I love this film!
Two scenes stick out in my mind.
The first is when Charles Martin Smith is going across the ice and has his misshape.
The second scene is where Martin decides to "mark" his territory like the wolf's do ;D
That scene of him running around the perimeter of his camp was just hilarious.
I can't "mark" my territory when on a paddling trip without that scene popping into my mind's eye ;)
That was a classic movie, great acting and managed to educate with humor and intelligence.