Circulating concentrations of gonadal and adrenocortical hormones in wild nine-banded armadillos (Dasypus novemcinctus)

We performed a retrospective analysis of hormone concentrations found in blood sera from culled nine-banded armadillos (Dasypus novemcinctus) with the goal of identifying important sources of variation in, and relationships among, circulating levels of testosterone (males), estradiol and progesterone (females), and cortisol (all animals). Testosterone concentrations were greater in adult males than in yearling or juvenile males. Variation in estradiol was limited to significant differences across months, although no pair-wise comparisons between months were significant. Adult females had higher concentrations of progesterone than did juvenile and yearling females. Among adult females, progesterone varied significantly from year-to-year as well as month-to-month, and was positively correlated with body weight. Progesterone in yearling and juvenile females varied significantly from year-to-year, was positively correlated with levels of estradiol, and was higher in animals that were live-caught as opposed to shot. All animals that were live-caught exhibited higher cortisol concentrations than those that were shot. Among shot animals, there were no sex differences in cortisol concentrations but there were for live-caught armadillos. Live-caught adult females exhibited strong positive correlations of cortisol with estradiol and progesterone. Within each sex there was significant month-to-month variation in cortisol, with concentrations the lowest in June and July.