Gervais' Beaked Whale
Common Name: Gervais' Beaked Whale.
Irish Name: Míol mór socach an tSrutha.
Key Identification Features
Max. adult body length/weight: 6.7m / 2,700kg
Average adult body length/weight: 5m / 1,200kg
Average length/weight of calf at birth: 2.2m/ 50kg
Head: Rounded forehead, which tapers to a rather narrow beak.
Dorsal Fin: Small fin located two-thirds along back varies from blunt and triangular to shark-like.
Colouration: Dark blue, blue-grey or black with a slight lightening on the undersides.
Markings: In some individuals there is a bright white patch around the genital or anal openings. Older animals also have rake marks over much of the upper body.
The flippers are very low down on the body, are quite narrow and sit into depressions (pockets) on the body wall. The triangular teeth, near the tip of the lower jaws, are diagnostic in adult males and are absent on females and young animals. The body is somewhat laterally compressed.
Species Similar in Appearance
Other Mesoplodon species.
Scarring suggests that males fight during the breeding season, as with most Mesoplodon species.
Status and Distribution
Gervais' beaked whale is very rarely seen at sea and is known mainly from around 100 strandings, all but two of which come from east coast, North America. They are probably centred in the deep, warm waters of the gulf-stream in the western North Atlantic. Only two specimens are from Europe. The only complete specimen from Europe was found in Ballysadare Bay, Co. Sligo in 1989. The skeleton from this animal is housed in the Ulster Museum.
Where and When Best Seen in Ireland
The main centre of distribution for this species seems to be the warmer waters off the coasts of North & Central America. It may be that the occasional animal passes to the east Atlantic via the Gulf Stream. This species is only known in Europe through two strandings in the past two centuries.
Food and Feeding
Feed exclusively on Squid.
Reproduction and Life Cycle
Max. life expectancy:At least 27 years.
Average life expectancy: Unknown.
Mating Occurs: Unknown.
Season of birth: Unknown.
Little is known of their social structure but they may live largely solitary lives or in pairs.
Not enough is known to determine threats, although trends in deep water trawling may pose a threat, as these whales rely on deep-water canyons for primary habitat. They have been known to become entangled in fishing nets off the American coast. Another potential threat in Irish waters is noise pollution from off-shore exploration and drilling along the West Coast.
This is one of the largest Mesoplodon species. There is no notch in the flukes. Adult males have a single tooth sticking up either side of the lower jaw, about 10cm from the tip of the jaw. The teeth of which there is only one in each lower jaw, are approx. 10cm tall, triangular in shape and sharply pointed. The teeth lie with the tips facing slightly forward towards the tip of the jaw. The first 3 vertebrae are fused. There is a pair of grooves in the throat.