The coipo is the largest rodent in the country, measuring between 40 to 60 cm. in length, plus a tail of 30 to 45 cm, and weighing between 5 and 9 kg.  It's an acquatic animal just like the beaver. However, instead of having a paddle-shaped tail, the coypou has a long and rounded tail, just like a mouse. Its paws have membranes that allow it to swim.
Builds subterranean refuges and floating platforms that uses for shelter, feeding and rest.

Family: Myocastoridae

Distribution: Lives from the Elqui to Malleco Regions (4th and 9th), from the sea level up to 1.100 m in altitude.

Habitat: Found in fresh water areas: swamps, meadows, rivers on flat zones, lagoons, riversides and wet areas where there's always a lot of acquatic vegetation like reed mace.