I don't know. My great grandmother is full blooded Cherokee, and YES I can prove it. She is alive NOW as a matter of of fact. I mean dude, THINK about it. Not everyone walks around with their family tree tucked away in their back pocket. For instance on my fathers side there is some Sioux indian, but I could not tell you exactly where-but my father being very "In" to geneology informed me of this(and showed it to me)....therefore I can "claim" Sioux blood without being 100% sure about exactly where it was.... Plus, if their family settled in America Hundreds and hundreds of years ago (as a good deal of caucasian ancestors DID), there is a pretty good chance that they DO have native american ancestry, and are not just 'claiming' it, as you put it.. Plus, how the hell do you "prove" it? If someone ever asked me to "Prove" to them anything about my ancestry, I'd knock them in the balls. How would you like it if you were telling someone about your heritage and they said "oh yeah??? PROVE it!"......I think that sounds pompous. If you have your doubts (which would more than likely be based on stereotypes of what an "indian" should look like) to the point you need "proof" of their indian-ness, why not just take it as a compliment? Not all people with NA ancestry LOOK like 'indians'.....