i have often wondered about polygamy and the effect it has on a society. it's common with many animals (deer, lions, etc) where a few males monopolize the breeding rights.

1 hand, this tends to select for only strong males breeding. on the other, it limits genetic diversity, can lead to inbreeding problems, and in human populations tends to result in large numbers of unmarried males with no prospect of pairing. that tends to lead to either large scale outmigration, war, or some sort of societal unrest. i wonder if the reason that polygamous systems tend to be transient and seem to have been selected against in modern humans whose survival rates are high lies therein: that societies with lots of unpaired military age males get seriously unstable.