SHIPS ATTACKED BY WHALES 



Although the blue and finback whales of the At- 

 lantic and Pacific have been given different names, yet 

 there is little doubt but that each is represented in all 

 oceans by a single cosmopolitan species. 



Apparently no definite barriers exist to curtail the 

 wanderings of the fin whales (Balccnopterintf), for 

 they seem to be indifferent alike to tropic or Arctic 

 temperatures and travel where they will. Probably 

 the presence or absence of the little shrimp which 

 forms their food is one of the greatest determining 

 factors of their movements. 



In most oceans whales live under very similar con- 

 ditions and naturalists are gradually coming to recog- 

 nize that the laws of geographical separation which 

 hold universally good for land mammals are not 

 equally true in the case of cetaceans. In other words, 

 if any group of land mammals is separated from 

 others of its kind by impassable barriers such as water, 

 mountains, deserts, etc., it will gradually develop 

 changes in structure or external appearance due to 

 differences of climate, food, or other conditions of 

 environment. 



But this is not true of the fin whales for the con- 

 ditions under which they live in the North Pacific 

 are very similar to those in the North Atlantic; 

 consequently, even if the animals of the two oceans 

 never mingled, they could probably continue to repro- 

 duce themselves without material change for an al- 

 most indefinite period. But there is strong evidence 

 to show that all the fin whales do travel from one 

 ocean to another by way of Capes Horn and Good 



183 



