Sublime

If we compare gibbons, which are monogamous, with baboons, which are not, we see that baboons have marked sexual size dimorphism and enlarged canines. Polygyny—which is associated with strategies two and three from the previous chapter—leads inexorably both to male-male violence and to the morphology that enables that violence.

The experiment was elegant in its simplicity. Using a toy lion and a toy zebra, Barrett asked each child, “When the lion sees the zebra, what does the lion want to do?” The results were surprising: 75 percent of the three-year-olds in both groups answered with some variation of “The lion wants to chase/bite/kill the zebra.” (It must be remembered t

20. Sahlins (1972), p. 37. 21. http://www.newyorker.com/online/blogs/books/2009/04/the-exchange-david-plotz.html.

When a population reaches carrying capacity, though, and zero-sum dynamics are once again in play, the incentives of high-ranking men tend to shift in the direction of polygyny. Male-male competition becomes a driving force, as men with wealth and power seek to dominate the reproductive output of multiple women.

“Nós somos”, conclui Wrangham, “mais cozinheiros do que carnívoros.”

Humans lack these restrictions because (1) our lungs do not compress when we stride (we’re bipedal) so (2) our breathing rates can vary independent of our speed, and (3) our thermoregulation is managed by our fancy sweating system, so the need to pant does not constrain our breathing. Because of this, within our range of aerobic running speeds (not