Why do cats leap to their feet and go tearing around the house?

Dear Matt:

Why does my usually docile cat suddenly leap to her feet and go tearing around the house? Is she hallucinating? It's weird.

-- Marko, El Cajon

In kitty's mind, she's probably being chased by wolves. Or maybe she's in pursuit of imaginary field mice. Your household friend is merely releasing all her pent-up predator instincts in a burst of speed the cat-knowledgeable call "vacuum activity." When dinner arrives, pre-killed on a plate by the refrigerator, the fun of the chase and the kill has gone out of the meal. And since your cat never sees anything more dangerous than a vacuum cleaner, well, life just lacks that satisfying little twinge of terror that means so much to her.