At any one time, elephants have one molar in each jaw bone (two upper, two lower). Each weighs about 11 lbs and measures about 12 inches long. As they wear away at the front, new molars emerge in the back of the mouth and gradually replace the old ones. Elephants replace their teeth six times. If it survives to 60 years of age the elephant no longer has teeth and will die of starvation.