One of the smallest of the dolphin clan, porpoises often suffer at the fins of their larger relations. In Scotland, for example, a quarter of all the dead porpoises washed up on the beaches have been slaughtered by other dolphins, especially bottlenose dolphins. Add in the dangers that they face at the hands of the commercial fishing fleet and their natural enemies and it is not surprising that they are somewhat shyer than some of the other species.
							Harbour porpoises are found in cold waters in the Northern Hemisphere.They have small, robust bodies which taper towards the tail.Their flippers are small, dark and slightly circular at the ends while the dorsal fin is a triangular shape with a broad base on its leading edge. Their backs are black or dark grey, as are the lips and the chin, which do, however, turn a slightly lighter shade of grey towards the edges. There are a few stripes, usually either one, two or three, between the jawline and the flippers. Adults measure between 1.4 and 1.9 m in length and weigh a maximum of 65 kg. With its small dorsal fin and its small body size it is very recognizable when out at sea. Another dead giveaway is that they rarely, if ever, jump completely free of the surface. Usually only their backs will show. They also tend to be rather solitary, unlike most other species of dolphin, travelling either on their own or in very small groups. When porpoises do travel together they do so in small groups of two to five animals. Larger units, containing up to twelve of these creatures, have been sighted but they are not common..They move by rolling slowly forward in the water and are not as acrobatic as other small cetaceans. (The fancy name for the whale family.) They can also remain still, especially at night, and it is thought that this is how they remain undetected by their main natural predator - the shark. It may also be a defence against other dolphins.