First, he had to compile genealogies of the Yanomamö. No easy task: Chagnon visited scores of villages, learned the language, overcame their practical jokes, and gained the trust of a people reluctant to divulge personal names.
Charles C. Mann in the Wall Street Journal reviews Chagnon’s autobiography Noble Savages:
The genealogies paid off, though, when Mr. Chagnon used them to show that Yanomamö violence had a reproductive payoff. On the whole, he wrote in a 1988 Science article, village men who had killed other people had roughly three times as many offspring as non-killers.
Today, this claim may seem unexceptional. After all, genetic studies suggest that about 10% of the men living in the old Mongol Empire are descended from Genghis Khan, one of history’s great killers. Why wouldn’t this kind of thing be replicated on a smaller scale? But in the 1980s, Mr. Chagnon writes, “to have the lead article in Science suggesting that ‘killers have more kids’ was like pouring gasoline on a smoldering academic fire.” …
Mr. Chagnon, who seems to have an instinct for leading with his chin, embraced sociobiology. He argued that Yanomamö men fought over women and that this male conflict was not only the fundamental cause of war in simple societies but “the most important single force in shaping the evolution of political society in our species.” Conflicts over reproduction are fundamental in other mammals, he noted. There is no reason to see Homo sapiens as an exception.
A fascinating discovery and one more nail in the coffin of human exceptionalism.