Stress-induced adrenal changes and their relation to reproductive failure in captive nine-banded armadillos (Dasypus novemcinctus)

Histological features of adrenal glands from captive and unstressed free-ranging nine-banded armadillos were compared to determine if undefined stress factors associated with captivity were capable of causing changes in adrenal morphology. Animals in captivity less than 3 mo showed histological features identical to unstressed free-ranging animals. Animals in captivity 6 mo or longer, however, showed adrenal changes like those previously described in other mammals exposed to various types of stress, except that there was no accompanying increase in adrenal weight. Similar adrenal changes were found in free-ranging animals exposed to extremely harsh winter weather. Females from both the chronic captive population and this stressed free-ranging population were seen to suffer reproductive failure. Reproductive function in males was not affected. There was no detectable sex difference in gross or histological adrenal changes; however, previous reports indicate there is a sex difference in the secretory product from the adrenals of captive nine-banded armadillos. A possible relationship between reproductive failure in the female and the sex difference in adrenal secretory products is discussed.