Green’s Dictionary of Slang

(US, Western) a Native American.

1925		Z. Grey Vanishing Amer. 129: Your tribe of gut-eaters are too ignorant to see anything, let alone the white man’s religion [HDAS].
1965		Fink et al. Major Dundee [film script] Don’t look like them gut-eaters was gonna feed ’em very good [HDAS].
2005		C. Ellis et al. Powwow 147: As the boy rounded the bases, a white man next to her yelled, ‘Come on, get that little gut-eater out.’.