North American Beaver (Castor canadensis)
We thought this guy (girl?) was an otter when we saw it, but my photos of it clearly show the ears are too big, and you can see what looks like a beaver tail in some of the photos (including this one), so I'm pretty sure it was a (skinny) beaver now.
The North American beaver is one of two extant beaver species. It is native to North America and introduced to Patagonia in South America and some European countries.
Similar species: Rodents

By Joe Spandrusyszyn
All rights reserved
Uploaded Apr 20, 2015. Captured in 74 Park Acre Road, Pittsford, NY 14534, USA.