The New World primates have radiated widely in tropical America, evolving a variety of adaptations to cope with different ways of life. This comparative survey examines many species. Some are highly specialized in unique ways; others have paralleled the lemurs of Madagascar or the monkeys and apes of Africa and Asia. The author's emphasis is on natural history, behavior, and ecology. Topics include geographical distributions, habitat preferences, territorial arrangements, activity rhythms, feeding techniques, defense mechanisms, and competition and cooperation among individuals of the same species. Much of the material is new, based on recent research in the field. Social reactions and organizations, and communication systems, are discussed in order to consider their implications for the evolution of primates in general and the development of languages and intelligence. Originally published in 1976. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.