Estimating age of mule deer in the field: Can we move beyond broad age categories?

PLoS One. 2023 Jul 28;18(7):e0284565. doi: 10.1371/journal.pone.0284565. eCollection 2023.

Abstract

Age of individuals is an intrinsic demographic parameter used in the modeling and management of wildlife. Although analysis of cementum annuli from teeth is currently the most accurate method used to age ungulates, the age of live ungulates in the field can be estimated by examining tooth wear and tooth replacement patterns. However, there may be limitations to aging based on tooth wear as the rate of tooth wear likely varies among individuals due to factors such as age, diet, environment, and sex. Our objective was to determine the reliability of estimating age for mule deer based on tooth wear and tooth replacement patterns. We compared ages estimated by tooth wear (collected at time of capture for a statewide monitoring effort) to ages determined from cementum analysis (from teeth collected after mortalities of radio-tracked animals from the monitoring effort). Accuracy was high; ages estimated from tooth wear were within one year of cementum ages >75% of the time when aged by experienced observers. Bias in accuracy for estimates of age was low but slightly biased toward underestimation (i.e., 0.6 years on average)-especially as cementum age increased. Our results indicate that aging mule deer using patterns in tooth wear can be reliable if observers estimating age have experience using this method.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Deer*
  • Equidae
  • Reproducibility of Results
  • Tooth Attrition* / veterinary
  • Tooth*

Grants and funding

Funding for this research was provided by the American Society of Mammalogists (https://www.mammalsociety.org/), Brigham Young University (https://www.byu.edu/), the Bureau of Land Management (https://www.blm.gov/), the Mule Deer Foundation (https://muledeer.org/), the Rocky Mountain Elk Foundation (https://www.rmef.org/), Safari Club International (https://safariclub.org/), Sportsmen for Fish and Wildlife (https://sfw.net/), the Utah Archery Association (https://www.utaharchery.org/), and the Utah Division of Wildlife Resources (https://wildlife.utah.gov/). Grant numbers 196313 and 206012 from Utah Division of Wildlife Resources were awarded to BRM and RTL. Additionally, the Utah Division of Wildlife Resources contributed to the data collection associated with this research. All other funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.