Stejneger’s beaked whale has the characteristic Mesoplodon body shape. Apparently, both sexes are uniformly gray to black. The body often is covered with white mottling, which may represent healed scars from cookie-cutter shark bites.
The flattened tusks of males are situated near the middle of the lower jaw, and point forward. They are located on raised prominences, so that the crowns extend above the rostrum. Both sexes reach lengths of at least 5.4 m. Newborns are assumed to be between 2 and 2.5 m in length.
Can be Confused With
Adult males will be distinguishable from most other mesoplodonts by tooth shape and position. Within Stejneger’s beaked whale’s range, both Hubbs’ and Blainville’s beaked whale males have similar teeth.
Stejneger’s beaked whales are found in continental slope and oceanic waters of the North Pacific Basin, from southern California, north to the Bering Sea, and south to the Sea of Japan. This appears to be primarily a cold temperate and subarctic species. It is most commonly stranded in Alaska, especially along the Aleutian Islands.
Ecology and Behavior
Groups of 5-15 individuals have been observed, often containing animals of mixed sizes. Calving appears to occur mainly from spring to autumn.
Feeding and Prey
Stejneger’s beaked whales are known to feed on squid of the families Gonatidae and Cranchiidae.
Threats and Status
Not much is known about this species’ status, but some were taken in the Japanese salmon drifnet fishery in the Sea of Japan. Currently, Stejneger’s beaked whales are ‘Data Deficient’ (IUCN) and ‘Not Listed’ (ESA).
Dalebout, M.L. 2002. Species identity, genetic diversity, and molecular systematic relationships among the Ziphiidae (beaked whales). Ph.D. dissertation, University of Auckland, New Zealand.
Houston, J. 1990. Status of Stejneger’s beaked whale, Mesoplodon stejenegeri, in Canada. Canadian Field-Naturalist 104:131-134.
Loughlin, T.R. and M.A. Perez. 1985. Mesoplodon stejengeri. Mammalian Species 250:1-6.
Mead, J.G. 1989. Beaked whales of the genus Mesoplodon. pp. 349-430 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Vol. 4: River dolphins and the larger toothed whales. Academic Press.
Pitman, R.L. 2002. Mesoplodont whales Mesoplodon spp. pp. 738-742 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.
Walker, W.A. and M.B. Hanson. 1999. Biological observations on Stejneger’s beaked whale, Mesoplodon stejnegeri, from strandings on Adak Island, Alaska. Marine Mammal Science 15:1314-1329.