Send to

Choose Destination
See comment in PubMed Commons below
Trends Ecol Evol. 1997 Feb;12(2):58-62.

Evolution of genital masculinization: why do female hyaenas have such a large 'penis'?

Author information

The Psychology Dept, University of California, Berkeley, CA 94720, USA.


In place of a 'normal' external vagina, female spotted hyaenas bear a fully erectile, penis-sized clitoris through which they mate and give birth. Early hypotheses on the evolution of this organ have focused on its signal function, because the erect phallus is used by both sexes as part of submission or appeasement displays. However, a quite different hypothesis is suggested by recent data on the ecological function of female aggressiveness, and on the role of androgens in the development of aggressiveness and male genital development. In this view, the female phallus may have originated as an unselected side effect of selection for androgen-mediated bellicosity, a major advantage in the extraordinarily competitive hyaena social system.

PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center