Free‐ranging Cayo Santiago rhesus monkeys (Macaca mulatta): I. Body size, proportion, and allometry

Abstract

This paper presents comprehensive baseline data on body size and proportion of 661 (315 male, 346 female) free-ranging Cay0 Santiago rhesus monkeys (Macaca muZatta) ranging in age from 24 hours to 25 years. All animals were born and raised in the free-ranging colony on Cay0 Santiago, and exact ages were known for all. Tabular data from this cross-sectional study are provided to enable comparisons with data from laboratory, wild, and other captive populations of rhesus monkeys, as well as with other species. Despite the extensive literature on rhesus monkey behavior and biology, to date published accounts of its morphometrics have been limited to only a few measurements from animals of unknown age, small sample sizes, or caged colonies. Results of this study showed a distinct intraspecific pattern for body proportions throughout the life cycle. Relative linear increases in overall body proportions of maturing animals appeared to be from greatest to least in the trunk, hindlimb, and forelimb, respectively. Within the limbs, allometric scaling appeared to be fastest in the proximal segment and slowest in the distal segment. Males and females differed in the duration of growth, and gender dimorphism was associated primarily with differences in size rather than proportion. Although the primary purpose of this paper is to present numerical data on the Cay0 Santiago colony, the results are compared with previous studies of both laboratory and free-ranging rhesus monkeys.

Morphometrical comparison between Indian- and Chinese-derived rhesus macaques (Macaca mulatta)

“…7.0 years (Indian-origin: van Wagenen and Catchpole, 1956) had a CRL comparable with the PRI Indian-derived rhesuses, but the latter had relatively shorter thighs and longer legs. Cayo Santiago rhesuses (Indian-origin: Turnquist and Kessler, 1989), which were reared under semi-wild conditions, were slightly larger than the PRI rhesuses not only in CRL but also in limb segment lengths by up to 13%. Although the number of morphometric characters is limited and the way of measurement differs (e.g.…”

“…Although the number of morphometric characters is limited and the way of measurement differs (e.g. they measured forearm length from the olecranon to the tip of styloid process ulna: Turnquist and Kessler, 1989), Cayo Santiago rhesuses could be compared with the PRI rhesuses in limb segment lengths. They have relatively (against CRL) shorter upper arm and foot like PRI Indianderived rhesuses, but have relatively longer thighs.…”

“…Although some morphological evaluations have been conducted on rhesuses from various localities (Fooden, 1964(Fooden, , 1971(Fooden, , 1997(Fooden, , 2000Jiang et al, 1991) and colonies (van Wagenen and Catchpole, 1956;Gavan and Hutchinson, 1973;DeRousseau and Reichs, 1987;Turnquist and Kessler, 1989;Clarke and O'Neil, 1999), detailed morphometric comparisons have not been made. In particular, only few studies have reported on the body size and proportions of macaques based on standardized morphometric methods (Iwamoto, 1971;Hamada et al, 1986Hamada et al, , 1996.…”

A Comparison of Dual‐Energy X‐Ray Absorptiometry and Somatometrics for Determining Body Fat in Rhesus Macaques

“…Male rhesus macaques reach sexual maturity between 2.5 years and 4.5 years, and the adolescent growth spurt is complete by -6 years (40). Average adult males range in body weight from 9 kg to 13 kg (8,12).…”

“…Traditional methods (e.g., body weight, skinfold thickness), often used to assess body composition in nonhuman primates (4,(8)(9)(10)(11)(12), have inherent shortcomings due in part to assumptions and measurement errors inherent to them. These somatometric measurement errors have been examined for over a decade (13)(14)(15)(16)(17)(18)(19)(20).…”