RELATIONSHIP OF INCISOR SIZE TO DIET AND ANTERIOR TOOTH USE IN SYMPATRIC SUMATRAN ANTHROPOIDS

Researchers often relate anthropoid incisor size to diet and ingestive behaviors. It is suggested that primates that frequently consume larg e, tough foods (i.e., fruits) require large incisors to process these items. This idea has been difficult to test because of a lack of data on anterior tooth use in wild primates, and a lack of understanding co ncerning the relationships between food properties and ingestive behav iors. The first field study of primate ingestive behaviors has recentl y been completed for four species of Sumatran anthropoids: Hylobates l ar, Macaca fascicularis, Pongo pygmaeus, and Presbytis thomasi [Ungar, American Journal of Physical Anthropology 95:197-219, 1994; Internati onal Journal of Primatology 16: 221-245, 1995]. This paper documents b oth relative and absolute incisor row width differences among these ta xa, and evaluates the relationships between incisor size and feeding b ehaviors for specific taxa. Results indicate that differences in incis or size among these species cannot all be explained by degree of frugi vory, food item size, or even degree of incisor use in ingestion alone . It is therefore suggested that inferences of dietary differences bas ed on largely or solely on differences in incisor sizes of specific fo ssil anthropoid taxa should be approached with caution. (C) 1996 Wiley -Liss, Inc.