An article in the Guardian says that at a conference next week, David Attenborough will voice his support for the aquatic ape hypothesis. I grew up watching Attenborough documentaries. I am a huge fan and would credit him with helping to ferment my interest in biology. But, I am no fan of the aquatic ape hypothesis because it is adaptationist and fails to provide parsimonious explanation for human evolution.
The aquatic ape hypothesis tries to force large number of human traits together under one umbrella explanation, that our ancestors had a close association with water. But no time period in the history of our evolution is specified and the fossil record shows that the traits claimed to have evolved in association with water appeared at widely different times. Without good fossil evidence demonstrating a strong association with water the hypothesis is dead... in the water.
The hypothesis is driving the evidence presented, not the other way around as it should be in science. A mish-mash of highly derived and rudimentary adaptations to water are used as evidence. Few of these are consistently associated with aquatic animals, such as hairlessness, which is present in several terrestrial mammals and absent in the majority of aquatic mammals. There are also a number of features that we humans have that are inconsistent with aquatic ancestry, such as internal testicles.
I am at a loss to explain how the aquatic ape hypothesis keeps getting coverage in popular press given how weak it is as an explanation. I get that human evolution is interesting, but it is such a bad explanation on the basis of both evidence and the methodology of its proponents. It's the phlogiston of explanations for the evolution of human traits. Fortunately, the recent coverage has spawned some well deserved ridicule, which has had a strong response on Twitter.