BEHAVIORAL AND ADRENOCORTICAL RESPONSES OF RHESUS MACAQUE MOTHERS TO INFANT SEPARATION IN AN UNFAMILIAR ENVIRONMENT

The behavioral and adrenocortical responses of rhesus macaque mothers to a series of four consecutive 4-day separations from their 5-month o ld infants in an unfamiliar environment were examined. A biphasic beha vioral response to separation was observed, with passive behavior, loc omotion, and vocalization highest on Day 1 of separation, and self-dir ected behaviors and environmental exploration peaking during Days 2 - 4. Stereotyped locomotion increased, and passive behavior decreased, a cross successive weeks of separation. The rhesus mothers exhibited sub stantial cortisol elevations one and two hours postseparation, with co rtisol decreasing on the fourth day of separation. The cortisol respon se was strongest during the first week of separation, but robust eleva tions occurred in response to repeated separations. No signs of behavi oral depression were observed. The results indicate that infant separa tion combined with removal to a novel environment can be a potent stre ssor for rhesus macaque mothers.