Urogenital tract and possible hormones affecting masculinization in female spotted hyenas (Crocuta crocuta)

Authors

DOI:

https://doi.org/10.5281/zenodo.15324107

Keywords:

Androgens, estrogens, penil clitoris, sexual differentiation, Spotted hyena, urogenital sinus

Abstract

The genital system of female spotted hyenas (Crocuta crocuta) in the Hyaenidae family shows significant morphological and anatomical differences compared to other hyena species. The outer vagina found in other mammals is absent in spotted hyenas. The clitoris is enlarged, capable of erection, and has a penis-like appearance. This unique structure, called the pseudopenis or penile clitoris, has functional functions such as urination, mating, and childbirth. In the presented review, general information about female spotted hyenas is conveyed. In addition, studies on the possible effects of estrogen and androgens on the formation of the external genital tract are reviewed.

References

Holekamp KE. Spotted hyenas. Current Biology. 2006;16(22):R944-R945. doi:10.1016/j.cub.2006.10.009

Allen J, Lang H, Chapin J. Carnivora collected by the American Museum Congo Expedition. Bull Am Mus Nat Hist. 1924;(47):73-281.

Kruuk H. The Spotted Hyena, a study of predation and social behavior. J Mammal. 1973;54(2):553-554. doi:10.2307/1379154

Matthews HL. Reproduction in the spotted hyaena, Crocuta crocuta (erxleben). Philos Trans R Soc Lond B Biol Sci. 1939;230(565):1-78. doi:10.1098/RSTB.1939.0004

Deane NN. The spotted hyaena Crocuta crocuta crocuta. Lammergeyer. 1962;2(2):26-43.

Frank LG, Holekamp KE, Smale L. Dominance, demographics and reproductive success in female spotted hyenas: a long term study. In: Sinclair ARE, Arcese P, eds. Serengeti II: Research, Management, and Conservation of an Ecosystem. University of Chicago Press; 1995:364-384.

Drea CM, Place NJ, Weldele ML, Coscia EM, Licht P, Glickman SE. Exposure to naturally circulating androgens during foetal life incurs direct reproductive costs in female spotted hyenas, but is prerequisite for male mating. Proc R Soc Lond B Biol Sci. 2002;49(191):1981-1987. doi:10.1098/RSPB.2002.2109

Hayssen V, Noonan P. Crocuta crocuta (Carnivora: Hyaenidae). Mammalian Species. 2021;53(1000):1-22. doi:10.1093/MSPECIES/SEAB002

Cunha GR, Wang Y, Place NJ, Liu W, Baskin L, Glickman SE. Urogenital system of the spotted hyena (Crocuta crocuta Erxleben): a functional histological study. J Morphol. 2003;256(2):205-218. doi:10.1002/JMOR.10085

Muller MN, Wrangham R. Sexual mimicry in hyenas. Q Rev Biol. 2002;77(1):3-16. doi:10.1086/339199

Cunha GR, Place NJ, Baskin L, et al. The Ontogeny of the Urogenital System of the Spotted Hyena (Crocuta crocuta Erxleben). Biol Reprod. 2005;73(3):554-564. doi:10.1095/BIOLREPROD.105.041129

Funk H. R. J. Gordon’s discovery of the spotted hyena’s extraordinary genitalia in 1777. J Hist Biol. 2012;45(2):301-328. doi:10.1007/S10739-011-9285-5/METRICS

A J. Problems of fetal endocrinology : the gonadal and nypophyseal hormones. Recent Progr Hormone Res. 1953;8:379-418. Accessed April 10, 2025. https://cir.nii.ac.jp/crid/1571417126349328896

Jost A. A new look at the mechanisms controlling sex differentiation in mammals. Johns Hopkins Med J. Published online 1972.

Phoenix CH, Goy RW, Gerall AA, Young WC. Organizing action of prenatally administered testosterone propionate on the tissues mediating mating behavior in the female guinea pig. Endocrinology. 1959;65(3):369-382. doi:10.1210/endo-65-3-369

Lindeque M, Skinner JD. Fetal androgens and sexual mimicry in spotted hyaenas (Crocuta crocuta). J Reprod Fertil. 1982;65(2):405-410. doi:10.1530/JRF.0.0650405

Licht P, Hayes T, Tsai P, et al. Androgens and masculinization of genitalia in the spotted hyaena (Crocuta crocuta). 1. Urogenital morphology and placental androgen production during fetal life. J Reprod Fertil. 1998;113(1):105-116. doi:10.1530/JRF.0.1130105

Browne P, Place NJ, Vidal JD, et al. Endocrine differentiation of fetal ovaries and testes of the spotted hyena (Crocuta crocuta): timing of androgen-independent versus androgen-driven genital development. Reproduction. 2006;132(4):649-659. doi:10.1530/REP.1.01120

Cunha GR, Risbridger G, Wang H, et al. Development of the External Genitalia: Perspectives from the Spotted Hyena (Crocuta crocuta). Differentiation. 2014;87(0):4. doi:10.1016/J.DIFF.2013.12.003

Yalcinkaya TM, Siiteri PK, Vigne JL, et al. A Mechanism for Virilization of Female Spotted Hyenas in Utero. Science (1979). 1993;260(5116):1929-1931. doi:10.1126/SCIENCE.8391165

Drea CM, Weldele ML, Forger NG, et al. Androgens and masculinization of genitalia in the spotted hyaena (Crocuta crocuta). 2. Effects of prenatal anti-androgens. J Reprod Fertil. 1998;113(1):117-127. doi:10.1530/JRF.0.1130117

Downloads

Published

2025-05-02

How to Cite

Büyükbaki, B. (2025). Urogenital tract and possible hormones affecting masculinization in female spotted hyenas (Crocuta crocuta). Animal and Veterinary Journal, 1(1), 21–25. https://doi.org/10.5281/zenodo.15324107