Some gangs of chimpanzees beat their neighbors to death in bids to expand their turf, according to a new study. While scientists have long known that chimps will kill each other on occasion, the finding shores up a long-held hypothesis that humans' closest living relatives sometimes turn to violence to annex valuable parcels of land. Researchers observed predominantly male patrol groups sent out by a 150-strong chimp group at Ngogo in Kibale National Park in Uganda. The chimp gangs killed 21 of their neighbors between 1999 and 2008. "Just fists and feet" were used in the attacks, study leader John...