This leaves four turtles alive: One male turtle living in Suzhou Shangfangshan Forest Zoo, the female turtle in Dong Mo Lake in Vietnam, perhaps another one in Dong Mo Lake, and another one in Xuan Khanh Lake in Vietnam. Scientists don't know whether the Xuan Khanh lake turtle is male or female. Scientist Tim McCormack thinks the two lake turtles became trapped when people built dams on their rivers. Scientists say there might be more in other lakes and rivers. Some scientists have gone on boats to look for them.