The Atlantic White-sided Dolphin is slightly smaller and more streamlined than his close relative the White beaked dolphin. He is also more pelagic in his ways so that he's not seen as often from shore or whale watching crafts as the other. A swift fast swimmer he hunts small fish in groups that can be counted in the hundreds. The white sided dolphin has a complicated colour pattern on the sides like so many dolphins, but diagnostic to this species is the variably yellowish patch on the dorsal part of the tail-stock, and an almost solid black back that distinguishes him from the white beaked even at a brief glance.