Common Dolphin

Taxonomy

Scientific name: Delphinus delphis
Order: Artiodactyla (Ceteacea)
Family: Delphinidae
Genus: Delphinus

IUCN Status

Least Concern.

Other names

Short-beaked common dolphin
Saddleback dolphin
White-bellied porpoise
Criss-cross dolphin
Hourglass dolphin
Cape dolphin

Appearance

Common dolphins are highly distinctive. A medium-sized dolphin that can grow between 1.9 metres to 2.5 metres, they are sleek, but also quite chunky.

They have blackish or charcoal grey upper parts with a sharp delineation from the flank pattern, with a well defined inverted black triangle beneath the dorsal fin, and 'hourglass' pattern when viewed from the side.

They often have a brownish tinge, with a usually pale tan or dull yellow panel back from the eye to the inverted 'V' at the mid point, with grey tail stock.

Common dolphins usually have a pronounced beak and a relatively tall pointed dorsal fin, usually with a swept back, quite straight leading edge, and concave trailing edge.

Habitat and distribution

Several populations occur in different oceans around the world, but without continuous distribution; some may be isolated and/or distinct subspecies.

Common dolphins are associated with warm temperate to tropical waters, but mostly where upwellings occur eg along continental shelf slopes and seamounts.

Globally abundant, with population estimates in the millions. However, as there is likely more than one species, with two suggested in the Pacific Ocean, and at least one elsewhere, then individual conservation statuses need to be reviewed.

Common dolphins are seen throughout the Bay of Biscay and well into the English Channel to at least the Channel Islands at times, especially in the warmer summer months.

Behaviour

Common dolphins travel in pods of 10 to 50 individuals but have been seen in pods of several hundred.

They are often seeing breaching, bow-riding, and tail slapping. These dolphins are attracted to the bows of ships and have been observed in groups with other species of dolphins. Common dolphins are very acrobatic and fast swimmers.

They have occasionally been seen foraging around large whales, but can be aggressive to potential predators of their calves, such as Bottlenose Dolphins and Pilot Whales.

Confusion with other species

They are sometimes confused with the Striped Dolphin, however the distinct colourings and markings on the common dolphin should make it easy to identify.

Threats

Common dolphins are often the victims of bycatch and entanglement in ghost fishing gear; they are often found stranded on beaches along the coastlines of Cornwall and Devon. Other threats to common dolphins include pollution, decrease in available prey and habitat degradation.

Interesting facts

The common dolphin is probably the most abundant cetacean species on the planet - with global population estimates in excess of six million (although this is likely built up of several subspecies).

Common Dolphins are the main subject of the mural, "Fresco of the Dolphins" (found in Knossos Palace, in Crete, Greece) estimated to have been painted in 1800 to 1400 BCE, among the earliest recognisable depictions of dolphins.