Taxonomy & Nomenclature
Physical Description / Field Identification
Gray’s beaked whales have small heads, with extremely long, narrow beaks. Although mostly gray, white patches are found in the genital region and the beak becomes white in adults (Gray’s beaked whales observed in the eastern tropical Pacific have had white lower jaws and dark upper jaws, separated by a straight mouthline).
There are two small, triangular teeth set in the middle of the lower jaw, which erupt only in bulls, and 17-22 pairs of small teeth in the upper jaw. Maximum known sizes are 5.6 m for both sexes. These animals are known to reach weights of at least 1100 kg. Length at birth is probably between 2 and 2.5 m.
Can be Confused With
The long white beak (often stuck up out of the water as the animal surfaces) and straight mouthline may allow Gray’s beaked whales to be distinguished from other other mesoplodonts, if a good look is obtained.
Distribution
This is primarily a Southern Hemisphere cool temperate species, which is possibly Circum-Antarctic in occurrence. There are many records from New Zealand and Australia, and others from South Africa, Argentina, Chile, and Peru. This species may wander into the Northern Hemisphere on occasion, if a stranding record in the Netherlands is accurate.
Ecology and Behavior
Very little is known of the biology of this species. Gray’s beaked whales are seen mostly as singles or pairs; however, there is one record of a mass stranding of 28 of these whales. Gray’s beaked whales generally raise their long snouts out of the water when surfacing.
Feeding and Prey
Like other mesoplodonts, they are thought to feed mainly on cephalopods in deep waters.
Threats and Status
This species may not be as rare as some other species of the genus. No significant exploitation is known. Currently, Gray’s beaked whales are ‘Data Deficient’ (IUCN) and ‘Not Listed’ (ESA).
Links
References
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.
Gales, N.J., M.L. Dalebout and J.L. Bannister. 2002. Genetic identification and biological observation of two free-swimming beaked whales Hector’s beaked whale (Mesoplodon hectori, Gray 1871), and Gray’s beaked whale (Mesoplodon grayi, von Haast, 1876). Marine Mammal Science 18:544-551.
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.
