Three years ago, an Indian from the Amazonian backwaters arrived at the house in Manaus, Brazil, of biologist Marc van Roosmalen holding a tin can with a little monkey shivering inside. "'Oh, no. Not another one,' I thought," recalls the Dutchman. He didn't need another monkey. Already he and his wife Betty, an artist, were caring for 50 orphaned monkeys, who swung in and out of mischief in the garden. Gingerly, Van Roosmalen poked a finger at the small ball of copper-colored fur. It squeaked fearfully.
Van Roosmalen, 53, nearly squeaked back, with amazement. An expert primatologist, he was staring at an unknown genus of pygmy marmoset. It was a remarkable discovery; the last time any scientist had identified a new primate genus was in the late 19th century. Trouble was, the Indian knew only that the marmoset had been trapped somewhere near the Madeira River, a 2,000-mile stretch of water flowing into the Amazon from the Bolivian Andes. This clue propelled Van Roosmalen on an epic, nine-month odyssey in which he found far more than the elusive marmosets.
His quest led Van Roosmalen into a previously unstudied region of the Amazon, bursting with biodiversity. So far, he and his colleagues have identified seven never before seen species of primates, a distinct species of peccary (a wild pig), a lost cousin of the Brazil-nut tree and an anthurium with leaves bigger than elephant ears. And best of all, Van Roosmalen stumbled on traces of an agricultural technique--invented by Stone Age tribes around 10,000 years ago--that may help save the Amazon from the damage caused by farmers who slash and burn the forest to clear land.
The Dutchman eventually tracked down his marmosets to a black-water branch of the Amazon, 200 miles southeast of Manaus. A farmer pointed toward the edge of the forest, where five marmosets happily snacked on the resin of a morototo tree. On later visits, Van Roosmalen noticed that the soil of this farm was 3 1/2 ft. deep and richer than any he knew of in the Amazon, where the earth is sandy and gives out after a couple of years, forcing farmers to raze hundreds of square miles of rain forest every year.
Intrigued, he found other patches of this black earth elsewhere in the Amazon. Mixed into this loamish soil was evidence of prehistoric man: charcoal, occasional stone axheads made from meteorites, and a lump of manioc bread preserved in natural tree gum. "If we can find out how these so-called primitives made this soil," reckons Van Roosmalen, "we can use it as an alternative to destructive slash-and-burn agriculture." Unfortunately, since the river tribes that knew the secret were all wiped out by European raiding parties 500 years ago, the scientist must start from scratch.
Besides his monkey business, Van Roosmalen specializes in medicinal plants (he even apprenticed to a shaman of the Kamayura tribe) and in rain-forest conservation. He knew he wanted to do fieldwork when he studied primates in Holland. There Van Roosmalen clashed with his university professors over the value of observing lab monkeys. "It was like putting a child in a cage and drawing conclusions about all Homo sapiens," he huffs.