ABSTRACT
This chapter discusses a new approach of ecology and behavior of free-ranging primates: specifically, their study at waterholes. Waterholes are of two general types. The first has various names and is an area of low elevation and has a relatively impermeable substrate. The second general type of waterhole is one whose input results from an underground source as well as from rainfall. The waterhole strategy offers a unique opportunity to study the terrestrial behavior of the typically arboreal forms. To exemplify the methodology of waterhole studies and some of the types of data which can best be collected using this approach, they summarize and abstract aspects of Ceylon study which pertain to primates, and indicate the relevance of these data to several ethological, anthropological, and evolutionary issues involving primates. One troop of Ceylonese gray langurs, whose home range included the waterhole, was observed for 3,889 minutes, 32.4 percent of the total observation time.
