The incisors and the canines have sharp lateral edges. The large upper canines grow outward and backward, tending to form a complete circle. Usually, however, the canine teeth wear against each other, thus producing the sharp edges. The cheek teeth are cuspidate, and the upper premolars are simpler in structure than are the molars. With age, the enamel wears away and all the teeth disappear except for the canines and back molars.
Pigs generally live in forests and woodlands.
They shelter in tall grass or reedbeds and in burrows that are either self-excavated or abandoned by other animals. Pigs are surefooted and rapid runners and good swimmers, and they are fond of mud baths. When cornered or wounded, they frequently fight courageously. In such battles their tusks are deadly weapons. They are active mainly at night, especially in areas where they are molested by people.