In their extensive and long-continued migrations over a territory composed in large part of lakes, ponds, and rivers, the Caribou have almost daily need, from June to October, of surmounting these barriers by swimming. The low temperature of the water seems to have no deterring effect on them. Yet it appears that some of the animals may fail in attempting the passages of wide waters. Charles Schweder spoke of finding a number of dead Caribou, including bucks as well as fawns, that had apparently succumbed in crossing a 4-mile-wide lake on the Thlewiaza River. (Or had they perhaps come to grief in some upstream rapid and finally been washed ashore on the lake?) Bones on the shore indicated that this sort of tragedy might be more or less of an annual occurrence. Perhaps some of the victims had been wounded or were otherwise in poor condition. The buoyant, hollow hairs of a Caribou’s coat enable the swimming animal to keep almost the whole median dorsal line of its body perhaps 2 or 3 inches above the surface (figs. 9, 12). In a doe noticed on August 28 the lowest point on the top of the neck, just in front of the shoulders, was practically level with the surface, but elsewhere the dorsal line, from snout to tail, was out of the water. In both doe and fawn the head is held so high that the lower side of the snout at the tip does not touch the water; in the older bucks of the autumn, however, the weight of their antlers presses the head down until the lower side of the snout is frequently in contact with the water. The swimming position tilts the antlers backward until the basal portion is practically horizontal (figs. 9, 12). All ages and sexes, while swimming, hold the tail nearly erect; but the very tip (perhaps only the tuft of hairs) inclines toward the rear. [Illustration: FIG. 19. Caribou tracks in mud; one about 114 by 95 mm.; another, 102 by 102 mm. Between Bear Slough and Eider Pond, September 3, 1947.] [Illustration: FIG. 20. Caribou track in 2-inch snow; hind foot superimposed on track of front foot. Combined track about 153 by 127 mm. Camp Ridge, October 29, 1947.] [Illustration: FIG. 21. A Caribou doe (specimen No. 1101). Mouth of Windy River, September 21, 1947.] [Illustration: FIG. 22. A Caribou buck (specimen No. 1111). Mouth of Windy River, September 29, 1947.] [Illustration: FIG. 23. A male Caribou fawn (specimen No. 1095), in its first, woolly pelage. Mouth of Windy River, September 7, 1947.] [Illustration: FIG. 24. Hoofs of a male Caribou fawn (specimen No. 1072); hind hoofs in the middle. Mouth of Windy River, August 21, 1947.] [Illustration: FIG. 25. Enormous set of old antlers of a Barren Ground Caribou, with exceptional palmation. (A 10.5-inch length of a steel rule visible.) Simons’ Lake, October 15, 1947.]