Use of pulp cavity/tooth width ratios to determine the age of adult wild dogs (Canis lupus dingo, C. l. domesticus and their hybrids)

Abstract

Determining the age of wild dogs destroyed in control programs is useful management practice. We compared the pulp cavity: tooth width ratio measurement and ratio calculation of the Thomson and Rose (TR) method to that of the Knowlton and Whittemore (KW) method on upper and lower canine teeth from a CSIRO collection of 68 skulls. The skulls were from mixed gender, known-age wild dogs ranging in age from 9 months to 13 years and reared at either Alice Springs or Canberra. The relationships between age and pulp cavity ratios for both TR and KW methods were significant (p=0.0001). The KW ratios exhibited stable error variance and normal distribution, whereas the TR ratios exhibited heteroscedasity in error variance. Significant differences in KW pulp cavity ratios were detected between upper and lower jaw teeth (p<0.0001) and gender (p=0.01) but not geographic origin. The KW method of calculating pulp cavity as a proportion of tooth width measured 15 mm from the root tip and averaged over both upper canines, is the more accurate of the two methods for estimating the age of adult wild dogs.