Environmental, not individual, factors drive markers of biological aging in black bears
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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.
KeywordsBiological 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.
- Alldredge MW (2008) Cougar demographics and human interactions along the urban-exurban Front Range of Colorado. Wildlife Research Report, Mammals Research, Colorado Parks and WildlifeGoogle Scholar
- Baldwin RA (2008) Population demographics, habitat utilization, critical habitats, and condition of black bears in Rocky Mountain National Park. Dissertation, New Mexico State UniversityGoogle Scholar
- Baldwin RA, Bender LC (2009) Survival and productivity of a low-density black bear population in Rocky Mountain National Park, Colorado. Human-Wildl Confl 3:271–281Google Scholar
- Costello C, Jones D, Inman R et al (2003) Relationship of variable mast production to American black bear reproductive parameters in New Mexico. Ursus 14:1–16Google Scholar
- Noyce K, Garshelis D (1994) Body size and blood characteristics as indicators of condition and reproductive performance in black bears. Int Conf Bear Res Manag 9:481–496Google Scholar
- Pritchard JK, Stephens M, Donnelly P (2000) Inference of population structure using multi-locus genotype data. Genetics 255:945–959Google Scholar
- Rogers L (1987) Effects of food supply and kinship on social behavior, movements, and population growth of black bears in northeastern Minnesota. Wildl Monogr 97:3–72Google Scholar
- Schwartz CC, Keating KA, Reynolds HV et al (2003) Reproductive maturation and senescence in the female brown bear. Ursus 14:109–119Google Scholar