Analysis of error from cementum-annuli age estimates of known-age Pennsylvania black bears

Wendi A. Sarshyne, Duane R Diefenbach, Gary L. Alt, Gary M. Matson

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27 Citations (Scopus)

Abstract

Cementum-annuli counts are considered the most accurate indicators of age for black bears (Ursus americanus), but tests of the technique have lacked large sample sizes of known-age teeth, and sources of error are not well documented. We estimated ages from cementum-annuli counts of 671 teeth from 521 Pennsylvania black bears and compared the estimated ages to their known age. We evaluated teeth aged during 1983-91 with aging criteria different from the criteria used during 1992-96, but we found no differences (M: P = 0.125; F: P = 0.748). Overall, 8.1% of the known-age teeth were aged incorrectly, and we found no differences in error distributions between sexes (P = 0.126). For both sexes, percent error increased as age class increased (Ps≤0.010). The number of incorrectly aged teeth was greater than expected (Ps ≤ 0.104) in black bears captured during September-November (M = 11%, n = 198; F = 13%, n = 181) than during March-May (M = 3%, n = 76; F = 4%, n = 49) and June-August (M = 3%, n = 120; F = 2%, n = 45). Of 51 incorrectly aged teeth we reevaluated, 19 (37%) were aged incorrectly because of irregular tooth characteristics to which standardized aging criteria could not be applied accurately. Thirteen (25%) probably would have been aged correctly via aging criteria revised in 1992, 13 (25%) had no discernible reason for being incorrectly aged and may have been mislabeled, 5 (10%) were broken during extraction, and 1 (2%) was aged incorrectly by the tooth reader even though the annuli were normal and distinct. We concluded that counting cementum annuli is a valid technique for aging Pennsylvania black bears.

Original languageEnglish (US)
Pages (from-to)1281-1291
Number of pages11
JournalJournal of Wildlife Management
Volume62
Issue number4
StatePublished - Oct 1 1998

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tooth
teeth
Ursus americanus
analysis
gender
age class
age structure
methodology
testing

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Nature and Landscape Conservation

Cite this

Sarshyne, W. A., Diefenbach, D. R., Alt, G. L., & Matson, G. M. (1998). Analysis of error from cementum-annuli age estimates of known-age Pennsylvania black bears. Journal of Wildlife Management, 62(4), 1281-1291.
Sarshyne, Wendi A. ; Diefenbach, Duane R ; Alt, Gary L. ; Matson, Gary M. / Analysis of error from cementum-annuli age estimates of known-age Pennsylvania black bears. In: Journal of Wildlife Management. 1998 ; Vol. 62, No. 4. pp. 1281-1291.
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abstract = "Cementum-annuli counts are considered the most accurate indicators of age for black bears (Ursus americanus), but tests of the technique have lacked large sample sizes of known-age teeth, and sources of error are not well documented. We estimated ages from cementum-annuli counts of 671 teeth from 521 Pennsylvania black bears and compared the estimated ages to their known age. We evaluated teeth aged during 1983-91 with aging criteria different from the criteria used during 1992-96, but we found no differences (M: P = 0.125; F: P = 0.748). Overall, 8.1{\%} of the known-age teeth were aged incorrectly, and we found no differences in error distributions between sexes (P = 0.126). For both sexes, percent error increased as age class increased (Ps≤0.010). The number of incorrectly aged teeth was greater than expected (Ps ≤ 0.104) in black bears captured during September-November (M = 11{\%}, n = 198; F = 13{\%}, n = 181) than during March-May (M = 3{\%}, n = 76; F = 4{\%}, n = 49) and June-August (M = 3{\%}, n = 120; F = 2{\%}, n = 45). Of 51 incorrectly aged teeth we reevaluated, 19 (37{\%}) were aged incorrectly because of irregular tooth characteristics to which standardized aging criteria could not be applied accurately. Thirteen (25{\%}) probably would have been aged correctly via aging criteria revised in 1992, 13 (25{\%}) had no discernible reason for being incorrectly aged and may have been mislabeled, 5 (10{\%}) were broken during extraction, and 1 (2{\%}) was aged incorrectly by the tooth reader even though the annuli were normal and distinct. We concluded that counting cementum annuli is a valid technique for aging Pennsylvania black bears.",
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Sarshyne, WA, Diefenbach, DR, Alt, GL & Matson, GM 1998, 'Analysis of error from cementum-annuli age estimates of known-age Pennsylvania black bears', Journal of Wildlife Management, vol. 62, no. 4, pp. 1281-1291.

Analysis of error from cementum-annuli age estimates of known-age Pennsylvania black bears. / Sarshyne, Wendi A.; Diefenbach, Duane R; Alt, Gary L.; Matson, Gary M.

In: Journal of Wildlife Management, Vol. 62, No. 4, 01.10.1998, p. 1281-1291.

Research output: Contribution to journalArticle

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