Sowerby's beaked whales are found in temperate to sub arctic waters in the eastern and western North Atlantic. They are found around the British Isles and are known to occur from Newfoundland to Massachusetts. Sowerby's beaked whales occur as far north as Labrador in the west and in the Norwegian Sea in the east, southern limit is thought to be somewhere between 33ºN and 41ºN.

Biogeographic Regions: nearctic (Native ); palearctic (Native ); atlantic ocean (Native )

occurs (regularly, as a native taxon) in multiple nations

Global Range: Mainly in cooler offshore waters of North Atlantic and Baltic Sea; a report for the coast of Italy may be valid; more common in European waters than in American waters, where single strandings have been recorded for near Nantucket, Massachusetts, and in eastern Canada (Mead and Brownell, in Wilson and Reeder 1993). Range may be centered in the North Sea. See Bonde and O'Shea (1989) for information on a 1984 stranding in Florida (regarded as a stray). Poorly known; as of late 1980s, less than 40 published stranding records, 11 in North America (Bonde and O'Shea 1989; 1990, Can. Field-Nat. 104:414-420). See Lien and Barry (1990) for information on status in Canada. Hooker and Baird (1999) described recent observations of groups of individuals in the Gully, Nova Scotia.

Mesoplodon bidens is bluish grey to slate grey in color, with a lighter underside, grey and white spots may be present on the body with limited scaring. Mesoplodon bidens have a long slender beak that contains a pair of teeth midway up the lower jaw. They have a long think body, long flippers for the Mesoplodon family, and no notch in the fluke. The dorsal fin is quite small with a rounded tip and may appear falcate. Young M. bidens have a light blusih grey to white underside, more prominant than in adults.

Range mass: 1000 to 1300 kg.

Range length: 5 to 5.5 m.

Sexual Dimorphism: male larger

Length: 4900 cm

• Marine

Sowerby's beaked whales are found in cool to warm temperate offshore waters of the North Atlantic Ocean. They are usually observed in open water and most often seen in areas were depths range from 198 to 1524 m.

Range depth: 198 to 1524 m.

Habitat Regions: temperate ; saltwater or marine

Aquatic Biomes: pelagic

Habitat Type: Marine

Comments: Deeper areas of the open ocean.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

The diet of Sowerby's beaked whales consists mostly of squid, octopus, and fish. A necropsy of one individual showed stomach contents that included bottom-dwelling and deep water fish.

Animal Foods: fish; mollusks

Primary Diet: carnivore (Piscivore , Molluscivore )

Comments: Diet probably includes small offshore squid (Ostrom et al., 1993, Can. J. Zool. 71:858-861) and deepwater fishes.

Little is known about the role of Sowerby's beaked whales in the northern Atlantic ecosystem. They are undoubtedly predators of marine organisms.

There is no information about predation on Sowerby's beaked whales. Once they reach their adult size it is likely that they are protected from much predation. Killer whales and large sharks may target Sowerby's beaked whales.

Not highly gregarious; found alone or in groups of up to 8-10 individuals (Hooker and Baird 1999).

A young animal, that was kept in a dolphinarium for a few hours, was recorded using high frequency sound pulses to echolocate.

Communication Channels: acoustic

Perception Channels: visual ; acoustic ; echolocation

Comments: Active day/night.

The is no data on the lifespan in M. bidens.

Nothing is known about the mating systems of M. bidens.

Little in known about general reproductive behavior of M. bidens. Mating is thought to occur in late winter, with births late in spring and gestation lasting about 12 months. Young are about 2.4 to 2.7 meters in length and weigh about 185 kg.

Breeding interval: Breeding interval is not known for Sowerby's beaked whales.

Breeding season: Mating is thought to occur in late winter.

Average number of offspring: 1.

Average gestation period: 12 months.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Sowerby's beaked whale females provide milk for their young and protect them. There is no other available information on parental investment.

Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)

Limited data suggest that mating and birth ocuur in late winter and spring. Gestation lasts about 1 year.

There is very little data on Sowerby's beaked whales. As a result there is little information on population sizes, current or historic, to determine conservation status. This species is rarely seen in the open ocean, most records are from strandings.

US Federal List: no special status

CITES: appendix ii

State of Michigan List: no special status

IUCN Red List of Threatened Species: data deficient

Rounded Global Status Rank: G3 - Vulnerable

Reasons: Occurs mainly in cooler offshore waters of North Atlantic and Baltic Sea; more common in European waters than in American waters, where single strandings have been recorded for near Nantucket, Massachusetts, and in eastern Canada; poorly known--as of late 1980s, less than 40 published stranding records, 11 in North America.

Sowerby's beaked whales are occasionally caught in fishing gear, damaging nets in the process. Arguably this is more traumatic for the whales than fishing crews.

Sowerby's beaked whales were once infrequently harvested by Norwegian whalers. They are no longer hunted actively.

Positive Impacts: food