Northern right whale dolphins have an unusually slender body shape, and they do not have a dorsal fin or ridge. They have small, curved flippers, and small flukes. They are mostly black, but they have a well defined white band on their belly. Behavior Northern right whale dolphins usually travel in large groups of up to 2,000 individuals. Average herd size is about 200.
Groups sometimes swim in various geometric configurations, such as a V-shape.
They can swim near the surface without greatly disturbing the water surface, probably because they do not have a dorsal fin. They are known to occasionally perform fluke slaps and breaches. The maximum dive time that has been recorded for them is 6.25 minutes. They often travel with other species of marine mammals, most commonly the Pacific white-sided dolphin. C. They approach shore only where very deep water can be found near the coast.