There is also a very considerable variation in habits. As compared with the mule-deer, the whitetail is not a lover of the mountains. As compared with the prongbuck, it is not a lover of the treeless plains. Yet in the Alleghanies and the Adirondacks, at certain seasons especially, and in some places at all seasons, it dwells high among the densely wooded mountains, wandering over their crests and sheer sides, and through the deep ravines; while in the old days there were parts of Texas and the Indian Territory where it was found in great herds far out on the prairie. Moreover, the peculiar nature of its chosen habitat, while generally enabling it to resist the onslaught of man longer than any of its fellows, sometimes exposes it to speedy extermination. To the westward of the rich bottom-lands and low prairies of the Mississippi Valley proper, when the dry plains country is reached, the natural conditions are much less favorable for whitetail than for other big game. The black bear, which in the East has almost precisely the same habitat as the whitetail, disappears entirely on the great plains, and reappears in the Rockies in regions which the whitetail does not reach. All over the great plains, into the foothills of the Rockies, the whitetail is found, but only in the thick timber of the river bottoms. Throughout the regions of the Upper Missouri and Upper Platte, the Big Horn, Powder, Yellowstone, and Cheyenne, over all of which I have hunted, the whitetail lives among the cottonwood groves and dense brush growth that fringe the river beds and here and there extend some distance up the mouths of the large creeks. In these places the whitetail and the mule-deer may exist in close proximity; but normally neither invades the haunts of the other.