My protagonist is an average human as we know it in a world populated by different animal-like species. The narrator (different character) is a member of a species that resemble polar bears. As far as the characters (including the narrator and MC) are aware, the MC is the only/first human to have ever existed. Hence the word "human" does not even exist: no one has ever seen anything like him before. The problem is, if the narrator has never seen a human before and does not know what a human is, how would he describe the human MC?
What I have written is simply the narrator pointing out all the differences between the MC and the people of that region:
He was all angles and corners where the rest of us were curved. Even Nuktuk, the runt from a few miles seaward, towered a foot taller than him on his toes. His claws were frail, his canines diminutive, and he had to wrap a length of fur around his head to avoid freezing his oversized ears off. Not to mention his blubber — if it could even be called that — which was so lightly packed that when he shed all those pelts and layers his belly barely bulged at all.
I tried to make it clear that the narrator's comments don't make sense in a human context (claws, blubber, etc) to edge the reader in the direction of thinking, "er, wait, isn't he just normal looking??" But the comments I received said that it wasn't clear to them what species he was.
So my question is: does anyone have any ideas on how to clarify that a character is human without using the word "human"?