The short-beaked common dolphin is one of three species in the Genus Delphinus (in addition to D. capensis or the long-beaked common dolphin and the endemic D. tropicalis in the Indian Ocean).

Short-beaked common dolphin © M. Camm

Physical Description & Behaviour

The species has a characteristic slender body shape combined with a relatively long beak, which is sharply separated from their forehead. Their colour pattern usually involves a dark back and white underbelly, and an hourglass pattern coloured light grey and yellow on each side of their body.

Adult common dolphins can reach up to 2.7 metres in length and 135 kg. As very social animals, they are usually found in groups of 10-15 animals, which often join up to form schools of several hundred to several thousand individuals.

They are fast swimmers and sometimes approach moving vessels to bow-ride. Aerial behaviour typical of them includes “pitch polling” where dolphins leap high vertically and fall lengthwise back into the water.

Common dolphins feed on various small mid-water fish and squid. Their diet varies with the season as well as by region.

Distribution & Abundance

Common dolphins are typical oceanic dolphins and live in the tropical to warm temperate zone. They are often associated with schools of other whales and dolphins, such as pilot whales for example.

In the ASCOBANS area they are normally restricted to the southwest of the British Isles and the English Channel. According to the SCANS II Project, about 75,000 individuals inhabit this region.

IUCN Red List of Threatened Species™ Assessment

• ASCOBANS Area: LC (least concern)

Threats

Common dolphins die in large numbers in purse seine fisheries in the eastern tropical Pacific and in gillnet fisheries around the world. In the Celtic Sea and Bay of Biscay, it suffers incidental capture in fishing gear from multi-national pelagic trawl and drift net fisheries. In addition to bycatch, they are increasingly threatened by marine pollution, underwater noise and habitat loss.

More information on the common dolphin can be found at
http://www.cms.int/reports/small_cetaceans/data/d_delphis/d_delphis.htm.