Having dealt with literally thousands of people in and immediately after emergency, survival and disaster situations, there is a trait or set of traits I'd rank higher than either intelligence/survival knowledge or physical fitness/endurance in contributing to a successful outcome. Mental and emotional toughness, resilience, flexibility and endurance are the traits that seem to correlate most closely with survival in adversity.

I've seen competitive level athletes in their prime fall apart and frail looking grandmothers in their 80's thrive in disasters. I've seen experienced outdoors-men fold up and highly educated physicians and tough street cops lose it under adverse conditions, while quiet suburban housewives and teenage drop-outs emerged as neighborhood leaders and towers of strength in times of trouble. You just never know how people are going to react to extreme, prolonged stress, until it happens. Some people do well initially, then seem to run dry of inner resources and give up, while others just need a little time or support at first to get their act together, then do fine thereafter. Many others, especially the pro's, go from can to can't, rest up, and go right back to it, time and time again. Generally speaking, most people do pretty good most of the time, and bring on their best game when the situation calls for it. Still, everyone, and I mean everyone, has their limits, and no one knows where theirs is on any particular day. May God grant that we never have to find out.