Seeing the wood for the trees

A while back I wrote a piece about bonobos and chimpanzees – how different they are and how human political differences might be a reflection of these two ways of life.

One thing that struck me about bonobos is that they are separated from chimpanzees by nothing more than a river. The Congo River is apparently what separated two populations of their common ancestors a couple of million years ago and prevented them from interbreeding. One population went on to become modern chimpanzees and the other bonobos. Once their genes were no longer able to mingle, it was inevitable that they would diverge from each other in both physiognomy and behavior.

What was it about the south side of the Congo that favored collaboration and appeasement instead of dominance and aggression? I have no idea, but it needn’t have been very much at all. The tiniest difference in habitat could lead to a change in culture (such as a shift in the roles of males and females) and this in turn would have knock-on effects. Positive feedback would soon lock in these changes and drive an expanding wedge between the two populations.

In modern humans, chimpanzee-like right-wing behaviors and bonobo-like left-wing behaviors coexist, but very uneasily. Empathy, for instance, serves different purposes in each mode: “socialism” (with a small “s”) is fundamentally based upon empathy in the form of sympathy – the understanding that other people suffer like we do, and if we help and support each other we can minimise this suffering for all. “capitalism”, meanwhile, makes use of empathy to outwit other people. A CEO who can walk into a business meeting and immediately grasp what everyone around the table is thinking will come away with a better deal. The consequences of this difference are profound. To a libertarian conservative, for instance, government is an unwanted imposition – a Them who controls Us. It’s an Alpha Male to be feared, opposed and ideally got rid of. Meanwhile, from the perspective of a liberal, the government actually is us; it is the collective will; the way we look out for each other. It’s no wonder the two sides fail to understand each other. In America and the UK this tension is very strong at the moment and it sometimes makes me feel that humans must be descended from the interbreeding of two previously separated species, because the two points of view aren’t very compatible and evolution might have been expected to opt for either one or the other. Bonobos and chimpanzees certainly did.

All this came back into my mind this morning when I read this article in Machines Like Us. The gist of it is that Australopithecus afarensis appears to have walked upright on two feet, in roughly the front-of-foot way that we humans do, rather than the bowlegged way that other primates do. And they did this almost four million years ago at the latest – around the time the human bloodline separated from the chimp/bonobo bloodline.

It made me wonder what kind of “Congo river” might have separated the two lines, and it’s really not hard to imagine. Chimpanzee and orangutan feet are designed for living in trees – their mastery of the arboreal mode of transport is astounding from the perspective of a human being, whose feet are utterly useless for dangling from branches. Every time I watch a primate leap confidently from branch to branch I find myself in awe and not a little envious.

But suppose the trees thin out? There are clear limits to how far apart branches can be whilst still being able to support two hundred pounds of leaping flesh. When trees get too thin on the ground, primates have to climb down and walk. For a quick dash, followed by a rapid climb back into safety, chimpanzee feet are ideal, but there will come a point when efficient running becomes far more important than efficient climbing and leaping. There are no tigers in the trees (which is basically why primates live in them), so being a bit ungainly in the canopy is not nearly as serious as being unable to reach the safety of the next trunk. The evolutionary advantage of good running feet would very quickly be tested, once running became necessary.

And what then? Once you perform better on the ground than in the canopy, you can free your hands. You have to watch out more carefully for predators and find ingeneous ways to thwart them (even using sticks as weapons, maybe). Sex becomes different. Meetings tend to happen face-to-face instead of face-to-ass. Perhaps females carrying young need protection. You are presented with vistas that exceed a mere wall of leaves. A thousand things have suddenly changed, and each of those thousand things would go on to create a thousand other changes. And all because the trees got too far apart to leap between.

Perhaps this was all it took to make the human race? Perhaps we’re just the descendants of incompetent leapers who had to evolve bizarre and expensive tricks like literature and intelligence in order to survive on the ground when we could no longer stay hidden in the trees. As we dash (by elevator) from the safety of our office-trees to the safety of our house-trees and climb the wooden stairs to bed, on feet and hips that are very much designed for the ground, it’s sobering to think that most of what we see around us might have been caused by a bit of a lingering drought, four million years ago.

Maybe I should go for a run…

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