Ageing wolves through crown height measurements and its implications for ageing canids

Abstract

People, wolves, and dogs have interacted in various ways for millennia, but most aspects of these relationships remain poorly understood. Understanding canid age at death can provide insights into these relationships and how they vary geographically, temporally, and by species. Existing methods for ageing canids are limited, highlighting a need for a method that is pragmatic, reliable, and stems from a population of known age individuals. This study uses 368 known-age modern wolves from Alberta, Yellowstone National Park, and the Northwest Territories to examine how tooth wear rates correlate with age. Wolves are employed in this study because they have relatively restricted body sizes and diets, especially in comparison to modern dogs. Our results show a moderately strong correlation (r<-0.63 for all measurements) between tooth crown height and age when examined across the total wolf sample. Correlations improve when populations are examined individually, with the NWT wolves yielding a correlation of -0.83 for the mandibular M1-2 dimension. Body size, sexual dimorphism, and diet likely influence the variance seen in crown heights and their relationship to age, though the differences are statistically insignificant in many of our samples. Using tooth crown heights to age archaeological dogs will be more difficult due to the increased variation in body size, diet, and living conditions. Crown height measurements will be most informative about age at death when correlations are established for specific, local populations of wolves and dogs. Ultimately, the use of multiple ageing methods, including crown height measurements, cementum ageing, and perhaps cranial suture closure and obliteration, will produce the most reliable results for ancient canid remains.