Elephants have the longest gestation period of any living mammal. African elephants are pregnant for an average of about 22 months, while Asian elephants have a gestation period ranging from 18 to 22 months

. This extended pregnancy allows the baby elephant to develop a large and complex brain and a physically mature body, which is essential for survival immediately after birth. For example, elephant calves can stand within 20 minutes and walk within an hour of being born