In
future eaters, Tim Flannery reasons that there was a distinct shift in skin color, determined primarily by the tides. We were, he argues, early on, land-based organisms, fearing the great water, and all our sustenance therefore, whether we were hunting, gathering, or farming, was gained during the cooler hours, from the land, when life is easier.
Melanin is released to form darker skin as a protection against radiation, as is revealed in OP's clip. But, when your culture has been forced to the margins, because of population growth, over time, the
oceans become your hunting grounds, as a matter of course. Here, you are governed, not by the sun, the dusk and dawn, but by the tides, especially before you learn watercraft tech., where you still must act as land-based organisms.
So, when the tide's low, and it's the middle of the day, you can't afford yourself the luxury of a siesta, ceasing your farming, hunting, and gathering, for a while. Out you must go, into the shallows, with the sun belting down upon you, in order that you may gain your sustenance and feed your village.
Our people, those who stem from these coastal cultures, keep nothing back. All their melanin is released — this is documented — so they can better survive the radiation. Furthermore, the extraordinarily rich protein diet, gleaned especially by fisherfolk, presents us with some very interesting, somewhat novel potentials, like leisure-time, and, consequently, art production — or so the story goes
