In this photograph taken by explorer Chuck Clark, he recorded recently contacted Ashaninka (Campa) Indian children cooking over an open campfire.  Note the use of aluminum pots instead of ceramic pottery.  Anthropologists have discovered that many previously uncontacted indigenous people use western artifacts, such as pots and machetes, long before making contact with Westerners.  Typically, uncontacted tribal groups obtain these modern artifacts through trade with other tribes who are in direct contact with outsiders.