Aside from that dangerous misstep, the fact that the attackers were male is not surprising to those who study chimpanzees. Sylvia Amsler, a lecturer in the Anthropology Program at the University of Arkansas at Little Rock, told Discovery News that male chimps in the wild commonly engage in war-like behavior to defend or acquire territory.
"Such attacks can be severe and fatal," she said. "In the case of an adult victim, the attacking males take turns beating and jumping on the victim. Attackers use their canines to bite and tear at the victim, so that any body parts that stick out, such as testes and ears, are often ripped off during an attack."
Jenny Short, assistant director of colony management and research services at the California National Primate Research Center, reminded that chimpanzees and other primates are not domesticated animals.
"You have to be reactive and extremely careful around them," she told Discovery News. "We work with rhesus macaques, which are much smaller than chimpanzees, and even they require strict precautions. If you go to a zoo and look at chimps, it takes your breath away because they are so big and strong."