Safari Books Online, the folks who bring O'Reilly's menagerie of books and thousands more online in the form of an implement. And when the blade started to take shape, he put a spray of saliva along the leading edge to sharpen it. That’s when what they call the “shit knife” took form. He used it to butcher a dog. Skinned the dog with it. Improvised a sled with the dog’s rib cage, and then, using the skin, he harnessed up an adjacent living dog. He put the shit knife in his belt and disappeared into the night. TED Talk: Wade Davis, Cultures At the Far Edge of the World" book (eBay)