I see your point. This assumes that squirrels are humans, or at least close enough to humans. It would probably be more correct to write "the place was empty".

Or maybe I could remove the word "else." What do you think?

I would say " dark" instead of "darkness"
"darkness" is a concept, but when you turn the lights out, it's just plain "dark".
-----------------------
(Unfortunately someone has cancelled the comment to which you replied) I think the word "else" can stay, when I compare your English sentence to the German. The way I understand it is this: "There was nobody there, and the closest living or breathing being was a squirrel." The squirrel being considered almost human is a good example of anthropomorphism.

This is the original sentence. The German one is only a translation, but I'm sure that it's a good one as it was done by one of our elite translators. :) I think that darkness is better than dark, because it's more literary. But otherwise I agree with your comment and this statement especially: "The squirrel being considered almost human is a good example of anthropomorphism."