Here is a neat list of cat facts. Some examples:
Cats have more bones and skeletal muscles than humans
Cats can see green and blue
They have better hearing and nightvision than humans
Cats don't have a functioning collarbone, allowing them to fit through any opening bigger than their heads.
Cats' jaws can only move vertically
10% of a cat's bones are in its tail
Domestic cats are the only animals that can walk with their tail vertical