By John Organ — Polygamous species include those we are quite familiar with: whitetail and mule deer, elk, and moose, where one male may breed several females. Polygamous cervid species display what biologists term sexual dimorphism, meaning the two sexes exhibit differences in some physical features. In the case of cervids, this is represented by males typically having larger body size than females. This is true of many species of mammals that are polygamous.