cat shakes his head, it sounds like there's rocks or something clanking together, is this alright?

Question

One of my other cats has the same issue, but she's had it for so long, i just overlooked it. But now one of my cat's has this issue, and he's been acting kind of strange, do you think there's anything severely wrong with him?

Answer 1

It's the ears. Nothing to worry about.

Answer 2

why would your cat have rocks in its head?! go to the vet..

Answer 3

It's their ears flapping against their heads.  That or their collars.  

Answer 4

The vet would have your answer. Besides it being the ears the only thing I can think of would be solidified ear wax - which may need a quick check by the vet.