Behavioral Management as a Coping Strategy for Managing Stressors in Primates: The Influence of Temperament and Species

Abstract

Primates involved in biomedical research experience stressors related to captivity, close contact with caregivers, and may be exposed to various medical procedures while modeling clinical disease or interventions under study. Behavioral management is used to promote behavioral flexibility in less complex captive environments and train coping skills to reduce stress. How animals perceive their environment and interactions is the basis of subjective experience and has a major impact on welfare. Certain traits, such as temperament and species, can affect behavioral plasticity and learning. This study investigated the relationship between these traits and acquisition of coping skills in 83 macaques trained for cooperation with potentially aversive medical procedures using a mixed-reinforcement training paradigm. All primates successfully completed training with no significant differences between inhibited and exploratory animals, suggesting that while temperament profoundly influences behavior, training serves as an important equalizer. Species-specific differences in learning and motivation manifested in statistically significant faster skill acquisition in rhesus compared with cynomolgus macaques, but this difference was not clinically relevant. Despite unique traits, primates were equally successful in learning complex tasks and displayed effective coping. When animals engage in coping behaviors, their distress decreases, improving welfare and reducing inter- and intra- subject variability to enhance scientific validity.

Keywords: behavior; coping; nonhuman primates; temperament; training; welfare.

Figure 1

Training Completion Time by Primate Species. Kaplan–Meier time-to-event analysis comparing the time required to successfully complete all phases and individual phases of the training paradigm between rhesus and cynomolgus macaques. There was a significant difference between species for the completion of (a) all phases (Log-rank χ² = 31.6 (df = 1), p = <0.0001), (b) P-Phase (Log-rank χ² = 4.2 (df = 1), p = 0.04), (c) Phase-1 (Log-rank χ² = 22.3 (df = 1), p = <0.0001), and (d) Phase-2 (Log-rank χ² = 18.7 (df = 1), p = <0.0001).

Figure 2

Training Completion Time by Temperament in Rhesus Macaques. Kaplan–Meier time-to-event analysis comparing the time required to successfully complete all phases and individual phases of the training paradigm between inhibited and exploratory rhesus macaques. There were no significant differences between groups for completing (a) all phases (Log-rank χ² = 0.03 (df = 1), p = 0.86), (b) P-Phase (Log-rank χ² = 1.15 (df = 1), p = 0.30), (c) Phase-1 (Log-rank χ² = 0.50 (df = 1), p = 0.50), or (d) Phase-2 (Log-rank χ² = 0.26 (df = 1), p = 0.61).

Figure 3

Training Completion Time by Temperament in Cynomolgus Macaques. Kaplan–Meier time-to-event analysis comparing the time required to successfully complete all phases and individual phases of the training paradigm between inhibited and exploratory cynomolgus macaques. There were no significant differences between groups for completing (a) all phases (Log-rank χ² = 0.41 (df = 1), p = 0.52), (b) P-Phase (Log-rank χ² = 0.60 (df = 1), p = 0.45), (c) Phase-1 (Log-rank χ² = 0.02; (df = 1), p = 0.88), or (d) Phase-2 (Log-rank χ² = 0.63 (df = 1), p = 0.43).