Nonhuman primate abnormal behavior: Etiology, assessment, and treatment

Abstract

Across captive settings, nonhuman primates may develop an array of abnormal behaviors including stereotypic and self-injurious behavior. Abnormal behavior can indicate a state of poor welfare, since it is often associated with a suboptimal environment. However, this may not always be the case as some behaviors can develop independently of any psychological distress, be triggered in environments known to promote welfare, and be part of an animal's coping mechanism. Furthermore, not all animals develop abnormal behavior, which has led researchers to assess risk factors that differentiate individuals in the display of these behaviors. Intrinsic risk factors that have been identified include the animal's species and genetics, age, sex, temperament, and clinical condition, while environmental risk factors include variables such as the animal's rearing, housing condition, husbandry procedures, and research experiences. To identify specific triggers and at-risk animals, the expression of abnormal behavior in captive nonhuman primates should be routinely addressed in a consistent manner by appropriately trained staff. Which behaviors to assess, what assessment methods to use, which primates to monitor, and the aims of data collection should all be identified before proceeding to an intervention and/or treatment. This article provides guidance for this process, by presenting an overview of known triggers and risk factors that should be considered, steps to design a comprehensive evaluation plan, and strategies that might be used for prevention or treatment. It also outlines the tools and processes for assessing and evaluating behavior in an appendix. This process will lead to a better understanding of abnormal behavior in captive primate colonies and ultimately to improved welfare.

Chimpanzee and Human Risk Preferences Show Key Similarities

“…Studies involving chimpanzees from different groups and environments will further enrich the discussion about the generalizability of behavioral variations. Because of their early-life experiences, sanctuary chimpanzees might display different risk preferences and behavior from those living in zoos and those in the wild (for a discussion on the generalizability across groups, see King et al, 2005; Laméris et al, 2021; Lutz et al, 2022; Weiss et al, 2007; Wobber & Hare, 2011). Last but not least, because it has been proposed that bonobos ( Pan paniscus ) and chimpanzees (humans’ two closest living relatives) show divergent risk preferences (see Rosati, 2017), for a complete reconstruction of our last common ape ancestors preferences, it is essential to also study bonobos’ willingness to take risks in more depth in the future.…”

“Long-Term Quarantine is Associated with High Cortisol and Low DNA Methylation in New World monkeys”

“…That being said, stereotypic behaviours such as pacing, and somersaults were observed in the quarantined animals included in this study ( Nofre Sanchez, personal communication ). Since stereotypic behaviours are often seen in captive primates, and are widely considered indicators of poor mental wellbeing in suboptimal environments (Lutz et al, 2022), it is possible that the observed behavioural pathologies are associated with physiological and or genomic alterations recorded in quarantined primates.…”

Challenges with Assessing and Treating Pain in Research Primates: A Focused Survey and Literature Review

“…Primates are social species, thus evaluating social behaviour with conspecifics or humans can be helpful. In a worksheet developed to assess behaviour as a quality of life assessment in nonhuman primates, researchers incorporate several social behaviours such as affiliate behaviour (i.e., grooming, huddling, embracing, or proximity to others), play behaviour (i.e., wrestling, pulling, tickling, chasing, or play biting), aggressive behaviour (i.e., threatening, chasing, hitting, attacking, fighting, or biting), submissiveness to other (i.e., pant-grunting, lip-smacking, bobbing, avoiding, crying, or grimacing), and interest in a novel situation that includes humans [ 73 ]. Using a primate’s natural daily activity budget as a benchmark for measuring welfare can be useful.…”