WHITE-BEAKED DOLPHIN (T) 



Lagenorhynchus albirostris Gray 1846 



Other Common Names 



White-beaked porpoise, squidhound (Newfoundland). 



Description 



White- beaked dolphins reach a maximum overall length of 

 about 10 feet (3.1 m). The body is robust in form with a tall, 

 uniformly dark- gray dorsal fin, and a short but distinct beak 

 which, as the common name implies, is often light gray to 

 white above and below, at least in European waters. The 

 beak of animals in the western Atlantic populations is less 

 frequently white. The back and sides are basically dark gray 

 to black, and the belly is white to light gray. 



Swimming white-beaked dolphins can be most readily 

 identified by the two areas of pale coloration on the sides, one 

 in front of and another below and behind the dorsal fin. These 

 areas are clearly visible from a ship or aircraft as the animals 

 roll at the surface. 



Natural History Notes 



White- beaked dolphins may sometimes occur in herds of 

 up to 1,500 individuals. Like their cousins, the Atlantic 

 white-sided dolphins, they do not commonly ride the bow 

 waves of vessels. 



White- beaked dolphins feed on squid, octopus, cod, 

 herring, capelin, and sometimes on benthic crustaceans. 



May Be Confused With 



In their northerly range white-beaked dolphins are likely 

 to be confused with only the Atlantic white-sided dolphins. 

 The most distinctive features of white-beaked dolphins are 1) 

 the two areas of paleness described above, 2) the prominent, 

 dark-gray dorsal fin, and sometimes 3) the white beak. Other 



features by which the two species may be distinguished in the 

 brief encounters typical at sea are tabularized on p. 127. 



Distribution 



White-beaked dolphins are the more northerly of the two 

 species of Lagenorhynchus in the western North Atlantic. 

 They are found from Cape Cod, Mass., north to western and 

 southern Greenland and Davis Straits, though they are 

 apparently far more numerous to the north of this range. 

 They appear in Davis Straits in spring and summ.er and leave 

 that area in autumn, sometimes as late as November, to move 

 southward. They winter as far south as Cape Cod, where they 

 are the common dolphin species in April, May, and June 

 (sometimes to July). Their migrations are poorly known. 



Stranded Specimens 



Stranded white-beaked dolphins can be most readily 

 distinguished from white-sided dolphins by the substantial 



"^WiW, 



Figure 1 10. — Two viewH of white-beaked dolphins off Newfoundland. This species is characterized by a prominent uniform dark gray dorsal fin and two 

 areas of paleness on the sides, one in front of and one below and behind the dorsal fin. White-beaked dolphins are distributed from Newfoundland north, 

 extending to more northerly waters than Atlantic white-sided dolphins. (Photos by H. E. Wirm [bottom] and W. A. Watkim [top].) 



126 



