Abstract 126 – Validation of a hair-hormone tool kit for long-term monitoring of grizzly bears

Abbey Wilson, Sarah A. Michaud, Jun Han, Gordon Stenhouse, Kristenn
Magnusson, Karen Graham, Darío Fernández-Bellon

Population surveys using non-invasive grid-based DNA hair-snag sampling are a common tool
for managers to determine density, distribution, and sex ratios of bear populations. Measuring
hormones in hair samples may complement this approach by providing biomarkers indicative of
physiological state that cannot be addressed by genetic methods alone. This study aimed to
determine if an established targeted hormone profile measured in hair samples collected from
live captured grizzly bears (Ursus arctos) in Alberta, Canada can assist in population monitoring
and support management decisions. We hypothesized that the concentration of hormones can
be used to determine demographic parameters for grizzly bear populations, including age-class
ratios and rates of pregnancy and lactation. Approximately 25mg of hair (equivalent to about
80 guard hairs) was washed with methanol, homogenized, and extracted for liquid
chromatography-mass spectrometry analyses. We detected and quantified 15 hormones with
high precision and accuracy that were classified by biosynthesis pathway: progestogens,
mineralocorticoids, glucocorticoids, androgens, estrogens, and thyroid hormones. We
compared individual hormone concentrations and individual hormone ratios to identify
biomarkers of demographic parameters. We further calculated biosynthesis pathway group
means and group ratios to create a metric that represented the entire profile. Preliminary
analysis revealed that multiple hormones, hormone ratios and group ratios may be indicators of
age class. These results aligned with previous research completed on captive bears, where
reproductive and stress hormones were identified as predictors of age class. Androgens and
mineralocorticoids were found to be related to pregnancy and lactation, respectively. By
applying this metabolomic approach to hair samples collected from captured grizzly bears, we
demonstrate the potential use of this method in non-invasive monitoring of grizzly bear
populations.