1. the defense by a nonhuman animal of a specific geographic area (its primary territory) against intrusion from other members of the same species. Territory differs from home range in being an area that is actively defended and from personal space in being a geographic area. Territoriality is observed in a wide range of animals and is found most often where there are specific defensible resources, such as a concentration of food or shelter. It is maintained through singing in birds and through scent marking in many mammals (e.g., antelope, dogs), as well as by active patrolling of territory boundaries.

2. in humans, behavior associated with the need or ability to control and regulate access to a space, which reflects feelings of identity derived from use of and attachment to a familiar place. See also public territory.