This project will test the hypothesis that the dentition of the black saki monkey reduces resistant dietary items (hard fruits, seeds, nuts) that are critical to the animal's diet; and that these hard food items are opened with canine teeth specialized for applying high pressure during puncturing and chewed with flat, thick enameled molars capable of applying high pressure during crushing, and that these foods are not accessable to similar primates with different tooth formations. These hypotheses will be tested by observation of feeding and ranging behavior of black saki and similar spider monkeys in the forests of Northern South America, and by analysis of availability, use, and the physical and chemical properties of the food items eaten. The project will use a new method of measuring the resistance to puncturing and crushing of the foods.
