Isn't it implied in the film that Tuco is itself an alias, rather than a real name?
Is Tuco a real Mexican name, or made up for the film. I did a Google search and found that "tuco-tucos" are South American rat-like rodents http://www.absoluteastronomy.com/topics/Tuco-tuco, any connection there?"Known as the rat !!!"
Don't they say his whole name one time when they're "hanging" him?
As stated above, Tuco is Spanish for "maimed", and Tuco is also the name of an owl and several cities in South America. Although it's possible (and vaguely appropriate, although said rodents are more like gophers than "true" rats), I'm skeptical of the idea that Leone had much knowledge of South American rodents.
As stated above, Tuco is Spanish for "maimed"...
Agreed. I wasn't advocating for the connection between Tuco and some kind of rodent, I was just pointing out that if there was some kind of connection between Tuco's name and the "tuco-tuco", then it would have to be a post-dub kind of thing because in Italian Tuco's nickname is "The Pig".