Understanding the role of olfaction in regulating male primate behavior and physiology

Differences in appearance, behavior, and physiology are associated with differences in male status across primates. Achieving dominant status has important consequences for primate males, including in terms of their ability to sire offspring. While the role of hormones in regulating the achievement of dominant status is well characterized, much less is known about how odor and olfaction contribute to status outcomes.

The researchers use an integrative approach to measure phenotypic, physiological, and behavioral variation among male white-faced capuchin monkeys to advance a comprehensive understanding of the roles that olfactory communication plays in regulating rank achievement. The research contributes to a broader understanding of what roles olfaction plays in the biology and behavior of primates.

Throughout the project, the research team will engage in K-12 STEM education outreach by providing workshops to students and teachers. Additional STEM talent building will occur through the training and mentorship of a diverse group of young scientists, including undergraduate, post-baccalaureate, and graduate students, as well as an early-career postdoctoral scientist.

The aim of this research is to test the hypothesis that odors regulate the expression of dominant and subordinate male morphs in male white-faced capuchins. Specifically, the investigators will 1) quantify the morphology and physiology of capuchin male morphs in relation to rank (dominant versus subordinate); 2) characterize olfactory behavioral variation (e.g., sniffing, urinary marking) in relation to rank; and 3) determine the chemical basis for differences in scent in relation to rank.

The researchers use cutting-edge, integrative methods to track changes in morphology, behavior, and physiology, including digital photogrammetry, behavioral observation, and assessment of hormonal changes, to facilitate causal understanding of the temporal sequence of changes related to attainment of dominant status. Moreover, by simultaneously measuring behavioral and biological variation involved in male rank morphs in a wild primate, this research contributes creative, original insights to advance knowledge of the proximate mechanisms underlying rank, with important implications for understanding status and phenotypic differentiation – as well as the roles played by sensory biology – in primate evolution.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.