Well, we had a rather interesting observation while birding at The Pinery recently. While I was photographing birds a lady hurriedly approached me and was frantic about me getting an image of this creature in the water, which I assumed to be a Muskrat. She insisted and was adamant that it was a Nutria, something I’d never heard of. We realized that this indeed was very large for a Muskrat and had an enormously long round tail (there is even more tail under the water in my image) and that it definitely was not a Beaver. Personally, I was extremely skeptical until we questioned Pinery staff which, to my surprise, had very mixed reactions from like us skeptic to yes, it’s possible. They asked me to send in all my images, which I have done. When I posted on iNaturalist all replies were Muskrat. However, it got me curious, and here is some info on this incredibly invasive species which was brought to North America for its fur, is all over the United States apparently and has just started to invade Canada, especially in British Columbia.
The Nutria is a large, invasive, semi-aquatic rodent that resembles a beaver or muskrat and originates from South America. They typically inhabit areas adjacent to bodies of water but can adapt to a variety of habitats. They are most active from dawn until dusk but can be seen at any time of the day. Female nutria are highly reproductive, capable of giving birth multiple times in a single year. Beyond their native range, there are no natural forms of population control, allowing nutria populations to establish and grow rapidly. They are voracious herbivores, known for clearing areas of their vegetation before migrating. Coupled with their proficiency in traveling both on land and in water, nutria pose a significant threat to the environment, particularly wetlands. They serve as vectors for a number of pathogens and parasites that are harmful to humans and livestock.
Nutria measure approximately two feet in length and weigh between 15-20 pounds, with males being slightly larger than females. Upon first impression, they closely resemble and are often mistaken for beaver or muskrat. Nutria, however, are smaller than beaver but larger than muskrat. They have a large head, dark-brown fur, and solid body that often appears hump-backed when on land. Their eyes, ears, and nostrils are located higher up on their heads allowing them to remain above the waterline while swimming. The females’ four mammary glands, situated on either side of their body, supposedly facilitate a similar function, allowing their young’s noses to remain above the water’s surface while they feed. Their hind feet are partially webbed, making them highly effective swimmers.
Nutria have relatively large front teeth that are typically yellow or orange in colour. They have long white whiskers that protrude from both sides of their nose and are noticeable from far away. Their tails are large and rat-like in appearance, measuring up to 45 cm (17.7 inches) and containing thin bristly hairs on the surface. Comparing the nutria tail to the flattened, broad tails of beavers and the thinly flattened tails of muskrats effectively distinguishes them from one another.
All information here was garnered from the Invasive Species Center website.
