The Aquatic Ape Theory

Throughout human history, one of the great questions has always been: where did we come from? Answers, until recently, were religious or philosophical. Sometimes, they were genuine attempts to explain based on observation and contemporary knowledge; sometimes, they were just colourful folklore.

More recently, in the last two or three hundred years, modern science has tried to solve this mystery. Charles Darwin, in the mid-19th century, discovered that animals had developed into different types across millions of years, first coming out of the water and then, in some cases, learning to fly or, in others, returning to the water and learning to live there again, like whales or seals.

This makes sense but the problem is not in explaining where apes came from but in explaining why human beings, technically just another primate without a tail are so different from their fellow apes both physically and in social organisation.

For many decades now, the savannah theory has been the explanation accepted by academics and scientists. This states that when our monkey ancestors came down from the trees, millions of years ago, they found themselves in a flat, hot, virtually treeless environment known as a savannah. It's the kind of landscape we see in documentaries about African animals like the zebra, antelope or giraffe.

In this environment, claim the savannah theorists, it made sense to lose most of our body hair and start sweating as a method of cooling down. We also learned to stand on two legs, and walk or run that way, because we could see further, and reach up to the branches of trees for birds' eggs or honey. Savannah theory goes on to explain other human specialities and, although they are logical up to a point, they fall apart on closer examination.

If we came down from the trees, surely we spent the next several hundred millennia in forests not on savannah? Geologists and biologists agree that our ancestors lived on the floors of forests for a very long time after coming down from the trees. And, if we lost our body hair in order to sweat, we chose very badly because, in the dry heat of a savannah, replacing water is very difficult and so, animals adapted to that thirsty environment would risk huge loss of body liquid just to cool down a bit.

Which brings us to one of the strongest arguments against savannah theory: if it made sense to move on two legs and, so, be slower than on four, if it made sense to stand up and show our position to our enemies, if it made sense to sweat litres of important body liquid under a hot sun and expose our delicate hairless skins, if all this makes any sense to evolutionary survival on the savannah, why did no other animal, not even closely related primates, do any of these things to adapt?

The answer, at least from critics of savannah theory, is that we didn't do these things, as a species, to adapt to the hot, dry savannah. We did them to adapt to living in shallow water, at least part of the time.

The hairless body and the heavy sweating are perfectly adapted to creatures who have easy ways to get water and whose bodies are protected from the sun by being in the water all day. Now, imagine an ape that moves on all fours, that wants to get further into a body of water but doesn't want to drown. As it moves in, it will try to keep its head above the water which, obviously, will make it 'stand up'; a process made far easier by the natural support of the water all around it.

Next, and very quickly, it would learn to swim which would help many of the muscles needed for standing up or moving about on two legs to develop. It is worth noting at this point that our nearest animal cousins, chimpanzees, gorillas, bonobos, orang-utans, etc. are all very poor swimmers.

And talking of swimming, did you know that human babies are born strong swimmers who instinctively know how to control their breathing under water? Human babies are also born covered in a layer of wax. The only other mammals whose young are born this way are seals and it is very well understood that this is to protect them from slightly cold water when they are born into it. Nobody has any explanation, except for the aquatic ape theory, as to why human babies have this in common with seals. In fact, in recent years, giving birth in water has become very popular with human mothers and especially because it is seen as more natural for both mother and baby.

Another problem for scientists trying to explain human origins is that the human brain is bigger than the time evolution would allow – this is known as 'the anomalous expansion of the brain'. It grew very, very quickly at one stage in our development. It's difficult to explain because the only thing that might cause such a rapid growth in brain size would be huge amounts of nearly pure protein in the human diet for many generations.

The only natural way to do that would be by eating plenty of fish and shell-fish which, at the risk of sounding obvious, is exactly what an aquatic ape, good at wading and swimming, would be able to get. As the brain grew, the intelligent new ape began to 'think' of better ways to fish or open shells. This was the stage at which our ancestors invented tool technology and, from simple hooks and nets for fish, we have gone on to invent space rockets and travel to the moon.

These are just a few of the main ideas in 'aquatic ape' theory which has explanations for different questions about human development but the theory is not widely accepted by scientists. One reason for this rejection of aquatic ape theory is because it was first proposed by someone who was not an anthropologist but a pathologist, the German, Max Westenhöfer, in 1942, and then backed by a marine biologist who had noted the similarities between marine mammals and human beings.