INCISOR SIZE AND SHAPE - IMPLICATIONS FOR FEEDING BEHAVIORS IN SABER-TOOTHED CATS

Although the great size and procumbency of the incisor teeth of many s aber-toothed carnivorans have long been recognized, the potential func tional significance of carnivoran incisor size and shape remains large ly unexplored. Here, we explore upper incisor design and incisor arcad e shape in living felids, canids, and hyaenids. In addition, we compar e upper incisors of saber-toothed carnivorans with those of modern car nivorans and use these data to infer aspects of saber-tooth killing an d feeding behaviors. Results demonstrate that the shape of individual upper incisors of extant carnivorans is intricately related to the den tal arcade in which the teeth are rooted. Canids and hyaenids have rob ust incisors in parabolic arcades, whereas felid incisors are weaker, particularly in mediolateral bending, and are located in transversely linear arcades. It is proposed that the strength of the medial incisor s is in part a consequence of arcade shape. Incisors in linear arcades can be weaker because they are better buttressed by adjacent incisors than is the case for incisors in curved arcades. Incisor strength in anteroposterior bending is better explained by differences in killing and feeding behavior. Arcade procumbency and incisor robusticity also appear to be common features of the upper incisors of saber-toothed ca rnivorans, although these features are variably developed. The upper i ncisors of saber-toothed felids tend to equal or exceed those of livin g (conical-toothed) felids in strength and are located in moderately p arabolic arcades. By contrast, nimravids have massively constructed in cisors in arcades that are markedly curved comparable to those of cani ds. We hypothesize that saber-tooths may have relied on their incisors more intensively than do living felids for prey stabilization during killing bites and for the ingestion of flesh during feeding.