The black-footed ferret (Mustela nigripes) was driven to near extinction due to habitat loss and an introduced disease, sylvatic plague (Yersinia pestis). After 35 years of breeding in ex situ facilities, the black-footed ferret has been experiencing infertility with seminal traits declining in males and only about a third of breeding-aged females are whelping. Our goal was to use hair cortisol analysis to determine if the ex situ population was experiencing chronic stress that was affecting reproduction by comparing captive ferrets to wild individuals. Our specific objectives were to (i) compare hair cortisol concentrations (HCCs) between age classes (juveniles versus adults), (ii) compare the HCCs of in situ and across different ex situ facilities and (iii) determine the relationship between HCCs and reproductive success. Overall, wild juveniles had higher HCC than wild adults. Our generalized linear mixed model determined that the parameters that best predict HCC for adults were the interactions among sex, in situ versus ex situ facilities and season. During both seasons, wild females had higher HCCs compared to the ex situ females. During the breeding season, male HCCs across breeding facilities varied and males at the breeding facility with the largest ferret habitats had HCCs similar to wild males. At one breeding facility, HCC was higher in males that sired compared to those that did not sire. In conclusion, ex situ ferrets do not have higher HCC than wild individuals when controlling for season and ex situ habitat size, and ex situ males with higher HCC tended to sire. This suggests that HCC may be metabolically driven and/or that low HCC may be an indication of hypothalamus–pituitary–adrenal axis dysregulation and warrants further investigation both for laboratory validation and biological relevance.

中文翻译：

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使用毛发皮质醇分析了解影响黑足雪貂 (Mustela nigripes) 应激生理的生物学因素

黑足雪貂（Mustela nigripes）由于栖息地丧失和外来疾病——森林鼠疫（鼠疫耶尔森菌）而濒临灭绝。在异地设施中繁殖 35 年后，黑足雪貂一直在经历不育症，雄性的精液性状下降，只有大约三分之一的育龄雌性正在产仔。我们的目标是通过将圈养雪貂与野生个体进行比较，使用毛发皮质醇分析来确定异地种群是否正在经历影响繁殖的慢性压力。我们的具体目标是 (i) 比较不同年龄段（青少年与成人）之间的头发皮质醇浓度 (HCC)，(ii) 比较原位和不同异地设施之间的 HCC，以及 (iii) 确定 HCC 与生殖之间的关系成功。全面的，野生幼鱼的HCC高于野生成年鱼。我们的广义线性混合模型确定，最能预测成人 HCC 的参数是性别、原位与非原位设施和季节之间的相互作用。在这两个季节，野生雌性的 HCC 均高于异地雌性。在繁殖季节，繁殖设施中的雄性 HCC 各不相同，在拥有最大雪貂栖息地的繁殖设施中，雄性 HCC 与野生雄性相似。在一个育种设施中，与未生育的雄性相比，已生育的雄性的 HCC 更高。总之，在控制季节和异地栖息地大小时，异地雪貂的 HCC 并不高于野生个体，并且具有较高 HCC 的异地雄性倾向于父亲。