Years ago, at a zoo where I was working, I had a woman run up to me in a panic because "One of your birds is loose!" As I followed her to where she said it was, I tried getting a description from her of what it was, but all she kept saying was that it was a big, black bird - which, depending on your definitions of big and black, could cover a lot of species. Anyway, I finally got there and she froze and, with a trembling finger, pointed to... a Canada goose. Just like the dozens of others that were all over the park, and which she must have walked past in the parking lot to get into the zoo. When I told her what it was, she acted like she'd never heard of one before, and asked if I was *sure* it wasn't a zoo bird.
This was an adult woman, with no discernable accent to suggest she was from a foreign location, apparently sound of mind and body, who either was 1) an epic troll, or 2) had no idea what a Canada goose was.
Likewise, when I was in college, I had a classmate react in shock and amazement when an animal walked across the path in front of us on our way to class. It was a groundhog. My classmate, an ANIMAL SCIENCE major, who lived in New York state for her entire life, was unfamiliar with the species.
I guess what I'm saying is, the prospect of someone seeing a relatively common species such as a muskrat or beaver and not knowing what it is doesn't strike me as all that implausible
