Print PageEnergetic balance is a central driver of individual survival and population change, yet estimating energetic costs in free and wide ranging animals presents a significant challenge. Accelerometers deployed on animal collars presents a promising method of meeting this challenge and opens new avenues for exploring energetics in natural settings. Activity patterns, estimated via body acceleration, were measured over thirteen months for 131 woodland caribou (Rangifer tarandus caribou) ranging across 450,000 km2 in northern Ontario. Activity was modeled against individual displacement, vegetation abundance (NDVI), snow depth, and temperature.
Results/Conclusions
The best model included all parameters and explained over half of the variation in the data. Individual displacement had the strongest relationship with activity levels, suggesting that broad differences in energetic demands are primarily explained by differences in movement strategies. After accounting for displacement, activity was highest at intermediate levels of vegetation abundance, presumably due to foraging behaviour. Snow depth, associated with digging for winter forage, moderately increased activity. Activity levels increased significantly at the coldest winter temperatures, suggesting behavioural thermoregulation and a clear energetic cost of thermoregulation. These results illustrate the landscape characteristics that increase energetic demands for caribou and confirm the great potential for the use of accelerometry in studies of animal energetics.
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