[Clutch Martin]

I know several Blackfoot and they insist that the plural of Blackfoot is Blackfoot. I have seen the common english plural of Blackfoot used on maps, signs leading up to the res etc... but if tribal members themselves use Blackfoot as the plural than I can only surmise that it is indeed Blackfoot.

[pacific_waters]

http://blackfeetnation.com/

[Don W]

There are many nouns that both singular and plural are the same word. Moose, deer, aircraft are the first ones that pop into my head.