The orca, once also known as the killer whale, is in fact the largest of the dolphins (2). They are easily identified by the black and white colouration; the underside is white and there are white patches behind the eyes, and a greyish white area called a 'saddle-patch' behind the dorsal fin (2). The shape of the saddle is unique in each animal, and can help to identify individuals (4). The dorsal fin is also used to recognise individuals (4). Male orcas have the tallest dorsal fin known in the animal kingdom (4), measuring up to six feet high in mature males (2), it can be as tall as a man (4). Females have shorter, more curved dorsal fins (4).