Nutria

Nutria (Myocastor coypus)
Also known as Coypu
Species Code: MYCO

Description: Nutria are large, web-footed brown rodents that are more agile in the water than on land. They live in burrows near a lake or stream. Nutria typically inhabit a riverbank or lakeshore, or dwell in the midst of wetlands where they eat aquatic plants and roots.

Adult nutria average 24 inches long from the nose to the base of the tail. The tail alone is 12-16 inches long, round, and nearly hairless.

Nutria have large incisors that are yellow to orange-red on the outer surface. The head of the nutria is large and almost triangular. Nutria have five clawed toes on each foot; the front feet are not webbed.

The Nutria is sometimes misidentified as a beaver, but it is smaller in size and has a round narrow tail. Nutria can grow larger than a domestic cat. To some people it looks like an giant rat with long wiskers and small ears (see photo). The generic name is derived from two Greek words (mys, for mouse, and kastor, for beaver) that translate as "mouse beaver".

Nutria once lived only in the southern part of South America, but they have been domesticated as fur animals and transplanted around the world. Fur farm escapees quickly establish large wild populations near lakes and wetlands.

Weight: 15 to 22 lbs (7 to 10 kg)

Range / Habitat: The Nutria live in irrigated farmlands, and freshwater wetlands. In the late 1940s, nutria were promoted as biological agents for controlling aquatic weeds, primarily water hyacinth, and were transplanted throughout the US.

In Washington, the Nutria is an introduced species from South America brought here for fur-farming. It first escaped captivity into the Green River in 1935 and has escaped or been released and spread in the lower elevation areas from Skagit County to the Vancouver, Washington area. It is thought that their sensitivity to cold has limited their spread although some are found in Yakima County.

Muskrat

Diet: Nutria are herbivores and consume approximately 25 percent of their weight daily. Nutria prefer eating aquatic plants and roots. They also feast on small animals including snails and mussels.

Behavior: Nutria are capable of swimming long distances underwater. When pursed while underwater, nutria can see and will take evasive action to avoid capture.

Reproduction: Nutria breed year round and are extremely prolific. Nutria can be rather social animals and sometimes live in large colonies. Females have two litters every year, each consisting of five to seven young. Nutria mature quickly and remain with their mothers for only a month or two before they become independant.

Females have four pairs of mammary glands that are located on the side of the body, rather than on the belly. Presumably, this positioning of the mammary glands allow the young to nurse with their nose above the water's surface while the mother is floating.

Did you know?

• In the wild, most nutria live less than three years.
• Nutria can swim long distances underwater.

Nutria

More information:
Nutria - WFW, Living with Wildlife
Nutria Biology