Lions are the only big cats that form prides, or groups, to hunt and defend their territory. Lions prey on a variety of animals, including baboons, water buffalo, rodents, zebras, and antelopes. Sometimes they scavenge or steal from other predators like cheetahs or hyenas. As human populations increase and encroach on lion habitat, conflicts between humans and lions arise. Humans and lions are forced to compete for food and space. In certain areas of Tanzania, some lions prey upon humans. Between 1932 and 1947, three generations of lions killed 1,500 people in the Njombe District in southern Tanzania. Man-eating lions in Tanzania are being studied to determine whether or not they intentionally set traps to catch human prey. Their strategy to lure people out of their homes and then attack them is similar to how lions hunt other prey. The cubs within a pride learn to hunt by imitating the lionesses. Thus, the killing of humans could be a learned behavior passed on from generation to generation.