Elephants form deep family bonds and live in tight matriarchal family groups of related females called a herd. The herd is led by the oldest and often largest female in the herd, called a matriarch. Herds consist of 8-100 individuals depending on terrain and family size. When a calf is born, it is raised and protected by the whole matriarchal herd. Males leave the family unit between the ages of 12-15 and may lead solitary lives or live temporarily with other males.