Sowerby's beaked whale
Sowerby's beaked whale, also known as the North Atlantic or North Sea beaked whale, is a species of toothed whale. It 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.
Physical description
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 cookiecutter shark bites and scars from teeth. The whale reaches 5 metres in females and 5.5 metres in males, with a weight of 1000–1300 kilograms. The gestation period lasts for 12 months and the young are born at a length of 2.4 to 2.7 metres with a weight of around 185 kilograms.Diet
The diet of Sowerby's beaked whales consists primarily of small mesopelagic and benthopelagic fish, with cephalopods accounting for a much smaller proportion of the diet.Population and distribution
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. They typically range in waters deep. No population estimates have been made. In 1991, there were about 90 records of the species, 80 from the eastern North Atlantic and less than ten from the western North Atlantic; the majority of the records are from around the British Isles.On 10 January 2009, a female Sowerby's beaked whale was found at the port of Fethiye on the Aegean coast of Turkey, far away from her natural habitat. The whale was successfully saved and released back to the open sea.
On 25 July 2015, biologists with the New England Aquarium investigated the death of a beaked whale in Massachusetts. The carcass of the long female, which weighed almost, was found on Plymouth Long Beach in Plymouth, Massachusetts. Biologists from the aquarium and the International Fund for Animal Welfare said they would perform a necropsy at the Woods Hole Oceanographic Institution. The whale was initially identified as a Sowerby's beaked whale, but the aquarium said a more thorough examination and consultation with additional experts was needed as staff had not seen a beaked whale since 2006.
On 26 October 2018, a whale was found beached near the town of Saltdean, on the UK coast. The carcass was subsequently taken to the Natural History Museum, London for post-mortem. On 29 August 2019, a stranded whale was rescued from Dungarvan Bay, in southeast Ireland. On 4 July 2020, a whale became disorientated and strayed into Wicklow harbour on the east coast of Ireland but was later discovered dead on Wicklow beach.
On 21 August 2020, a long female Sowerby's beaked whale washed up on the shore of a beach in Caister-on-Sea, Norfolk. Emergency services assisted the whale out to sea in an attempt to encourage the animal to live. Unfortunately the next morning a report was received to suggest the whale was stranded and deceased at Lowestoft, on the UK coast, following reported sights of two whales in the nearby towns of Brancaster and Blakeney in Norfolk earlier in the month.
On successive days in October 2020, two Sowerby's beaked whales were washed up on separate beaches in East Lothian. Both animals died. The necropsy revealed that one of the whales had an unusually high density of small gas bubbles in the lung tissue, and both whales showed signs of gas emboli in the mesenteric arteries. These symptoms are often associated with decompression sickness, however it was not clear if this was the cause in this case. The MOD later revealed that, one day before the first whale stranded, airborne ASW sonar exercises had been carried out within of the stranding sites. There was not enough evidence from the necropsy to confirm decompression sickness as the cause of death, so the still consider these as live strandings. However, given the otherwise good physical health of the beaked whales combined with the unusual proximity in both time and location of their strandings, the use of sonar in the surrounding area should still be considered a possible factor in the stranding.
On 28 September 2024, the bodies of two Sowerby's beaked whales, initially thought to be large dolphins, were sighted on a beach of near Éculleville, France on the Cotentin Peninsula. Before their bodies could be examined, they were pulled off the beach by the tide and washed up 50 km further down the coast off Biville, three days later. The whales were identified as an adult female and her young daughter. The local coast guard hypothesized that the adult became disoriented during a recent storm and ended up lost and unable to return to her usual swimming grounds and the daughter followed her to end up later beached, where both perished.