Some years ago I read a book by a European anthropologist that created quite a stir because of its theory on the effects of cannibalism on evolution.
The thesis of the book was that the human-to-be species were—or became—cannibalistic. The eating of the brain tissues somehow related to the release and assimilation of ‘smart’ ‘vitamins’ or ‘calories’ or produced extra brain gene material-—and that’s why humans got smarter than apes or chimpanzees or giant sloths for example.
(I forget what he called the process so that proves I’m not a cannibal???).
Over millenniums that accretion of whatever the brain tissue gave to the diet accounted for the evolution of Man into a more sentient species than the rest, able to visualize and build tools and otherwise outwit their competition.
He had lots of diagrams and notes in the book to make his case.
I know, I know, it’s a wild theory, but something has to account for the quantum jump in IQ in the evolution of one species to the top of the evolutionary ladder.
Personally, I believe we are ‘cattle’ being raised on this planet for the amusement of little green aliens until we are ready for harvesting.
Neanderthal.
Oh, Mom, we had Neanderthal last night!