From National Geographic's Expedition Week comes this unique peek into the lives of Headhunting and shrinking. Supposedly it occurred in many regions of the world. But the practice of headshrinking has only ever been recorded in the northwestern region of the Amazon rain forest. In the Amazon rain forest the only tribes known to have shrunken human heads are the Shuar (mainly), Achuar, Huambisa and Aguaruna, collectively classified as the Jivaroan peoples of Ecuador and Peru. Among the Shuar....