The Hunting Apes: Meat Eating and the Origins of Human Behavior

  • Craig Stanford
Princeton University Press: 1999. 245pp $24.95, £14.95, (pbk)
Share and share alike: were the demands of meat-sharing behind the evolution of the big human brain?. Credit: IAN REDMOND/BBC NATURAL HISTORY UNIT

The quest to understand what makes us human and how we became so is one of the most controversial and fascinating scientific adventures. Many scientific disciplines, including anthropology, psychology, biology and philosophy, join in this debate. The fossils of our ancestors have made it clear how closely related they were to chimpanzees. Two particularly striking differences, however, became apparent quite early in evolution: an upright walking gait and a big brain. Since most of us think that there must be more to being human than walking upright, the quest to understand human uniqueness has centred around our ancestors' development of an enlarged brain.

Craig Stanford uses some observations of wild chimpanzees to suggest a new approach to this question. Classically, anthropologists have relied on fossil bones and the artefacts associated with them. This approach gives us limited information about our ancestors' behaviour, forcing us to make inferences. Others have used knowledge of contemporary hunter-gatherer communities to make such inferences, based on the assumption that we had a similar lifestyle for most of our history. However, our ancestors were morphologically very different from modern humans. Thus, an additional source of comparison is the information we have on chimpanzees, to which our ancestors were physically similar. Stanford's attempt to add some of our growing knowledge on chimpanzees to this debate is to be welcomed.

Jane Goodall began her pioneering work on the chimpanzees in the Gombe Stream National Park, Tanzania, some 39 years ago. Her observations of the Gombe chimpanzees using and making tools and hunting small monkeys for meat profoundly changed our view of the human-chimpanzee differences. Throughout the book, Stanford takes chimpanzee behaviour to be Gombe chimpanzee behaviour, but this produces a distorted image of what chimpanzees really are.

As Michael Tomasello and I have suggested, we should speak of different chimpanzee cultures from both biological and psychological points of view. William McGrew has shown that the tool-using habits of chimpanzee populations differ greatly; the more populations we study, the more diverse these sets of behaviour become. Similarly, many authors have shown that hunting and many other aspects of social behaviour differ strikingly between chimpanzee populations.

Chimpanzees in the Taï forest, Ivory Coast, search actively for prey, hunt in groups and coordinate their actions for most hunts, but chimpanzees at Bossou in Guinea in West Africa hunt rarely and solitarily by ‘collecting’ passing prey. Chimpanzees at the Mahale Mountains, Tanzania, like those at Gombe, hunt quite frequently, but rarely coordinate their actions. The diversity of chimpanzee cultures contrasts with what has been seen in other animals, but is reminiscent of humans. Whatever aspects of chimpanzee behaviour we look at, we see important differences between populations which do not reflect genetic, or sometimes ecological, differences.

The ‘Man the Hunter’ theory of human evolution, proposed in the early 1960s, that Stanford seeks to resuscitate, has been much criticized for ignoring women. The chimpanzees of Gombe differ from other populations, such as the Taï chimpanzees, by having females with low sociality and seemingly limited choice in their reproductive strategy. In the Taï forest, female chimpanzees are highly social, play a decisive role in many aspects of social life and make their own choice of male partners. The differences between chimpanzee cultures make us realize the flexible but important role of females in both chimpanzee and human evolution.

In addition, I don't expect that just one activity — namely hunting — could explain the evolution of humans. Humans and chimpanzees are different from other species in many ways, and it seems reasonable to expect that other activities, such as the use and the making of tools and the use of complex social strategies, would influence our evolution. Females are prime tool users in most chimpanzee populations, and the increasing knowledge of tool use in chimpanzees reveals how complex it can be. The role in our history of females in this domain is undeniable.

What made our ancestors develop such a big brain? Stanford proposes that it was the machiavellian demands of meat-sharing: not hunting itself, and not making and using tools. However, we are left puzzled as to what about meat-sharing is so demanding that it produces the modern human mind. Large brains could mean large memories or sophisticated cognitive abilities. The skills that required such an enlargement of the brain are not stated, and we can only speculate about them. Many authors have tried to define our cognitive uniqueness, and the responses propose that it lies in the domain of abilities to understand complex causal relations about external objects, or in our ability to understand the minds of others. Meat-sharing, which in humans is often viewed as tolerated theft, is not really a convincing candidate as the driving force behind higher cognitive abilities. “What makes us human?” and “How did we become so?” remain among the most exciting questions to be studied, and many more books will have to be written to find convincing clues.