Adaptability is not human nature, it is a trait of all living beings. Human nature is hierarchical because humans are social beings, i.e. tending to organize into hierarchical societies. And yes, it is programmed into us before we are born... 
House cats are true anarchists!
House cats are true anarchists!
No, that's not human nature that is hierarchical (patriarchical). This is the nature of the citizen, but a citizen is not a human. A citizen is a collectivist. A human lived in a stateless non-patriarchal community, for several hundred thousand years. The last 10'000 years only were the epoche of the citizen, the hierarchist, the collectivist, the idiot.
I always thought that collectivism was another word for social nature of humans, individualism being the opposite. If the ancient man hadn't been a collectivist, he would soon have been eaten by predators. I think it is exactly due to collectivism in the first place that we managed to survive as a specie during those wild times...