Primate Behavior: Developments in Field and Laboratory Research, Volume 4 examines developments in field and laboratory research on primate behavior. Topics range from facial expressions in nonhuman primates to the behavior and malnutrition in the rhesus monkey. The population structure and dynamics of the Borneo orang-utan in relation to its ecology and reproductive strategy are also discussed, along with the social organization of Macaca fascicularis. Comprised of six chapters, this volume begins by discussing a field study that uses sound analysis to investigate the link between vocal pattern and social situation in the Japanese monkey (Macaca fuscata). The next chapter focuses on one particular and very important means of visual communication in nonhuman primates: facial expressions. The behavior of marmoset monkeys (Callithricidae) is then considered, with emphasis on their social structure and social organization as well as patterns of social and sexual communication. The remaining chapters explore feeding behavior and malnutrition in the rhesus monkey; the population structure and dynamics of the Borneo orang-utan in relation to its ecology and reproductive strategy; and the social organization and intergroup behavior of Macaca fascicularis. This book should be of interest to biologists and primatologists.