Following hotly on the heels of Richard Wrangham’s exceptional book, Catching Fire, about how cooking made us human, is Elaine Morgan’s exquisite “The Aquatic Ape Hypothesis” (affiliate links: UK
A really remarkable suggestion
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The Aquatic Ape Hypothesis? What on earth is that?
The Aquatic Ape Hypothesis, in layman’s terms, is an explanation for how our ancestral hominid diverged from the last common ancestor with the other apes. About eight or nine million years ago, apparently, something radical happened and we evolved sharply in a completely different direction. Why was this?
The Aquatic Ape Hypothesis (AAH) tries to answer this question. In the process, it claims also to find the reasons for some of our most defining characteristics. For example, why are we the only naked ape? Why are we the only bipedal ape? Why do we alone have noses? Why do we love being in and around water?
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Looking at the physical clues
The AAH recognises that the physical characteristics that differentiate us from other apes are the clues:
Two legs good, four legs bad?
The AAH asks in what circumstances apes find themselves typically having to stand on two legs. The answer is that most apes dislike being on two legs and spend very little time doing it. However, the AAH notes that the proboscis monkey and the bonobo both spend time on two legs, wading in water. Could a watery habitat have led to our ancestors evolving longer legs and a more upright form?
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The naked ape
The AAH asks what other animals have evolved to become hairless. Clearly, marine mammals such as seals and sea-lions are obvious parallels. But other good examples are the semi-aquatic mammals, such as the hippopotamus, and animals which once started to become aquatic but then went back to the land, such as the elephant. The evidence is fairly overwhelming that we lost our hair in order to swim better.
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Survival of the fattest?
Following on from our nakedness, the AAH looks at why we are so much fatter than all other apes. A normal level of bodyfat for most other apes is around 2%. Competitive bodybuilders reach around 4% and they often make themselves ill doing it. We are clearly designed to be fatter. What other mammals tend to have higher bodyfat? You’ve guessed it, it’s those marine mammals again!
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The diving reflex
The AAH notes that humans have the diving reflex. You may know about it. If you grab a passing friend and dunk their heads into a bucket of cold water, you’ll find that their heart rate slows down (assuming you can get close enough to measure it while they’re flailing around). This is a phenomenon only observed in diving animals. Incidentally, it’s a great way to calm down if you’re stressed, sticking your face into a sink of cold water.
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Who nose?
The AAH notes that we are alone of the great apes in having a rather strange protruberance sticking out the front of our faces. In other words, we have a nose. Why is this? Well, one possible explanation is that it stops us drowing when we dive into the water. Try diving into water with two great holes in the front of your face and see what happens.
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Blood is thicker than water
The AAH notes that the percentages of haemoglobin in blood cells tend to be higher in marine animals. In chimpanzees, it is 12.2%. In gorillas it is 13.2%. In humans it is 18.6%. Spot the odd one out.
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Fishing for answers
The AAH notes that one of the key developments that made us human was the increase in our brain size. The brain needs lots of omega-3 fatty acids to grow. Most people who follow the paleo diet will know that this is normally attributed to the consumption of brains and other omega-3 rich organ meats. However, it is also possible that the omega-3 fats could have come from fish, the typical diet of a wading ape…
By the way, if you’re a Loren Cordain follower, like I am, you’ll know that he isn’t too impressed with the idea that we ever ate much fish because it’s not really seen in the fossil record. The trouble is, fish bones and shells don’t survive that well in the fossil record so they’re hard to pick up. It’s a tricky one to prove either way.
The one thing I would say is that there seem to be a lot of people out there who are getting some big benefits from taking fish oil supplements these days. It can’t be a coincidence.
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Further reading
For a criticism of The Aquatic Ape Hypothesis, see here. This is a somewhat rambling criticism that’s desperately in need of a good editor but well worth a trawl through if you find yourself in need of an alternative point of view.
Try and ignore the self-important tone because there are a few well-made points hidden in these lengthy paragraphs. Alternatively, for a more supportive analysis, see here.
Ultimately, I have found that most people disagree with Morgan for two basic reasons. Firstly, they are incredibly jealous that someone who is not one of their own academic circle could have come up with such a great theory. Secondly, they don’t like the fact that she is less well-versed in the nitty-gritty of the archaeological record as they are. But nevertheless, she has come up with something remarkable, which is more than they will ever do.
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Conclusion
I have to admit I love this book. It resonates very powerfully with me. For me, it is the prosaic explanation of everything I know instinctively every time I dive into the swimming pool.
Water is in our blood. We are designed to swim.
