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Testing the use of remote cameras to index body condition in brown and black bears
Garth Mowat, Troy Malish, Laura Smit, Kelly Forrester, Jonathan Van Elslander, Bruce McLellan, Clayton T. Lamb
Ursus 2026 (37e3), 1-10, (13 February 2026). https://doi.org/10.2192/URSUS-D-25-00006
KEYWORDS: American black bear, body fat, brown bear, fitness, nutrition, population monitoring, remote cameras, Ursus americanus, Ursus arctos
Body condition of large mammals is a highly labile parameter that is influenced by recent nutrition, the seasonal hormonal cycle, intrinsic traits such as age and reproductive status, and extrinsic stress factors such as predation risk, social dominance, or human disturbance. Body condition thus integrates many population- and individual-level factors into a single measure of performance, making it useful in long-term population monitoring. We measured body condition of brown (grizzly) and American black bears (Ursus arctos and U. americanus) using remote cameras during 2016–2024 in southwestern Canada, and compared these data with measures derived from live-captured brown bears from the same study area. We found that on average, photograph-derived measures of body condition predicted late-summer and autumn weight gain similar to weight-per-length and body fat metrics measured from live-captured bears. The photo-derived metric predicted more modest declines in condition in spring than body fat whereas the weight-per-length metric did not indicate declines in condition through spring. We tested the repeatability of the photo measurements using untrained observers and the methods were generally repeatable but can be improved with training. Photographs are much less invasive than live capture–based condition metrics and they allow the comparison of body condition among individuals, seasons, and populations through time, while also considering the variation within the sample. Collection of many samples should enable the examination of novel aspects of the dynamics of population trend and individual performance of bears, and perhaps other species.
High-resolution techniques reveal the palaeoecology of an exceptionally large Ursus arctos from the Late Pleistocene of East Siberia
Natalya E. Prilepskaya, Paulo Duñó-Iglesias, Florent Rivals, Irena Debeljak, Gennady G. Boeskorov
Ursus 2026 (37e4), 1-22, (12 March 2026). https://doi.org/10.2192/URSUS-D-24-00017
KEYWORDS: age-at-death, brown bear, cementum and dentin increment analysis, dental microwear analysis, diet, enamel, palaeoecology, season-of-death, teeth
Cementum and dentin increment analysis and dental microwear analysis were used for the first time to study the dental remains of a giant brown bear (Ursus arctos) from the Late Pleistocene of Yakutia, Russia. Dental increment analysis showed that this bear died during the warm season (May–Sep) in the prime of its life—at the age of 15+ years. Dental microwear analysis inferred that this bear had a varied diet consisting of a wide range of plant items, varying from soft-mast during warm season to hard-mast during hyperphagia period, but with regular intake of animal protein throughout the year. Diet in the last few weeks before death was inferred as mainly herbivorous and mainly comprising soft-mast abrasive grasses. Data on vegetation and climate in the territory of Yakutia during the Late Pleistocene, and comparisons with the dietary habits of extant U. arctos from Yakutia, allowed us to narrow the period of death of the animal within the warm season. The exceptionally large size of the bear combined with its omnivorous diet may indicate favorable living conditions for brown bears in the Mammoth steppe of Yakutia.