Hamlin, Kenneth L., David F. Pac, Carolyn A. Sime, Richard M. DeSimone, and Gary L. Dusek. 2000. Evaluating the accuracy of ages obtained by two methods for Montana ungulates. Journal of Wildlife Management 64: 441-449



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Wlf 315 Wildlife Ecology I Lab

Hamlin, Kenneth L., David F. Pac, Carolyn A. Sime, Richard M. DeSimone, and Gary L.

Dusek. 2000. Evaluating the accuracy of ages obtained by two methods for

Montana ungulates. Journal of Wildlife Management 64:441-449.
We evaluated the accuracy of ages assigned by Matson's Laboratory from examination of annuli in the cementum of incisor root tips of 111 known-age Rocky Mountain elk (Cervus elaphus), 108 known-age mule deer (Odocoileus hemionus), and 74 known-age white-tailed deer (Odocoileus virginianus). Accuracy rates were 97.3% for elk through age 14, 92.6% for mule deer through age 14, and 85.1 % for white-tailed deer through 9 years old. There was no

pattern of error relative to age. Accuracy for a sample of known-age mandibles aged by eruption-wear criteria was lower for mule deer (62.3%) and white-tailed deer (42.9%) than accuracy of ages in subsequent samples determined from cementum analysis of incisors. Accuracy of ages of elk assigned at check stations by eruption-wear criteria was >50% only for age classes 3 and 4, and averaged 16% for elk >5 years old. Ages assigned by eruption-wear criteria were not reliable for comparing physical measurements and population parameters by age among populations. Further, errors in ages assigned by eruption-wear in one age class were not equally balanced by offsetting errors in assigned ages among other age classes. This resulted in inaccurate estimates of population age structure when ages were assigned by eruption-wear criteria. The accuracy provided by the cementum annuli method is necessary to determine whether various physical and populationparameters change significantly with age of the animal.


Deelen, Timothy R. Van, Karmen M. Hollis, Chris Anchor, and Dwayne R. Etter. 2000.

Sex affects age determination and wear of molariform teeth in white-tailed deer.

Journal of Wildlife Management 64:1076-1083.
Field estimation of the ages of adult white-tailed deer (Odocoileus virginianus) and other ungulates often requires assessment of the degree to which molariform teeth wear over time. This widely used technique is applied without regard to the sex of the animal being aged, but sex-based differences in ungulate life history traits such as diet, habitat use, and foraging behavior may affect tooth wear patterns differently for males and females. We examined sex-specific differences in tooth wear and morphology for adult (>1.5 yrs old) deer collected in northeastern Illinois (1993-97). We randomly sampled 100 mandibles from adult deer (50

M:50 F), stratified by cementum annuli year classes 2-7, to obtain 29 measurements of width, height, length, and visible dentine on premolars 2 and 4, and molars 1 and 3. Principle components (PC) analysis indicated that 61% of the overall sample variation was explained by PCs 1-3. Analysis using MANOVAs suggested effects (P < 0.05) due to sex and age when component scores from PCs 1-3 were used as dependent variables. Teeth from male deer were wider and tended to show more visible dentine (wear) on occlusal surfaces. Age class estimates of 10 experienced observers indicated substantial observer variation in the wear-replacement aging technique. A repeated measures ANOVA indicated that sex effects in the wear-replacement aging technique become significant when the effects of observer variation are controlled. Stage-based projection models based on sex-specific age ratios of white-tailed deer had different growth rates and adult sex ratios when corrected for a sex bias in wear-replacement aging, indicating that common population analysis methods are sensitive to a sex-based bias. Managers should use caution when comparing adult age ratios derived from tooth wear because of potential sex biases in tooth wear patterns.


Gee, Kenneth L., John H. Holman, M. Keith Causey, Ashley N. Rossi, and James B.

Armstrong. 2002. Aging white-tailed deer by tooth replacement and wear: a

critical evaluation of a time-honored technique. Wildlife Society Bulletin. 30:387-

393.
The ability to accurately assign adult white-tailed deer (Odocoileus virginianus) to specific year age-classes is important in making management decisions and interpreting management and research results. We attempted to validate or modify the widely used and accepted technique of tooth replacement and wear for aging adult white-tailed deer (Severinghaus 1949) on a study area in south-central Oklahoma. A sample of 106 jawbones or dental casts from known-age deer was accumulated for study. Tooth replacement and wear characteristics allowed us to confidently place deer into 3 basic age-classes only (i.e. fawn, yearling, and adult). Attempst to assign adult deer to specific year-classes with this tradition technique were very inaccurate. Thirty-four white-tailed deer biologists from various southeastern states who attempted to correctly age our collection of know-age jawbones and dental casts using the Severinghaus (1949) method or modifications thereof also failed 60% of the time for deer > 2 years old. Measuring and comparing heights of buccal and lingual crests of molars from jawbones of known-aged deer did not distinguish between years. Our findings do not support the efficacy of using tooth wear to accurately age deer beyond the general categories of fawn, yearling, and adult.
Gipson, Philip S., Warren B. Ballard, Ronald M. Nowak, and L. David Mech. 2000.

Accuracy and precision of estimating age of gray wolves by tooth wear.

Journal of Wildlife Management 64:752-758.
We evaluated the accuracy and precision of tooth wear for aging gray wolves (Canis lupus) from Alaska, Minnesota, and Ontario based on 47 known-age or known-minimum-age skulls. Estimates of age using tooth wear and a commercial cementum annuli-aging service were useful for wolves up to 14 years old. The precision of estimates from cementum annuli was greater than estimates from tooth wear, but tooth wear estimates are more applicable in the field. We tended to overestimate age by 1-2 years and occasionally by 3 or 4 years. The commercial service aged young wolves with cementum annuli to within +/-1 year of actual age, but under estimated ages of wolves ≥9 years old by 1-3 years. No differences were detected in tooth wear patterns for wild wolves from Alaska, Minnesota, and Ontario, nor between captive and wild wolves. Tooth wear was not appropriate for aging wolves with an underbite that prevented normal wear or severely broken and missing teeth.
Landon, David B., Carol A. Waite, Rolf O. Peterson, and L. David Mech. 1998.

Evaluation of age determination techniques for gray wolves. Journal of Wildlife

Management 62:674-682.
We evaluated tooth wear, cranial suture fusion, closure of the canine pulp cavity, and cementum annuli as methods of age determination for known-and unknown-age gray wolves (Canis lupus) from Alaska, Minnesota, Ontario, and Isle Royale, Michigan. We developed age classes for cranial suture closure and tooth wear. We used measurement data obtained from known-age captive and wild wolves to generate a regression equation to predict age based on the degree of closure of the canine pulp cavity. Cementum annuli were studied in known-and unknown-age animals, and calcified, unstained thin sections were found to provide clear

annulus patterns under polarized transmitted light. Annuli counts varied among observers, partly because of variation in the pattern of annuli in different regions of the cementum. This variation emphasizes the need for standardized models of cementum analysis. Cranial suture fusion is of limited utility in age determination, while tooth wear can be used to estimate age of adult wolves within 4 years. Wolves <7 years old could be aged to within 1-3 years with the regression equation for closure of the canine pulp cavity. Although inaccuracy remains a problem, cementum-annulus counts were the most promising means of estimating age for gray wolves.

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