Socialization in pigtailed macaques (Macaca nemestrina)

Abstract

In response to new emphasis by regulatory agencies regarding socialization, behavioral management programs are allocating greater resources to maximize socialization opportunities for laboratory primates. Information regarding predictors of compatibility and risk of injury for all laboratory-housed species of macaques are needed to make social introductions and pairings as efficient and safe as possible. This study presents data on 674 pairs of pigtailed macaques (Macaca nemestrina) at the Washington National Primate Research Center over a 7-year period. During pair introduction, behavior was monitored while the degree of tactile contact was gradually increased. Based on observed behavior, pairs were assigned a behavioral introduction score (BIS), rating the quality of their interactions for each day of introduction. Animals deemed compatible, based on the BIS and technologist judgment, were allowed to progress to continuous contact with no staff present. A small proportion of animals deemed compatible at introduction was later separated for subsequent incompatibility or aggression; these proportions were higher in full contact compared to protected contact pairings. Of 674 pairs, 75% were deemed compatible at introduction in protected contact; 86 of these pairs were later transitioned to full contact with 98% compatibility. Predictors of decreased compatibility assessed during protected contact introductions included age (adult pairs were less compatible), the BIS on the last day of introduction, and aggression or injury during the introductory period. Predictors of injuries during the protected contact introduction process included: aggression on the first day of introduction, a negative BIS on the first or last day of introduction, and, surprisingly, the presence of grooming on the first day of introduction. Injuries during both introduction and subsequent pairing in protected contact were rare; however, injury rates increased significantly during full-contact pairing. These findings underscore the necessity of species-specific data to guide decision-making during the social introduction process.

Pair housing of Vervets/African Green Monkeys for biomedical research

“…Both the Animal Welfare Act and the Guide recommend that behavioral management plans should be tailored to each species [see also Williams et al, ; Worlein et al, ]. The Guide states that “group composition is critical and numerous species‐specific factors such as age, behavioral repertoire, sex, natural social organization, breeding requirements, and health status should be taken into consideration when forming a group” [NRC, , p. 59].…”

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

“…Second, it is somewhat surprising that body weight differences did not contribute to the predictability of the statistical model, since it has been reported previously (Baker, ) at least among males (rhesus macaques (Capitanio, Blozis, Snarr, Steward, & McCowan, ); vervets ( Chlorocebus aethiops ) (Jorgensen et al, ). The role of weight may vary by species (e.g., pigtailed macaques ( Macaca nemestrina ); Worlein et al, ); cynomolgus macaques ( M. fascicularis Abney, Toscano, Poor, & Moomaw, ). Such analyses, however, may be very vulnerable to the inclusion of sexually‐immature animals in the subject pool (Maguire‐Herring, Stonemetz, Lynch, & Fahey, ; West et al, ).…”

“…For some of these studies, contrasting findings may relate to the fact that the focus is on introduction success per se, rather than injury. Indeed, Worlein et al () found differences in predictors between wounding and compatibility in pigtailed macaques. It is important for the reader to be aware that the findings of the current study relate only to the former and not the latter.…”

“…There is emerging evidence that there are relevant behavioral contrasts even within the macaque genus. For example, a recent study of pair introductions of pigtailed macaques found that aggression during the initial day of introduction predicted injuries, and, rather than having no effect, grooming was actually positively correlated with later injuries (Worlein et al, ).…”

Socialization of adult owl monkeys (Aotus sp.) in Captivity

“…One of the biggest challenges associated with managing a socialization program for nonhuman primates in the laboratory is accurately assessing the cost–benefit ratio associated with formation of any new groups or pairs [Truelove et al, ]. Worlein et al [] correctly point out that these costs include pre‐screening animals for behavior characteristics by both behavioral and care staff, as well as time moving the animals, and dealing with the consequences of unsuccessful pairing attempts. This is especially true when socializing adult males of the species typically seen in laboratory research [Baer, ; Baker, ], and as reported here for owl monkeys.…”