Most cultural anthropologists now believe that the wars Chagnon witnessed were provoked by Chagnon himself. He offered axes, machetes, fishhooks and pots in exchange for ethnographic information, creating tensions among villages that vied for monopoly control of his wares. Within months of Chagnon's arrival in 1964, three different fights broke out between villages that had previously been at peace for decades. Anthropologist Brian Ferguson reports that Chagnon was "very much involved in the fighting and the wars. Chagnon becomes a central figure in determining battles over trade goods and machetes." A Yanomami reports that Chagnon offered him an outboard motor in exchange for help, including the procurement of a Yanomami wife. Shotguns, a seemingly unlimited supply of trade goods and willingness to don feathers, face paint and a loincloth allowed Chagnon to transform himself from an "improverished Ph.D. student at the bottom of the totem pole to being a figure of preternatural power."
Tierney argues that many of Chagnon's data are simply false. The Yanomami do not have a particularly high murder rate, nor do men who kill reproduce more than those who don't. Neither are the Yanomami particularly well-nourished--a claim that Chagnon uses to argue that men fight over women and not food.