It must be remembered, however, that with the mule-deer, as with all other species of animals, there is a wide variability in habits under different conditions. This is often forgotten even by trained naturalists, who accept the observations made in one locality as if they applied throughout the range of the species. Thus in the generally good account of the habits of this species in Mr. Lydeker’s book on the “Deer of All Lands” it is asserted that mule-deer never dwell permanently in the forest, and feed almost exclusively on grass. The first statement is entirely, the second only partly, true of the mule-deer of the plains from the Little Missouri westward to the headwaters of the Platte, the Yellowstone, and the Big Horn; but there are large parts of the Rockies in which neither statement applies at all. In the course of several hunting trips among the densely wooded mountains of western Montana, along the water-shed separating the streams that flow into Clarke’s Fork of the Columbia from those that ultimately empty into Kootenay Lake, I found the mule-deer plentiful in many places where practically the whole country was covered by dense forest, and where the opportunities for grazing were small indeed, as we found to our cost in connection with our pack-train. In this region the mule-deer lived the entire time among the timber, and subsisted for the most part on browse. Occasionally they would find an open glade and graze; but the stomachs of those killed contained not grass, but blueberries and the leaves and delicate tips of bushes. I was not in this country in winter, but it was evident that even at that season the deer must spend their time in the thick timber. There was no chance for them to go above the timber line, because the mountains were densely wooded to their summits, and the white goats of the locality also lived permanently in the timber.[3] It was far harder to get the mule-deer than it was to get the white goats, for the latter were infinitely more conspicuous, were slower in their movements, and bolder and less shy. Almost the only way we succeeded in killing the deer was by finding one of their well-trodden paths and lying in wait beside it very early in the morning or quite late in the afternoon. The season was August and September, and the deer were astir long before sunset. They usually, but not always, lay high up on the mountain-sides, and while they sometimes wandered to and fro browsing on the mountains, they often came down to feed in the valleys, where the berries were thicker. Their paths were well beaten, although, like all game trails, after being as plainly marked as a pony track for a quarter of a mile or so, they would suddenly grow faint and vanish. The paths ran nearly straight up and down hill, and even when entirely undisturbed, the deer often came down them at a great rate, bouncing along in a way that showed that they had no fear of developing the sprung knees which we