The foraging behavior of Japanese macaques Macaca fuscata in a forested enclosure: Effects of nutrient composition, energy and its seasonal variation on the consumption of natural plant foods

In the wild, primate foraging behaviors are related to the diversity and nutritional properties of food, which are af- fected by seasonal variation. The goal of environmental enrichment is to stimulate captive animals to exhibit similar foraging be- havior of their wild counterparts, e.g. to extend foraging time. We conducted a 12-month study on the foraging behavior of Japa- nese macaques in a semi-naturally forested enclosure to understand how they use both provisioned foods and naturally available plant foods and what are the nutritional criteria of their consumption of natural plants. We recorded time spent feeding on provi- sioned and natural plant foods and collected the plant parts ingested of their major plant food species monthly, when available. We conducted nutritional analysis (crude protein, crude lipid, neutral detergent fiber-'NDF', ash) and calculated total non-structural carbohydrate - 'TNC' and total energy of those food items. Monkeys spent 47% of their feeding time foraging on natural plant species. The consumption of plant parts varied significantly across seasons. We found that leaf items were consumed in months when crude protein, crude protein-to-NDF ratio, TNC and total energy were significantly higher and NDF was signifi- cantly lower, fruit/nut items in months when crude protein and TNC were significantly higher and crude lipid content was sig- nificantly lower, and bark items in months when TNC and total energy were higher and crude lipid content was lower. This pre- liminary investigation showed that the forested enclosure allowed troop members to more fully express their species typical flexi- ble behavior by challenging them to adjust their foraging behavior to seasonal changes of plant item diversity and nutritional con- tent, also providing the possibility for individuals to nutritionally enhance their diet (Current Zoology 56 (2): 198-208, 2010).