Bakhtiaris were semi-nomadic and their livelihood depended on the survival of their herds of sheep, cattle, and horses. Migration of the tribe in search of greener pasture by crossing over the great snow-clad mountains of Zard e Kuh and braving the icy rivers while carrying their worldly possessions, have been subject of books and films. Merian Cooper in "Grass", published in 1925, captures the best-known account of such migration vividly in picture and text.