the study of chimpanzee behaviour in nature began in earnest only in the 1960s with one field site set up by jane goodall in gombe stream, and another by japanese scientists led by nishida. both teams were in it for the long haul rather than the brief expeditions others had previously undertaken. nishida chose a forest in the foothills of the mahale mountains, at lake tanganyika, where he waited patiently for chimpanzees at a patch of sugarcane, planted to attract them. the primates started to make regular visits only after about six months. based on his field observations, nishida defended his dissertation at kyoto university in 1968.