This is what intense selective pressure does. Also consider that back then in the days of Noah, humans were extremely collectivistic, which itself can act as another mode of intense selective pressure by placing societal conditions that favor certain attributes in a sort of negative feedback loop kind of thing - you want to have sex with people that have this trait because it's socially encouraged, and it gets more socially encouraged because your parents had sex for that reason.
Tigger traits are traits that could easily have been the result of such a selective spiral. Smart tiggers are nails that stick up so they get the hammer. Inbreeding and social hierarchy jockeying spiral into hyper aggression (see Arabs for another example) and a tendency for muscular development that favors appearance over substance (hence why tiggers can get so big so fast when working out, but they crumple like paper tigers in a fight).
