Nutritional Requirements And Feeding Strategy Of Golden Snub-nosed Monkeys (Rhinopithecus Roxellana) In The Qinling Mountains

An important goal in nutritional ecology is to understand what mechanism governs diet selection in animals. The Nutrient Balancing theory holds that animals utilize a specific feeding strategy for their daily food intake to meet requirements for multiple nutrients. The Geometric Framework for nutrition (specifically, the Right-angle Mixture Triangles, RMT) is a multidimensional approach designed to assess intake amount, relationship between nutrients, and relative priorities that animals assign to different macronutrients.This study conducted continuous focal animal recording to understand the feeding strategy of golden snub-nosed monkeys (Rhinopithecus roxellana)in the Zhouzhi National Nature Reserve,on the northern slope of the Qinling Mountain in Shaanxi Province, China. Observations covered two seasons:winter (26November2012to12January2013) and spring (12April2013to26May2013). We followed a total of56individuals:6adult males,7lactating females,11adult non-lactating females and5juveniles (from6one-male units; OMU’s) during the winter; and during spring,8adult males,8lactating females,5adult non-lactating females and6juveniles from8OMU’s.We observed monkeys consuming58food items and collected and analyzed55of them. We analyzed the content of each food item for crude protein (CP), lipid, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and ash content. Results showed that bark contained more carbohydrates and NDF than leaves (young leaves and mature leaves), while leaves (young leaves and mature leaves) contained more protein than bark. Lipid concentrations did not differ between leaves and barks, and was low in both. This variation in nutrient content among different food items is essential in allowing golden snub-nosed monkeys to match their feeding requirements. Using the geometric framework to combine right-angle mixture triangles and intake plots, we concluded the following:first, golden snub-nosed monkeys can balance their macronutrient intake. Second, they are able to maintain a consistent balance of protein to non-protein (lipid and carbohydrate) energy. Because lipid content was low and stable, we removed lipid contribution from our analysis, and found that the carbohydrate to protein ratio was also stable. Third, energy intake in winter was much higher than in spring. These conclusions are likely adaptations to the monkey’s high altitude, low temperature, and highly seasonal habitat of the Qinling Mountain.