Phocoena phocoena, also known as the "Common" or "Harbor" Porpoise, is a small cetacean that is 1.5 to 2 meters long and weighs from 45 - 65 kilograms. The female of the species is usually slightly larger than the male. The color of the animal varies from individual to individual, but the most common coloration pattern is a dark dorsal surface that shifts to a lighter colored hue ventrally. Although the dark color is usually black or deep gray, albinos have been reported in which the dark segments are completely or partially white. The flippers, dorsal fin, and tail are all dark in color, and there is a black stripe that runs from the edge of the mouth or eye to the flipper on either side. There is no noticeable forehead or beak on this species, and the snout is short, giving the head a somewhat cone-like shape. P. phocoena has two pectoral flippers, a single dorsal fin, and a tail with two partially separated flukes. All of these appendages are short and not very sharp, with the dorsal fin being triangular shaped and usually around 15 - 20 cm tall. There is a noticeable keel located near the all dark tail flukes, with the tail itself spanning anywhere from 30-65 cm. Inside the slightly upturned mouth there are rows of 16-28 spade-shaped teeth. There is no variance in the shape or type of teeth in P. phocoena.

Range mass: 45 to 60 kg.

Range length: 1.5 to 2 m.

Sexual Dimorphism: female larger

Average basal metabolic rate: 107.675 W.