Stereotypies in Captive Primates and the Use of Inositol: Lessons from Obsessive–Compulsive Disorder in Humans

The Promise of Behavioral Tracking Systems for Advancing Primate Animal Welfare

Simple Summary

Computerized tracking systems for primates and other animals are one of the great inventions of the 21st century. These systems have already revolutionized the study of primatology, psychology, neuroscience, and biomedicine. Less discussed is that they also promise to greatly enhance animal welfare. Their potential benefits include identifying and reducing pain, suffering, and distress in captive populations, improving laboratory animal welfare, and applying our understanding of animal behavior to increase the “natural” behaviors in captive and wild populations, especially those under threat. We are optimistic that these changes will greatly increase the welfare of primates, including those in laboratories, zoos, primate centers, and in the wild.

Abstract

Recent years have witnessed major advances in the ability of computerized systems to track the positions of animals as they move through large and unconstrained environments. These systems have so far been a great boon in the fields of primatology, psychology, neuroscience, and biomedicine. Here, we discuss the promise of these technologies for animal welfare. Their potential benefits include identifying and reducing pain, suffering, and distress in captive populations, improving laboratory animal welfare within the context of the three Rs of animal research (reduction, refinement, and replacement), and applying our understanding of animal behavior to increase the “natural” behaviors in captive and wild populations facing human impact challenges. We note that these benefits are often incidental to the designed purpose of these tracking systems, a reflection of the fact that animal welfare is not inimical to research progress, but instead, that the aligned interests between basic research and welfare hold great promise for improvements to animal well-being.

Costs and benefits of living in a vegetated, compared with non-vegetated, enclosure in male Japanese macaques (Macaca fuscata)

Improving captive environments for primates has been an important tool to enhance animal welfare. One method has been to provide primates with naturalistic vegetated enclosures to promote species-specific behaviors, enhancing interactions with their social and natural environment, such as an increase in feeding, foraging, and positive social behaviors such as play. To investigate the benefits in which living in naturalistic environments promote general animal well-being, we observed immature and adult males living in two outdoor housed groups of Japanese macaques (Macaca fuscata) in the Kyoto University Primate Research Institute (KUPRI), Inuyama, Japan, from June of 2015 until June 2016. One enclosure was naturally vegetated and the other was not. We recorded male activity budgets, affiliative (groom, play) behaviors, and rates of agonistic interactions. To examine health status, we recorded and compared coat conditions for both groups. We found that males in the vegetated enclosure spent more time in social play than males in the non-vegetated enclosure, while males in the non-vegetated enclosure displayed more stereotypic behaviors and agonistic interactions. We recorded better coat conditions in the vegetated enclosure males while rates of social grooming or self-grooming were no different between males in the two enclosures. The males in the vegetated enclosure did not have activity budgets more similar to their wild counterparts; but they spent more time in feeding-related activities and less time resting, which was more similar to their wild counterparts than males in the non-vegetated enclosure. Our findings suggest that individuals housed in naturalistic environments have significantly greater behavioral and physical markers of wellbeing than those housed in unnatural, large outdoor enclosures. Although we found that males in both types of enclosures overall had similar time budgets to males in the wild, the detailed behavioral and health results suggest that the welfare benefits to males were greater in the vegetated enclosure, compared with non-vegetated enclosures. Efforts to mimic more natural environments should promote the well-being of primates.

Diagnostic and Therapeutic Guidelines to Abnormal Behavior in Captive Nonhuman Primates

Abnormal behavior in nonhuman primates is oftentimes prematurely blamed on certain conditions, in the case of captive non-human primates, readily so on their husbandry, largely ignoring the underlying pathophysiological processes in the brain. Each life history shapes an individual's predisposition to develop or resist the development of a psychopathological disorder, which manifests itself in abnormal behavior when triggered by certain situations or conditions. In order to sustainably address the symptoms of psychopathologies, therapeutic approaches must be based on a structured, comprehensive diagnostic procedure, including behavioral and functional analyses, research into life history, and personality assessment..

REVIEW: PSYCHOPATHOLOGIES IN CAPTIVE NONHUMAN PRIMATES AND APPROACHES TO DIAGNOSIS AND TREATMENT

  Despite the growing knowledge and literature on primate medicine, assessment and treatment of behavioral abnormalities in nonhuman primates (NHPs) is an underdeveloped field. There is ample evidence for similarity between humans and great apes, including basic neurologic physiology and emotional processes, and no substantial argument exists against a concept of continuity for abnormal conditions in NHPs that emerge in response to adverse experiences, akin to human psychopathology. NHPs have served as models for human psychopathologies for many decades, but the acquired knowledge has only hesitantly been applied to primates themselves. This review aims to raise awareness among the veterinary community of the wealth of literature on NHP psychopathologies in human medicine and anthropology literature and calls for the necessity to include mental health assessments and professionally structured treatment approaches in NHP medicine. Growing understanding about causes and pathogenesis of abnormal behavior in NHP will not only help to prevent the development of undesirable behaviors but also allow for treatment and management of long-lived, already affected animal patients.

Effects of Anxiety on Spontaneous Ritualized Behavior

Environmental uncertainty and uncontrollability cause psycho-physiological distress to organisms, often impeding normal functioning. A common response involves ritualization, that is, the limitation of behavioral expressions to predictable stereotypic and repetitive motor patterns. In humans, such behaviors are also symptomatic of psychopathologies like obsessive-compulsive disorder (OCD) and autism spectrum disorders (ASDs). Although these reactions might be mediated by different neural pathways, they serve to regain a sense of control over an uncertain situation by engaging in behavioral patterns characterized by redundancy (superfluous actions that exceed the functional requirements of a goal), repetitiveness (recurrent behaviors or utterances), and rigidity (emphasis on fidelity and invariance). We examined whether ritualized behavior will manifest spontaneously as a dominant behavioral strategy in anxiogenic situations. Manipulating anxiety, we used motion-capture technology to quantify various characteristics of hand movements. We found that induced anxiety led to an increase in repetitiveness and rigidity, but not redundancy. However, examination of both psychological and physiological pathways revealed that repetitiveness and rigidity were predicted by an increase in heart rate, while self-perceived anxiety was a marginally significant predictor of redundancy. We suggest that these findings are in accordance with an entropy model of uncertainty, in which anxiety motivates organisms to return to familiar low-entropy states in order to regain a sense of control. Our results might inform a better understanding of ritual behavior and psychiatric disorders whose symptoms include over-ritualization.