The Gombe Chimpanzee War (also known as the "Four-Year War" of Gombe), lasting from 1974 to 1978, was a violent conflict between two communities of chimpanzees in Gombe Stream National Park, in Tanzania. 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]

The first outbreak of violence occurred on January 7, 1974,[4] when a party of six adult Kasakela males attacked and killed "Gobi", a young Kahama male, who had been feeding in a tree.[1] This was the first time that any of the chimpanzees had been seen to deliberately kill a fellow chimp.[4]

Over the next four years, all six of the adult male members of the Kahama were killed by the Kasakela males.[5] Of the females from Kahama, one was killed, two went missing, and three were beaten and kidnapped by the Kasakela males.[5] The Kasakela then succeeded in taking over the Kahama's former territory.[5]

These territorial gains were not permanent, however; with the Kahama gone, the Kasakela's territory now butted up directly against the territory of another chimpanzee community, called the Kalande.[6] Cowed by the superior strength and numbers of the Kalande, as well as a few violent skirmishes along their border, the Kasakela quickly gave up much of their new territory.[6]

(http://www.autoadmit.com/thread.php?thread_id=4026702&forum_id=2#36432148)