White-beaked dolphin
| White-beaked dolphin | |
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| Size compared to an average human | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Infraorder: | Cetacea |
| Family: | Delphinidae |
| Genus: | Lagenorhynchus |
| Species: | L. albirostris |
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Lagenorhynchus albirostris (Gray, 1846) |
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| White-beaked dolphin range | |
The white-beaked dolphin (Lagenorhynchus albirostris) is a marine mammal belonging to the family Delphinidae (dolphins) in the suborder Odontoceti (toothed whales).
The species was first described by the British taxonomist John Edward Gray in 1846. Due to its relative abundance in European waters, it was among the first of the genus Lagenorhynchus (lagenos, Latin for "bottle" or "flask"; rhynchos, "beak" or "snout") to be known to science. Its specific name, albirostris, translates to "white beak", a reference to the color of the species' beak, a diagnostic (albeit variable) trait useful in identification.
The white-beaked dolphin is a robust species of dolphin with a short beak. Adults can reach 2.3 to 3.1 m (7 ft 7 in to 10 ft 2 in) long and weigh 180 to 354 kg (397 to 780 lb). Calves are 1.1 to 1.2 m (3 ft 7 in to 3 ft 11 in) long at birth and probably weigh about 40 kg (88 lb). The upper body and flanks are dark grey with light grey patches, including a 'saddle' behind the dorsal fin, while the underside is light grey to almost white in color. The flippers, fluke, and the tall, falcate, dorsal fin are all a darker grey than the body. As the common name implies, the beak is usually white in color, but it may be a dark, ashy grey, in some older individuals.
White-beaked dolphins have 25 to 28 teeth in each jaw, although the three teeth closest to the front of the mouth are often not visible, failing to erupt from the gums. They have up to 92 vertebrae, more than any other species of oceanic dolphin. Although the young are born with two to four whiskers on each side of the upper lip, these disappear as they grow, and, as in other , the adults are entirely hairless. The humerus of the right flipper has been recorded as being longer and more robust than that on the left, indicating a degree of lateralized behavior.
The white-beaked dolphin is endemic to the cold temperate and subarctic waters of the North Atlantic Ocean, most commonly in seas less than 1,000 m (3,300 ft) deep. They are found in a band stretching across the ocean from Cape Cod, the mouth of the St. Lawrence River and southern Greenland in the west, around Iceland in the centre, and across in the west from northern France to Svalbard; however, they are not well adapted to truly Arctic conditions. Due to the fact they are not fully adapted to Arctic conditions, they are more vulnerable to predators, most notably polar bears. Within this wider region, white-beaked dolphins are most commonly found in four locales: on the Labrador Shelf close to southwestern Greenland, around Iceland, off the northern and eastern coasts of Britain, and off the coast of Norway. There are no recognised subspecies.
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Wikipedia