Scent-marking and olfactory investigatory behavior in the squirrel monkey (Saimiri sciureus)

Olfactory-related behaviors were observed in social groups of Guyanese squirrel monkeys (Saimiri sciureus) during three distinct phases of the annual reproductive cycle. Olfactory investigation of females and environmental objects by males showed marked increases in frequency from the nonmating to the mating season and intermediate levels during a period of transition from mating to nonmating. Olfactory investigation by females also showed evidence of seasonality, though females engaged in investigatory behaviors less frequently than did males. Females sniffed environmental objects and the anogenital area of other females more often during the mating season than during either of the other two observation periods. The frequency of three probable scent-marking behaviors (rump rubbing, back rubbing, and urine washing) showed no evidence of seasonal variation. Overall, females rump-rubbed more than males, and males back-rubbed more than females. These data suggest that olfactory investigation of females by males is an important component of reproductive activities in the squirrel monkey. The seasonal pattern of male investigatory behavior does not appear to result from an increase in female scent marking during the mating season. Rather, it seems likely that female odors change during this phase of the reproductive cycle so as to provoke increased investigation by males.