The belligerent groups were the Kasakela and the Kahama, which occupied territories in the northern and southern areas of the park, respectively.[1] The two had previously been a single, unified community, but by 1974 researcher Jane Goodall, who was observing the community, first noticed the chimps dividing themselves into northern and southern sub-groups.[2] Later computer-aided analysis of Goodall's notes would reveal that the social rift between the two groups had been present as early as 1971.[3]