Jane Goodall became famous studying a group of about 30 chimps at the Gombe National Park in Tanzania in the 1960s, a group she found on the whole to be peaceful. In the 1970s, this group broke up into what could only be described as two rival gangs in the northern and southern parts of the range. The biological anthropologist Richard Wrangham with Dale Peterson in their 1996 book Demonic Males describes what happened next. Parties of four or five males from the northern group would go out, not simply defending their range, but often penetrating into the rival group's territory to pick off individuals caught alone or unprepared. The murders were often grisly, and they were celebrated by the attackers with hooting and feverish excitement. All the males and several of the females in the southern group were eventually killed, and the remaining females forced to join the northern group. The northern Gombe chimps had done, in effect, what Rome did to Carthage in 146 B.C.: extinguished its rival without a trace.
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