Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

© 2018 Deutsche Gesellschaft für Säugetierkunde Field biologists often rely on examination of external genitalia as a proxy for mammalian reproductive condition. In seasonally breeding European badgers, scrotal testes are used as an indicator of spermatogenesis, while a pink and swollen vulva with mucosal secretion is assumed to indicate oestrus. Systematic validation of these assumptions is lacking. Here we analysed sex steroid hormones from plasma samples collected from sexually mature adults during the winter mating season, the spring post-weaning period, the summer minor mating peak, and autumn reproductive quiescence, to compare circulating testosterone levels in males (n = 216), and oestrone (n = 143) and oestradiol (n = 36) levels in females with concurrent external genitalia condition (males: descended, intermediate, ascended testes, as well as testes volume; females: swollen, intermediate, normal vulva). Sex-steroid levels exhibited seasonal patterns, broadly reflecting the seasonal variation in genital condition. Nevertheless, on an individual level, male testosterone levels correlated significantly with testes condition and testes volume only during the mating season in spring, and neither oestrone nor oestradiol differed between female EGM categories. We thus conclude that, in males, EGM is a reliable indicator of reproductive activity during the mating season, but can provide only a tentative indication of physiological reproductive status outside this period, while in females EGM is generally less precise for assessing female reproductive status.

Original publication

DOI

10.1016/j.mambio.2018.09.007

Type

Journal article

Journal

Mammalian Biology

Publication Date

01/11/2018

Volume

93

Pages

97 - 108