The northern bottlenose whale has a bulbous forehead and an obvious tube-like beak, these features are more pronounced in older male individuals (2). The specific part of the scientific name, ampullatus, means 'flask' and refers to the bottle-like shape of the head (5). Young individuals are dark on the dorsal surface (back) with a light belly, and become paler as they age (6). In males a whitish patch develops on the forehead, which becomes larger as the male gets older (6). The robust body is spindle-shaped, and the dorsal fin is triangular (7) and placed far behind centre. Northern bottlenose whales have two teeth on the lower jaw; these only erupt on males (8).