The tusks of elephants begin as two front teeth which drop out after about a year. In their place grow ivory tusks which eventually protrude from beneath the upper lip. The tusks of female Asian elephants, however, remain short and are barely visible. Male African elephants grow the largest tusks, the longest recorded measuring approximately 137 in (348 cm) and weighing over 220 lb (100 kg) each. Today, however, tusks are much smaller in wild elephants because most of the older animals have been slaughtered for their ivory. Although there are variations, the long, cylindrical tusks grow in a gradual upward curve, somewhat resembling the sliver of a new moon. Elephants use their tusks as weapons in combat, and to dig up roots, strip bark off trees, lift objects, and (for females) to establish feeding dominance. Tusks continue to grow throughout an animal's life at an average of about 5 in (12.7 cm) a year; however, their length is not an accurate measure of the animals age, as the tips wear and break with daily use and during combat.
Elephants have large, grinding, molar teeth which masticate (chew and grind) their plant diet with a backward-forward jaw action. These teeth fall out when worn down, and are replaced by new, larger teeth. During its lifetime, an elephant may grow 24 of these large molar teeth, each weighing up to 9 lb (4 kg) in older animals. Only four teeth, two on each side of the jaw, are in use at any one time. As the teeth wear down, they move forward; the new teeth grow from behind and the worn teeth drop out. This pattern repeats up to six times over the elephant's lifetime, and the most common method of determining an elephant's age is by tooth and jaw examination. Once all of its teeth have fallen out, an elephant can no longer chew its food, and will soon die.
Science EncyclopediaScience & Philosophy: Electrophoresis (cataphoresis) to EphemeralElephant - Evolution, Body, Limbs, Head, Mouth And Trunk, Teeth, Ears, Group Structure - Eyes, Social behavior, Death