• abnormal;
  • anxiety;
  • behavior;
  • introduction;
  • stress


Background  The purpose of this study was to test whether long-term pair housing of male rhesus macaques ameliorated negative responses to stressful events that can occur in the course of routine husbandry or research procedures.

Methods  Twelve singly housed individuals were videotaped during two potentially stressful events before and after social introduction into pairs. During each stressor, abnormal behavior and anxiety-related behavior were quantified from videotape.

Results  When visually exposed to the restraint and anesthesia of other monkeys, subjects showed significantly reduced frequencies of abnormal behavior when pair-housed in comparison to their reactions when housed singly. Noisy and disruptive conversation between technicians standing immediately in front of the subjects’ cage did not elicit the same reduction in abnormal behavior. Neither test showed a significant difference across housing settings for anxiety-related behaviors.

Conclusions  These findings suggest that pair housing buffers adult male rhesus macaques against common stressors in the laboratory setting.