Reproductive health from hair: Validation and utility of hair progesterone analysis in the Asian black bear, Ursus thibetanus

Hair hormone analysis has received increasing attention in the fields of wildlife management and conservation over the last decade. However, few studies focused on sex steroid hormones, even though hair sex steroid hormone analysis has the potential to provide information on an individual's reproductive health, leading to a better understanding of animal reproductive biology and the assessment of individual and population health. Here, we tested the assay validation and examined whether hair progesterone concentration (HPC) differs between different sexes and age classes in the Asian black bear, Ursus thibetanus. We also investigated the effects of reproductive condition, age, and body condition index (BCI) on HPC to determine the utility of hair progesterone analysis in bears. The assay validation was reported in our study. We found a significantly higher HPC in adult females than in juvenile females and juvenile and adult males. In addition, we found no effects of age and BCI on HPC but a significant positive effect of reproductive condition, as the HPC in breeding adult females was significantly higher than in nonbreeding adult females. These results suggest that hair progesterone analysis has the potential to evaluate the reproductive condition of Asian black bears.