How many species of pink dolphins are there?
There are six dolphin species that could be described as pink: three South American river dolphins – the Amazon (or boto) River dolphin, Araguaian and Bolivian; the Ganges and Indus river dolphins of South Asia; and the Indo-Pacific humpback dolphin, a coastal and estuarine species.
Why are pink dolphins pink?
It might be no coincidence that all five river dolphins have poor eyesight. In murky rivers, patterns and colours are likely to be about as redundant as good vision.
So the pinkness might not be the result of skin pigments, but rather a lack of them, which reveals the colour of the underlying blood vessels.