Manu National Park, Peru, which holds 13 species of monkeys among the various types of Amazonian fauna, is praised as a monkey kingdom. Deep in its jungles is a strange open spot about 20 meters in diameter where a peculiar behavior of monkeys can be observed. The monkeys spend a majority of their time up in the canopies of the rainforest, but come down to the ground to consume gluttonously the soil of the spot. The program looks at how this strange behavior most likely developed in the competition for survival in the Manu's rainforests during the ice age.