Reproductive performance in a breeding colony of Brazilian squirrel monkeys (Saimiri sciureus).

: In a captive colony of Brazilian squirrel monkeys (Saimiri sciureus) a discrete birth season has been retained for 5 years although its duration increased from 3 months in 1972 to 6 months in 1976. The ages of breeder females in this colony ranged from 3 to 14 years, and within this range reproductive performance was not affected by age, although it was significantly better in feral than in colony-born females. The latter had a lower pregnancy rate and a higher incidence of neonatal and fetal deaths than did the feral monkeys. It is our belief that the reproductive and maternal capabilities of the colony-born females were adversely affected by the practice of removing neonates from their mothers at weaning and raising them with age-mates.