I came across this animal eating at the side of the walking path while walking along the river last week. I didn’t know what it was and after searching the internet for a bit, I believe it is a nutria. . . or maybe a muskrat. The nutria is a large rat-like semiaquatic rodent which is considered and invasive species here in Oregon.
Nutria are native to South America and were introduced deliberately into North America for fur farming in the 1930s. In Oregon the species is limited to areas in the southern Willamette Valley and central Coastal Region (I don’t live in these areas). It usually occurs in or adjacent to rivers, lakes, sloughs, marshes, ponds, and temporarily flooded fields.
You can find more information about the nutria here.
I am now thinking that the animal I thought was a beaver in my recent post (here) was actually a nutria or a muskrat.
I’m so confused!!!
Maralee
Through My Lens 
I’m sure I have seen one of these waddling beside the Arno in Florence.
The tale is in the tail. Beavers have a distinctive tail.
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiP3by_v5jLAhVPwWMKHT21CRUQjRwIBw&url=http%3A%2F%2Fskagitnutria.com%2Fwhat-is-nutria.cfm&psig=AFQjCNHZXMf4iSWAQ8N7lNdXfie7XWjxmw&ust=1456681471876104
Sorry, try this link.
Beaver, Nutria, Groundhog, Muskrat.
I wish I could have seen the tail. This wasn’t a very big animal so I’m thinking it may not be a Nutria.
From the whiskers and what little I can see of the hind legs, Muskrat (black whiskers and rear legs not webbed). But, hard to tell from just one picture without something to establish size. The previous picture (the one swimming) shows what looks like a long tail, also making it a muskrat (the other two have tails much shorter than their bodies).
I have some photos that I took of a muskrat, and it sure looks a lot like your animal!