Anatomy: Nutrias range up to about 3 ft (0.9 m) long and weigh up to about 35 pounds (16 kg). They have reddish-brown outerfur and a soft dense, gray underfur (the valuable underfur of this rodent is also called nutria). Webbed toes on the hind feet help this mammal swim. It has a long, cylindrical, sparsely-haired tail. The ears are small and the legs are short.

Diet: Nutrias are herbivores (plant-eaters); they eat fresh-water plants, leaves, stems, roots, bark, and grains. Like all rodents, their two front teeth continue to grow throughout their lives, and the nutria must gnaw and chew to wear these teeth down.

Reproduction: Females give birth to a litter of 4-6 young in a litter. Newborns have hair and teeth at birth; their eyes are open as newborns. Nutrias are mature at about 6 months of age. Adult females have 2 to 3 litters each year.

Predators: Predators of the nutria include wild cats, red wolves, large snakes (like the anaconda), and people (who raise and kill nutria for its soft undercoat and its meat). When in danger, the nutria often goes into the water; it is a strong swimmer (but is clumsy on land).

Classification: Kingdom Animalia (animals), Phylum Chordata, Subphylum Vertebrata (vertebrates), Class Mammalia (mammals), Order Rodentia (rodents), Suborder Hystricognathi, Family Myocastoridae, Genus Myocastor, Species M. coypus.