Pair housing of Macaques: A review of partner selection, introduction techniques, monitoring for compatibility, and methods for long‐term maintenance of pairs

Abstract

Pair housing of macaques has become a widely implemented compromise between meeting the social needs of the monkeys and allowing for their use in biomedical research. While beneficial to the animals, pair housing can provide challenges for those caring for them. Drawing from both scientific literature and direct experience, this paper provides a review of practical aspects of pair housing including partner selection, pairing methodologies, staff education, and equipment considerations. Recommendations include selecting a pairing method appropriate to the facility and the individual animals being paired, educating staff on social behavior, and establishing a pair monitoring program to facilitate long-term pair maintenance. Assessment of behavior is essential in determining the compatibility of new pairs and in identifying established pairs that may need interventions to enhance their long-term compatibility. The pair housing program at the Yerkes National Primate Research Center is described as one model of a successful program. Am. J. Primatol. 79:e22485, 2017. © 2015 Wiley Periodicals, Inc.

Higher levels of submissive behaviors at the onset of the pairing process of rhesus macaques (Macaca mulatta) are associated with lower risk of wounding following introduction

“…Moreover, in some cases, the injury may be an acute manifestation of social tension that has been building‐up in the period proceeding to it. In cases such as these, the animals’ welfare is being affected not just by the stress associated with the actual trauma, but also by the detrimental psychological effects of behavioral incompatibility (Novak & Suomi, ; Truelove et al, ). Early separation of ultimately incompatible partners will spare them unnecessary stress.…”

“…The value of our findings for guiding social housing decision‐making may be strongest in situations in which the composition of potential partners is somewhat to entirely constrained. Literature is available for guiding partner choice (for a review, see Truelove et al, ) but when choice is not available, wise decisions based upon early behaviors must be relied upon. Our findings therefore, underscore the need for considerable early monitoring of social introductions.…”

“…Therefore, the importance of maintaining compatible social groups (pairs and above) has been recognized by the U.S. Department of Agriculture (), Public Health Service Policy (U.S. Department of Health and Human Services, ), and the Association for Assessment and Accreditation of Laboratory Animal Care International (AAALAC) (National Research Council, ). Social housing is considered to be the cornerstone of most behavioral management programs in biomedical research facilities (Baker, , ; Truelove, Martin, Perlman, Wood, & Bloomsmith, ). However, there are also risks that are involved when maintaining animals together, in particular the risk of socially inflicted trauma (Hannibal, Bliss‐Moreau, Vandeleest, McCowan, & Capitanio, ; Reinhardt, ; Reinhardt & Reinhardt, ).…”

Intermittent pair‐housing, pair relationship qualities, and HPA activity in adult female rhesus macaques

“…Another study found that pair‐housed NHPs had better immune function than single‐housed NHPs (Schapiro, Nehete, Perlman, & Sastry, ). While the benefits of pair‐housing are now well established, pairing laboratory macaques with compatible companions is challenging and requires knowledge of and experience with species‐specific social behavior (Truelove, Martin, Perlman, Wood, & Bloomsmith, ). Thus, research on laboratory macaque pair‐housing has shifted focus to refining pairing practices to improve partner compatibility, welfare, and pairing success (e.g., Capitanio et al, ; Pomerantz & Baker, ; Truelove et al, ).…”

“…While the benefits of pair‐housing are now well established, pairing laboratory macaques with compatible companions is challenging and requires knowledge of and experience with species‐specific social behavior (Truelove, Martin, Perlman, Wood, & Bloomsmith, ). Thus, research on laboratory macaque pair‐housing has shifted focus to refining pairing practices to improve partner compatibility, welfare, and pairing success (e.g., Capitanio et al, ; Pomerantz & Baker, ; Truelove et al, ). Relatively little progress has been made, however, to improve our understanding of how frequent changes to pair‐housing affect NHP physiology, despite the implications for biomedical research (reviewed in Hannibal et al, ).…”