Elephants are large land mammals of the order Proboscidea and the family Elephantidae. There are three living species: the African Bush Elephant, the African Forest Elephant and the Asian Elephant (also known as the Indian Elephant). Other species have become extinct since the last ice age, the Mammoths being the best-known of these. They were once classified along with other thick skinned animals in a now invalid order, Pachydermata.
Social orderElephants live in a structured social order. The social lives of male and female elephants are very different. The females spend their entire lives in tightly knit family groups made up of mothers, daughters, sisters, and aunts. These groups are led by the eldest female, or matriarch. Adult males, on the other hand, live mostly solitary lives.
CommunicationIn addition to their bellows, roars and widely recognized trumpet-like calls; elephants communicate over long distances by producing and receiving low-frequency sound (infrasound), a sub-sonic rumbling, which can travel through the ground farther than sound travels through the air. This can be felt by the sensitive skin of an elephant's feet and trunk, which pick up the resonant vibrations much as the flat skin on the head of a drum. To listen attentively, every member of the herd will lift one foreleg from the ground, and face the source of the sound, or often lay its trunk on the ground. The lifting presumably increases the ground contact and sensitivity of the remaining legs.
FeedingElephants are herbivores, spending 16 hours a day collecting plant food. Their diet is at least 50% grasses, supplemented with leaves, bamboo, twigs, bark, roots, and small amounts of fruits, seeds and flowers. Because elephants only digest 40% of what they eat, they have to make up for their digestive system's lack of efficiency in volume. An adult elephant can consume 140–270 kg (300–600 lb) of food a day. 60% of that food leaves the elephant's body undigested.
Life cycleElephant social life revolves around breeding and raising of the calves. A female will usually be ready to breed around the age of thirteen, when she comes into estrus, a short phase of receptiveness lasting a couple of days, for the first time. Females announce their estrus with smell signals and special calls. Females prefer bigger, stronger, and, most importantly, older males. Such a reproductive strategy tends to increase their offspring's chances of survival.
After a twenty-two-month pregnancy, the mother will give birth to a calf that will weigh about 113 kg (250 lb) and stand over 76 cm (2.5 ft) tall. Elephants have a very long childhood. A new calf is usually the centre of attention for all herd members. All the adults and most of the other young will gather around the newborn, touching and caressing it with their trunks. The baby is born nearly blind and at first relies, almost completely, on its trunk to discover the world around it.
As everyone in the herd is usually related, all members of the tightly knit female group participate in the care and protection of the young. After the initial excitement, the mother will usually select several full-time baby-sitters, or "allomothers", from her group. According to Cynthia Moss, a well known researcher, these allomothers will help in all aspects of raising the calf. They walk with the young as the herd travels, helping the calves along if they fall or get stuck in the mud. The more allomothers a baby has, the more free time its mother has to feed herself. Providing a calf with nutritious milk means the mother has to eat more nutritious food herself. So, the more allomothers, the better the calf's chances of survival. An elephant is considered an allomother when she is not able to have her own baby. A benefit of being an allomother is that she can gain experience or receive assistance when caring for her own calf.