approved: The causes of natural mortality and disease in free ranging black bears, Ursus americanus, in California, Oregon, and Washington are poorly known. Life history components, such as scavenging and overlapping habitat with many species of carnivores, potentially expose bears to a wide range of infectious disease agents. To date, no disease has been identified that appears to greatly infl...

Trade-offs between locomotory costs and foraging gains are key elements in determining constraints on predator-prey interactions. One intriguing example involves polar bears pursuing snow geese on land. As climate change forces polar bears to spend more time ashore, they may need to expend more energy to obtain land-based food. Given that polar bears are inefficient at terrestrial locomotion, a...

Wildlife biologists often use grid-based designs to sample animals and generate abundance estimates. Although sampling in grids is theoretically sound, in application, the method can be logistically difficult and expensive when sampling elusive species inhabiting extensive areas. These factors make it challenging to sample animals and meet the statistical assumption of all individuals having an...

Subpopulation growth rates and the probability of decline at current harvest levels were determined for 13 subpopulations of polar bears (Ursus maritimus) that are within or shared with Canada based on mark-recapture estimates of population numbers and vital rates, and harvest statistics using population viability analyses (PVA). Aboriginal traditional ecological knowledge (TEK) on subpopulatio...

While there has been recent concern about the effects of sound on marine mammals, including polar bears, there are no data available measuring the hearing of any bear. The in-air hearing of three polar bears was measured using evoked auditory potentials obtained while tone pips were played to three individually anaesthetized bears at the Kolmården Djurpark. Hearing was tested in half-octave ste...

Locomotion of plantigrade generalists has been relatively little studied compared with more specialised postures even though plantigrady is ancestral among quadrupeds. Bears (Ursidae) are a representative family for plantigrade carnivorans, they have the majority of the morphological characteristics identified for plantigrade species, and they have the full range of generalist behaviours. This ...

Quantitative fatty acid signature analysis has become an important method of diet estimation in ecology, especially marine ecology. Controlled feeding trials to validate the method and estimate the calibration coefficients necessary to account for differential metabolism of individual fatty acids have been conducted with several species from diverse taxa. However, research into potential refine...

Ware JV, Nelson OL, Robbins CT, Jansen HT. Temporal organization of activity in the brown bear (Ursus arctos): roles of circadian rhythms, light, and food entrainment. Am J Physiol Regul Integr Comp Physiol 303: R890–R902, 2012. First published September 12, 2012; doi:10.1152/ajpregu.00313.2012.—Seasonal cycles of reproduction, migration, and hibernation are often synchronized to changes in day...

The current study deals with the anterior premolar pattern in the cave and brown bear lineage, and its signifi cance in species determination. The occurrence of single premolars and its combinations in skulls and mandibles is recorded for various chronological and regional groups. Both lineages stay more “conservative” in the upper than in the lower dentition, but show contrasting reduction ten...