Cro-Magnon man had a larger brain and better muscles than modern man. Until recent times, they stood taller, too.
In most of the places where modern humans live, the very largest predators have been wiped out or driven to the margins and this has held true in some long-civilized places as far back as we can find records. There aren't any raptors big enough to hunt adult humans, for example, though there used to be.
So: large, strong, healthy, big-brained hunter-gatherers, who were on the planet for a long, long time, building mostly of perishable materials-- What big thoughts did they think? How closely did they manage their environment? We don't know; they didn't leave us anything obvious.
Or did they? They left us a safer world, a world where if you know what you're looking at, there's plenty to eat in a vacant lot or forest, where dire wolves, wooly mammoths and sabertooth tigers have been rubbed out, a world where you can survive even if you're slower, weaker, dumber--
Are we the Eloi, living in the ruins left us by giants?
T. R. MCELROY'S STREAMLINED TELEGRAPH KEYS
7 months ago