Abstract

Hyperphagia is a critical part of the yearly cycle of bears when they gain fat reserves before entering hibernation. We used heart rate as a proxy to compare the metabolic rate between the Asian black bear (Ursus thibetanus) in Japan and the Eurasian brown bear (Ursus arctos) in Sweden from summer into hibernation. In the hyperphagic period, black bears feed on fat- and carbohydrate-rich hard masts whereas brown bears feed on sugar-rich berries. Availability of hard masts has quantitative and spatial annual fluctuations, which might require increased activity and result in intraspecific stress. Using generalized additive mixed models we analysed the differences in heart rate between the two species. Black bears had decreased heart rates during summer but had doubled heart rate values throughout the hyperphagic period compared to brown bears. This letter illustrates the different physiological consequences of seasonal differences in food availability in two species of the same genus dealing with the same phenological challenge.

Keywords

hyperphagia; heart rate; Asian black bear; brown bear; Ursus

Published in

Biology Letters
2019, Volume: 15, number: 1, article number: 20180681
Publisher: ROYAL SOC

SLU Authors

• Arnemo, Jon

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    
  • Inland Norway University of Applied Sciences

UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1098/rsbl.2018.0681

Permanent link to this page (URI)

https://res.slu.se/id/publ/98385