Do pigs go under "food" or under "pets"?

I was reading this article in The New Yorker about a book called "Eating animals" today and something came to my mind. Somehow categories define how we feel. I like eating "pork", but maybe I wouldn't like to eat "pig". We also do not want to have "cow sausages", let's better call them "beef sausages". Why don't we eat "dog" or "cat"? Well... because they are pets, aren't they? They aren't food, at least until you go to a restaurant in China or Vietnam