In chapter 4 How did the sapling scare One Eye?

The sapling was actually a trap; this is a perfect example of natural instincts.

"But at the same time there was a suspicious crackling movement beside him, and his astonished eye saw a young spruce sapling bending down above him to strike him. His jaws let go their grip, and he leaped backward to escape this strange danger, his lips drawn back from his fangs, his throat snarling, every hair bristling with rage and fright. And in that moment the sapling reared its slender length upright and the rabbit soared dancing in the air again."