Guest essay by Eric Worrall
High profile British Climate Advocate David Attenborough, who in 2015 was invited to the Whitehouse by President Obama to advise on climate issues, has come under fire for promoting a discredited “Aquatic Ape” theory.
Sorry David Attenborough, we didn’t evolve from ‘aquatic apes’ – here’s why
Occasionally in science there are theories that refuse to die despite the overwhelming evidence against them. The “aquatic ape hypothesis” is one of these, now championed by Sir David Attenborough in his recent BBC Radio 4 series The Waterside Ape.
The hypothesis suggests that everything from walking upright to our lack of hair, from holding our breath to eating shellfish could be because an aquatic phase in our ancestry. Since the theory was first suggested more than 55 years ago, huge advances have been made in the study of human evolution and our story is much more interesting and complicated than suggested by the catch-all aquatic ape hypothesis.
In 1960, marine biologist Alister Hardy published an article in New Scientist, titled: Was man more aquatic in the past? He re-told the familiar tale of the evolution of land animals from ancient fish, and then considered the return of various groups of reptiles, birds and mammals to an aquatic existence: ichthyosaurs and plesiosaurs, crocodiles, sea-snakes, penguins, whales, dolphins and porpoises, manatees and dugongs, and seals – as well as polar bears, otters and water voles, who hunt in water. Then he suggested that many of the unique characteristics of humans and their ancestors, marking them out as different from the other apes, could be explained as adaptations to spending time in water.
Hardy put forward all sorts of features which could be explained as “aquatic adaptations”: our swimming ability – and our enjoyment of it; loss of body hair, as well as an arrangement of body hair that he supposed may have reduced resistance in the water; curvy bodies; and the layer of fat under our skin. He even suggested that our ability to walk upright may have developed through wading, with the water helping to support body weight.
All the suggested anatomical and physiological adaptations can be explained by other hypotheses, which fit much better with what we actually know about the ecology of ancient hominins. Hairlessness, for instance, is only a feature of fully aquatic mammals such as whales and dolphins. Semi-aquatic mammals such as otters and water voles are extremely furry. Sexual selection and adaptations to heat loss better explain our pattern of body hair. Sexual selection may also explain our body fat distribution, which differs between the sexes. Voluntary breath control is more likely to be related to speech than to diving.
I’m open to the idea that early humans spent a lot of time living on beaches. Gathering shellfish is a very easy way to get a decent high protein meal – kids in my old hometown used to gather more shellfish than we could carry in a matter of minutes.
But suggesting humans went through a “Man from Atlantis” phase seems a bit far fetched. The truth is we are quite poorly adapted to water. Humans are slow swimmers. Our eyes don’t work well underwater. Thanks to our lack of waterproof fur, getting out of water even in the tropics is sometimes a rather chilly experience, until you dry off.