Long-term studies of the chimpanzees of Gombe National Park, Tanzania

The study of chimpanzees at Gombe National Park, which has continued for over 50 years, has yielded many discoveries that would have been impossible without long-term data. The basic data collection procedure has remained constant since the early 1970s, with a team of Tanzanian field assistants conducting all-day focal follows of individual chimpanzees in the Kasekela (1974-present) and Mitumba (1994-present) communities. Field assistants record map location and party composition at 15-min intervals and keep a continuous record of the focal subject's feeding behavior and narrative notes on behavior, including mating, agonistic interactions, tool use, hunting, boundary patrols, and intergroup interactions. Field assistants have also monitored the unhabituated Kalande community since 1999. A relational database developed from these data provides a powerful tool for analyzing long-term patterns. Studies using this database in combination with new technologies have deepened our understanding of chimpanzee pathogens, genetics, hormones, tool use, hunting, meat sharing, social relationships, habitat use, dispersal, life histories, and demography. This chapter focuses on life histories and demography, followed by a section that highlights findings on two topics for which long-term data have proven especially informative: intergroup aggression and disease ecology.