Collectiveness of A Caravan

We all are familiar with the image of a long winding caravan making its way across deserts.A closer look at it will show the essential need of people to work together to achieve a difficult task. Crossing a desert is one task which an individual can not perform on his own, given the high risk involved. So even if there a rich merchant in an oasis, he will never set out on his own but wait for a group to accumulate so that they can set for the journey.