I think Survivorman can eat what ever he wants, because hes really out there alone with just a few things and a camera. If he finds a snake or what ever, he will eat it because hes hungry with no other means of eating.

ManvsWild on the other hand is a fake, and I would probably die if I got lost in his care. If He sees a snake, he probably calls up his producer to see if they can save it for later because he just ate a Bigmac from the store right out of view of the camera man and is full.