Rumen Contents and Habitat Selection of Peary Caribou in Winter, Canadian Arctic Archipelago

We obtained data on geographical variation in the rumen contents of Peary caribou (Rangifer taranduspearyi) by visual estimation of the proportionate composition of plants in 188 rumen samples obtained in March and April from five regions (eight islands). The floral composition of the samples obtained in 1974 through 1977 were highly variable among sites on some of the islands and among some of the regions. Among-year differences were slight despite highly variable snowfalls. Only a few species dominated the rumen samples from all regions but the apparent winter diets were more diverse and there was more variability among sites on Somerset and Prince of Wales islands than on the more northerly islands. Monocotyledons (predominantly Luzula spp.) and mosses each comprised 13 to 58% and together 33 to 97% (.X 70%) of the rumen contents of caribou in the five regions. They and lichens (2 to 15%) were the only plant groups common to the samples from all regions. High proportions of mosses (34 to 58%) characterized the rumen samples from caribou on Bathurst, Melville, and Eglinton/Prince Patrick islands. Mosses comprised > 50% of the rumen contents of caribou sampled on Bathurst and Melville islands in March 1974 when foraging was extremely difficult and malnutrition widespread.