Common dolphins are easily recognised by the hourglass pattern and tan or yellowish patch on each side, although they can sometimes be confused with striped dolphins. They have a dark cape ranging from black to brown with a v-shape under the dorsal fin. They also have a white underside with occasional yellow streaks and a white tail stock. Their flukes are dark on both sides, and their dorsal fins range from curved to triangular and can be black, greyish white or somewhere in-between. They vary so much that people have suggested there are a number of different species. Only two distinct forms are recognised; the long-beaked and short-beaked. There are only subtle differences between the sexes and males and females are difficult to tell apart.
Streamlined body, long slender beak, single blowhole, pointed flippers, hourglass pattern on sides, dark flippers, tail and fin, dark cape (area of the back around the dorsal fin), fast active swimmer.
When they are born, common dolphins are about 80cm long. They grow to between 1.7 and 2.4 metres in length.
Common dolphins feed on small fish as well as squid and octopus. Small fish include young herring, pilchard, anchovies, nocturnal hake, sardines, small bonito. Individual dolphins eat up to 18 to 20 pounds of fish per day. These feeding forays can last up to an hour. During these, each dolphin rushes to the centre of the school the group has been pursuing and tries to seize as many fish as possible, which it swallows whole. Common dolphins have also been known to dive below schools and drive them to the surface. They push their prey completely out of the water and catch them in midair.