Sexual Monomorphism in Spotted Hyenas, Crocuta crocuta

Authors

  • William J. Hamilton III,

    Corresponding author
    1. Institute of Ecology, University of California, Davis
    2. Desert Ecological Research Unit, Gobabeb, Namibia
    3. Museum of Vertebrate Zoology, University of California, Berkeley
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  • Ronald L. Tilson,

    Corresponding author
    1. Institute of Ecology, University of California, Davis
    2. Desert Ecological Research Unit, Gobabeb, Namibia
    3. Museum of Vertebrate Zoology, University of California, Berkeley
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  • Lawrence G. Frank

    Corresponding author
    1. Institute of Ecology, University of California, Davis
    2. Desert Ecological Research Unit, Gobabeb, Namibia
    3. Museum of Vertebrate Zoology, University of California, Berkeley
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Institute of Ecology, University of California, Davis, CA 95616, U.S.A.

Biological Programs, Minnesota Zoological Garden, Apple Valley, MN 55124, U.S.A.

Department of Psychology, University of California, Berkeley, CA 94720, U.S.A.

Abstract

Intersexual and intrasexual interactions by female spotted hyenas, (Crocuta crocuta), are correlated with the ability of the heavier and more aggressive females to dominate males at large carcasses, the principal food of spotted hyenas.

Female spotted hyenas have a modified clitoris closely resembling a penis. A slightly bilobed scrotum containing fat and connective tissue contributes to the male-like appearance of the female sexual facies. Penile and pseudopenis erection by spotted hyenas occurs primarily during social encounters at carcasses and elsewhere.

Analyses here, based on interspecies comparisons of spotted hyena, brown hyena (Hyaena brunnea) and striped hyena (H. hyaena) morphology, behavior and ecology and interpopulation comparisons of spotted hyenas suggest possible gradualistic evolutionary interpretations of the pseudopenis.

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