MOLAR WEAR RATES IN RUMINANTS - A NEW APPROACH

Molar wear rates were estimated for nine ruminant species by using lea st-squares regression of height on age estimated from counts of cement um annuli. The relationships of molar wear rate, body mass, longevity, and new estimates of dental durability were investigated. Browsers, m ixed feeders, and grazers had significantly different wear rates, but the pattern of rates was exaggerated by the body size distribution of the species examined. Height estimates divided by wear rate provide es timates of dental durability expressed in time units, and thus bypasse s scaling problems. Two such durability estimates were calculated: one based on the y-intercepts of the regression equations and the other o n the heights of the lower third molars. Dental durability plotted aga inst known longevity revealed patterns among the species which can be used to evaluate the species in terms of diet and proportions of the m olar row. The roe deer (Capreolus capreolus, a browser) has more durab le molars than would be expected from its longevity and diet. The graz ers have less durable first and second molars than expected, but this is compensated for by their highly durable third molars. The mixed fee ders appear to have an overall dental durability in proportion to long evity. Wear rate and durability offer simple but powerful tools to est imate and investigate longevity and other parameters related to life h istory when longevity data are not available. Wear rate and durability seem to be the only methods presently available that is capable of ge nerating longevity information for extinct species.