How the Aquatic Ape Theory Keeps Floating On

A rumor gets halfway around the world, while the truth is still in peer review.

May 10 2013, 8:00pm
Image via Flickr/tristanf

To many, Sir David Attenborough’s soothing, oaken British voice represents the pinnacle of broadcasting the natural world. The naturalist/TV personality/voiceover master/national treasure’s half-century career at the BBC has run the gamut from the massive—like the awe-inspiring, hi-def Planet Earth—to the miniscule—daily, 90-second podcasts on bird songs, that launched this week. He’s beloved, he’s in the public eye and he’s sharp as a tack.

Where Sir David goes, the eye follows. This explains why the event’s planners were so proud to hear that Attenborough wanted to attend both days of the “Human Evolution Past, Present & Future” symposium in London this week, and why evolutionary biologists and biological anthropologists collectively face-palmed at the same news. That’s because, in spite of the symposium’s generic-sounding title, Attenborough—deliberately or not—is lending his name and considerable credibility to a 50-year-old fringe theory of human evolution that just won’t go away. It isn’t the first time that Sir David has hung out with the aquatic ape crowd, either.

If you haven’t heard of the aquatic ape theory, it’s either because of a vast, academic conspiracy, or just because you have better things to do than explore unproven, fringe pseudoscience.

For the uninitiated, the aquatic apes theory or hypothesis states that “at some stage during the last few million years, our human ancestors were exposed to a period of semiaquatic evolution which led to the acquisition of unique and primordial human characteristics.” This explanation makes it sound simple enough, even innocuous, and it belies the fact that the theory doesn’t really have two upright legs to stand on.
While the aquatic ape theory was first popularized in the English-speaking world by the British marine biologist Sir Alister Hardy in 1960, it was then taken up by Elaine Morgan, who is enough of a face of the movement to get her own TED talk and requisite standing ovation.

The gist of the argument is that we humans look so different from our chimpanzee relatives that we couldn’t have emerged from the same environment in Africa, lo those many years ago. How does one explain that people are hairless bi-peds, who have the sufficient breath control to speak, who eat seafood and who can dive well enough to earn Olympic gold medals? It’s easy: we came out of the trees and into the water.

A livid-sounding Henry Gee, senior editor at Nature, took to the Guardian to give a succinct and amusing take down of the theory that basically boils down to this: the fossil and archeological record doesn’t support it and the “support” offered by proponents of the theory is total bunk. In less than 900 words, Gee made the notion of humans descending from wading apes seem ridiculous. So how has this theory carried on for 50 years? And what is David Attenborough up to?

The aquatic ape theory’s resilience follows a well-trodden pseudoscience path that has emerged everywhere from astronomy to zoology and goes something like this:
1.    One or more people who have credentials, albeit usually in a different field than the one in which they are plowing, present the theory. In AAT's case, Hardy was an expert on whales and plankton, while Morgan cheekily described herself as a “Welsh TV-writer housewife," although she also has an English degree from Oxford.
2.    The theory is far enough from the mainstream that the tops of the field either don’t notice it, or they don’t want to give it the exposure of a public tearing-down. The science journals, edited by tops of their field who also don’t see any merit in the theory, don’t want to waste the space on publishing the theory or slamming it; it just doesn’t seem to have anything to do with them.

With the normal route to scientific acceptance blocked, the theory then either disappears quietly, or can be brought straight to the general public.

Unburdened by little complexities—such as fact or detail—a lot of pseudoscience can have an intuitive, reasonable ring to it, and the scientific community’s blind-eye backfires, and the dubious book shoots to the top of the best-sellers list and the author has a sufficient platform to dismiss objections as petty jealousy, or a hateful conspiracy, and followers to agree.

One of the few times that AAT theory has been closely examined was when John H. Langdon at University of Indianapolis published a critique in the Journal of Human Evolution, in 1997. Langdon wrote that upon initial publication, “the aquatic ape hypothesis encountered the coldest reception and received the least attention from anthropologists,” but it has continuously had supporters outside the field.

