Abstract. Japanese macaques Macaca fuscata inhabit the Japanese archipelago where they experience markedly seasonal warm and cool temperate climates. Their reproduction and their nutritional status follow clearly seasonal patterns. Their status can be effectively evaluated based on their total body fat, but making such measurements has been difficult. In this study, the body fat of Japanese macaques was studied using Double Energy X-ray Absorptiometry (DXA). Adult males were found to have a median fat mass of 7% and adult females 9%. Using the 90th percentile as the criterion, we determined the levels of obesity in Japanese macaques as 17% in males and 27% in females. Fatness indicators (physique index and skinfold thickness) were found to correlate well with total body fat and fat mass percentage. Fat mass is estimated fairly well from these indicators. Fatness indicators change seasonally in artificially reared Japanese macaques.

Using standard methods, we describe the morphometric characteristics of Indian-and Chinese-derived rhesus macaques (Macaca mulatta) reared at the Primate Research Institute of Kyoto University. The most significant morphometric difference found between the two populations was in tail length, which was ca. 45% and 35% of crown-rump length in the Indian-and Chinese-derived rhesuses, respectively. There were no major differences between the two populations in terms of the other parameters of body size/proportion, although the Chinese-derived rhesuses tended to be larger than the Indian-derived rhesuses by 2-5% and there were some differences in the proportions of extremities. This morphometric similarity can be interpreted from either phylogenetic (recent divergence) or adaptive (similarities in habitat) perspectives.

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