Separation from mothers at birth has long-lasting harmful effects on health that are not remedied by a normal social environment later in life, according to a recent study in primates (Conti G et al. Proc Natl Acad Sci U S A. doi: 10.1073/pnas.1205340109 [published online May 21, 2012]).
In the study, 231 rhesus monkeys were allocated at birth to different groups at a National Institutes of Health primate facility in Poolesville, Md. In one group, monkeys remained with their biological mothers from birth and were raised in large cages with other monkeys (the mother-reared group). Other monkeys were separated from their mothers and were nursery-raised individually for 37 days; some were then either raised with peers (the peer-reared group) or spent 22 hours every day with a hot water bottle suspended from a cage and the remaining 2 hours with peers in a play cage (the surrogate peer–reared group).
Hampton T. Effects of Maternal Separation. JAMA. 2012;308(1):21. doi:10.1001/jama.2012.7386