North Atlantic bottlenose whale, Bottlehead
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 whale 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 2,339 m (7,674 ft) and capable of diving for up to 130 minutes.
The Northern bottlenose whale belongs to the family Ziphiidae or beaked whale. The beak of this whale is very similar to that of a dolphin. The animal has the distinctive melon, which is typically white in males, and grey and more bulbous in females. Young whales are identified by a dark dorsum and light belly. Their coloration gradually becomes paler as they grow up. Male individuals exhibit a whitish marking on their forehead, which is larger in older males. Females of this species lack teeth, while males have two teeth at the front of their lower jaw, which are slightly slanted forward.
The north Atlantic is the only area, where these animals can be found. Small populations of this species can be found in the UK waters, usually around the Northern and Western Isles of Scotland, the northern North Sea as well as along the continental shelf break to the west of Ireland. Northern bottlenose whales also occur off western Norway and in the Barents Sea. The preferred habitat of this whale is deep (deeper than 1,000 meters), cold-temperate to sub-arctic waters.
These social animals gather in groups, typically consisting of 4 - 10 individuals, though groups of up to 25 animals have been recorded. Observations of whalers have shown that adult males of this species may occasionally travel separately from females and young males, particularly before and during their annual migration. Northern bottlenose whales are normally migratory. During spring and early summer, the animals live in northern parts of their range, travelling south by the winter. These animals make low-intensity sounds, which can be heard by humans. They also give out ultrasonic clicks, which are amplified in their melon and help them in echolocation of prey in deep or murky waters with low lighting. Surface behavior of these whales may vary amongst individuals. However, they often approach to sluggish ships, swimming around them for more than an hour.
Northern bottlenose whales are polygynous animals, meaning that each male of this species mates with multiple females. They usually mate in spring and early summer. Females give birth in every 2 - 3 years. After a gestation period of a year, a single calf is born, typically in April - June. The baby is nursed for a year, after which it is able to hunt and survive independently. Males of this species reach sexual maturity at a length of 7.3-7.6m, which matches the age of 7 - 9 years. Females are mature at 6.7-7m or at 8 - 14 years.
One of the primary threats to this animal is human disturbance in a form of acoustic disturbance. As deep-diving animals, these whales are exposed to mid-frequency active sonar, which used by the military in order to detect submarines. The animal is also threatened by sound disturbance from oil and gas exploration. In addition, the Northern bottlenose whale is currently the most commonly hunted species of beaked whale. Other notable concerns include chemical pollution as well as decline in numbers of prey populations.
According to the IUCN Red List, the global population size of the Northern bottlenose whale is unknown for today. However, specific populations have been estimated in following areas: in the eastern North Atlantic - 40, 000 whales; in the Icelandic and Faroese waters - 3,142 and 287 whales; in the Gully (Scotian Shelf) - 163 whales. Currently, the Northern bottlenose whales are classified as Data Deficient (DD) on the IUCN Red List.