The NRC and AEBC agree that adverse environmental impacts are less likely for livestock breeds than for fish, because most farm animal species have no wild relatives remaining and farm animal reproduction is confined to managed herds and flocks. The danger of becoming feral is low in cattle, sheep and domestic chickens, which are less mobile and highly domesticated, but higher in horses, camels, rabbits, dogs and laboratory animals (rats and mice). Non-transgenic domestic goats, pigs and cats have been known to become feral, causing extensive damage to ecological communities (NRC, 2002).