DISTRIBUTION AND MIGRATION 



345 



Figure i88. The Chinese 

 River Dolphin, Lipotes 

 vexillifer Miller, from 

 Tung Ting Lake. [Kel- 

 logg, 1940-) 



probably due to movements of its food and particularly of the cuttlefish, 

 lUex illecebrosus. 



Similar migratory movements have also been established in the case of 

 the Common Dolphin and of the Pacific White-sided Dolphin (Lageno- 

 rhynchus obliquidens) . Of the former, Capt. Mörzer Bruins observed that in 

 summer it visits Algerian waters in large schools, while it is extremely rare 

 in the winter. The migration of the Pacific White-sided Dolphin is, 

 according to Brown and Norris (1956), connected with the migration of 

 the anchovies on which they feed. In winter and spiing these animals 

 keep close to the coast, and in autumn they move far out to sea. 



Various strains and species of Bottlenose Dolphin seem to have different 

 feeding habits as well. According to Capt. Mörzer Bruins, the N. Atlantic 

 species {Tursiops truncatus) always keeps to within the top 100 fathoms, 

 whereas Tursiops adunciis (a Red Sea and Indian species) generally keeps 

 to deeper waters. 



While some Bottlenose Dolphins have been observed as far north as 

 Spitsbergen, the Common Dolphin keeps to more temperate seas, and is 

 rarely found much farther north than Iceland and Finmark. 



A scattered distribution is shown by the genera Berardius (two species 

 in the Atlantic part of the Antarctic and the N. Pacific respectively), 

 Lissodelphis (N. Pacific and southern seas) and Feresa (Pacific, S. Atlantic, 

 and probably Australia - stranding of two unknown dolphins near 

 Sydney - reported by Dawbin in 1959.) 



Other Cetaceans keep to far more restricted areas. Thus most dolphins 

 of the genera Stenella [Prodelphinus) and Sotalia keep generally to tropical 

 and sub-tropical waters, although at least three representatives oï Stenella 

 have stranded on the British coast. Sotalia, which looks like a small 



