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Elephants are perhaps the only animals that are hunted for their teeth.Elephant tusks，or very large teeth growing on either side of their mouths，are composed of a valuable material called ivory（象牙）.
（78）An elephant uses its long，pointed tusks as tools for digging in the ground for food.He also uses them as weapons in combat.
The tusks of male elephants are usually large and heavy.In Africa，female elephants have long，light tusks.In India and other parts of southern Asia，female elephants have small，short tusks or none at all.
（79）Tusks in good condition are in great demand，and may sell for as high as two thousand dollars or more.Because of this，large numbers of elephants have been killed.Some countries have initiated （开始）methods to protect elephants.They have established elephant preserves，areas of land set aside for herds of elephants where no one is allowed to harm them.Elephants on the preserves are safe from ivory hunters.