Week 7: Food and Social Organization

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Just like any other animals, primates have various ways to obtain nutrition through the foods that they eat. Much like what we might see in Benson or in the Pit, how primates get the foods they do affects aspects of their social behavior and social organizations. In primates, we see two major types of foods: high quality foods and low quality foods. High quality foods, such as easily digestible foods that are high in protein like fruits and insects are high in caloric value while low quality foods might be considered fall back foods at times when those high quality are unavailable. The different types of foods are important because of the ways in which they are distributed.

A major part of social organization related to food is how types of foods are distributed, or how they are laid out within a primates habitat or niche. “Food patches” occur when food resources inhabit patchy distributions. High quality foods occur in patchier distribution, according to Strier, which creates competition in primates. This competition is what inevitably creates or highlights social organization within primates. As we talked about in class, there are many forms of competition. One form of competition that can create social organizations within primates is called “contest competition” when there are clear winners and losers in competition for food resources, while scramble competition is more like a tragedy of the commons scenario, where everyone may have access, but resources dry up quickly.

Feeding groups in primates are largely affected by the size of the food patch, dictated by this competition for food resources I just mentioned. In contest competition, social hierarchies come into play regarding who has access to resources. Higher ranking individuals will gain access to better resources while lower ranking primates generally wait until the others are done. Strier mentions that many primates in lower ranks might even be better off foraging alone, something that I found particularly interesting from our readings.

I also found it interesting the role that being a female plays regarding social organization and food availability. Many female groups and their social structures are even more closely related to the food that is available, because of the high metabolic costs of female reproductive processes. As a female, gestation and pregnancy requires more food to be sustained, and the process of nursing newborn babies is even more metabolically costly. Because of this increased need for food, female social structures and competition will be highly dependent upon the food that is available. It seems as though female social structures will be more fluid to avoid competition and therefore many females will end up going off alone to forage. I also found interesting, but not necessarily surprising that reproductive cycles will be in align with periods that have plentiful amounts of food.

It is often beneficial to look at species that are closely related and compare their behavior regarding food foraging and social structure, because while there are always similarities, differences in behavior can reveal much about the nature of social structure and food resources. Chimpanzees and bonobos are good examples of closely related species that exhibit varying behaviors regarding food foraging. Bonobo societies are cohesive and have much social stability. It is easier for female bonobos to forage together and avoid competition. On the other hand, chimpanzees are much more fluid, the status of female chimpanzees is weakly defined and can therefore be adjusted to account for varying food patches and scarcity. Both of these tactics to address how females get food have pros and cons, but seem to work for each species! This might also be related to varying behaviors in chimpanzees and bonobos when dealing with competition outside of food.

I’ve included some pictures of chimps and bonobos eating food.

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2 thoughts on “Week 7: Food and Social Organization

  1. I didn’t see the Strier comment about lower ranking primates being better off foraging alone! That’s interesting! It says a lot about the importance of dominance and the strategies of overcoming rank.

  2. I enjoyed the comments you made on the food acquisition being a determinant in the reproduction cycle. I never really thought that the seasonality of higher quality foods would affect their cycle so much but like you said its not that hard to believe. I think it will be interesting to see the impacts that human encroachment will make on the availability of higher quality food in the future. In parallel, I think it will be even more interesting to see how the reproduction cycles will be affected.

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