Artificial weaning of Old World monkeys: benefits and costs.

Permanent mother-infant separation prior to natural weaning is a common hus-bandry practice in monkey breeding colonies. In the United States, all eight Re-gional Primate Research Centers have such colonies. Under undisturbed conditions, Old World monkey mothers wean their infants at the age of about 1 year (Hall & DeVore, 1965; Poirier, 1970; Roonwal & Mohnot, 1977; Southwick, Beg, & Siddiqi, 1965). Natural weaning is a gradual process. It implies that the mother, over a period of several weeks or months, more and more consistently discourages her infant to suck on her breasts. Once the mother stops nursing the infant for good, the affectionate bond between the two is not broken (Altmann, Altmann, Hausfater, & McCuskey, 1977; Lindburg, 1971; Poirier, 1970; Roonwal & Mohnot, 1977). The young usually remains in the ma-ternal group at least until prepuberty. Under confinement conditions, artificial weaning is an abrupt occurrence that takes place several months prior to the biologically normal age of weaning. It im-plies that the still-nursed infant is taken away from the mother and subsequently reared alone or with other artificially weaned infants.