This unbridged gap between the ape-like australopithecines and the abruptly appearing human-like members of our genus challenges evolutionary accounts.
Underlying the significant differences in brain — to say nothing of the vast difference in mind — is a genetic mystery.
Woodpeckers absorb 1200 to 1400 g shock driving their beaks into wood — but a shock absorbing skull doesn’t explain the absence of damage.
Brains are not simple, so many “just common sense” theories have fallen by the wayside.
Scientists clash over how to measure animal intelligence: brain volume, brain organization, numbers of neurons…?