 Complete the following phrase:  Arikara scouts were enlisted men from the Arikara Nation serving in the U.S. Army at different frontier posts in present-day North Dakota from 1868 to 1881. The enlistment period was six months with re-enlistment possible. Each scout received a uniform, firearm and drew rations. Scout duties ranged from carrying mail between commands to tracking down traditional enemies perceived as hostile by the Army in far ranging military campaigns. Detailed to secure the horses in located enemy camps, the scouts were often the first to engage in battle. The Arikara took part when the Army protected survey crews in the Yellowstone area in the early 1870s. They participated in the 