The reason for differences. Some can adapt better and will survive - which leads me to this question....if there are multiple natural disasters which severly compromise our manmade modern creature comforts, who will ultimately survive? The ones who could not kill an animal to eat (no time to grow food in a crisis) or cannot live without a cell phone, who are overweight, unfit and unhealthy, who drive everywhere, who have lost what it means to survive - OR those who live off the land, walk everywhere, can livewithout eating for a day and who know what it means to survive becuase they live it everyday? HMMMMM And you wonder why I took up hunting...just saying!