Black Chilean Dolphin

Extensive research on Chilean dolphins has yet to be conducted. They were previously called "black dolphins" because specimens that had died were darkened from exposure to air and sun. Animals seen at a distance in the water appeared black as well. This was largely unhelpful and ill-chosen as the species is shades of dark and light gray as opposed to black.

Chilean dolphins are agile and fast swimmers. Natural predation on Chilean dolphins has not been observed, but they may fall prey to sharks and killer whales.

Resembling fellow Cephalorhynchus species, Chilean dolphins are generally described as small and chunky with lengths of about 1.65 m for both males and females. These dolphins weigh approximately 57 kg, females may be slightly larger than males. Chilean dolphins have a stout, torpedo-like shape and can have a girth of up to two-thirds of their length. The head is conical in shape and lacks a beak and melon. The mouth line is fairly long and a groove on the sides of the face is present. The eyes are positioned just behind the mouth. The dorsal fin is low and triangular, with a long leading edge that is almost S-shaped. The flippers are rounded and medium sized. Some animals may also have serrations occurring along the edge of the flippers. Chilean dolphins are dark except for three areas of white on the throat, behind the flippers, and around the anal area. The rest of the body is a complex mix of dark tones. Areas of dark gray cover the flippers, flukes, back and dorsal fin whereas lighter gray tones cover the head and sides. The blowhole may be pale gray.

Chilean dolphins overlap in habitat with Commerson's dolphins (Cephalorhynchus commersonii). They can be distinguished by the lack of a conspicuous white area on the sides and back. Burmeister's porpoises (Phocoena spinipinnis) may also be confused, but they have more slender dorsal fins that are positioned farther back and a lower profile and more pointed peak.

Range mass: 25 to 75 kg.

Average length: 1.6 m.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: female larger

Although longevity has not been determined in Chilean dolphins, the related species, Commerson's dolphins and Hector's dolphins have a lifespan of up to 20 years.

On Chile's convoluted coastline, Chilean dolphins prefer to live near areas of particularly strong tidal flow above a steep dropping shelf. They are most commonly found in channels and open coasts and bays. They are also found in areas of tide rips at the mouth of fjords. They prefer cold, shallow water at depths of 3 to 15 m. They may also enter rivers and estuaries and can be seen as far as 5 kilometers upstream.

Range depth: 20 to 3 m.

Habitat Regions: temperate ; saltwater or marine

Aquatic Biomes: rivers and streams; coastal ; brackish water

Chilean dolphins live in the coastal waters of Chile, ranging from near Valparaiso (33°S) to south of Navarino Island (55°15'S) and as far south as Tierra del Fuego. The farthest east that this dolphin has been sighted is near the eastern mouth of the Strait of Magellan.

Biogeographic Regions: pacific ocean (Native )

Chilean dolphins commonly feed on small schooling fish, such as sardines (Strangomera bentincki), squid (Loligo gahi, for example), and crustaceans (such as Munida subrugosa). Chilean dolphins which have been observed near salmon hatcheries may eat young, newly released salmon.

Animal Foods: fish; mollusks; aquatic crustaceans

Primary Diet: carnivore (Piscivore , Eats non-insect arthropods, Molluscivore )

It is unknown how Chilean dolphins impact their ecosystem.

Commensal/Parasitic Species:

• Whale lice
• trematodes (Trematoda)

Chilean dolphins have been hunted in the past for food and as bait for lucrative crab farming. Fisherman use the meat from the dolphins as bait to catch king crabs although this practice is now illegal.

Positive Impacts: food

There are no known adverse effects of Chilean dolphins on humans.

Chilean dolphins are listed as near threatened by the IUCN. Exact populations are difficult to measure but populations are considered in decline. Chilean dolphins have been hunted for food and as crab bait for generations. These dolphins are also accidentally caught in coastal gillnets. They also suffer from habitat encroachment by coastal salmon farming. More accurate information on Chilean dolphin populations and the threats they face is needed to formulate a conservation plan.

US Federal List: no special status

CITES: appendix ii

IUCN Red List of Threatened Species: near threatened

Chilean dolphins produce "cries" consisting of rapid pulses at very low levels. Recording equipment at the time was not sufficient to capture the full extent of their sounds. They use echolocation to navigate their environment.

Communication Channels: visual ; acoustic

Perception Channels: visual ; tactile ; acoustic ; ultrasound ; echolocation ; chemical

Little is known about the mating system and mating behavior of this species.

Chilean dolphins mate in the early winter and bear young in the spring. Females have one calf every two years. Sexual maturity is reached in 5 to 9 years. Other aspects of Chilean dolphin reproduction are not well understood.

Breeding interval: Females generally have one calf every two years.

Breeding season: Chilean dolphins breed in the winter.

Average number of offspring: 1.

Range age at sexual or reproductive maturity (female): 5 to 9 years.

Range age at sexual or reproductive maturity (male): 5 to 9 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous

Female Chilean dolphins invest heavily in young through gestation and lactation. Like other dolphins, young are likely to remain with their parents for long periods during which they learn complex social behaviors, navigation, and foraging.

Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Protecting: Female)

The Black dolphin (scientific name: Cephalorhynchus eutropia), is more commonly known as the Chilean dolphin, is only found in freshwater estuaries, and coastal areas surrounding Chile. It is a marine mammal, a member of the family Delphinidae, part of the order of cetaceans. The species is so named for its black coloring on its fins, tail, and back. It is also known as the Chilean dolphin, Piebald dolphin, Southern dolphin, and White-bellied dolphin. Because of their preference for shallow coastal waters, these dolphins are often threatened by local fisherman. This dolphin is frequently used in Chile as crab bait, as well as a food source for humans. The species population is decreasing because of this practice, and is now considered Near Threatened. Hunting restrictions have been established in Chile, however, the government has had difficulty enforcing this law in remote areas. Resembling fellow Cephalorhynchus species, Chilean dolphins are generally described as small and chunky with lengths of about 1.65 meters for both males and females. These dolphins weigh approximately 57 kilograms, females may be slightly larger than males (slight sexual dimorphism). Chilean dolphins have a stout, torpedo-like shape and can have a girth of up to two-thirds of their length. The head is conical in shape and lacks a beak and melon. However, black dolphins have a large number of teeth: 24 to 31 on each side of each jaw.

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.

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.

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.

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: insufficiently known.

The Chilean dolphin (Cephalorhynchus eutropia), also known as the black dolphin, is one of four dolphins in the genus Cephalorhynchus. The dolphin is found only off the coast of Chile; it is commonly referred to in the country as tonina.

East South Pacific near Chilean coast

in shallow coastal waters and estuaries

Near Threatened (NT)