Identifying guard hairs of Rocky Mountain carnivores

Abstract

Increasing use of hair to survey carnivore distribution and identify carnivore scavengers or predators at prey kill sites requires methods for cost-efficient identification of predator hair. Although DNA analysis can be used to identify species-specific hairs, reliability depends on quality of hair, collection method, and environmental conditions, with cost that can exceed CAD$35/hair. In contrast, features of guard hairs including hair length, banding, and macro-and microscopic characteristics of the hair cuticle and medulla offer an alternative approach when hair quality is poor or funding is limited. Past keys focused on hair identification of prey species (e.g., ungulates, rodents) in predator scat analysis or were general because they contained all mammals in a region, thus complicating the focus on dichotomous keys for large carnivores. We used Random Forest (RF) to identify features that best classified known-origin guard hairs (n ¼ 175) and used these characteristics to develop a dichotomous key for hair identification of the 7 major, large carnivore species common to the Rocky Mountains of Alberta, Canada. We found relative medulla width and pattern, cuticle-scale characteristics, and hair length provided the greatest probability of correctly distinguishing among hairs of different carnivore species. Correct classification of within sample hairs with RF based on Area Under the Curve (AUC) averaged 0.95 AE 0.10, with coyote (Canis latrans) hairs having the lowest classification accuracy. Blind trials classifying 21 hairs using the dichotomous key yielded correct classifications of 88% AE 7% to the family level and 60% AE 10% to the species level. Hair preparation and identification by a trained technician was estimated at 30 AE 15 min/hair and CAD$8/hair. Our carnivore hair key provides an alternative approach to DNA hair analysis when either funds are limited, or hair samples are not of sufficient quality to be successfully sequenced. Ó

The Hair Scale Identification Guide to Terrestrial Mammalian Carnivores of Canada

“…The more recent key by Debelica and Thies (2009) is internet accessible but may not be easily located. A variety of hair keys have been published in scientific journals, such as Normandeau et al (2018), but may not be accessible to conservation agency staff and enforcement officers that lack access to scientific journals. In addition, all currently published guides have geographic specificity.…”

“…In addition, all currently published guides have geographic specificity. For example, there are guides specific to Ontario (Adorjan and Kolenosky 1969), Wyoming (Moore et al 1974), Texas (Debelica Thies 2009), and the Rocky Mountains (Normandeau et al 2018). This new guide by Kestler (2022) adds an accessible reference that improves upon existing publications and covers a large geographic range.…”