Rachel Riley was frightened before she even flew out to film new reality show Shark! Celebrity Infested Waters. But here she ...

So step one to understanding why cats wag their tails: Read up on cat body language. Learn, for instance, the signs your cat is secretly mad at you and how to tell if your cat is depressed.

Cats don't typically greet their humans at the front door with a rapidly wagging tail or undeniable excitement at their return, but that doesn't mean your kitty didn't miss you while you were away.