Great Basin (e.g., O'Connell and Hawkes, 1981; O'Connell et al., 1983; Steward, 1938), also require much processing to extract the nutrients (Simms, 1984).
Meat is also an important part of human diets. Whereas meat accounts for no more than 5 percent of total caloric consumption (and usually much less) in any nonhuman primate, hunted and fished foods account for between 15 and 100 percent of total calories consumed among human foragers (Kelly, 1995: table 103.1). Although there is no comparative, quantitative database on the factors affecting hunting ability in humans, my own observations hunting with four South American groups suggest that hunting, as practiced by those peoples, is a very skill-intensive activity. Because people are slow runners, they rely on knowledge of prey behavior to find and kill prey. Conversations with men among the Aché, Piro, Machiguenga, and Yora foragers suggest to me that they have detailed knowledge of the reproductive, parenting, grouping, predator avoidance, and communication patterns of each prey species, and this takes decades to learn. For example, in a test with wildlife biologists, an Aché man could identify the vocalizations of every bird species known to inhabit his region and claimed to know many more, which the biologists have yet to identify (Kim Hill, personal communication). After most hunts, details of the hunt and the prey's behavior are discussed and often recounted again in camp. Even the stomach and intestinal contents of the animal are examined to determine its recent diet for future reference. In addition, knowledge of predator behavior may also be very important. Villagers in Botswana reported to me that one reason why teens hunt little is because they are at risk of predation themselves. According to some informants, the ability to detect potential predators such as lions, hyenas, and leopards and then escape them requires years to learn. It should be mentioned, however, that available empirical data do not allow us to assess the relative impacts of skill, knowledge, strength, endurance, and ambition on hunting returns. Those impacts may vary across ecologies and individuals.
Nevertheless, the age patterning of hunting success is striking. Figure 10-5 shows the age distribution of hunted calories acquired per day among the Aché. Fifteen- to seventeen-year-old boys acquired 440 calories of meat per day, 18- to 20-year-olds acquired 1,530 calories, and 21- to 24-year-olds acquired 3,450 calories, whereas 25- to 50 year olds acquired about 7,000 calories of meat per day. The fourfold increase between 18 and 25 years of age exists in spite of the fact that by age 18, young men are hunting about as much as fully adult men. This pattern is not unique to the Aché. From independent samples acquired in different !Kung camps, both Lee (1979) and Draper (1976) report that men under age 25 acquired very little meat and were considered incompetent hunters. Among the Hadza, although boys spend much time pursuing game, their returns are quite low. Blurton Jones et al. (1989) report that during 31 observation days the total meat production for Hadza boys was about 2 kg, mostly composed of small-to-medium-sized birds. This is less than the daily production of a single adult Hadza man, who acquires a mean of 4.6 kg per day (Hawkes et al., 1991).