12.3 Evolution of Food Sharing

Food sharing, though seen in many other primates and other social species, is incredibly uncommon in the great apes. This is particularly true among the solitary orangutans and the competitive chimpanzees. We see it more commonly in bonobos, but usually as immediate reciprocation – not for the act of sharing itself or as part of delayed reciprocity.

So how did humans become such frequent sharers?

Meat Eating Favors Food Sharing

The truth is meat eating favors food sharing in many species. Most other apes do not eat meat regularly. But when they do eat meat, it takes multiple participants to achieve a successful hunt, and it is in those moments that food sharing occurs.

Chimpanzees’ hunting behaviors have been studied in an effort to understand the catalyst to human hunting and food sharing. When they do hunt, there is usually one or two hunt leaders, while other chimpanzees provide support (e.g., cutting off the prey’s escape route). Once a hunt is successful, the leader of the hunt maintains control over the kill and is the sole decider for if and with whom the meat is shared.

In most cases, chimpanzees will share with a particularly strategic partner or potential mate. In some cases, they will also share with members of the troop who were especially helpful during the hunt. And on rare occasions, they will simply share a small piece of meat in an effort to keep the peace with a particularly persistent scrounger or beggar.

Still, none of these examples from chimpanzee hunting come close to the degree of sharing that occurs in human cultures. For that, we turn to Frank Marlowe’s work with Hadzabe of Tanzania.

Human Reasons for Food Sharing

Frank Marlowe (1954-2019) was a well-known and respected anthropologist who spent decades working with Hadzabe of Tanzania. Many of today’s scholars in the field have worked with him at one time or another. His book, The Hadza Hunter-Gatherers of Tanzania, explores the lives and experiences of these foragers as a potential glimpse into our species past.

In “Chapter 9: Cooperation and Food Sharing,” Marlowe unpacks the keen connections between cooperative behavior, relationship and reputation building, and the role of food sharing in these spaces. There, he identified the following food-sharing hypotheses:

• Nepotism: The food giver is motivated to share with their closest kin. This is the most directly connected to Hamilton’s Rule and the idea of inclusive fitness. There is also an expectation that kin will reciprocate in the future.
• Mate Provisioning: Males are more likely to engage in this form of food-sharing, though in modern societies, females also share quite a bit (think of cooking for a romantic partner). The recipient of the food is the potential or current mate, and the goal is to maintain the bond shared by demonstrating the willingness to engage in care.
• Reciprocity: As we learned in the previous chapter, reciprocity goes a long way to building cooperative partners. This can be done in one of two ways.
  • Not-in-kind exchange: The goal of the food giver is to diversify their diet and resources by exchanging food items for other foods or favors. The recipient is usually someone with different food items or who can provide a favor or service (e.g., watching children).
  • In-kind exchange/delayed reciprocity: In these instances, the goal of the food giver is to achieve relatively consistent caloric intake for themselves and others for whom they are responsible. They are likely to seek willing partners with whom to share, resulting in the long-term mutualism of reciprocal altruism.
• Costly signaling: Remember in Chapter 9, when we discussed costly signaling? Food sharing, especially if it impacts one’s total daily calories, can demonstrate that they are worthy mates and allies.
• Tolerated scrounging: This is most often engaged as a way to avoid conflict within one’s group. In general, this is the only form of food sharing that occurs despite the food givers wishes. This may be the result of pressure from the social group or through the persistence of the scrounger.

In any case, it becomes clear that human food sharing goes above and beyond the basic need to reciprocate and certainly overcomes group conflict. In fact, we might be one of the few, if not the only, species on the planet that invites political and territorial adversaries to the dinner table to talk.