In the early 19th century, the Pawnee numbered more than 10,000 people and were one of the largest and most powerful tribes in the west. Although dominating the Loup (ickariʾ) and Platte (kíckatuus) river areas for centuries, they later suffered from increasing encroachment and attrition by their numerically superior, nomadic enemies: the Sioux (or Lakota (páhriksukat / paahíksukat) (“cut throat / cuts the throat”), Cheyenne (sáhe / sáhi), and Arapaho (sáriʾitihka) (“dog eater”); the Pawnee called these collectively as cárarat (“enemy tribe”) or cahriksuupiíruʾ (“enemy”). The Pawnee were occasionally at war with the Comanche (raaríhtaʾ) and Kiowa (káʾiwa) farther south. They had suffered many losses due to Eurasian infectious diseases brought by the expanding Europeans, and by 1860, the Pawnee population was reduced to 4,000. It further decreased, because of disease, crop failure, and warfare, to approximately 2,400 by 1873, after which time the Pawnee were forced to move to Indian Territory in Oklahoma. Many Pawnee warriors enlisted to serve as Indian scouts in the US Army to track and fight their tribal enemies resisting European-American expansion on the Great Plains.