Did Human Evolution Include a Semi-Aquatic Phase?

Very recommendable! Sounds almost fantastic like wild speculation! Food for thought! I am not an expert enough to make a judgment on the soundness of the presented arguments. Perhaps, fishing in water as a source of food was at some point way back in time beneficial and an advantage compared to other hominids.

" ... But in 1960, a different twist on human evolution emerged. That year, marine biologist Sir Alister Hardy wrote an article in New Scientist suggesting a possible aquatic phase in our evolution, noting Homo sapiens’s differences from other primates and similarities to other aquatic and semi-aquatic mammals. In 1967, zoologist Desmond Morris published The Naked Ape, which explored different theories about why modern humans lost their fur. Morris mentioned Hardy’s “aquatic ape” hypothesis as an “ingenious” theory that sufficiently explained “why we are so nimble in the water today and why our closest living relatives, the chimpanzees, are so helpless and quickly drown.” ... In 1992, I published a paper describing a curious ear condition colloquially known as “surfer’s ear,” which I and other ear, nose, and throat doctors frequently see in clinics. Exostoses [of the external auditory canal] are small bones that grow in the outer ear canal, but only in humans who swim and dive on a regular, almost daily basis. In modern humans, there is undisputed evidence of aural exostoses in people who swim and dive, with the size and extent being directly dependent on the frequency and length of exposure to water, as well as its temperature. ... Researchers have now found these features in 1 million– to 2 million–year-old hominin skulls. In a recent study on nearly two dozen Neanderthal skulls, about 47 percent had exostoses. ... Other Homo sapiens–specific features that may be tied to a semi-aquatic stage of human evolution include erect posture, loss of body hair, deposition of subcutaneous fat, a completely different heat-regulation system from other primates, and kidneys that function much like those of aquatic mammals. This combination of characteristics, which do not exist in any other terrestrial mammal, would have gradually arisen over several million years."

Did Human Evolution Include a Semi-Aquatic Phase? | The Scientist Magazine®: A recent book outlines fossil evidence supporting the controversial hypothesis.

Aural exostoses (surfer's ear) provide vital fossil evidence of an aquatic phase in Man's early evolution.