As with other cetaceans, Chilean dolphins turn black after death. Once called the 'black dolphin', the Chilean dolphin was little known in the wild so the name was due to the paucity of wild "live" observations. Local fishermen knew of them, as they were hunted for use as bait and food and despite now being illegal, this practice is thought to continue to this day, albeit in reduced numbers.
The Chilean dolphin is one of the world's smallest cetaceans. It has a small stocky body with a conical head, low sloping forehead and no beak. There are between 58-68 small pointed teeth in the upper jaw and 58-66 in the lower one. The dorsal fin is low and rounded, the flippers small and also rounded, and there is a notch in the middle of the flukes. The flukes and dorsal fin have concave trailing edges. The body is grey, with a lighter grey melon and dark lower jaw which extends into a black band to the flippers. There is a also a diagnostic black band extending from the blowhole to just above the eye and it has a distinctive white throat as well as a white patch behind each of the flippers. The belly is white with grey markings around the genital slit which vary between sexes. In the wild it may be confused with the spectacled porpoise or the Burmeister's porpoise, but the placement of the dorsal fin and the rounded shape at the top of the fin is a distinguishing feature. Attention to the dorsal fin will lead to correct identification.
There is little information on the behaviour of this species, but it has been described as shy, difficult to approach, and slightly acrobatic. It can be observed in groups of 2 to 15 animals, though larger concentrations have been observed. It has a peculiar circular or zigzag swimming motion that it uses to herd fish. It can be seen associating with Peale's dolphins and, when it is hunting, as with other Delphinid species, it is often associated with feeding seabirds.
The Chilean dolphin, as can be construed from its name, is endemic to cold, shallow, coastal waters, estuaries, and channels around Chile from 33°S to the tip of South America. It seems to prefer areas with high tidal range and is frequently found in the mouths of fjords, bays, and sometimes entering rivers. They also occur in the Strait of Magellan and channels of Tierra del Fuego. Threats to the Chilean dolphin include hunting for consumption and use as bait in the Chilean crab fishery. It also suffers from bycatch and habitat degradation. Aquaculture farms and anti-sea lion nets restrict its natural range, and it is often disturbed by boat traffic. The total population is unknown but thought to be only several thousand. The IUCN Red List categorises the conservation status of this species as Near Threatened (2008).