Evaluating scat analysis methods to assess wolverine Gulo gulo diet

A feeding trial was carried out on two captive wolverines Gulo gulo to evaluate methods to assess wolverine diets through scat content. During the feeding trial, wolverines were offered known quantities of five prey species. All scats were collected and their contents analysed. We evaluated four widely used methods of quantifying dietary composition: dry weight, index of relative contribution, frequency of occurrence, and percentage of occurrence. Based on the outcome of this evaluation, percentage of occurrence was found to be the most appropriate method for wolverine diet studies given the extreme variation in prey items (e.g. prey type and age) and undigested items (e.g. hide and bones) in the wolverine's diet. Dry weight may provide additional information on the amount of biomass consumed, which is biologically more meaningful than just the composition assessment derived from using the percentage of occurrence.