Great story of survival. Part of that I would think could also be attributed to them being acclimated to that climate. When I moved to South America at first the heat would sap all my strength in a relatively short period of time but as time went on and I acclimated I could then handle the constant heat. When just standing around in the sun we Americans would be sweating like there was no tomorrow yet you couldn't see a bead of sweat on the natives. Would also think that being familiar with living in that environment and knowing the perils associated with it they would most probably go into survival mode relatively quickly.
LTM,
Don