Among cats, the olfactory sense (sense of smell) is an extremely important means of communication. When outdoors, cats will mark shrubs and trees on the borders of their home by means of skin gland secretions, anal-sac secretions, urine spraying and also leaving their feces uncovered, which makes an impressive visual and olfactory signal. Urine marks retain their olfactory-communicative component for roughly three days, and are then re-marked by the cat when the odor begins to fade. This is thought to explain ritualistic re-marking of previously soiled spots.
Scent marking is a form of olfactory communication that has territorial and personal implications. It allows cats to advertise their priority with respect to living space, objects, other cats and people. It also serves as a method of advertising breeding status in the case of females. Domestic cats often engage in scent marking of one form or another. While we enjoy their bunting, other forms of marking behavior - in the form of urination, deposition of feces, and furniture scratching - are not so attractive to us! If a cat defecates on an owner's bedspread or urinates its owner's legs, its behavior should be taken as a great compliment (signifying close attachment) though this is rarely the owner's interpretation.
Cats scent mark in several ways: by bunting, urine/fecal marking, and by scratching objects.
Pheromones are chemical messengers that convey information about an individual's status and intentions. Some pheromones are secreted by sebaceous glands in the skin of the cat's forehead, lips, front paws, and around the anus. When a cat head-bunts, rubbing the side of her head against a person or object, glandular secretions from the cat's face are left on the surface, leaving a calling card of sorts.
Spraying is a form of urine marking performed mainly by male cats. Tomcats use spraying to demarcate territorial limits and lay claim to females in estrus. Females in estrus will also spray urine to advertise their sexual receptivity. Altered indoor cats sometimes engage in this form of scent marking too. Feline house soiling is the most common feline behavior problem in the United States.
Urine spraying is the most classical form of urine marking but cats can also urine-mark from the squatting position.
In colonies of feral cats, subordinate individuals cover up their feces while more dominant cats leave their feces uncovered in a blatant display. Most indoor cats bury their feces, presumably because they feel subordinate to their human family. Burying feces reduces odors and this might be an important factor for the survival of the weaker individual that does not want to advertise its presence to others. Dominant household cats sometimes use fecal marking to signify their territorial claims.
Scratching at objects (e.g. trees, furniture) is also a form of scent marking behavior in which cats deposit odor-giving secretions from glands around their footpads on to a chosen object. Scratching objects is a visual marking behavior, too. It is as though the cat is saying: "this is mine: no trespassing" or "Kilroy was here."