Book Review

Demonic Males: Apes and the origins of human violence

N Engl J Med 1997; 336:968-969March 27, 1997

Article

Demonic Males: Apes and the origins of human violence
By Richard Wrangham and Dale Peterson. 350 pp. Boston, Houghton Mifflin, 1996. $24.95. ISBN: 0-395-69001-3

Demonic Males is a fascinating account that draws on data ranging from observations of apes (the authors' main interest) to findings of human paleontology, molecular biology, and ancient history, and even modern fiction. Its thesis is that in our species men act violently and make war because of temperaments inherited from chimpanzee-like ancestors. The book races on and is easy to read. Nevertheless, it is scholarly. The evidence in support of opposing arguments is presented, and full documentation is unobtrusively supplied. However, without reading critically, one may be overly impressed by the initial broad statements. The publisher has detracted from the scholarly tone of the book by covering it with a regrettable dust jacket that pictures the apes shaved and standing in an anatomically impossible posture.

Genetically, chimpanzees are very similar to humans. The authors accept the interpretation of evidence from fossils and DNA indicating that the lines of descent separated only about 5 million years ago. In addition, male chimpanzees, like men, form raiding parties that leave their own territory to attack and kill members of other groups belonging to their own species. This book also documents the behavior of another ape, the bonobo, that does not act in these “demonic” ways. Bonobos “make love, not war,” and their DNA resembles human DNA just as much as does chimpanzee DNA. Furthermore, the genetic differences between bonobos and chimpanzees are very small and are less than half as numerous as the differences between these apes and humans.

Why, then, do the authors conclude that the last common ancestors of the three species, chimpanzees, bonobos, and humans, behaved like chimpanzees and passed on their male aggressiveness to us? They are obliged to lean on ecologic lines of evidence. But what we know about the environment in Africa at the time the human line of descent originated is limited, partly because we do not know exactly when that event occurred. The authors accept that it occurred 5 million years ago, but it may have taken place somewhat later or many years before. Furthermore, extinct species may not have been limited to the places where their fossils are found. The gorilla, which has its own lifestyle, is also closely related to chimpanzees, bonobos, and humans. The interpretation of the evidence bearing on the behavior of our ancient forebears is more speculative than the authors of this book imply. Others have reached different conclusions and placed less emphasis on the importance of genetic influences.

In any case, the authors do not fall for what they call the Galton error of dichotomizing “nature versus nurture.” Nature and nurture are always present together and, whatever the extent to which genetic temperaments are established through evolution, the authors recognize the possibility for less bellicose human behavior.

Gabriel W. Lasker, Ph.D.
Wayne State University School of Medicine, Detroit, MI 48201