The scientific name of the Nutria (Myocastor coypus) comes from the greek myo (mouse) and caster (beaver); coypu is the name for this species in its native South America.

Nutria were introduced into Louisiana from Argentina in 1938. As a result of escapes and later releases, they became widespread across south Louisiana in a mere five years, eventually spreading across the state and causing the rapid decline of the native muskrat.