Competition for Food and Sex among Apes - Equality Versus Hierarchy

Sex, Power, and Partisanship: How Evolutionary Science Makes Sense of Our Political Divide - Hector A. Garcia 2019

Competition for Food and Sex among Apes
Equality Versus Hierarchy

By considering the behaviors of our closest relatives, chimpanzees, we gain greater insight into how male mate competition formed our own political orientations, into their emphases on hierarchy or equality, as well as their underlying gendered psychologies. In the robust chimpanzee (Pan troglodytes), male alliances are central to survival, particularly in competition with outside troops. It is remarkable how much competition between chimpanzee groups resembles human warfare. Using a cadence reserved exclusively for raids, all-male squads will set off on patrol, moving silently and in single file toward the edges of their territory, scanning the trees and looking out across valleys in search of the enemy.13 When these chimps on patrol find a lone male, or a smaller squad from the rival troop, they will gang up, strike, stomp on, and rip their opponents to death, sometimes biting off genitalia, at other times going so far as to drink the blood of their victims.

Through raiding, male coalitions will expand their existing territory and absorb females of the conquered troop into their own.14 In doing so they not only expand their mating opportunities but also their access to fruit trees and colobus monkeys, a favorite chimpanzee prey species.15 In the world of chimpanzees, there is no egalitarian order between groups—that is, there is no sharing between groups of male chimpanzees; competition for sex and food is normative and brutal, and one group's loss is the other group's gain.

Chimpanzees exhibit in-group competition as well, fueled by a competition for rank and the privileged access to resources that rank provides. Higher-ranking males steal meat more often and are given meat more often by lower-ranking males.16 Dominant males also feed higher in the canopy of trees, where fruit is more plentiful and its sugar content higher. When conflict arises, lower-ranking chimpanzees are pushed down to less bountiful parts of the tree, or off the tree altogether.17 Further, dominant males will monopolize in-group mating whenever they can by attacking rival males or punishing females that stray. In short, there is little egalitarian order within the male-dominated chimpanzee in-group as well. It is worth noting that the “moral community” among robust chimpanzees may also unite to contain male despots—both male and female chimps have been observed forming alliances to overthrow overly aggressive alphas. Sometimes despotic alphas will be killed and even cannibalized.18

Patterns among robust chimpanzees suggest a common root with political conservatism among humans. Their societies are male dominated, highly stratified, xenophobic, and warlike. They compete with outside troops and seek to monopolize food and mating. By contrast, our other chimpanzee cousins, bonobos (Pan paniscus), differ from robust chimpanzees in ways that resemble political liberalism. Bonobo societies are female-led, egalitarian, open to outside groups, and largely peaceable. There is little competition between bonobo groups, and groups often eat and mate relatively freely with one another.

How do we understand such radical differences between our respective cousins? Competition for resources. Unlike that of the robust chimpanzees, bonobo territory does not interweave with that of gorillas. Separated from gorillas by the Zaïre River, bonobos have more access to foods normally consumed by their colossal cousins. Thus one critical reason that male bonobos don't wage war on one another, why they can afford to be female oriented, egalitarian, and “liberal,” appears to be that their opulent food supply doesn't force violent competition. Or as primatologists Richard Wrangham and Dale Peterson put it, “Bonobos have evolved in a forest that is kindlier in its food supply, and that allows them to be kindly, too.”19 Conversely, robust chimpanzees were pressured to adapt to the overall less available plant life. They did so by becoming male dominated and militaristic, and by conducting raids on rivaling troops to secure greater resources for the in-group. This male orientation pushed male reproductive imperatives to the foreground, and chimpanzees evolved to be more sexually controlling and competitive than bonobos. And so, among our closest primate relatives, both “liberal” egalitarianism and “conservative” allegiance to male social hierarchies appear to have been driven by male competition (or the relative lack of male competition) for natural resources.