摘要：Bob Chastain is standing calf-deep in the tumblingwaters of the San Antonio River in eastern Panama,staring intently at the rocky banks and mossyboulders. It’s an overcast morning in late June, andthe leaves of the tropical plants above are stilldripping from an early shower. Here, on the flanks ofauspiciously named Cerro Sapo (Toad Mountain), in aremote part of Darien National Park, Chastain and agroup of other biologists are stalking some small,slippery creatures.
