(Gray, 1846) - Black dolphin
Distinctive Characteristics
This insufficiently 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 grey, with a darker grey band extending from the blowhole to above the eye. There is often darker grey 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 grey band between the flippers. There are also small white patches in the axillae, and thin grey patches around the urogenital area (the latter are sexually and individually variable).
Black dolphins have 29 to 34 small pointed teeth in each row.
Can be confused with
Black dolphins can be confused with Commerson's dolphins around the southern tip of South America. The large white areas on Commerson's dolphins are 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.
Size
Adults of this species are up to at least 1.7 m (size at sexual maturity has not been sufficiently documented). Black dolphins reach weights of up to 63 kg. Length at birth is unknown, but is probably somewhat less than 1 m.
Geographical Distribution
This dolphin is found only on 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.
Biology and Behaviour
Until recently, there have been very few sightings of these animals by researchers. Groups tend to be small, between 2 and 15 members, but aggregations of up to 400 have been recorded. Although active and very conspicuous, they tend to be shy and difficult to approach, but may occasionally ride bow waves.
Most sightings of newborn black dolphins have been from October to April.
Black dolphins feed on fish, cephalopods, and crustaceans.
Exploitation
Black dolphins are taken both incidentally in gillnets (and occasionally in seines) and directly by harpoon in a fishery for crab bait off southern Chile. Incidental catches are also sometimes utilized for oil and human consumption. The effects of these fisheries on black dolphin population(s) are not known.
IUCN Status
Insufficiently known.