Hyperoodon ampullatus

The northern bottlenose whale (Hyperoodon ampullatus) is a species of beaked whale in the ziphiid family, being one of two members of the genus Hyperoodon. The northern bottlenose was hunted heavily by Norway and Britain in the 19th and early 20th centuries. It is one of the deepest-diving mammals known, reaching depths of 1,453 m (4,767 ft). When physically mature, northern bottlenose whales can reach 9.8 metres (32 ft) in length, smaller than giant beaked whales, and larger than known records of southern bottlenose whales. Their foreheads, or melons are sexually dimorphic, so that mature males have larger melons, which are flattened or square shape, while mature females and juveniles have rounder melons. Melon coloration can vary, though it appears the head of most males becomes more white or buff colored with age. The beak is not as long as other beaked whale species, and only mature males have two small teeth, which erupt at the front end of the bottom jaw, but are not easily seen. Females also have teeth, but they are buried in the jaw and do not erupt. The dorsal fin is relatively small, at 30–38 centimetres (12–15 in) and about ​2⁄3 of the way back on their bodies. It is falcate (sickle-shaped) and usually pointed. The back is mid-to-dark grey with a lighter underside. They weigh approximately 5,800–7,500 kilograms (12,790–16,530 lb). Unlike many species of beaked whale, northern bottlenose whales are known to approach and appear curious about vessels, which made them relatively easy targets for whale hunters. However they have demonstrated avoidance to certain sounds such as those emitted by naval sonar in controlled dose response studies. Underwater recordings have found that northern bottlenose produce regular high frequency clicks in click trains, which have a characteristic frequency modulated pulse or 'upsweep', commonly found in other species of beaked whales. Northern bottlenose feed mainly on deep water squid, primarily Gonatus fabricii or Gonatus steenstrupi, and bottom fish, such as Greenland halibut. Foraging dives can last an hour or more. The northern bottlenose whale is endemic to the North Atlantic Ocean and populations are found in the deep (>500 m) cold subarctic waters of the Davis Strait, the Labrador Sea, the Greenland Sea and the Barents Sea, but can range as far south as Newfoundland and Nova Scotia. The total population size across their global range is unknown. 'The Gully', a large submarine canyon east of Nova Scotia, is the home of the 'Scotian Shelf' population of around 140 whales, currently listed under Canada's Species at Risk Act as endangered. This population is the focus of a long-term research project conducted by the Whitehead Lab, at Dalhousie University since 1988. On 20 January 2006, a northern bottlenose whale was spotted in Central London in the River Thames. The River Thames whale reached as far up river as Albert Bridge. It was moved onto a barge and rescuers hoped to take it out to sea, but it died following a convulsion on 21 January during its rescue. Its skeleton is now in the Natural History Museum in London.