Background & Objectives
New U.S. regulations require research facilities to address the psychological well-being of non-human primates. One widely adopted strategy is the use of foraging devices, which encourage natural feeding behaviors and may reduce abnormal, stress-related behaviors like self-grooming or hair-plucking. This short-term study aimed to evaluate the acceptability and behavioral impact of a novel foraging device on individually housed male cynomolgus monkeys (Macaca fascicularis).
Methodology
• Subjects: 8 adult male cynomolgus monkeys, individually housed.
• Design: 4-week study with distinct phases:
1. Week 0: Training and acclimation.
2. Week 1: Baseline (standard food in hopper only).
3. Week 2: Foraging device + standard food.
4. Week 3: Foraging device + novel food (e.g. fruit loops, granola, raisins, peanuts).
• Behaviors observed:
• Foraging, Self-directed (e.g., scratching, grooming), Hopper feeding, Other.
• Observations: 3 times/day, over 5 days per week, for 20-minute sessions using instantaneous sampling.
Key Findings
• Device acceptance: 7 of 8 monkeys used the foraging device within one day. One did not use it at all, even when novel food was provided.
• Foraging behavior:
• Increased 240–500% in Week 2 (device with standard food) compared to baseline (Week 1).
• Increased 300–1200% in Week 3 when novel food was introduced.
• Device remained engaging when filled with novel treats, overcoming the usual “extinguishing” effect (loss of novelty).
• Self-directed behaviors:
• Decreased up to 23% in Week 2.
• Decreased further (by 58–84%) in Week 3 with novel food.
• Reductions were statistically significant (p < 0.05).
• Hopper usage declined in favor of the foraging device, even when the same food was present in both.
Conclusions & Implications
The foraging device was highly effective at increasing natural foraging behavior and reducing self-directed behaviors in the short term. Introducing novel food helped maintain interest, suggesting that rotating food types is critical for long-term engagement. The device was durable, easy to sanitize, and is now used in rotational enrichment programs at the facility.
This study supports the inclusion of interactive feeding devices as part of a comprehensive enrichment plan to support the psychological welfare of laboratory primates. Individual variation (as with the one monkey who didn’t use the device) highlights the need for diverse enrichment options.
