Cambodians enjoy passing on traditional folklore, and stories about the Mekong dolphin's origin have been told for generations.
Traditionally, the dolphin was neither hunted, nor its meat eaten. It is believed to be bad karma to kill a dolphin.
One tale is of a beautiful girl born to a poor family in a village along the river. One day, she met the son of a wealthy man from the next village and they fell in love.
But the rich father wanted his son to marry a girl from another wealthy family.
The poor girl, however, was pregnant with the rich man's child. As her stomach got bigger, her parents realised that the rich man's son had deserted her. Her parents scolded her, but she did not shed a tear because she believed the boy would return to her.
Then one day she went to his home, but he did not accept her. She returned to her parent's home so distraught that she resolved to commit suicide.
The next day, she walked to the river and put a heavy bowl on her head. With three incense sticks in her hand, she prayed not meet any men in her next life. Suddenly, there was a big storm and a whirlpool sucked her body into the river.
The girl was then reborn as a dolphin; the bowl on her head is the reason that Cambodian dolphins today have round heads.
It is also believed that when Cambodian men die in the Mekong River, it is the girl taking her revenge.
From
http://ipsnews.net/mekong/stories/myths.html