Querechos lived "in tents made of the tanned skins of the cows (bison). They dry the flesh in the sun, cutting it thin like a leaf, and when dry they grind it like meal to keep it and make a sort of sea soup of it to eat. ... They season it with fat, which they always try to secure when they kill a cow. They empty a large gut and fill it with blood, and carry this around the neck to drink when they are thirsty." Coronado described many common features of Plains Indians culture: skin tepees, travois pulled by dogs, Plains Indian Sign Language, and staple foods such as jerky and pemmican. Siouan language speakers may have originated in the lower Mississippi River region. They were agriculturalists and may have been part of the Mound Builder civilization during the 9th–12th centuries. Wars with the Ojibwe and Cree peoples pushed the Lakota (Teton Sioux) west onto the Great Plains in the mid- to late 17th century. The Shoshone originated in the western Great Basin and spread north and east into present-day Idaho and Wyoming. By 1500, some Eastern Shoshone had crossed the Rocky Mountains into the Great Plains. After 1750, warfare and pressure from the Blackfoot, Crow, Lakota, Cheyenne, and Arapaho pushed Eastern Shoshone south and westward. Some of them migrated as far south as Texas, emerging as the Comanche by 1700. European explorers and hunters (and later, settlers) brought diseases against which the Indians had no resistance. Between a half and two-thirds of the Plains Indians are thought to have died of smallpox by the time of the Louisiana Purchase. The 1837 Great Plains smallpox epidemic spread across the Great Plains, killing many thousands between 1837 and 1840. In the end, it is estimated that two-thirds of the Blackfoot population died, along with half of the Assiniboines and Arikaras, a third of the Crows, and a quarter of the Pawnees. Horses The Plains Indians found by Coronado had not yet obtained horses; it was the introduction of the horse that revolutionized Plains culture. When horses were obtained, the Plains tribes rapidly integrated them into their daily lives. People in the southwest began to acquire horses in the 16th century by trading or stealing them from Spanish colonists in New Mexico. As horse culture moved northward, the Comanche were among the first to commit to a fully mounted nomadic