African elephant society is highly complex and arranged around family units composed of groups of closely related females and their calves. Each family unit contains around ten individuals (7), led by an old female known as the 'matriarch' (2). Family units often join up with other bands of females to form 'kinship groups' or ‘bond groups’, and larger herds may number well over a hundred individuals (8). The male elephant leaves its natal group at puberty and tends to form much more fluid alliances with other males (2).
The African elephant communicates with other elephants in a variety of ways. For example, changes in the posture and position of the tail, head, ears and trunk convey visual signals and messages, while smell plays a significant role in maintaining social contact within the herd, in detecting threats, and in assessing the health or sexual condition of another elephant. Touch is also an important method of communication, and the elephant will use its dextrous, tactile trunk in greetings and other social behaviours (2) (5).
Vocalisations, however, provide the primary mode of communication between individuals (2) (5). The distinctive, trumpeting call of the elephant is produced mainly in excitement or surprise, during attack, or when playing, while the most common elephant vocalisation is a growl used in warning and to maintain contact between individuals (2).
Other sounds made by the African elephant range from high-pitched squeaks to deep rumbles, and two-thirds of the calls are emitted at a frequency below the range of human hearing (2) (5) (10). These low frequency sounds enable the African elephant to communicate over large distances (2) (5), with some calls being heard by other elephants at distances of at least eight kilometres (5). It is thought that the ability of the African elephant to communicate over such distances is essential to successful reproduction, as male and female elephants tend to range separately for much of the year. During the female’s short oestrus period, which lasts only two to four days, the female will emit a series of powerful, low-pitched calls to attract breeding males from several kilometres away (2).
The African elephant is extremely long-lived, sometimes surviving for up to 70 years (5). Although the female African elephant may reach sexual maturity at 10 years old, it is most fertile between the ages of 25 and 45 (2). There is no distinct breeding season and the female will typically produce a calf every three or four years, although the interval between births may be longer when conditions are not favourable (2), and birth peaks in certain areas may relate to the local rainfall patterns (11).
Elephant calves are born after an exceptionally long gestation period of nearly two years, and continue to be dependent on the female for several years (2). The calves are also cared for by other females in the group, especially by young females known as 'allomothers' (2). The social bonds between elephants are very strong, and if faced with danger the group will form a protective circle around the young calves, with the adults facing outwards and the matriarch adopting a threatening pose or even charging the intruder (2). African elephants are known to care for their wounded and also show recognition of, and particular interest in, elephant bones (12).
African elephant groups will spend the day wandering their home range in search of food and water (2). During the wet season, the African elephant feeds mainly on grasses, as well as leaves from a range of trees and shrubs. It will often dig for roots after the first rains of the season, and will also eat flowers and fruits when they are abundant. At other times of the year, the African elephant will also feed on the woody parts of trees and shrubs (2). An adult elephant requires 160 kilograms of food a day; using its highly mobile trunk it plucks at grasses and leaves, or tears at branches and bark with its tusks, which can cause enormous damage (8). The African elephant also needs to consume an extraordinary amount of fluid each day, and in the dry season, may dig holes into dried river beds in search of water (2).