Wyoming’s arid basins and prairies lie in the rain shadow of great mountain ranges, and the shortgrass prairie of eastern Wyoming and Colorado is all that remains of this native grassland type. Buffalo grass and grama grasses typify this prairie, where short grasses grow on arid, windblown plains along the Rocky Mountain front. Water is limited to a few potholes filled by early snowmelt and holding water into early summer, while people have pumped water with windmills to create summer-long supplies for livestock and wildlife, and some buttes provide spring and seep water. For wildlife on the prairies, however, the rivers such as the Belle Fourche are the lifeline, providing water year-round. The winding Belle Fourche bisects many coulees and breaks and places water within daily travel distance of large numbers of wildlife. Large cottonwoods and lush vegetation grow near the riverbanks, providing food and shelter for pronghorn antelope, jackrabbits, sage grouse, mule deer, and other wildlife that live on the shortgrass prairie. In arid areas especially, water is essential to maintaining Wyoming’s abundance and diversity of wildlife.