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How to Identify a Nutria...


Nutria, or coypu, (Myocastor coypus) are a large, stout-bodied animals that can be easily confused with other species. With careful observation, nutria can be positively identified in the field. 

Adult nutria are large rodents. They are larger than muskrats and smaller than beaver. Adult nutria can weigh up to 20 pounds with total length of about 3 feet. They are found in, or near, water and can be confused with the wholly terrestrial groundhog which has a much smaller tail. Nutria tails are long, round, and finely haired. Beavers have a broad, flat tail. The keeled tail of a muskrat can be clearly seen undulating behind the body while swimming, whereas nutria tails remain still. Nutria also have orange colored teeth not found on muskrats.

The presence of nutria can also be confirmed through the sign they leave. The first three toes of the hind foot are webbed leaving a diagnostic track.  They build burrows, and platforms of floating vegetation 20-30 inches wide and 6-9 inches above the water. This species is primarily nocturnal. Their scat is unique in that it is of a 2-3 inches long and floats. 

Face Characteristics

Nutria have a long, thin rat-like tail unlike the beaver's (broad, flat) or muskrat's (thin, scaled) tails. Muskrat also undulate their tails back and forth while swimming whereas nutria do not.

Comparison of swimming

Click on the images below for a larger version



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