If you watch the Survivorman DVDs and look at the behind the scenes stuff, much of what he does it not pre-planned. He improvises and tries stuff just for the hell of it sometimes. He also openly admits that he's human, makes mistakes like anybody else, and I don't ever recall him refer to himself as an expert in anything.
He does however do a LOT of research on the area he is going to, the local wildlife, plant life, skills, etc. He also trains hard. He runs through the bush with a fully loaded pack and does it without much food just for the practice.
A few more things you just have to respect. He's alone (unlike Bear) and he has to carry all his own equipment. When you see a shot of him walking over the horizon...he has to walk all the way back to get that camera when the shot's done...sometimes that's in -40 weather or half way up a cliff. Plus when he married his wife, they spend the first year or two of their marriage living in a shack in the woods san civilization...if I recall their first kid was born there...or something like that.
http://en.wikipedia.org/wiki/Les_Stroudhttp://en.wikipedia.org/wiki/Survivorman