Oliver, 1937 - Shepherd's beaked whale
Distinctive Characteristics
Similar in body shape to the species of Mesoplodon, Shepherd's beaked whales have a long pointed beak, distinct from the relatively steep forehead. There is a shallow pair of throat creases. The flippers are small and rounded, and the dorsal fin, set far back, is short and falcate. Generally, the notch between the flukes (characteristic of most cetaceans) is absent.
Although all the descriptions are based on partially decomposed specimens, the colour pattern appears to be largely countershaded, dark grey above and lighter below. There are often several dark diagonal bands on the sides.
Unique to beaked whales, this species has a mouthful of sharp functional teeth. There are 17 to 21 per row in the upper jaw, and 17 to 29 in the lower. At the tip of the lower jaw is a pair of typical beaked whale tusks, which erupt only in adult males.
Can be confused with
Shepherd's beaked whales can be confused with other beaked whales, especially Mesoplodon. However, they appear to be somewhat larger than most species of Mesoplodon, and have a more steeply rising forehead.
Size
Lengths of 6.6 m (female) and 6.1 to 7 m (males) have been reported. Length at birth is unknown, but is presumed to be around 3 m.
Geographical Distribution
Shepherd's beaked whales are thought to have a circumpolar distribution in cold temperate waters of the Southern Hemisphere. There are records from New Zealand, southern and western Australia, both coasts of South America, and islands of the South Atlantic. Like other members of the family, these are probably exclusively oceanic, deep water animals.
Biology and Behaviour
Very little is known of the natural history of this species. All of the confirmed records are at least partially decomposed strandings. There are only 2 possible sighting records.
They are known to feed on several species of fish, possibly near the bottom in deep waters.
Exploitation
No records of human exploitation exist.
IUCN Status
Insufficiently known.