Effects of Food Fracture Toughness on Chewing Efficiency in Yakushima Japanese Macaques

抄録

Chewing, as an intermediate step between food handling and chemical digestion in the whole nutrition intake process, is one of the initial steps that deals with the mechanical defenses of food. It has been associated with the fitness of mammals by influencing digestive efficiency. As a major mechanical defense of plant, toughness is one of the most prominent extrinsic factors that limits chewing efficiency in primates. This study aims to clarify the seasonal variation of food fracture toughness and chewing efficiency in Yakushima Japanese macaque (Macaca fuscata yakui). We collected feeding behavior data and fecal samples in Yakushima lowland. Food fracture toughness was measured with a rheometer. Fecal particle size was measured by sieving analysis to show the variation in chewing efficiency. Here, we report the preliminary results about the seasonal and age-sex related variation in dietary fracture toughness and fecal particle size. And we would like to discuss the relationship of food mechanical properties and chewing efficiency.