For fully ten minutes Thor did not move. His eyes took in the hollow, the edge of the lake, and the approach to the timber, and his nose gauged the wind as accurately as the pointing of a compass. The reason he remained quiet was that he was almost on the danger-line. In other words, the mountains and the sudden dip had formed a "split wind" in the hollow, and had Thor appeared fifty yards above where he now crouched, the keen-scented caribou would have got full wind of him. With his little ears cocked forward and a new gleam of understanding in his eyes, Muskwa now looked upon his first lesson in game-stalking. Crouched so low that he seemed to be travelling on his belly, Thor moved slowly and noiselessly toward the creek, the huge ruff just forward of his shoulders standing out like the stiffened spine of a dog's back. Muskwa followed. For fully a hundred yards Thor continued his detour, and three times in that hundred yards he paused to sniff in the direction of the timber. At last he was satisfied. The wind was full in his face, and it was rich with promise. [Illustration: "Like the wind Thor bore down on the flank of the caribou, swung a little to one side, and then without any apparent effort--still like a huge ball--he bounded in and upward, and the short race was done."] He began to advance, in a slinking, rolling, rock-shouldered motion, taking shorter steps now, and with every muscle in his great body ready for action. Within two minutes he reached the edge of the balsams, and there he paused again. The crackling of underbrush came distinctly. The caribou were up, but they were not alarmed. They were going forth to drink and graze. Thor moved again, parallel to the sound. This brought him quickly to the edge of the timber, and there he stood, concealed by foliage, but with the lake and the short stretch of meadow in view. A big bull caribou came out first. His horns were half grown, and in velvet. A two-year-old followed, round and sleek and glistening like brown velvet in the sunset. For two minutes the bull stood alert, eyes, ears, and nostrils seeking for danger-signals; at his heels the younger animal nibbled less suspiciously at the grass. Then lowering his head until his antlers swept back over his shoulders the old bull started slowly toward the lake for his evening drink. The two-year-old followed--and Thor came out softly from his hiding-place. For a single moment he seemed to gather himself--and then he started. Fifty feet separated him from the caribou. He had covered half that distance like a huge rolling ball when the animals heard him. They were off like arrows sprung from the bow. But they were too late. It would have taken a swift horse to beat Thor and he had already gained momentum. Like the wind he bore down on the flank of the two-year-old, swung a little to one side, and then without any apparent effort--still like a huge ball--he bounded in and upward, and the short race was done.