Enticing nonhuman primates to forage for their standard biscuit ration

Ordinary feeder‐boxes for macaques were converted into food puzzles by remounting them onto the square mesh (22 × 22 mm) of the front of the cages, away from original access holes. Feeding a standard ration of bar‐shaped biscuits (40 × 24 × 16 mm; Purina Monkey Chow #5038; 236 g per animal), 8 adult pair‐housed male rhesus macaques spent, on average, 61.0±15.6% of the first 30 min retrieving biscuits from food puzzles, but only 0.5±0.1% from feeder‐boxes. Their total amount of time engaged in gathering food was, on average, 141 times higher at food puzzles (42.2±7.2 min) than at feeder‐boxes (0.3±0.1 min). It was concluded that using feeder‐boxes as food puzzles, baited with the standard biscuit ration, offers a cost‐ and work‐effective way to promote foraging activities in captive nonhuman primates. © 1993 Wiley‐Liss, Inc.