Truelove, M. A., Martin, A. L., Perlman, J. E. et al. 2018. Behavioral predictors of successful pairing of rhesus macaques (Macaca mulatta) at the visual contact phase of social introduction. American Journal of Primatology 80(S1), 32 (40th Meeting of the American Society of Primatologists Scientific Program, Abstract #65).

Identification of behaviors early in the process of rhesus macaque social introductions that might predict social housing success would allow primate managers to best allocate resources and minimize animal stress by aborting introductions unlikely to lead to successful pairings. We compared behavior during the initial visual contact phase of social introductions in pairs later determined to be successful (e.g., maintained 14+ days, prosocial behavior, no frequent minor and no major wounding, no resource monopolization) to unsuccessful pairs. Each unsuccessful pair (n = 53) was matched with a successful pair (n = 53) on sex (26 male, 80 female) and approximate age (range 1.9 − 16.8 years, matched within one year). A conditional logistic regression with the presence/absence of seven behaviors (lunge, avoid‐withdraw, lipsmack, present, enlist/co‐threaten, fear, anxiety) as the predictors of pairing success showed statistical significance (λ (df = 7) = 14.979, p =.036); only one individual predictor was significant. Pairs observed lunging were less likely to be successfully pair housed (Wald λ (df = 1) = 9.274, p =.002, odds ratio =.130). In 42% of the matched pairs, monkeys in the successful pair lunged, while those in the unsuccessful pair did not. In contrast, the reverse happened in only 6% of the matched pairs. Results suggest caution for progression past the visual stage of social introductions when lunging is observed.