1911 .45
For survival, I suggest that .22LR papoose because it's light, it breaks down for easy carry, it runs dirty, and you can carry plenty of ammunition. Contrary to popular myth, .22LR can take down a deer inside 75yd. For the defense side of things (including large animals, 2 and 4 legged), pack a 1911 .45ACP or Glock 10mm with the right lube for whatever environment you're going to be in. The combined weight/space claim of the .22LR and sidearm is less than that of most larger-caliber rifles, and serves your purposes quite well in my opinion.