Pulp cavity-tooth width ratios from known-age and wild-caught coyotes determined by radiography

Although the relative sizes of pulp cavities in teeth are used frequently to identify various age classes of carnivores, validation of the technique has received little attention. We measured the pulp cavities and tooth widths based on radiographs of canine and premolar teeth from a large sample of known-age, pen-reared coyotes (Canis latrans) and from samples of wild-caught coyotes of unknown age. The ratio of pulp cavity to tooth width decreased rapidly through the first year of life. Although canine tooth ratios of juvenile, yearling, and adult coyotes differed, variations within yearling and adult groups precluded accurate assignment of individual coyotes to other than juvenile and mature age categories. A value of 0.45 in this ratio appeared to reasonably delineate the 2 groups among wild coyotes from northern Utah between November and February. Pulp cavity-tooth width ratios of upper canines and premolars were larger than ratios from lower canines and premolars from the same coyotes. Females had slightly smaller tooth ratios than males of the same age