Trivia: Johnny Depp's character Rango says "interesting" a few times throughout the movie and while that isn't trivia in itself, the fact that Johnny Depp says it in "his way" in a lot of his movies at some point or another.
Trivia: At the beginning of the movie when Rango is flying around on the highway he lands on the windshield of a red car with a bald man smoking a cigarette, that is a reference to the movie Fear and Loathing in Las Vegas in which Johnny Depp stars.
Trivia: The character Rango was modeled after Don Knotts' character, Barney Fife, from "The Andy Griffith Show".
Answer: TV Tropes mentions that the big eye might be an enormous alligator, because alligators are known to live in sewers.
Alligator eyes are different from what was shown in the movie.