Recipient of the Distinguished Teaching Award
Article in Framing the Question: "Man and Beast: Two colleagues cross disciplines to probe the human-animal dynamic"
We are currently studying an unusual animal, the spotted hyena, in order to understand general mechanisms of sexual differentiation. Female spotted hyenas are more aggressive than males, dominate males in social interactions, and are somewhat larger than males. The external genitalia are highly "masculinized," i.e., the clitoris has hypertrophied to form a pseudopenis, traversed by a central urogenital canal. There is no external vagina. The female spotted hyena urinates, copulates and gives birth through her clitoris. According to our current understanding of sexual differentiation, production of such masculinized genitalia requires the influence of androgens during fetal life. Such androgens might also enhance the size and aggressiveness of female hyenas. Through the study of a breeding colony of hyenas, maintained in a large enclosure in the hills above the Berkeley Campus, we have found that the androgen androstenedione is secreted in quantity by the ovaries of female hyenas throughout life. We have recently also noted that this androgen is converted to testosterone by the placenta and passed to the developing fetus during gestation. Behavioral observations of aggression and play are compatible with the possibility that androgens are promoting the development of these behavior patterns in female hyenas.
Over the years, my students have worked with a wide range of animals in field and laboratory settings. I maintain a serious interest in comparative psychology, in relation to social behavior, and to the evolution of exploratory behavior.
Frank, L. G., Glickman, S. E., & Licht, P. (1991). Fatal sibling aggression, precocial development, and androgens in neonatal spotted hyenas. Science, 252, 702-704.
Glickman, S. E., Frank, L. G., Licht, P., Yalcinkaya, T. M., Siiteri, P. K., & Davidson, J. M. (1992). Sexual differentiation of the female spotted hyenas: One of nature's experiments. Annals of the New York Academy of Sciences, 662, 135-159.
Yalcinkaya, T. M., Siiteri, P. K., Vigne, J.-L., Licht, P., Pavgi, S., Frank, L. G., & Glickman, S. E. (1993). A mechanism for virilization of female spotted hyenas in utero. Science, 260, 1929-1931.
Glickman, S. E., Frank, L. G., Holekamp, K. E., Smale, L., & Licht, P. (1993). Costs and benefits of "androgenization" in the female spotted hyena: The natural selection of physiological mechanisms. In P. P. G. Bateson, P. H. Klopfer, & N. S. Thompson (Eds.), Perspectives in ethology (Vol. 10). New York: Plenum.
Stephen E. Glickman