Evolutionary Ecology

, Volume 31, Issue 4, pp 571–584 | Cite as

Environmental, not individual, factors drive markers of biological aging in black bears

  • Rebecca KirbyEmail author
  • Mathew W. Alldredge
  • Jonathan N. Pauli
Original Paper


Aging negatively affects individual survival and reproduction; consequently, characterizing the factors behind aging can enhance our understanding of fitness in wild populations. The drivers of biological age are diverse, but often related to factors like chronological age or sex of the individual. Recently, however, environmental factors have been shown to strongly influence biological age. To explore the relative importance of these influences on biological aging in a free-ranging and long-lived vertebrate, we quantified the length of telomeres—highly conserved DNA sequences that cap the ends of eukaryotic chromosomes and a useful molecular marker of biological age—for black bears sampled throughout Colorado, and measured a variety of environmental variables (habitat productivity, human development, latitude, elevation) and individual characteristics (age, sex, body size, genetic relatedness). Our extensive sampling of bears (n = 245) revealed no relationships between telomere length and any individual characteristics. Instead, we found a broad-scale latitudinal pattern in telomere length, with bears in northern Colorado possessing shorter telomeres. Our results suggest that environmental characteristics overwhelm individual ones in determining biological aging for this large carnivore.


Biological aging Landscape variation Stress Telomere Ursus americanus 



Funding for this project was provided by Colorado Parks and Wildlife and an American Society of Mammalogists Grant-in-Aid. We thank all of the Colorado wildlife managers and bear hunters for generously collecting and providing samples. We are also grateful to Cristina Vaughan, Garrett Johnson, and Samantha Paddock for laboratory help.


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Copyright information

© Springer International Publishing Switzerland 2017

Authors and Affiliations

  1. 1.Department of Forest and Wildlife EcologyUniversity of Wisconsin – MadisonMadisonUSA
  2. 2.Mammals Research SectionColorado Parks and WildlifeFort CollinsUSA

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