I enjoyed this sentence. (: Keep up the creative phrases! It keeps things interesting.
Well-known would be stretching it, but it's known by some and understood by most.
Is this referring to, say, someone with little ability in a group of people of great ability, or is it referring to the "Elephants are afraid of mice" idea and thus conjuring up images of a mouse causing a herd of elephants to panic and stampede?
It's closer to the former, but often has as much to do with perceived ability as actual ability.
It could be referring a small and unknown company trying to compete with several bigger and well-known ones for a contract, for instance. They may be just as capable, but as they're smaller and less known they're still the underdog.
Or to a young PhD student, having been invited to a dinner with their supervisor and a group of other talented scientists with long and successful careers behind them. He or she might very well feel like a mouse among elephants - or indeed a man among giants - while nervously trying to come up with something clever to say in such erudite company.
How come "A mouse is among the elephants." is incorrect, if it is?
"is among" and "among," are, (I'd argue), pretty much the same thing in English. Besides, it seems much more natural to me to say "is among" rather than simply: "among," within the context of this sentence in Norwegian especially, that's why I was wondering. I'm no grammarian, I just simply don't see a meaningful distinction, (I'm not saying that there isn't one). Sure there is no "er" in the sentence, but it's not as if in other Norwegian sentences the implication of the present "am/is/are," is absent in a translation, despite there not being an "er" in the Norsk setning. . . Here's a example: Hun kjører på sporet. Which is, (please correct me if wrong), translated as: "She is running on the track."
This is a sentence fragment, which would be used in sentences like "I was feeling like a mouse among elephants". Adding an "is" changes the meaning to something else than what is meant in the Norwegian version.
What you're describing in your example is how the English present continuous tense is translated into the Norwegian present tense. The "is" is removed there, as it's an auxiliary verb forming a verb tense that simply does not exist in Norwegian. The main verb still remains.
I think it's exacly opposite. "a man among the giants" would be better.
Also, thanks for interesting AND useful excercise.
"A mouse among elephants" is an expression, kind of the opposite of "a giant among men." So while "a mouse between elephants" is similar in a literal sense, you probably wouldn't say it that way unless you were talking about an actual mouse between a couple actual elephants.