It is hard to imagine that much of scientific interest would be left in the once pristine jungles of Vietnam, site of almost uninterrupted warfare from the 1940s through the mid-'70s. The conflict with the U.S., with its carpet- bombing and wholesale spraying of Agent Orange, was especially devastating. Thus it was something of a surprise that the first scientific foray deep into the Vu Quang Nature Reserve, near Laos, found what amounts to a "lost world" of animal and plant species.
The most exciting discovery: a large, horned mammal that may be a kind of goat. Scientists brought out bones...