Sowerby's beaked whale
Sowerby's beaked whale ranges from Nantucket to Labrador in the western North Atlantic and from Madeira to the Norwegian Sea in the eastern North Atlantic.
Sowerby's beaked whale (Mesoplodon bidens), also known as the North Atlantic or North Sea beaked whale, was the first mesoplodont whale to be described. James Sowerby, an English naturalist and artist, first described the species in 1804 from a skull obtained from a male that had stranded in the Moray Firth, Scotland, in 1800. He named it bidens, which derives from the two teeth present in the jaw, now known to be a very common feature among the genus.
Sowerby's beaked whale has a typical body shape for the genus, and is mainly distinguished by the male's dual teeth positioned far back in the mouth. The whale's beak is moderately long, and the melon is slightly convex. The colouration pattern is a grey with light countershading on the bottom, and frequently has cookie cutter shark bites and scars from teeth (in males).
The whale reaches 5 metres (16 ft) in females and 5.5 metres (18 ft) in males, with a weight of 1000-1300 kilograms (2200-2900 lb). The gestation period lasts for 12 months and the young are born at a length of 2.4 to 2.7 metres (8 to 9 ft) with a weight of around 185 kilograms (400 lb).
Dietary information is available from stomach contents analyses of stranded beaked whales and from whaling operations. Their preferred diet is primarily deep-water squid,but also benthic and benthopelagic fish and some crustaceans, mostly taken near the sea floor. In a recent study, gouge marks in the seafloor were interpreted to be a result of feeding activities by beaked whales.
Very little is known about the life histories of beaked whales. There are currently no data available on their reproductive rates.
Sowerby's beaked whales are reclusive creatures that stay away from ships and are rarely sighted. The whales are occasionally in groups of 8 to 10 individuals (males, females, and calves) and have been known to strand in groups as well. They are believed to primarily feed on squid and molluscs, but cod has also been found in their stomachs. They have been known to dive down at times approaching 30 minutes.