These two Elephant bulls look about evenly matched in size. The one on the R, with a broken tusk, looks like he has a heavier body. The one on the L has nice intact tusks. Elephant tusks are an incisor tooth. Elephants can grow only 6 sets of teeth. When these wear out, the animal becomes edentulous and they are unable to chew their food, and they starve to death. Therefore, their life expectancy is influenced by their food. If their food has had a lot of sand it it, or if they are forced to eat a lot of bark, the teeth will wear down quicker, compared to teeth of those elephants who can feed on soft, succulent water grass. [Savuti, Chobe NP, Botswana].