Chinese-origin and Indian-derived rhesus monkeys (Macaca mulatta), ranging in age from 6 months to 15 years, were weighed and measured during the 1995 inventory of the SAIDS breeding colony at the Tulane Regional Primate Research Center. Data were analyzed separately for males (n=279) and females (n=554), and an analysis of variance was done for five measurements and two indices, with age and country of origin as independent variables. All measurements increased significantly with age, but Chinese-origin males were heavier, longer, and taller than Indian-derived males. Chinese-origin juvenile females were heavier and longer than Indian-derived juvenile females, but this pattern was reversed for adults. Chinese-origin rhesus monkeys exhibited more adult sexual dimorphism than did Indian-derived rhesus monkeys. An analysis of Chinese-origin adults that were Louisiana-born vs. China-born indicated that Louisiana-born adults were lighter, longer, and taller than their China-born parental generation. These differences were statistically significant for adult females and descriptively suggestive for adult males, and both suggest body and appendage adaptation to a warmer, wetter climate.