Kirk's eyes widen a little bit, though it's more holy-shit-what-is-that-because-that-is-kinda-cool than a fearful response. "I'm fine, thanks... what is that?" And it belatedly occurs to him that flat-out asking might be rude. You can never tell with different species and different cultures, and he's wracking his brain to come up with any lizard-people besides the Gorn and coming up pretty much empty.