information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Atlantic white-sided dolphin (Lagenorhynchus acutus)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.



Lagenorhynchus acutus is a toothed whale and can be recognised as such by the single blowhole and the presence of teeth (rather than baleen). It is a member of the dolphin family with a characteristic prominent median notch in the flukes, a smooth crease-less throat and sharply pointed teeth. The Atlantic white-sided dolphin reaches up to 2.8 m in length. It has moderately long and slender flippers and small tail flukes. The dorsal fin is tall, large and located on the middle of the back. The head is smoothly sloping with a distinct but small snout. It has a complex clearly demarcated colour pattern. It is black to dark grey on the back from the upper beak to the tail, changing sharply to light grey on the sides. The lower jaw and belly, as far as the anus, are white. A distinct white band is visible on the flanks under the dorsal fin between the black and light grey colouration, which turns into an olive-yellow stripe towards the rear at the lower margin of the dark dorsal colouration. A dark line runs from the upper beak to, and surrounding, the eye.

Recorded distribution in Britain and Ireland

Found off the coasts of Scotland, north-east England, south-west England and Ireland and off north-west Ireland. Occasionally seen in the North Sea, English channel and all other British waters.

Global distribution

Temperate and subarctic North Atlantic. Cape Cod to southern Greenland, Iceland, Svalbard, the Norwegian coast, north and western British Isles, and occasionally from the Norht Sea and English Channel, the Bay of Biscay and Western Spain.


The Atlantic white-sided dolphin is an oceanic species prefering deep waters on the outer continental shelf and slope.

Depth range


Identifying features

  • Slender body up to 2.8 m in length.
  • Tall, large dorsal fin located on the middle of the back.
  • Very deepened tail stock.
  • Dorsally dark grey to black, laterally light grey and ventrally white in colour.
  • Black line running from the upper beak to the eye.
  • Short slender flippers.
  • Gently sloping head with a short, thick beak.
  • Straight mouthline.

Additional information

Atlantic white-sided dolphins are usually found in large pods of up to several thousand individuals. Mixed schools with other species including white-beaked dolphins, Lagenorhynchus albirostris, have been recorded. Their surface behaviour is typical of dolphins with acrobatic leaps but bow-riding uncommon. Dive duration is unknown (Kinze, 2002).

Listed by

Further information sources

Search on:


  1. Bruyns, W.F.J.M., 1971. Field guide of whales and dolphins. Amsterdam: Publishing Company Tors.

  2. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  3. Jefferson, T.A., Leatherwood, S. & Webber, M.A., 1994. FAO species identification guide. Marine mammals of the world. Rome: United Nations Environment Programme, Food and Agriculture Organization of the United Nations.

  4. Kinze, C. C., 2002. Photographic Guide to the Marine Mammals of the North Atlantic. Oxford: Oxford University Press.

  5. National Biodiversity Network (NBN) Atlas website. Available from:  Accessed 01 April 2017

  6. OBIS,  2018. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2018-09-22

  7. Reid. J.B., Evans. P.G.H., Northridge. S.P. (ed.), 2003. Atlas of Cetacean Distribution in North-west European Waters. Peterborough: Joint Nature Conservation Committee.


This review can be cited as:

Barnes, M.K.S. 2008. Lagenorhynchus acutus Atlantic white-sided dolphin. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 22-09-2018]. Available from:

Last Updated: 02/06/2008