Time magazine reveals that Neandertal genetics can confer a risk of method acting:
So why is Leto so weird? We learn that, based on the results of a genetic test, Leto can claim a rather different gene makeup than most of us. “I have a lot of Neanderthal in me,” he told Rolling Stone. “Maybe that’s why I’m so good at climbing.” Among other things.
That’s from a profile of actor Jared Leto, soon to be on screens as the Joker in Suicide Squad.