Langdon allows that the story of human evolution is still being worked on by paleoanthropology, but rejects the alternative being offered by the AATists. In my own interpretation of his paper, Morgan and her ilk are like the dark side of the Force: appetizing, powerful and wrong.

Langdon explains that simple, “umbrella” explanations like the aquatic ape theory tend to hang around in the public sphere with a popularity that is all out of whack with their acceptance in the scientific realm because they are easier to understand on the surface.

It seems much tidier to think, “humans developed this or that adaptation because we were wading around in water,” in opposition to the “mosaic” explanation favored by the mainstream, where human evolution happens over millions of years and in response to myriad habitat. And it seems natural to Langdon that simpler explanations are going to catch on better with the public than a complex one, and paleoanthrology isn't even down to one complex explanation yet. “Unorthodox models are especially successful when consensus views are not easily communicated to the public,” he wrote.

Questions about evolution are easy to ask, and difficult to responsibly answer. “Simple narratives of adaptation, however far-fetched, are easier to recite than non-adaptive answers. 'We can hold our breath because we adapted for diving’ is a simple statement. ‘We can hold our breath because respiration is independent of locomotion in a biped’ requires more understanding,” he cited as one example.

The irony is that the so-called “simple explanations” become increasingly complicated when more data is examined. Human ancestors were in the water long enough to lose body hair but not long enough for their skeletal structure to reflect this time—excepting crucially, their hips, which during this aquatic period shifted to allow walking upright. It’s an explanation that picks and chooses its evidence, never able to account for all of the available data, but it neatly explains some very visible differences.  

Pseudoscientists love to fashion themselves as modern Copernicuses whose ground-breaking, paradigm-shifting discoveries are being oppressed by the "priests" of the age, just as the Church covered up the Renaissance astronomer’s theory of the Sun in the center of the solar system with the Earth revolving around it..

But the aquatic apes theory is more like Ptolemaic models of the cosmos that Copernicus overthrew. These models of the solar system had to be ever-more complex to keep the Earth in the middle and also account for the incongruous movement of the planets. In the end Copernicus’s moving the Sun to the center of the solar system simplified the model, but made how people understand themselves much more complicated. While the mosaic approach to human evolution requires a longer explanation than “because we were in water,” it nevertheless leads to fewer head-scratchers down the road.

Photo via

But what to make of Sir David Attenborough’s deflection to the aquatic ape theory side? Are he and his big brother Richard, star of Jurassic Park, competing to see who can muddle the public’s mind more thoroughly?

I watched this video of Attenborough explaining the aquatic ape theory, hoping that he would have a sly disclaimer—“one theory, which is far from exhaustive,” or something like that—but he either did it so slyly that I didn’t notice, or not at all.

But I think the explanation is in the video anyway. David Attenborough is a broadcaster, a life-long TV man. While researchers like John Langdon have obligations—to publish in peer reviewed journals—Attenborough’s job is to show us on the screen. While he’s intoning a discredited theory, he’s up to his waist in a river and has chimps slowly wading around behind in the background. It’s great footage, and he looks adorable in hip waders.

Granted, as a naturalist and one with such a noteworthy platform, he has an obligation not to pull some dumb shit like this, lest the aquatic ape theory get more attention than it already has. Maybe I’m feeling generous, since the good Sir David just celebrated his 87th birthday on Wednesday, so I’ll forgive him.

The incident can perhaps be put down both as a cautionary tale—beware of broadcasters!—and about the potential that the direct-to-public Interwebbed world offers us.

Even as aquatic apes caught on in newspapers around the world, Scientific American covered the counter-campaign that happened and was mostly made of jokes going around on Twitter. Riffing on a deliberate parody of the aquatic apes for which they had just as much evidence, gleeful researchers and laypeople collaborated to flush out the theory that human ancestors were space apes, under the hashtag #spaceape.

Maybe, just like the fanny pack, the aquatic ape theory can be banished through simple, good old-fashioned derision. If there’s one thing that the Internet teaches us over and over, it's that homo sapiens love a good pile-on.