For Plains Indian peoples such as the Arapahos and Cheyennes, who moved into the region after 1800, the buffalo became central to nearly every aspect of life, providing food, hides for clothing, tipi covers, and battle shields, and holding an important place in spiritual life. Once present in immense herds across the prairie, buffalo suffered catastrophic decline during the resettlement of the region in the 19th century, as hunting, farming, and ranching reduced a population that may have reached 60 million in 1800 to only a few hundred surviving in small scattered groups by 1900, narrowly avoiding extinction. The horse, unknown in the Americas before the Spanish arrived in the 1490s, transformed Plains Indian cultures by the 1700s as large wild herds developed and Native peoples adapted it for travel, hauling, wealth, symbolism, and spiritual life; among its practical uses was the horse travois, which replaced the older dog travois long used by the Arapahos, Cheyennes, and others to move possessions. The tipi was a portable, weather-resistant shelter well suited to people who followed the buffalo herds, with a top flap that deflected wind and vented smoke, and clusters of tipis formed relatively mobile villages; women owned the tipi, and in Cheyenne culture a divorced wife remained in the lodge while her husband's belongings were thrown out.