In the world's largest captive chimp colony at the Burger's Zoo in Arnhem, Netherlands, a struggle worthy of Machiavelli unfolded during the late 1970s. As described by primatologist Frans de Waal, the aging alpha male of the colony, Yeroen, was gradually unseated from his position of power by a younger male, Luit. Luit could not have done this on the basis of his own physical strength, but had to enter into an alliance with Nikkie, a still younger male. No sooner was Luit on top, however, than Nikkie turned on him and formed a coalition with the deposed leader to achieve dominance himself. Luit remained in the background as a threat to his rule, so one day he was murdered by Nikkie and Yeroen, his toes and testicles littering the floor of the cage.
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.
There are several notable aspects to these stories of chimp behavior. First, the violence. Violence within the same species is rare in the animal