Females usually begin oestrous cycles at 18 to 22 months of age. In the wild births occur in October and November, but in captivity most births occur in April and May.
The gestation is varying from 90 – 110 days.
Most of the births take place at night. Labour takes about half an hour. The interval between infants usually is 10 minutes. The afterbirth is eaten by the female. Babies are nursed nearly continuously by their mother during the first 2 weeks. They do not cling to their mother but stay the first days in the nest. The eyes of the infants are open at birth and they are covered with fur.
They usually give birth to twins. Sometimes 1 or 5 monkeys are born. When more than 2 monkeys are born it may be necessary to remove some infants for hand-rearing.
The weight of the infant is appr 80-120g. After 80 days the weight of the young is appr 1kg. When the weight of the infant is less than 80g after 6 to 8 hours it should be removed from their mother for hand-rearing. Don’t underestimate it, hand-rearing is not an easy job!
After 30 minutes the babies start sucking.
After 25 days the babies start to take some solid food.
After 5 weeks they can climb tops of trees
After a period of 6 months the infants are completely weaned.
Ruffed lemurs can live 26 years in captivity.