The nutria, also known as coypu, is a large, semi-aquatic rodent native to South America. These stout-bodied animals can be mistaken for other species, such as beavers or muskrats, due to their shared aquatic habitats and similar appearance. Nutria were introduced to various regions, including North America, for fur farming, and have since established populations in the wild.
Nutria’s Physical Dimensions
Adult nutria are substantial rodents, weighing between 9 to 20 pounds (4 to 9 kg), though some individuals can reach up to 37 pounds (17 kg). Their body length ranges from 16 to 25 inches (40 to 64 cm). Males tend to be slightly larger than females.
Their tail measures approximately 12 to 18 inches (30 to 45 cm). This means a full-grown nutria, from nose to tail tip, can span about 3 feet (90 cm). Their short legs contribute to a robust, highly arched body shape, which can appear hump-backed when they are moving on land.
Key Identifying Features
Their dense fur varies in color from light to dark brown, with a coarse outer layer of guard hairs and a soft, dense gray underfur. A defining characteristic is their long, round, and sparsely haired tail, which contrasts with the tails of other semi-aquatic rodents.
Their head is relatively large and triangular, featuring small ears and long, prominent white whiskers. One of the most striking features is their large incisor teeth, which are a vibrant orange-yellow color due to iron pigmentation in the enamel. The first four toes of their hind feet are webbed, making them efficient swimmers, while the fifth toe remains free.
Comparing Nutria Size
Nutria are larger than muskrats but smaller than beavers. An adult muskrat weighs around 3 to 4 pounds, while nutria average 11 to 22 pounds. This makes a nutria five to eight times larger than a muskrat.
Beavers, the largest North American rodents, are considerably bigger, with adults weighing 35 to 68 pounds, and some reaching up to 100 pounds. While a nutria’s overall length can approach that of a beaver, the difference in body mass is substantial. A nutria’s round, rat-like tail and orange incisors help differentiate it from a beaver’s broad, flat tail and a muskrat’s laterally flattened tail.