Regardless of one's training, you cannot be prepared to survive any environment. I went through survival school when I was in the Army; in those long-ago days it was called EES or escape, evasion and survival (I think). I thought then, and think now that the training I received was more aimed at building individual confidence than anything else. Too many in the military, especially those from cities, just gave up when confronted with an EES situation. This was especially so during the Korean conflict; EES training was aimed at rectifying the situation by teaching soldiers, Marines and airmen that even if you were alone and unequipped, if you kept your wits about you could, not would, survive and escape capture. Sadly, this training gave a lot of military people the notion that they could survive anywhere, anytime, and in any conditions; in many cases, this false confidence has carried over into civilian life.

Survival depends on training but also on circumstances. If one were to wind up in Antarctica, lightly clothed and without food, fuel and shelter you would die regardless of how well one was trained. The same applies with the desert. Survival in a temperate forest with full kit is another matter entirely.

I live in the desert and am intimately familiar with it, it's denizens, finding water and problems of travel. Again, if someone were to find themselves 80 miles from water in mid-summer, on foot, without gear and without water, survival would be problematic, at best, regardless of training. I also spent six months in Antarctic and have a keen appreciation for one's dependence on gear, fuel and food for survival there.

There are a lot of environments where the best survival strategy is to just get out of there as quickly and elegantly as possible. Eating a marmot or Pika (Perish the thought!) is a pale substitute for an expeditious walk to the nearest hamburger restaurant and, in fact, food is probably one of the less important requirements unless it is a marathon survival situation.
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May I walk in beauty.