I have to admit that I’m unconvinced by the full-blown “immersion” Aquatic Ape Hypothesis (AAH) for a number of reasons. Not least because the human characteristics that the hypothesis attempts to explain appear to have developed at significantly different times in our evolution. For example, the fossil record seems to show that bipedalism developed well before hominin brains started to get appreciably bigger. A long time before. But that doesn’t mean that water didn’t play an important part in human development. In fact, with the amount that leaks out of us every day, it’s hard to believe that we could have evolved far away from significant supplies of fresh water. We swim well and and there are a number of physiological differences between human species and other apes that are at least worthy of consideration in relation to water.
And that seems to me to be the problem. When I was writing Watermark, and still now, it was/is actually quite hard to find balanced discussions about the role of water in human evolution in scientific papers. I wonder if that is because some researchers and writers fear the spectre of the AAH arising in criticisms of their work. And that means that we end up with the role of water being an “unmentioned” element; almost taken for granted, or at least unexplained. In some blogs and commentaries the possibility of some aspects of human evolution being the result of hominins living close to water, rather than being immersed in it, are described as “the AAH backpedalling“, or similar derogatory terms. This is a shame. Water is clearly vital to us, and must have been so for a long time. In Alice Roberts’ excellent TV series “The Origins of Us”, first broadcast in October 2011, the first programme shows how we are built to run over long distances, “sweating 3 litres of water per day.” It is surely a legitimate question to ask how that method of cooling could possibly evolve in the absence of reliable access to a significant supply of fresh water. And if we had to be living close to such supplies, what other effects might that have had? For example, there is intriguing evidence of humans having a long history of eating marine and aquatic foods, unlike the other great apes.
Surely it’s time to move away from “water vs. something else” arguments, and towards “water as part of the environment” discussions?