BLUE GRASS, Va.—Americans say they buy country property for many reasons—investment, recreation, business, relaxation, second home and retirement.

Is there more to it than that? Are we also driven by a deeper motive—a need from our evolutionary past?

Some anthropologists believe that property -- house, stuff, retirement accounts, things we create -- is an extension of our primal instinct to possess territory.

Many animals, particularly those with social organization, claim territory, which provides food, shelter, security, the idea of “home” and, finally, a sense of order about who belongs where that reduces conflict. Some mammals -- but not all -- define and defend territory, usually from others of the same species. As you might expect, this has to do with boys fighting over girls.

Territoriality also explains my nightly battle over how much blanket I get and how much my wife, Melissa, gets using her crocodile death roll.

Humans mark territory with visual cues like signs and fences. Hippos, lions and wolves use smell, the details of which are presented regularly on television nature documentaries and certain sitcoms. We deal with trespass with law; others use teeth. Both systems work.

If the human need for territory goes back to the African savannah, why is the idea that any Tom, Dick and Hairy could own land and enjoy property-based rights less than 300 years old?

The answer seems to be that for most of human history land in most civilizations was considered royal property, and ownership was concentrated in a relatively few hands. Land being the source of wealth in agricultural societies, those who controlled it had little interest in spreading ownership around. Law backed by absolute authority trumped evolutionary biology. This went on until authority was forced to become less absolute, and law became more democratic.