(Forster, 1770) - Northern bottlenose whale
Distinctive Characteristics
Northern bottlenose whales are appropriately named; they have a long tube-like snout that is distinct from the melon. In young animals and females, the forehead slopes gently upward from the beak, but in adult males the forehead becomes very steep and bulging, with a squarish profile. A pair of forward-pointing grooves is found on the throat. The small dorsal fin is falcate and is located far back on the body. The flippers are small and blunt at the tips, and the flukes generally lack a median notch.
Calves are apparently either black or brownish in colour. There is some disagreement as to whether young animals are countershaded. Adults are dark greyish to chocolate brown above and somewhat lighter below. The brownish tinge is enhanced by a covering of diatoms. Some individuals are mottled with white to yellowish splotches and scars, which increase in number with age. Much of the melon and face may be light grey, or in adult males nearly white.
At the tip of the lower jaw are 2 conical teeth that erupt only in bulls, and are not visible outside the closed mouth. A second pair of teeth is sometimes buried in the gums behind the first, and 10 to 20 additional vestigial teeth may be found in the gums of both upper and lower jaws.
Can be confused with
Cuvier's beaked whales can be distinguished from bottlenose whales by differences in head shape and body colour. Species of the genus Mesoplodon are distinguishable by their smaller size and more cone-shaped head.
Size
Adult females are up to 8.7 m and adult males up to 9.8 m in length. At birth calves are about 3.5 m.
Geographical Distribution
Northern bottlenose whales are found only in the North Atlantic, from New England to Baffin Island and southern Greenland in the west and from the Strait of Gibraltar to Svalbard in the east. These cold temperate to subarctic whales are found in deep waters, mostly seaward of the continental slope.
Biology and Behaviour
Most pods contain at least 4 whales, sometimes with as many as 20, and there is some segregation by age and sex. These deep-divers can remain submerged an hour, possibly as long as 2. They are known for their habit of “standing by” injured companions, which permitted whalers to kill large numbers of whales at the same site. Bottlenose whales are also often curious and attracted to stationary vessels.
Northern bottlenose whales have a peak in calving in April.
Although primarily adapted to feeding on squid, these whales also eat fish, sea cucumbers, starfish, and prawns. They apparently do much of their feeding on or near the bottom.
Exploitation
Northern bottlenose whales have traditionally been the most heavily hunted of the beaked whales. Some hunting has been done by the British and Canadians, but by far the major bottlenose whaling nation was Norway. Early on, they were hunted primarily for oil, but later mainly for animal feed. No hunting has been conducted by Norway since 1973.
IUCN Status
Insufficiently known.