The prehensile tail exists within 5 New World primate genera (it also has evolved independently in two suborders of reptiles, an order of amphibians, an six orders of mammals). In the primates, it clearly evolved twice. Despite the importance of this structure, little is known regarding the function and pattern of prehensile tail use in any primate genus. This study will contribute to an understanding of how and why the prehensile tail is used by three primate genera - the howler (Alouatta), the spider monkey (Ateles), and the capuchin (Cebus). Earlier suggestions that the prehensile tail was an effective adaptation allowing the suspension of large bodied animals in small branch environments, where they could reach large fruits, for example, have become clearly insufficient. The feeding and positional behaviors of each of the three species will be compared in two forests which differ in canopy structure and plant species diversity. This research will involve analysis of the resources used by the primates and quantitative observation of their positional and feeding behavior.
