Male animals of many species use conspicuous coloration to attract mates. Among mammals, primates possess the most brilliant secondary sexual coloration. However, whether colour plays a part in primate female mate choice remains unknown. Adult male rhesus macaques undergo a hormonally regulated increased reddening of facial and anogenital skin during their mating season. We experimentally investigated whether red male facial coloration is preferred by simultaneously presenting female rhesus macaques (n = 6) with computer-manipulated pale and red versions of 24 different male faces. The duration and direction of gaze were measured to discern visual preferences. Females exhibited preferences for the red versions of male faces. It is proposed that male coloration might provide a cue to male quality.

As contact with caretakers is likely to make up the majority of human-primate interactions in laboratories, caretakers represent an important influence in the lives of captive primates. The aim of this study was to determine how caretaker-primate relationships affected the behavior of primates in the laboratory. We examined whether stump-tailed macaques (Macaca arctoides) who were evaluated by caretakers as being either friendly or unfriendly differed in the quality and quantity of interactions with their caretakers during husbandry procedures and in their behavior at times of high and low levels of caretaker activity. Results revealed that animals who had friendly relationships with caretakers were less disturbed by routine husbandry procedures, approached caretakers more often, and were willing to accept food offered by caretakers compared with animals considered unfriendly toward their caretakers. The study concluded that the quality of the primate-caretaker relationship may have an important impact on...