Characteristics of spontaneous obesity in the Cayo Santiago rhesus macaque: preliminary report.

As part of the January, 1988 trapping of the Cayo Santiago rhesus colony a number of morphometric measurements and serum were collected to examine metabolic and hormonal changes associated with spontaneous obesity. Measurements included body weights, crown-rump lengths, abdominal and scapular skinfolds and circumferences of the upper arm, upper leg, abdomen and chest. Overall, males had a significantly greater body weight and Quetelet Index (body weight/crown-rump) than females but abdominal skinfolds did not differ. Pregnant females exhibited suppressed cholesterol levels relative to non-lactating and lactating females and males. Approximately 10% of the sample (N = 12) were defined as obese according to morphometric criteria. There were no differences in cholesterol and triglyceride levels between obese and nonobese animals nor were differences observed for testosterone and estradiol levels in obese and nonobese males. All obese animals fell within 7 matrilines, several of which were high ranking. These data confirm previous findings that spontaneous obesity occurs in the Cayo Santiago colony. The absence of obesity-related metabolic and hormonal changes may be related to the free ranging environment of the colony.