No abstract

Grizzly bears have recently become more common on the Arctic Islands in the Inuvialuit Settlement Region, concurrently with a period of environmental change. Over the last decade, grizzly bear – polar bear hybrids have been confirmed within this region, triggering extensive discussion and speculation regarding the impact of hybridization on the parent species. Through harvests, sightings, and captures, we document an increase in the presence of grizzly bears and combine field observations of hybrids with genetic analysis and parentage analysis to identify four first-generation (F1) hybrids and four offspring of F1 hybrids and grizzly bears (backcross-to-grizzly-bear individuals). We trace these eight hybrid individuals to a single female polar bear who mated with two grizzly bears. We sampled one of her mates on the sea ice in the High Arctic and deduced the genotype of the other from his five offspring. The two male grizzly bears are sires of both the F1 generation and the backcross-to-grizzly-bear generation. So what initially appeared to be a sudden spate of hybridization in the western Canadian Arctic originated with the unusual mating between three non-hybrid parents. The breakdown of species barriers may start with atypical mating preferences of select individuals; however, the story we present can be traced to a single female polar bear who, along with three of her known F1 offspring, has been killed.

Gray wolves (Canis lupus L., 1758) are mobile opportunistic predators that can be infected by a wide range of parasites, with many acquired via predator–prey relationships. Historically, many of these parasites were identified only to genus or family, but genetic tools now enable identification of parasite fauna to species and beyond. We examined 191 intestines from wolves harvested for other purposes from regions in the Northwest Territories, British Columbia, Saskatchewan, and Manitoba. Adult helminths were collected from intestinal contents for morphological and molecular identification, and for a subset of wolves, fecal samples were also analyzed to detect helminth eggs and protozoan (oo)cysts. Using both detection methods, we found that 83% of 191 intestines contained one or more parasite species, including cestodes (Taenia spp., Echinococcus spp., and Diphyllobothrium sp.), nematodes (Uncinaria stenocephala Railliet, 1884, Trichuris spp., Physaloptera spp., and Toxascaris leonina (von Linstow, 1902)), a trematode (Alaria sp.), and protozoa (Sarcocystis spp., Giardia sp., and Cryptosporidium spp.). Molecular characterization identified one species of Diphyllobothrium (Diphyllobothrium latum (L., 1758) Cobbold, 1858), three species of Taenia (Taenia krabbei Moniez, 1879, Taenia hydatigena Pallas, 1766, and Taenia multiceps Leske, 1786), and two Giardia duodenalis (Davaine) Deschiens, 1921 assemblages (B and C). These results demonstrate the diverse diet of wolves and illustrate the possibility of parasite spillover among wildlife, domestic animals, and people.

No abstract

Polar bears (Ursus maritimus) display fidelity to large geographic regions, and their movements are influenced by sea ice distribution. Polar bear subpopulations are moderately distinct from one another, and long-distance movements between subpopulations are rare. We describe and analyze the movements of a female polar bear tracked by satellite telemetry from spring 2009 for 798 days. This female traveled an exceptionally long distance (totaling 11 686 km) from the sea ice off the Yukon Territory, Canada (Southern Beaufort Sea subpopulation) to Wrangel Island, Russia (Chukchi Sea subpopulation). In comparison to other polar bears in this study, this bear traveled farther, moved faster, and had a much larger home range in the first year. Furthermore, the calculation of the home range size by two different methods demonstrated that the commonly used minimum convex polygon method overestimated the home range compared to the less biased Brownian bridge movement model. This female’s long-distance movement was unusual and provides additional evidence for gene flow between subpopulations. Monitoring polar bear movements is useful to track such events, which is especially important at present because sea ice loss due to climate change can affect subpopulation boundaries and influence management.