Which animal has the longest gestation of any land mammal, lasting about 22 months?

The African elephant has the longest gestation of any land mammal, lasting about 22 months.

This unusually long pregnancy allows the calf’s brain and body to develop extensively before birth. Elephant calves are born at roughly 100 kilograms and can stand and walk shortly afterward, which is important because elephant herds travel widely and cannot leave a newborn helpless for long.

Asian elephants also have very long pregnancies, generally around 18 to 22 months, so the 22-month figure is not exclusive to every elephant species. The African bush elephant and African forest elephant are both African elephant species, and gestation length can vary slightly between individuals.

Elephant calves usually rely heavily on their mothers’ milk for several years. Females typically give birth to one calf, while twins are uncommon. The long interval between births contributes to the slow population recovery of elephants after poaching or habitat loss.