Cats are considered to be unpredictable, which some
people find attractive but others find maddening. One thing that is unpredictable is the female’s estrus, or heat. Dogs predictably go into heat every six months, with the estrus lasting for twenty-one days, but there is no such predictability with cats. A cat who just went out of heat might be in heat again in days—or weeks—or months. No one knows, and no one can predict.
