Bands of chimpanzees violently kill individuals from neighboring groups in order to expand their own territory

During a decade of study, researchers witnessed 18 fatal attacks and found signs of 3 others perpetrated by members of a large community of about 150 chimps at Ngogo, Kibale National Park. Then in the summer of 2009, the Ngogo chimpanzees began to use the area where two-thirds of these events occurred, expanding their territory by 22%. They traveled, socialized and fed on their favorite fruits in the new region. When they started to move into this area, it didn't take much time to realize that they had killed a lot of other chimpanzees there. Chimpanzees (along with bonobos) are humans' closest living relatives. Anthropologists have long known that they kill their neighbors, and they suspected that they did so to seize their land.