A rare river dolphin found in the River Yangtze in China may be extinct, according to a report published in the Royal Society Biology Letters journals. An international team of scientists could not spot the dolphin after six weeks of intensive lookout. They concluded that the mammal was probably extinct and warned that this was the first whale or dolphin to be doomed to eternity by human activity.
The dolphin also called as baiji, was last spotted in 2004. The WWF campaign group however said that it would be at least 50 years before the animal could be classed as extinct.
"WWF does not think that the baiji dolphin can be declared extinct or 'effectively extinct' because the search was conducted within a short period of time over a limited area of the river," a group spokesman confirmed.
The dolphin (Lipotes vexillifer) was thought to be the only surviving member of the Lipotidae family. The dolphin was reputed to have a low dorsal fin as well as a long and narrow beak. The freshwater animal thrived in groups of three and its staple diet was fish. Scientists theorize that these animals became separate from other whales and dolphins some 20 million years ago.
Co-author of the paper, Sam Turvey of the Zoological Society of London (ZSL), said the inability of the team to find the mammal was a tragedy. "This extinction represents the disappearance of a complete branch of the evolutionary tree of life and emphasizes that we have yet to take full responsibility in our role as guardians of the planet," he added.
The research team carried out their survey in November and December last year. They said that many human activities including construction of dams could be blamed for the dolphin's demise.
"Unlike most historical-era extinctions of large bodied animals, the baiji was the victim not of active persecution but incidental mortality resulting from massive-scale human environmental impacts," the team wrote.
The last survey to trace the Yangtze dolphin was carried out in 1999. At that time scientists were able to trace 13 dolphins.
