All the Trivia You Could Ever Hope to Find about CATS! Cat Food... Not all cats like catnip. The behavior of those who do like catnip is likened to a tom around a queen in heat. Catnip contains a chemical called trans-neptalactone, which is closely related to a substance excreted by the queen, usually in urine. The herb valerian can also produce this effect. On Fish: Fish isn't a "natural" food for cats. Cats' origins are in the desert where they hunted rodents, birds, and insects. One supposition of why cats have become such happy fish eaters is that during World War II, meat was expensive, hard to get and carefully rationed. Leave it to the cat food manufacturers to find a cheap source of protein. They started to use fish in cat food. In the wild, cats still won't hunt for fish. (Except for one cat breed in India). On Fish: There is a condition known as steatitus or "yellow fat disease" that occurs when cats are fed a diet of fish only. (This doesn't pertain to canned cat food fish with all of the additives.)  More On Fish: Canned fish-flavor cat food has another problem. When fish decomposes, it releases histamines. And histamines are the agents behind a lot of allergies. (That's why we take antihistamines for allergies and colds.) This fish isn't fit for human consumption, so guess who gets it? That's right. Our kitties.  Even More On Fish: Cat food with fish as an ingredient isn't recommended for cats with FUS (feline urinary symptoms). There is a higher amount of magnesium and ash in these (which helps the development of crystals--not good). Cats didn't evolve with fish as food. They lived in the desert on birds and rodents.  Tylenol and chocolate are both poisonous to cats.  The average canned or dry cat meal is the nutritional equivalent of eating five mice.