Sowerby’s Beaked Whale


Sowerby's Beaked Whale
Famiy: Ziphiidae
Genus: Mesoplodon
Species: M. bidens    (Sowerby, 1804)

Sowerby’s beaked whale is the most northerly of all beaked whales, and no other is likely to be found in its waters. It has the further distinction of being the first beaked whale ever discovered, in 1800, when one of the animals stranded at Moray Firth, Scotland.

Physical Description: For a Mesoplodon, the body is long and thin. The lower jaw protrudes ahead of the upper jaw from an elongated beak. The upper jaw smoothly meets the rising forehead, which drops slightly at the indentation of the blowhole. A pronounced bulge rises in front of the blowhole. The throat has typical wishbone indentations.

Color: Charcoal gray with occasional blue tint; white patches are evident on the ventral regions of some animals; scratches, wounds, and light colored scars are visible on most individuals, probably inflicted by others of the same species.

Fins and Flukes: A well-defined, falcate dorsal fin is located far to the rear of the mid-back region. Small, short flippers are somewhat paddle-shaped. The flukes are well developed, well spread, pointed backward at the tips, with no median notch.

Length and Weight: Males are known to reach more than 16.5 ft (5 m); females just over 16 ft (4.9 m). The average weight is 2,800 lb (1,270 kg).

Teeth: A pair of teeth is found in the lower jaw midway between the tip and the gape. No teeth are present in the upper jaw. The teeth seldom erupt through the gums in females; those in adult males are barely visible.

Feeding: Squid and small fish.

Breathing and Diving: No information available.

Mating and Breeding: Breeding season lasts from February to April. A calf estimated at 6.5 ft (2 m) is born in late winter or spring after a 12-month gestation period. Lactation lasts 12 months, at which time the calf is 9.75 ft (3 m) in length.

Herding: Pairs have been reported off of Iceland.

Distribution: Cool, temperate waters of the North Atlantic, from Newfoundland and Massachusetts east to southern Norway and the Bay of Biscay.

Migration: Individuals are found sometimes in the Newfoundland region in summer, presumably following prey species.

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