The African elephant lives in small family groups of 10-30 elephants, which often congregate in much larger herds at water or food sources. Elephant society is matriarchal, senior females dominating the herds while the bulls live alone or in bachelor groups. Depending almost entirely on its trunk for scent and communication, for washing, clearing, carrying, learning, drinking and eating, an elephant’s lifespan (60 -70 years) depends very much on its teeth, which are highly adapted to its mode of living. As one tooth wears away the next moves down the jaw to replace it, and when the last tooth has come forward and is worn down the elephant will die of starvation. Although their sight is poor, elephants have an excellent sense of smell and well-developed hearing. Like humans, elephants lead complex inter-dependant social lives growing from helpless infancy through self-conscious adolescence to adulthood. Surprisingly graceful on their padded and carefully placed feet, a large herd of elephants can merge into the trees and disappear within minutes; their presence betrayed only by the noisy cracking of branches as they strip trees and uproot saplings.