Taxonomy & Nomenclature
Physical Description / Field Identification
Similar in body shape to the mesoplodonts described below, Shepherd’s beaked whales have long pointed beaks, distinct from the relatively steep forehead. However, they have rather pronounced melons. 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 many descriptions are based on partially decomposed specimens, the color pattern appears to be largely countershaded, dark gray above and lighter below. The white ventral field extends up onto the flippers. 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 17-21 per row in the upper jaw, and 17-29 in the lower. At the tip of the lower jaw is a pair of enlarged terminal teeth, which erupt only in adult males.
Can be Confused With
Shepherd’s beaked whales can be confused with other beaked whales, especially mesoplodonts at sea. However, they appear to be somewhat larger than most mesoplodonts, and have a more sharp beak (from above) and more pronounced melon.
Lengths of 6.6 m (female) and 6.1-7.0 m (males) have been reported. Length at birth is unknown, but is presumed to be around 3 m.
Shepherd’s beaked whales apparently have a circumpolar distribution in cold temperate waters of the Southern Hemisphere, although the species is known almost exclusively from strandings. There are records from New Zealand (the majority), southern Australia, and both coasts of South America. Like other members of the family, these are probably exclusively oceanic, deep-water animals.
Ecology and Behavior
Very little is known of the natural history of this species. Many of the confirmed records are at least partially decomposed strandings. There are only a handful of fresh specimen and unconfirmed sighting records.
Feeding and Prey
These whales are known to feed on several species of fish, as well as squid and crabs, possibly near the bottom in deep waters. This is unusual, as most beaked whales feed almost exclusively on cephalopods.
Threats and Status
As is true for most of the beaked whales, this species has apparently never been hunted, and fisheries interactions are not known. Currently, Shepherd’s beaked whales are ‘Data Deficient’ (IUCN) and ‘Not Listed’ (ESA).
Baker, A.N. 1999. Whales and dolphin of New Zealand and Australia An identification guide. Victoria University Press, Wellington, N.Z.
Mead, J.G. 1989. Shepherd’s beaked whale Tasmacetus shepherdi Olivier, 1937. pp. 309-320 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Vol. 4: River dolphins and the larger toothed whales. Academic Press.
Mead, J.G. 2002. Shepherd’s beaked whale Tasmacetus shepherdi. pp. 1078-1081 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.
Watkins, W.A. 1976. A probable sighting of a live Tasmacetus shepherdi in New Zealand waters. Journal of Mammalogy 57:1-415.