The state is home to many animals and plants, including the endangered boreal toad, a small frog native to the Rockies. There are also cattle in the high plateaus and valleys, and bison in the eastern third. The river that flows through Colorado, the Colorado, was named red by Spanish explorers after Native American firebrands. While some people say the state is as red as its mountains, other history sources claim that the name comes from a Spanish word meaning "red." Regardless of who named Colorado, it has a colorful history and natural beauty.