Vervet monkeys mature slowly, taking around five years to become fertile, although this can vary depending on the available food supply. In an area where the monkeys are well fed, they can become fertile much sooner. Male monkeys probably will not breed at five years old, because it is unlikely that they will be high enough in the troop's social rankings. Generally, they have to wait for several years before they are senior enough to breed.
A single infant is born five to six months after mating. It is fully furred and its eyes are open, and from birth it is able to cling to its mother's belly fur, though she will usually support it with her arm during the first few hours. The young vervet suckles less and less as it grows, though it is still nursed by its mother, and is weaned and almost independent in just under a year, before the birth of her next baby.
Older vervets are allowed to look after the young when they are a few months old. This teaches them how to look after their own young when it is their turn to breed. Females often stay with their mothers for as long as they live, but males leave their family at about five years of age to join other troops and to start to breed.