My argument for why Neanderthals were monogamous and probobly later Cro-Marnon to a certian extent also, Monogamy seems to be a uniquly European trait up until quite recently historically. If you look up chinese Emporers of the past you will see that some of them had up to 200,000 wives and that they castrated the men (Eunics) that were tasked to gaurding these females so as not to be able to impregnate them whereas the less wealthy individuals would have only been able to afford 1-2 wives to bear their children. Sexual Dimorphism is greatest in African societies where there is an extreme difference in height between males and females. In societies with a high degree of sexual dimophism it has been observed that the duties of mles and females varies greatly with the men hunting while the females stay close to home to both rear the children as well as gather berries and local naturally occuring wild edibles and food sourses and tend to the household and mend clothing, this was not so with Neanderthals as much, there was only a 1-4 inch height difference between males and females in Neanderthal Society meaning Females took part in the hunt of large predators while the elderly minded the children. Monogamy is the Natural way of Europeans as we have inherited this behavior from Neanderthals, it promotes in group harmony and cohesion, so the modern trend towards women being attracted to men that are tall is a primitive trait and a leftover remnant of the polygamous genes we inherited from archaic homo sapiens when Neanderthals Bred with them. Monogamy also seems to go along with nomadic cultures who are more peaceful and non territorial whereas Polygamy seems to go along with more sedentary cultures where there is more tribal warfare amoungst males for the competition of the ownership of both territory and females. Not saying you should marry a manlett but someone who is only slightly taller than yourself is the monogamous Neanderthal way. ... https://www.youtube.com/watch?v=RzQ56CpdF6U