Common dolphin (Delphinus delphis)

The Common Dolphin is slender and streamlined, with a long or short beak, depending on the geographical location. All forms vary slightly in size but are recognisable as Common Dolphins due to the tell-tale 'hourglass' pattern on each side. The dorsal cape is dark (brown, black, grey or purplish), dipping to a distinct 'V' beneath the fin. The tail stock is pale grey, darkening to black flukes. The underside is cream-white, and extends higher up the sides than in most dolphins. It is broken by one or two yellow or grey stripes that stretch from beak to beneath the 'V'-shaped dip. Another stripe - this one black - streaks from the dark flippers to the middle of the lower jaw. Higher on the sides, behind the eyes, is a yellow-tan patch which - together with the pale grey further back - forms the criss-cross 'hourglass' pattern. A dark line circles the eyes and leads to the grey-black beak, which can be white-tipped. In some geographical forms, these colours can appear to be muted, or slightly varied. There are 80-120 teeth per jaw. Common Dolphins range in size from 1.7m to 2.6m, and weigh between 70kg and 135kg.
Common Dolphins can be identified from the yellow-tan patch on either side, just behind each eye, and the dorsal cape's 'V'-shaped dip.
Common Dolphins prefer waters with a surface temperature that is higher than 10ºC.
Common Dolphins prey on schooling fish (e.g. herring, pilchards) and squid. They have been known to adopt co-operative techniques when hunting (rather like the Orca) and have also been observed catching fish in mid-air.
Highly social, Common Dolphins can be seen in groups of up to 2,000 animals, although units of 10-500 are more usual. Active and exuberate, they bowride, breach, somersault, flipper-slap and lobtail. When porpoising, they often cannot be seen for the froth they produce - they leap as a co-ordinated whole. Also highly vocal, their cries - whistles, pulses and clicks - can be heard above water as they play around vessels.