The BBC reports that the Yangtze River dolphin, known as baiji in China, has apparently gone extinct. Its the first mega fauna extinction since the Caribbean monk seal disappeared from the planet in the fifties. Lipotes vexillifer was a member of an ancient mammal family, Lipotedae, that separated from whales and other dolphins 40-20 million years ago. The species was down to about 17 individuals. A six week scientific acoustic and visual survey in the polluted lower Yangtze river sighted no river dolphins in 3500 km of waterway above Shanghai. The only captive river dolphin known as 'Chi Chi' died in 2002. The disappearance of the river dolphin is scientifically significant since it represented an entire evolutionary branch of the tree of life. The extinction is also another example of man's inability to coexist with other species on this planet.Scientists believe that the dolphin was the victim of overfishing, human persecution, pollution, dam construction and shipping traffic. It was nearly blind, and its primitive sonar was easily confused by engine noise. While there may be few surviving individuals missed by the survey teams, the inability to detect them after an intensive search, "indicates that the prospect of finding and translocating them has all but vanished" said a co-author of the London Zoological Society report. Plans were being made to rescue the critically endangered mammal by translocating the few remaining dolphins to an oxbow lake which was part of the Yangtze River until 1970's. But moving wild animals to a safe haven is an expensive endeavor and time ran out on the dolphin.