The Third Chimpanzee

The Third Chimpanzee was Jared Diamond’s first book. It’s all about the human animal, and the likely evolutionary background to some of our behaviour, and the likely consequences of some of the rest of it. It’s well written, entertaining, and as far as I can tell would have been accurate when it was written, so it isn’t too badly wrong even now.

Diamond has a good attitude to evolutionary explanations of human behaviour. If a certain kind of behaviour is found in all societies, or very close to all, and particularly if it is not found in the other two species of chimpanzee, then it almost certainly evolved during the development of humans as humans. Thus our long lifespans and penises were probably part of the changes that made us human. The long lifespan has a plausible explanation available; the continued existence of old people, who remembered how everyone survived the last disaster seventy years ago, meant that the whole group could survive the next disaster. In effect, it provided insurance against disasters that were likely to occur only a couple of times in a human lifetime. There is, apparently, still no good explanation for why human penises are so big, however. (We have smaller testicles than chimpanzees, though, and there is an explanation for that. Go on, read the book.)

He also does a good job of tracing animal precursors to human behaviour. Genocide is found in other mammals, but on a much smaller scale, because they do not have the resources we have. Thus, genocide looks like the manifestation, in large, organised states, of the standard hostility to members of other groups found in small groups of people and groups of animals. Ecological destruction is also found in both the human past, and in other species.

Diamond does mention the native people who lived in harmony with their environment. However, there is a strong implication that they did that after trashing it when they first did that. We know that the Polynesians wiped out many species on the islands they found, before, in many cases, learning to live within their ecological means. The first Native Americans seem to have wiped out the large mammals (this is controversial, but I’m inclined to agree with Diamond; it looks like a bit too much of a coincidence), before learning to live in balance. In some cases, they didn’t. The inhabitants of Easter Island trashed the place completely, and the Anasazi of North America deforested themselves into oblivion.

It’s not just humans who do this, either. Rats introduced to islands tend to drive species to extinction by eating them. Sometimes those rats have stowed away on human ships, but even then it’s the rats, not the humans, who do the wiping out.

The general conclusion is that animals that can prey on more than one species, if introduced to a new region or provided with new capabilities, tend to drive other species to extinction, before either reaching a new equilibrium or going extinct themselves. Thus, if humans continue to behave in a natural way, like any other species would, we are likely to completely trash the planet. Personally, I think that humans as a species will survive, pretty much whatever we do. Civilisation could go down, though, and the deaths of billions from war, plague, and famine could easily be part of the process. So I think that avoiding environmental destruction is a good idea.

The unique thing about humans, of course, is that we can look at the past and try to avoid making those mistakes. We are actually doing that, right now. It’s not clear whether we are doing enough to avoid disaster, but at least we are thinking about it. This book won’t tell you how to save the planet, but it will give you a much clearer idea of why people might consistently make the sorts of decisions that would destroy it.

Posted in Books.

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