Search

Determining the nutrient factors influencing food choice provides important insight into the feeding strategy of animals, which is crucial for understanding their behavioral response to environmental changes. A bamboo‐leaf‐based diet is rare among mammals. Animals' food choice and nutritional goals have been explained by several frameworks; however, the influence of nutrients on food choice in bamboo‐leaf‐based macaques is not yet available. Assamese macaques (Macaca assamensis) inhabiting limestone forests are characterized by such a bamboo‐leaf‐based diet, predominantly consuming young leaves of Bonia saxatilis, a shrubby, karst‐endemic bamboo. We studied the feeding behavior of one group of Assamese macaques using instantaneous scan sampling in limestone forests of the Guangxi Nonggang National Nature Reserve in southwest Guangxi, China. We compared the nutrient content of staple food and nonfood items and examine the role of key nutrients in the food selection of macaques. Our results showed that young leaves of bamboo B. saxatilis contained more water, crude protein, phosphorus, and less tannin than nonfood items. Furthermore, staple foods contained a higher content of water and less content of calcium than nonfood items. More specifically, quantities of water, crude protein, calcium, and phosphorus in food items were critical factors affecting feeding time on a specific plant item. Our results suggest that young bamboo leaves could meet macaques' required protein and water intake, while enabling them to maintain their mineral balance, consequently facilitating to maintain the primates' bamboo‐leaf‐diet in the limestone forest. Our findings confirm the effects of nutrient contents in food choice of Assamese macaques, highlighting the importance of the nutrient contents in maintaining their bamboo‐based diet and the need to increase the knowledge on their nutritional strategy adapted to the bamboo‐dominated diet inhabiting the unique limestone habitat. [ABSTRACT FROM AUTHOR]

Information on the positional behavior and habitat use of primates can help elucidate relationships among species' morphology, behavior, and environment, and contribute to our understanding of species' behavioral and ecological adaptations. Limestone habitats provide a unique and challenging habitat for primates, but there have been few detailed studies of the genus Macaca in such habitats, making a comparative understanding of extant limestone primates' behavioral adaptations incomplete. We collected data on positional behavior and habitat use by sympatric Assamese macaques ( Macaca assamensis) and rhesus macaques ( M. mulatta) in limestone habitat at Nonggang Nature Reserve, southwestern Guangxi, China, and examined the effects of morphological and ecological factors on positional behavior and habitat use. Our results indicate interspecific differences in positional behavior, showing different preferences for locomotor modes and substrates. Rhesus macaques tended to walk horizontally, whereas Assamese macaques more often climbed vertically. Rhesus macaques used smaller substrates (twigs) more frequently than did Assamese macaques. Time spent in different zones of limestone hills and forest strata also varied significantly between the two macaques. Assamese macaques most often used cliff faces, and tended to be terrestrial. Rhesus macaques were most likely to stay low on the hillsides, and spent most of their time in the lower strata of trees. These differences in positional behavior and habitat use are linked to differences in limb length and body size in the two species, and may be explained by the spatial distribution of preferred foods and structure of the forest in different areas of the limestone hills. [ABSTRACT FROM AUTHOR]