Heavily hunted states like Pennsylvania and Ohio, for instance, are among those experiencing higher deer densities than perhaps ever before. When an area's deer population is reduced by hunting, the remaining animals respond by having more young, which survive because the competition for food and habitat is reduced. Since one buck can impregnate many does, policies which permit the killing of bucks contribute to high deer populations. If population control were the primary purpose for conducting deer hunts, hunters would only be permitted to kill does. This is not the case, however, because hunters demand that they be allowed to kill bucks for their antlers.
Few animals achieve full adulthood.
After twenty years of heavy deer hunting at the Great Swamp National Wildlife Refuge in New Jersey, for example, only one percent of the deer population lived longer than four years, and fewer than ten percent lived longer than three years. In a naturally regulated population, deer often live twelve years or longer. While hunting may not be the prime cause of the decline of these species, it must contribute to their decline and, at a minimum, frustrate efforts to restore them. Even deer populations may be damaged by hunting pressure. Unlike natural predators and the forces of natural selection, hunters do not target the weaker individuals in populations of deer or other animals.