Then he began to perfect himself in the art of following a human being through the forest.

Except a few old Indian trails, which the rain had half obliterated, he had no tracks to discover save Wetzel's, and these were as hard to find as the airy course of a grosbeak.

On soft ground or marshy grass, which Wetzel avoided where he could, he left a faint trail, but on a hard surface, for all the traces he left, he might as well not have gone over the ground at all.
Joe's persistence stood him in good stead; he hung on, and the more he failed, the harder he tried.

Often he would slip out of the cave after Wetzel had gone, and try to find which way he had taken.

In brief, the lad became a fine marksman, a good hunter, and a close, persevering student of the wilderness.