thus, in chinese folklore, river dolphins are usually female and porpoises and oceanic dolphins are usually male; plus, river dolphins are associated with femininity, sex appeal, seductiveness and elegance and are often said to be able to shapeshift into attractive women. also,in china,calling woman a "river dolphin" is considered a compliment and as such,it means she is beautiful and attractive. the association of river dolphins with women may come from the silverry shine of river dolphins' skin that reminds of the moon or crescent moon shape of river dolphins' body when they leap out of water.