From “Meat Eating Behind Evolutionary Success of Humankind, Global Population Spread, Study Suggests” (ScienceDaily, Apr. 20, 2012), we learn,
Learning to hunt was a decisive step in human evolution. Hunting necessitated communication, planning and the use of tools, all of which demanded a larger brain. At the same time, adding meat to the diet made it possible to develop this larger brain.
“This has been known for a long time. However, no one has previously shown the strong connection between meat eating and the duration of breast-feeding, which is a crucial piece of the puzzle in this context. Eating meat enabled the breast-feeding periods and thereby the time between births, to be shortened. This must have had a crucial impact on human evolution,” says Elia Psouni of Lund University.
What impact? Lund’s team claims that human weaning times are the same as those of other carnivores rather than those of omnivores/herbivores such as the great apes, and are dependent on the brain stage of the offspring.
Her team’s thesis about weaning times being dependent on brain stages is promising, but it is far from clear that our ancestors chiefly ate meat.or that eating meat is responsible for big brains. Humans do not require meat in order to live, and whole, complex societies have been mostly vegetarian for millennia. And what about the weaning times?
Ah yes, we hear,
“That humans seem to be so similar to other animals can of course be taken as provocative. We like to think that culture makes us different as a species. But when it comes to breast-feeding and weaning, no social or cultural explanations are needed; for our species as a whole it is a question of simple biology. Social and cultural factors surely influence the variation between humans,” says Elia Psouni.
This confused statement brings us back to weaning. If “social and cultural factors surely influence the variation between humans,” how can weaning be a matter of “simple biology”? Simple biology is what social and cultural factors presumably do not influence.
Because breastfeeding suppresses ovulation, earlier weaning would doubtless result in more births. But what happened after that is anyone’s guess. So we end where we began.
This story is a classic of a certain type of human evolution thesis: Find some way that humans differ from great apes and make it The Explanation for why we are not screaming naked in the trees.
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