Scientists say they have discovered a heretofore unknown species of 32 inch-long giant rat within the jungles of Papua New Guinea. The giant rat, among the largest ever discovered, has no fear of humans and was found by an expedition team filming a BBC documentary titled Lost Land of the Volcano, the British broadcaster reported Monday. Expedition members reported the new rat species, which has not yet been named, is believed to live only within the Mount Bosavi crater. This is one of the world's largest rats, Kristofer Helgen, a mammalogist for the Smithsonian National Museum of Natural History in Washington, told the BBC.