An old paleontological in joke proclaims that mammalian evolution is a tale told by teeth mating to produce slightly altered descendant teeth. - Stephen Jay Gould

[G]enes make enzymes, and enzymes control the rates of chemical processes. Genes do not make “novelty seeking” or any other complex and overt behavior. Predisposition via a long chain of complex chemical reactions, mediated through a more complex series of life's circumstances, does not equal identification or even causation.

I am not […] asserting that humans are either genial or aggressive by inborn biological necessity. Obviously, both kindness and violence lie within the bounds of our nature because we perpetrate both, in spades. I only advance a structural claim that social stability rules nearly all the time and must be based on an overwhelmingly predominant (but tragically ignored) frequency of genial acts, and that geniality is therefore our usual and preferred response nearly all the time. […] [T]he center of human nature is rooted in ten thousand ordinary acts of kindness that define our days.

A foltos hiénáról írt legújabb tanulmányok szerzői úgy találták, a hímek és nőstények annyira hasonlítanak, hogy nemüket biztonsággal csak a herezacskó megtapintásával lehet megállapítani.