"It is interesting that although it still occurs in a number of minor cultures today, all the major societies (which account for the vast majority of the world population of the species) are monogamous. Even in those that permit polygamy, it is not usually practiced by more than a small minority of the males concerned. It is intriguing to speculate as to whether its omission from almost all the larger cultures has, in fact, been a major factor in the attainment of their present successful status."