Lemurs mostly eat fruit, leaves, and other plant parts. They live in family groups of 5 to 42 members which is called a troop. Females are dominant and remain in the same troop for life. Males move between troops. The female's gestation period lasts four to five months, and they usually have one or two babies. Lemur mothers nurse their babies until they are about four months old. Then they begin to feed the babies solid food such as fruit. Lemurs spend most of their time in the trees. Some are great leapers, flinging themselves from tree to tree.