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Incisor wear and age in Yellowstone bison

January 1, 2005

Biologists commonly use tooth eruption and wear patterns or cementum annuli techniques to estimate age of ungulates. However, in some situations the accuracy or sampling procedures of either approach are undesirable. We investigated the progression of several quantitative measures of wear with age, using permanent first incisors from Yellowstone bison (Bison bison), and tested for differences between sexes and herds. We further investigated the relationship of wear and age to explore an age-estimation method. Labial-lingual width (LLW) correlated best with assigned age (r2=0.66, males; r2=0.76 females). Labial-lingual width differed between sexes, with females showing ∼0.2 mm more wear than males. Additionally, differences in rate of wear existed between bison of the northern and central Yellowstone herds (1.2 and 0.9 mm/year, respectively). We developed a regression formula to test the power of LLW as an estimator of Yellowstone bison age. Our method provided estimated ages within 1 year of the assigned age 73% and 82% of the time for female and male bison, respectively.

Publication Year 2005
Title Incisor wear and age in Yellowstone bison
DOI 10.2193/0091-7648(2005)33[669:IWAAIY]2.0.CO;2
Authors D.A. Christianson, P.J.P. Gogan, K.M. Podruzny, E.M. Olexa
Publication Type Article
Publication Subtype Journal Article
Series Title Wildlife Society Bulletin
Index ID 70029249
Record Source USGS Publications Warehouse
USGS Organization Northern Rocky Mountain Science Center