EFFECTS OF DURATION OF SEPARATION ON RESPONSES TO MATES AND STRANGERSIN THE MONOGAMOUS TITI MONKEY (CALLICEBUS MOLOCH)

Adult male and female titi monkeys form an intense social bond charact erized by high levels of affiliative interactions between pairmates an d agonistic responses to strangers. In natural settings, separation be tween mates can vary from brief periods, as when mates drift apart dur ing feeding, to permanent separation, occasioned by desertion or death . In this study we asked how different durations of separation altered the behavior of male and female titi monkeys (Callicebus moloch). We compared the effects of brief separation such as might occur incidenta lly during feeding (1-2 h) with prolonged separation such as might occ ur if one partner died or deserted (5 days). Effects were observed dur ing a 30 min reunion of pairmates or during a 30 min encounter with a stranger of the opposite sex. Following brief separation, interactions between mates and between strangers clearly differed in measures of a ffiliation, but not in behaviors indicative of arousal. Following prol onged separation, measures of arousal increased with both mated pairs and strangers. Females tended to interact more readily with a stranger following prolonged separation than after brief separation, but inter actions between mates were essentially unchanged and differed substant ially from those between strangers. The data suggest that the pair bon d persists in titi monkeys after prolonged social isolation, despite i ncreased interest in interacting with potential new partners. (C) 1997 Wiley-Liss, Inc.