Commerson’s dolphin is one of four dolphins in the genus Cephalorhynchus. Commerson’s dolphin has a very distinctive patterning. It has a black head, dorsal fin, and fluke, with a white throat and body. This stocky creature is one of the smallest of all
cetaceans growing to around 1,5 m. Its appearance resembles that of a porpoise, but its conspicuous behaviour is typical of a dolphin. Sexes are easily distinguished by the different shape of the black blotch on the belly — it is shaped like a teardrop in males but is more
rounded in females. The dolphin is found in two geographically disparate areas:
the southern coast of South America around Puerto Deseado, Tierra del Fuego and the Falkland Islands, and
waters near the Kerguelen Islands in the southern part of the Indian Ocean.
There are two subspecies. Commerson’s dolphin is very active. It is often seen swimming rapidly on the surface and leaping from the water. It also spins and twists as
it swims and may surf on breaking waves when very close to the shore. It
will bow-ride and swim behind fast-moving boats. It is also known to
swim upside-down, which is thought to improve the visibility of its
prey. This dolphin feeds on a mix of coastal and pelagic fish and squid. Those in the South American subpopulation supplement their diets with crustaceans.