The coypu (from the Mapudungun, koypu), (Myocastor coypus), also known as the river rat, and nutria, is a large, herbivorous, semiaquatic rodent and the only member of the family Myocastoridae. Originally native to subtropical and temperate South America, it has since been introduced to North America, Europe, Asia, and Africa, primarily by fur ranchers. Although it is still valued for its fur in some regions, its destructive feeding and burrowing behaviors make this invasive species a
This species is native to South America, and has been introduced to North America, Europe, Africa, and Asia (not all these introduced locations are mapped here) (Bertolino 2005). It is patchily distributed throughout its historic range in association with mesic habitats and water bodies. Its distribution in the Patagonian steppe is likely the result of human introduction (Ojeda, Lessa, and Bidau pers. comm.).