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Full-Text Articles in Life Sciences
Black Bear Population Health Monitoring In The Southeast, Kathleen Elizabeth Riese
Black Bear Population Health Monitoring In The Southeast, Kathleen Elizabeth Riese
Masters Theses
Recent growth of the American black bear (Ursus americanus) population in the southeast raises concerns about the potential spread of density-dependent diseases among bears, particularly sarcoptic mange. However, research on the health of bears in this area is limited. We analyzed samples from 169 bears in the region. We performed Knotts tests, skin scrapes, fecal floats; Canine adenovirus (CAV), canine parvovirus (CPV), canine distemper virus (CDV), and Toxoplasma gondii serology, Trypanosoma, Rickettsia rickettsii, and apicomplexan PCR, and identified ecto- and endoparasites found grossly or histologically. We found that 69% (63 of 91) had microfilaria; genetic analysis identified …
Recolonizing Carnivores: Is Cougar Predation Behaviorally Mediated By Bears?, Kristin N. Engebretsen, Jon P. Beckmann, Carl W. Lackey, Alyson M. Andreasen, Cody Schroeder, Pat Jackson, Julie K. Young
Recolonizing Carnivores: Is Cougar Predation Behaviorally Mediated By Bears?, Kristin N. Engebretsen, Jon P. Beckmann, Carl W. Lackey, Alyson M. Andreasen, Cody Schroeder, Pat Jackson, Julie K. Young
United States Department of Agriculture Wildlife Services: Staff Publications
Conservation and management efforts have resulted in population increases and range expansions for some apex predators, potentially changing trophic cascades and foraging behavior. Changes in sympatric carnivore and dominant scavenger populations provide opportunities to assess how carnivores affect one another. Cougars (Puma concolor) were the apex predator in the Great Basin of Nevada, USA, for over 80 years. Black bears (Ursus americanus) have recently recolonized the area and are known to heavily scavenge on cougar kills. To evaluate the impacts of sympatric, recolonizing bears on cougar foraging behavior in the Great Basin, we investigated kill sites of 31 cougars between …
Black Bear Use Of Forest Roads In Western Washington, Gary W. Witmer
Black Bear Use Of Forest Roads In Western Washington, Gary W. Witmer
United States Department of Agriculture Wildlife Services: Staff Publications
Radiolocations (108) of 20 black bears were used to assess use or avoidance of 3 forest road types in western Washington. Distances of bears to each type of road were compared to distances of 108 random points using t-tests. Females and males avoided 2-lane roads, while only males avoided 1-lane roads, the most common road type in the area. Females, but not males, were located closer to overgrown, spur roads than expected. This road type has substantial cover of grasses, forbs, and berry-producing shrubs along with protective tree cover. This situation may provide easy travel for females along with security …
Stress And Reproductive Hormones Reflect Inter-Specific Social And Nutritional Conditions Mediated By Resource Availability In A Bear–Salmon System, Heather M. Bryan, Chris T. Darimont, Paul C. Paquet, Katherine E. Wynne-Edwards, Judit E. G. Smits
Stress And Reproductive Hormones Reflect Inter-Specific Social And Nutritional Conditions Mediated By Resource Availability In A Bear–Salmon System, Heather M. Bryan, Chris T. Darimont, Paul C. Paquet, Katherine E. Wynne-Edwards, Judit E. G. Smits
Physiology Collection
Food availability can influence the nutritional and social dynamics within and among species. Our investigation focused on grizzly and black bears in coastal British Columbia, Canada, where recent and dramatic declines in their primary prey (salmon) raise concerns about potentially negative effects on bear physiology. We examined how salmon availability relates to stress and reproductive hormones in coastal grizzly (n = 69) and black bears (n = 68) using cortisol and testosterone. In hair samples from genotyped individuals, we quantified salmon consumption using stable isotope analysis and hormone levels by enzyme immunoassay. To estimate the salmon biomass available to each …