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…Vegetable foods are abundant, sedentary, and predictable. They grow in the same place year after year, and the gatherer is guaranteed a day’s return of food for a day’s expenditure of energy. Game animals, by contrast, are scarce, mobile, unpredictable, and difficult to catch. A hunter has no guarantee of success and may in fact go for days or weeks without killing a large mammal. During the study period, there were eleven men in the Dobe camp, of whom four did no hunting at all. The seven active men spent a total 78 man-days hunting, and this work input yielded 18 animals killed, or one kill for every four man-days of hunting. The probability of any one hunter making a kill on a given day was 0.23. By contrast, the probability of a woman finding plant food on a given day was 1.00. In other words, hunting and gathering are not equally felicitous subsistence alternatives.
Consider the productivity per man-hour of the two kinds of subsistence activities. One man-hour of hunting produces about 100 edible calories, and of gathering, 240 calories. Gathering is thus seen to be 2.4 times more productive than hunting. In short, hunting is a high-risk, low return subsistence activity, while gathering is a low-risk, high-return subsistence activity.
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A number of studies have noted that hunter-gatherers devote large amounts of time and energy to hunting, even when gathering plant food or farming would have maximized energy-return rates. For example, virtually all South American horticulturalists obtain much higher caloric return rates from farming than they do from hunting or fishing, yet most spend considerably more time hunting and fishing than farming.
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