He learned to know the tracks of all the animals of the region, and even how long it had been since the animals that made the tracks had passed by.

And he learned to make snares and traps, and how to handle his gun--the wonderful gun which Abel told him God had sent with him from the Far Beyond--and shoot it quickly and accurately, for the man who exists upon the wilderness must know how to do these things, and his sense of observation must be keenly trained; and he must train himself to be alert.
One other accomplishment he acquired from Skipper Ed.

He learned to swim.

Even in midsummer these northern waters are icy cold.

From the breaking up of the ice in summer until the sea freezes again in winter, the natives spend their time upon the water or near it, yet it is rare, indeed, that one of them can swim.