During the 1840s and 1850s, more than 300,000 traders and overland emigrants followed the Platte and Arkansas rivers westward across the Central Plains, the winter habitat of the bison. By the mid-1870s indigenous peoples at both ends of the grasslands, in places such as the Texas Panhandle and the upper Missouri River valley, fiercely defended the dwindling herds in an attempt to avoid starvation. The Indians' predicament was not theirs alone, however, as Native efforts at self-preservation posed a significant threat to Euro-American plans for the frontier. To that end, government officials on the peripheries of the Great Plains developed a remarkably similar strategy: the use of mounted constabularies to pacify indigenous peoples. Few scholars have situated the efforts of these constabularies within the context of the rapidly changing conditions for Indians on the Great Plains after 1865.