Aman Lau Lau feeding one of his prized cows sago. Unlike the government-established villages and towns downriver where most Mentawai live and wear Western clothing, communal life in the uma or longhouse affords little privacy; the shamans sing their songs and chant, babies and puppies cry, chickens cluck, pigs squeal, dogs fight all night over food scraps, and cows bellow below the floorboards of the uma. When I caught a dog peeing on my sleeping bag in Aman Lau Lau's house, I used a live ant's nest on the end of a stick to chase it off. This tools gets more use than any other. SIBERUT ISLAND is an isolated jungle paradise lying some sixty miles west of Padang, Indonesia. Although Siberut is part of the Mentawai Archipelago, famous the world over as the "Last Frontier of Surfing," it is extremely difficult to reach - especially if you want to visit the heavily tattooed Mentawai people who call the interior of this island home. To get here, you must first endure a bumpy, stomach