Abstract 44 – Using photographs from remote cameras to estimate bear body condition

Garth Mowat, Troy Malish, Laura Smit, Bruce McLellan

Body condition of individual large mammals is a highly labile parameter that is influenced by
the recent nutritional plane, the seasonal hormonal cycle, intrinsic traits such as age and
reproductive status, food availability and quality, 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 which makes it ideal for long-
term population monitoring. Long-term longitudinal studies are often the best way to learn
about how the vagaries of the environment affect population performance because they can
contrast short-term fitness with interesting covariates across time. In temperate environments
climate and weather interact to create good and bad periods for animals that are often
autocorrelated. Large mammals in temperate environments bet-hedge against future stress
periods by storing energy, usually as fat. We measured body condition of bears using remote
cameras and compared this data to live capture derived measures from the same study area.
We found that photograph derived measures of body condition were similar to weight per
length measures derived from bears in hand; both metrics were seasonally different from
measures of body fat. Photographs allow the comparison of body condition among individuals,
seasons, and populations through time, while also considering the variation within the sample.
The option to collect many samples should enable the examination of novel aspects of the
dynamics of population fitness of bears, and perhaps other species.