Humans need this level of sharing, the authors argue, because we have such long childhoods when we cannot fend for ourselves, and relatively short periods between births, ensuring parents are often supporting substantial numbers of children. Moreover, the paper notes, “We have moved to a dietary niche that often involves the exploitation of difficult to acquire foods with highly variable return rates.”
The only way to get through periods where it is difficult to secure food is to cooperate, the authors suggest, and despite major differences in culture and the foods being collected, similar structures have proven to provide the best support.
Nevertheless, the systems were adaptable for the circumstances. Among the Agta, who live primarily on fish and foods collected in the intertidal zone, camps averaged 63 individuals. The Mbendjele, whose food is more dispersed, average just 41 people to a camp.
The authors tracked every meal consumed over a period of more than three months, observing that 61 percent of the calories consumed by the Mbendjele were produced within the household, while among the Agta 74 percent of food was produced in-house. Although most of the rest came from closely related households, the wider camp provided a buffer that could be drawn upon in times of need.
Despite decades of anthropological studies of traditional societies, Dyble said this is the first to quantify how social networks shape food gathering and distribution
Dyble concluded: "The proverb that 'it takes a village to raise a child' is certainly true for hunter-gatherers, who, without food sharing to mitigate the day-to-day shortfalls in foraging, could simply not survive."
A Mbendjele household sharing food. Gul Deniz Salali