I was thinking him being a wolf. After all, if memory serves right, Luke is supposed to be a name derived from the Greek "Lycos" meaning wolf.
If that's not the case, maybe a German Shepherd then (or a Dalmatian).
The german Version of Luke comes from "leucos" (=light, bright, white) , it mean the "one born at dawn / in light".
Luke Skywalker mean "the bright one walking in the sky (chasing the sun or moon)."
Thanks for this interesting information!
