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- Title
Body condition and growth dynamics of American black bears in northern Canada.
- Authors
Bartareau, Tad M.; Latter, Nicholas C.; Cluff, H. Dean; Leone, Erin H.
- Abstract
We examined body condition and growth dynamics of wild American black bears (Ursus americanus) inhabiting interior regions of northern Canada, 1998-2009. Differences in body condition were unrelated to gender, but we found significant effects of age and season as well as an interaction between the two. We found a trend toward improved body condition in older bears that increased during summer and peaked in fall, with lowest values observed in spring. The yon Bertalanffy growth function showed that males reached asymptotic body length 9.3% longer, and mass 29.3% heavier, than females. Our growth models indicated an association between sexual growth divergence and the onset of reproduction in females, together with more rapid and prolonged male growth. We suggest that sexual size dimorphism develops in part from constraints on female growth from high energetic costs of reproduction. In contrast, males experience no comparable energetic trade-off after reaching sexual maturity and apparently allocate available energetic resources to growth of larger body size, which benefits more competitive males in terms of increased reproductive success.
- Subjects
NORTHERN Canada; BLACK bear behavior; DEVELOPMENTAL biology; BLACK bear; COMPETITION (Biology); BODY size; GENDER differences (Psychology); REPRODUCTION
- Publication
Ursus, 2012, Vol 23, Issue 1, p12
- ISSN
1537-6176
- Publication type
Article
- DOI
10.2192/URSUS-D-11-00003.1