Chimp wars

The authors say it's not like humans conducting war, but it  sure sounds like it.

During a decade of study, the researchers witnessed 18 fatal attacks and found signs of three 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 percent. 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," Mitani said. "Our observations help to resolve long-standing questions about the function of lethal intergroup aggression in chimpanzees."

I guess it's different than human wars because humans don't kill women and children in their wars.