There are several reasons cats hide, and and most cats include hiding as a normal, healthy activity in their repertoire of behaviors. First, cats are both predators and prey in the wild - they are instinctually driven to hide and conceal themselves when they are sneaking up on a prospective prey item, and avoiding being prey for other predators (i.e., any carnivore that is larger than they are). Second, hiding in the home can be a stress-reducing, relaxing thing to do. Third, cats may hide when they are ill or not feeling well. If your cat all of a sudden decides to start hiding for long periods of time or changes her hiding behavior, you will want to make a trip to the veterinarian to make sure everything is ok.