Female Rhesus Macaques (Macaca mulatta) Sexual Skin Color Variability

Abstract

Many primate species use colorful signals to communicate sexual receptivity, rank, pregnancy, health, and developmental maturity. Reproductive coloration may not be limited to signaling sexual receptivity or pregnancy, but may also communicate aspects of female quality. Our preliminary study examined the relationships between female sexual skin coloration, mating status, and female traits, including age and dominance rank. The study took place at the Cayo Santiago (CS) facility in Puerto Rico; data were collected May through August of 2006. We examined two questions: 1) Is sexual skin coloration related to mating status?; and 2) Are inter-and intra-individual color differences related to female traits? Facial coloration was not significantly related to mating status; genital saturation was significantly higher among mating females and among high-ranking females. Age was negatively correlated with both genital hue and genital saturation range; older females had more restricted coloration and younger females had more variable color. These preliminary results suggest that female coloration may reliably indicate aspects of female quality or condition to conspecifics, including potential mates.