Indo-Pacific Bottlenose Dolphin
Tursiops aduncus

These are the slightly smaller cousin of the Common Bottlenose Dolphin and are found more often in warmer parts of the world, although with a substantial overlap of territory. They tend to be found nearer the shore than the Common and in Adelaide, they will happily cruise well up the Port River. They are usually found in smallish groups and feed on fish and squid, as with most dolphins.
 

1-2: Rottnest Island, WA, 03/12/2011.