Polygamy comes from the Late Greek word polygamos, meaning “often married.” While viewed as controversial in the Western world, polygamy is a custom that's been practiced by humans throughout history, and is still practiced in many places. It was a distinguishing characteristic of early Mormonism — founder Joseph Smith had more than 30 wives. In zoology, monogamy, or having only one mate, is rare, while polygamy, the mating habit of animals with numerous mates, is much more common.