Dark, slate gray under-fur overlaid with long, glossy, dark brown or yellowish brown guard hairs. This large rodent can reach a total length of 0.9 m (3 ft) and weigh up to 15.9 kg (35 lbs). General size and shape of a Beaver but with a long, round, sparsely haired tail.
The Nutria breeds throughout the year and produces 4 - 8 offspring per litter. Females can produce two litters per year. At birth, the young are fully furred and already have erupted teeth. Although the young nurse for up to 2 weeks, they also can begin feeding on vegetation within a few hours after birth. They reach sexual maturity at 4 months but usually do not breed until they are at least 8 months of age.
This native of South America was originally introduced into California in 1899 and into Louisiana in 1938. The Nutria has invaded a variety of aquatic habitats, including swamps, marshes, and the margins of lakes and rivers. It can even survive in salt-water environments. The Nutria can often be seen moving about in the daytime but it is most active at night. Inn a stream bank or levee, it will dig a burrow up to 1.2 m (4 ft) long with an entrance at each end. It also builds "beds" beneath overhanging or collapsed marsh vegetation as places to rest, feed, or give birth to young. These "beds" are made of a pile of reeds and sedges slightly above water line and close to the water's edge.
The Nutria is now common to abundant in Gulf coastal marshes and along major waterways on the Coastal Plain. There are populations established on both the Atlantic and Pacific coasts as well.
The introduction of Nutria has had both advantages and disadvantages. The fur of Nutria has value as a pelt, and its ability to eat large quantities of aquatic weeds and vegetation has sometimes been of benefit in certain areas. On the negative side, the Nutria's hefty appetite has led to destruction of rice crops and native vegetation essential for wildlife. Nutrias also cause problems by damaging dikes and levees with their burrows.
The Beaver has an obvious wide, flat tail, and its fur is reddish brown.