Gestation in elephants typically lasts around two years with interbirth intervals usually lasting four to five years. Births tend to take place during the wet season. Calves are born 85 cm (33 in) tall and weigh around 120 kg (260 lb). Typically, only a single young is born, but twins sometimes occur. The relatively long pregnancy is maintained by five corpus luteums (as opposed to one in most mammals) and gives the foetus more time to develop, particularly the brain and trunk.
