The relationship between social dominance rank and diet quality was examined in pronghorn ( Antilocapra americana ) females at the National Bison Range in Montana. Rank was ascertained by observation of agonistic interactions between study animals. Diet quality of the same individuals was quantified by measuring the concentration of the chemical indicator of forage quality, 2, 6 diaminopimelic acid (DAPA) present in feces. A significant, quadratic relationship was found in which high-ranked and low-ranked females showed high levels of DAPA, and middle-ranked females showed low levels of DAPA. This finding indicated that high and low-ranked females acquired better quality diets than middle- ranked females. I discuss possible explanations for this interesting result which, to my knowledge, has not been anticipated in the literature.