On the Scaling of Tooth Size in Mammals

Abstract

We must establish the allometric regularities of functional scalingin interspecific, “mouse-to elephant” plots in order to provide criteria for the recognition of special adaptations unrelated to the requirements of size. The qualitative literature suggests that postcanine tooth areas of herbivorous mammals should increase with positive allometry in such plots. This positive allometry might reflect the demands of metabolism or the ecological strategies of large vs. small hervivores embodied in Levins' concept of environmental grain. Plots of postcanine area vs. body size display the expected postive allometry in all groups studied: hystricomorph rodents, suine artiodactyls (pigs, peccaries, and hippos), cervoid artiodactyls (deer, s.l), and four groups of primates considered separately (lemuroids, ceboids, cercopithecoids, and great apes). Sketchy data for australopithecines also indicate positive allometry and the relatively larger cheek teeth of robust forms may only reflect their larger body size and not the dietary differences so often advocated. Phyletic dwarfs of large herbivores display negative allometry (relatively larger cheek teeth in dwarfs) in opposition to the interspecific trend.