Responses of Brown Bears to Human Activities at O’Malley River, Kodiak Island, Alaska

We classified levels of direct response of brown bears (Ursus arctos middendorffi) to aircraft, watercraft, and groups of people on the O’Malley River area of Kodiak Island, Alaska. General public use occurred on the area in 1991 and 1993, whereas structured bear viewing programs used the area in 1992 and 1994. Brown bears displayed high […]

Brown Bear Diurnal Activity and Human Use: A Comparison of Two Salmon Streams

Brown bear (Ursus arctos) activity along salmon (Oncorhynchus spp.) streams has frequently been characterized as crepuscular. Suggested explanations include: responses to daily changes in salmon abundance, responses to daily cycles of light and temperature, natural feeding schedules, and avoidance of people. We investigated the last hypothesis by comparing bear activity at 2 adjacent streams in […]

Temporal and Spatial Activity Patterns among Coastal Bear Populations

We examined temporal and spatial activity of grizzly bears (Ursus arctos) and black bears (Ursus americanus) in 3 areas of coastal British Columbia to investigate (1) variation within and between the 2 species, and (2) the influence of human activity on bear activity. Bear detections at remote camera sites were used to measure activity. The […]

Field Use of Capsicum Spray as a Bear Deterrent

We analyzed 66 cases of field use of capsicum sprays between 1984-94. In 94% (15 of 16) of the close-range encounters with aggressive brown (grizzly) bears (Ursus arctos), the spray appeared to stop the behavior that the bear was displaying immediately prior to being sprayed. In 6 cases, the bear continued to act aggressively; in […]

A Comparative Bear Model for Immobility-Induced Osteopenia

The National Institutes of Health (NIH) and the National Aeronautics and Space Administration (NASA) are seeking solutions to the human problem of osteopenia, or immobility-induced bone loss. Bears, during winter dormancy, appear uniquely exempted from the debilitating effects of immobility osteopenia. NIH and ESA, Inc. are creating a large database of metabolic information on human […]

Bears as Induced Ovulators: A Preliminary Study

We visually verified corpora lutea and measured serum progesterone concentrations during the estrous cycle in 8 semi-captive black bears (Ursus americanus) in South Dakota. Our data suggested that black bears ovulate after they mate, indicating that black bears are induced ovulators. These preliminary findings may aid scientists in their efforts to save endangered bear species […]

Reproductive Characteristics of the Male Grizzly Bear in the Continental United States

We evaluated testicular growth, seminiferous tubule development, and age of sexual maturity in 20 male grizzly bears (Ursus arctos horribilis) killed in Montana and Wyoming between 1978 and 1992. Seminiferous tubule diameter did not differ among the regions of each testicle sampled. Testicular mass was related linearly to age. Seminiferous tubule diameter was related non-linearly […]

Diet and Morphology of Extant and Recently Extinct Northern Bears

I examined the relationship of diets to skull morphology of extant northern bears and used this information to speculate on diets of the recently extinct cave (Ursus spelaeus) and short-faced (Arctodus simus) bears. Analyses relied upon published skull measurements and food habits of Asiatic (U. thibetanus) and American (U. americanus) black bears, polar bears (U. […]

Physiology of Hibernation in Bears

Hibernation in the Ursidae has been extensively researched over the past 30 years. This paper reviews findings of that research in the areas of general physiology and energetics; protein, fat, and bone metabolism; metabolic endocrinology; reproductive physiology and lactation; serum chemistry and hematology; and the urea:creatinine ratio. Bears in hibernation exhibit several characteristics distinct from […]