Quantifying energetic costs and defining energy landscapes experienced by grizzly bears

Journal of Experimental Biology
By: , and 



Animal movements are major determinants of energy expenditure and ultimately the cost–benefit of landscape use. Thus, we sought to understand those costs and how grizzly bears (Ursus arctos) move in mountainous landscapes. We trained captive grizzly bears to walk on a horizontal treadmill and up and down 10% and 20% slopes. The cost of moving upslope increased linearly with speed and slope angle, and this was more costly than moving horizontally. The cost of downslope travel at slower speeds was greater than the cost of traveling horizontally but appeared to decrease at higher speeds. The most efficient walking speed that minimized cost per unit distance was 1.19±0.11 m s−1. However, grizzly bears fitted with GPS collars in the Greater Yellowstone Ecosystem moved at an average velocity of 0.61±0.28 m s−1 and preferred to travel on near-horizontal slopes at twice their occurrence. When traveling uphill or downhill, grizzly bears chose paths across all slopes that were ∼54% less steep and costly than the maximum available slope. The net costs (J kg−1 m−1) of moving horizontally and uphill were the same for grizzly bears, humans and digitigrade carnivores, but those costs were 46% higher than movement costs for ungulates. These movement costs and characteristics of landscape use determined using captive and wild grizzly bears were used to understand the strategies that grizzly bears use for preying on large ungulates and the similarities in travel between people and grizzly bears that might affect the risk of encountering each other on shared landscapes.

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Publication type Article
Publication Subtype Journal Article
Title Quantifying energetic costs and defining energy landscapes experienced by grizzly bears
Series title Journal of Experimental Biology
DOI 10.1242/jeb.241083
Volume 224
Issue 6
Year Published 2021
Language English
Publisher The Company of Biologists
Contributing office(s) Northern Rocky Mountain Science Center
Description jeb241083, 9 p.
Country United States
State Wyoming
Other Geospatial Greater Yellowstone Ecosystem
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