Mesoplodon bidens is a toothed whale and can be recognised as such by the single blowhole and the presence of teeth (rather than baleen). It is a member of the beaked whale family with the characteristic V-shaped crease on the throat and the short dorsal fin set relatively far back. Sowerby's beaked whale is a small beaked whale that can reach up to 5.5 m in length. The lower jaw has a single pair of teeth (exposed only in adult males). The forehead rises at a shallow angle and has a slight bump. It has a distinct beak and the mouthline is curved down at rear. Sowerby's beaked whale has a charcoal grey dorsal and lateral colouration with a lighter belly. Adults may also have light grey spots on the body and are often covered with scratches and scars.Sowerby's beaked whale may be confused with True's beaked whale Mesoplodon mirus but can be recognised by a slight bump on the forehead and a slightly longer beak. Sowerby's beaked whales are usually found either alone or in groups of up to 10 individuals. Little is known about their behaviour although tail-slapping has been recorded. Dives may last up to 15 minutes long (Kinze, 2002).