The scaling of tooth sharpness in mammals

The scaling of many aspects of mammalian biology remains to be thoroughly investigated. Isometric scaling of tooth sharpness over very large body size ranges appears unlikely from a theoretical viewpoint, as geometrically similar teeth will function differently in a masticatory system that scales isometrically. Taking into consideration developmental controls on tooth shape and the effects of tooth wear, tooth sharpness is predicted to be highest in small animals, with relatively lower tooth sharpness in medium and large animals. The results for small to large mammals (1—2500 kg) are reassessed to show that in this range of body size there is no isometric scaling in this body size range and that wear is probably the primary determinant of sharpness, producing sharpness that is relatively scale-independent when sufficient wear occurs. Including limited additional data on tooth sharpness for very small mammals (Microchiroptera) suggests that there may be an overall trend of isometry for functional tooth crests over the very broadest range in size (0.008—2500 kg), a hypothesis that can be tested in the future with broader taxonomic sampling.