In all of these stages the conjugal and consanguineal regulations are affected by the militant habits characteristic of primitive groups; more warriors than women are slain in battle, and there are more female captives than male; and thus the polygamy is mainly or wholly polygyny.
"The Siouan Indians"
W. J. McGee
polygyny was common; in several of the tribes the bride's sisters became subordinate wives of the husband.
"The Siouan Indians"
W. J. McGee
And what is that but countenancing polygyny?
"Modern marriage and how to bear it"
Maud Churton Braby