Recent genetic evidence from China shows that these ecotypes may in fact be distinct species which are reproductively isolated . The second morphotype has a longer snout and has been named Tursiops aduncus .
Calves often have a bluish colour.
There appears to be some variation in body colour from location to location. The beak is short and rounded. The lower jaw juts out beyond the upper. The line of the mouth curves up at the back to give an appearance of a 'smile'. The dorsal fin is sickle shaped.