Taxonomy & Nomenclature
Physical Description / Field Identification
This little-known dolphin is robust, with a short, poorly-defined beak. The dorsal fin is moderately low and rounded, and the flippers have rounded tips, much like those of other members of the genus.
The body is mostly gray, with a darker gray band extending from the blowhole to above the eye. There is often darker gray on the sides of the face, and in a wide band from around the eye to the flipper. On the belly are large white patches from behind the flippers to the urogenital area, and from ahead of the flippers to the snout tip. These patches are separated by a dark gray band between the flippers. There are also small white patches in the axillae, and thin gray patches around the urogenital area (the latter are sexually and individually variable).
Chilean dolphins have 29-34 small pointed teeth in each row.
Adults of this species reach at least 1.7 m (size at sexual maturity has not been sufficiently documented). Length at birth is unknown, but is probably somewhat less than 1 m. Chilean dolphins reach weights of up to 63 kg.
Can be Confused With
Chilean dolphins can be confused with Commerson’s dolphins around the southern tip of South America. The large white areas on Commerson’s dolphins will the best clue. Burmeister’s porpoises may also be confused with this species. Here, dorsal fin shape will be the best character to distinguish them.
Distribution
This dolphin is found only along the Chilean coast, from 30°S to the tip of South America. As is true of other members of the genus, it is found in shallow coastal waters, and enters estuaries and rivers.
Ecology and Behavior
Until recently, there have been very few sightings of these animals by researchers, and this is the least-known member of the genus. Groups tend to be small, between 2 and 15 members, but much larger aggregations have been recorded. Although active, they tend to be shy and difficult to approach, but may occasionally ride bow waves.
Most sightings of young Chilean dolphins have been from October to April. Little else is known of their reproductive biology.
Feeding and Prey
Chilean dolphins feed on fish, cephalopods, and crustaceans.
Threats and Status
Chilean dolphins have been hunted for many years for food and crab bait. Up to 1,300-1,500 per year were harpooned in the late 1970s and early 1980s. Such activities are now illegal, but enforcement is difficult. Gillnet catches also affect the species, which is thought to number in the hundreds or low thousands. It is almost certainly threatened, but is currently “Not Listed” (IUCN) and “Not Listed” (ESA).
Links
References
Dawson, S.M. 2002. Cephalorhynchus dolphins: Cephalorhynchus heavisidii, C. eutropia, C. hectori and C. commersonii. pp. 200-203 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.
Crovetto, A. and G. Medina. 1991. Comportment du dauphin chilien (Cephalorhynchus eutropia Gray, 1846) dans les eaux du sud du Chili. Mammalia 55(3):329-338.
Goodall, R.N.P. 1994. Chilean dolphin Cephalorhynchus eutropia (Gray, 1846). pp. 269-287 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Volume 5: The first book of dolphins. Academic Press.
