The maximum population of a species that can be supported by a particular habitat or area with the food potentially available to it from the resources of the area, including the most unfavorable period of the year. The carrying capacity is different for each species within a habitat because of the species' particular requirements for food, shelter, and social contact and because of competition with other species that have similar requirements. Studies of both human and animal groups suggest that few populations reach such a theoretical maximum level, but adjust themselves to a size which allows a margin for fluctuations in the actual food production in the area. In archaeological terms, carrying capacity is the size and density of ancient populations that a given site or region could have supported under a specified subsistence technology.