Table 5. General information on the Great Plains of North America (Wood 1998). Location The Great Plains lay west of the Mississippi River and east of the Rocky Mountains in North America, and make up more than 15% of the USA’s land area across 10 states. Climate The Great Plains have a wide variety of weather throughout the year, with very cold winters and very hot summers. Wind speeds are often high. Vegetation Native vegetation is mainly composed of prairie and steppe. Land use Much of the Great Plains became open range in late 1800s, hosting pastoralism/ranching operations for cattle production. Humans have converted much of the prairies for agricultural purposes or ranches since early 1900s. Animals Livestock including both grazing and grain-fed cattle operations dominate the Great Plains, e.g., it is home to over 60% of the nation's livestock. Some grazing mammals including bison (Bison bison), elk (Cervus canadensis), and mule deer (Odocoileus hemionus) also exist here. Population About 10 million people live in the Great Plains, about 3% of the USA’s population. Social problems Agricultural development and climate change are threatening ranching systems on the open ranges.