Female elephants come into estrus (heat), marking ovulation and the ability to get pregnant, for only a few days each year. Because the mating season is short, mature female elephants are never far from adult males. The scent of a female elephant in estrus attracts male bulls. A receptive female will hold her head high, producing a low, rumbling invitation as she leaves her group and runs quickly across the plains chased by the bulls. It appears she actually chooses her mate, for she seldom stops for a young bull but slows down for a larger, dominant male who, once she allows him to catch her, gently rests his trunk across her back in a caress. They may mate several times, and he may stay with her until the end of her estrus, warding off other bulls and fighting if necessary. She may, however, mate with others. Because males play no part in raising the young and are not needed to protect the mother or baby, their role appears to be purely reproductive.
At the end of estrus, the cow returns to her group and the male goes off in search of another mate. The gestation period of female elephants lasts for 22 months, longer than any other animal; pregnancies are spaced from three to nine years apart. There is usually only one offspring, but twin births do occur and both calves may survive under favorable conditions. There is much excitement in the group during a birth, and another female almost always tends to the birthing mother. An adult female and her sexually immature offspring are a "family unit" within the group. However, females assist each other in raising the young, with one mother even sometimes nursing the calf of another. In general, females reach sexual maturity between the age of 12 to 15 years and, over the course of 60 years, will bear from five to 15 offspring.
Science EncyclopediaScience & Philosophy: Electrophoresis (cataphoresis) to EphemeralElephant - Evolution, Body, Limbs, Head, Mouth And Trunk, Teeth, Ears, Group Structure - Eyes, Social behavior, Death