Refered from the bible story of israelites moving from egypt through the guidance of moses to canan. Thats what the animals do when they dont have plenty of food due to draught they prefer moving from one location to another in such of greener pastures. An examples is the movement of wildbeast from Maasai mara game reserve in Kenya to Serengeti national park in Tanzania and vice versasize 60cm x 40 cm
