Familiarity affects the assessment of female facial signals of fertility by free-ranging male rhesus macaques

James P. Higham, Kelly D. Hughes, Lauren J.N. Brent, Constance Dubuc, Antje Engelhardt, Michael Heistermann, Dario Maestriperi, Laurie R. Santos, Martin Stevens

    Research output: Contribution to journalArticlepeer-review


    Animals signal their reproductive status in a range of sensory modalities. Highly social animals, such as primates, have access not only to such signals, but also to prior experience of other group members. Whether this experience affects how animals interpret reproductive signals is unknown. Here, we explore whether familiarity with a specific female affects a male's ability to assess that female's reproductive signals. We used a preferential looking procedure to assess signal discrimination in free-ranging rhesus macaques, a species in which female facial luminance covaries with reproductive status. We collected images of female faces throughout the reproductive cycle, and using faecal hormone analysis to determine ovulation, categorized images as coming from a female's pre-fertile, ovulating, or post-fertile period. Weprinted colour-calibrated stimuli of these faces, reproducing stimuli perceptually the same in colour and luminance to the original appearance of females. These images were presented to males who were either unfamiliar or familiar with stimuli females. Overall, males distinguished ovulatory from pre-ovulatory faces. However, a significant proportion of males did so only among males familiar with stimuli females. These experiments demonstrate that familiarity may increase a receiver's ability to use a social partner's signals to discern their reproductive status.

    Original languageEnglish (US)
    Pages (from-to)3452-3458
    Number of pages7
    JournalProceedings of the Royal Society B: Biological Sciences
    Issue number1723
    StatePublished - Nov 22 2011


    • Cognition
    • Discrimination
    • Experience
    • Familiarity
    • Ovulation
    • Reproductive signals

    ASJC Scopus subject areas

    • General Biochemistry, Genetics and Molecular Biology
    • General Immunology and Microbiology
    • General Environmental Science
    • General Agricultural and Biological Sciences


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