76 ARGUMENT OF THE UNITED STATES. 



the Pribilof Islands leaves Bering Sea by the eastern passes of the 

 Aleutian chain. 



3. The fur-seals of the Pribilof Islands do not mix with those of the 

 Commander and Kurile Islands at any time of the year. In summer 

 the two herds remain entirely distinct, separated by a water interval 

 of several hundred miles; and in their winter migrations those from the 

 Pribilof Islands follow the American coast in a southeasterly direction, 

 while those from the Commander and Kurile Islands follow the Siberian 

 and Japan coasts in a southwesterly direction, the two herds being 

 separated in winter by a water interval of several thousand miles. 



This regularity in the movements of the different herds is in obedi- 

 ence to the well-known law that migratory animals follow definite routes 

 in migration, and return year after year to the same places to breed. 

 Were it not for this law, there would be no such thing as stability of 

 species, for interbreeding and existence under diverse physiographic 

 conditions would destroy all specific characters. 1 



The pelage of the Pribilof fur-seals differs so markedly from that of 

 the Commander Islands fur-seals that the two are readily distinguished 

 by experts, and have very different values, the former commanding 

 much higher prices than the latter at the regular London sales. 



4. The old breeding males of the Pribilof herd are not known to range 

 much south of the Aleutian Islands, but the females and young appear 

 along the American coast as far south as northern California. Return- 

 ing, the herds of females move northward along the coasts of Oregon, 

 Washington, and British Columbia in January, February, and March, 

 occurring at varying distances from shore. Following the Alaska coast 

 northward and westward, they leave the North Pacific Ocean in June, 

 traverse the eastern passes in the Aleutian chain, and proceed at once 

 to the Pribilof Islands. 



5. The old (breeding) males reach the islands much earlier, the first 

 coming the last week in April or early in May. They at once land and 

 take stands on the rookeries, where they await the arrival of the fe- 

 males. Each male (called a bull) selects a large rock, on or near 

 which he remains until August, unless driven oft by stronger bulls, 

 never leaving for a single instant, night or day, and taking neither 

 food nor water. Both before and for sometime after the arrival of the 

 females (called cows) the bulls fight savagely among themselves for 

 positions on the rookeries and for possession of the cows, and many 

 are severely wounded. All the bulls are located by June 20. 



6. The bachelor seals (holluschiekie) begin to arrive early in May, 

 and large numbers are on the hauling grounds by the end of May or 

 first week of June. They begin to leave the islands in November, but 

 many remain into December or January, and sometimes into February. 



7. The cows begin arriving early in June, and soon appear in large 

 schools or droves, immense numbers taking their places on the rook- 

 eries each day between themiddle and end of the month, the precise 

 dates varying with the neather. They assemble about the old bulls in 

 compact groups, called harems. The harems are complete early in July, 



1 The home of a species is the area over which it breeds. It is well known to nat- 

 uralists that migratory animals, whether mammals, birds, fishes, or members of other 

 groups, leave their homes for a part of the year because the climatic conditions or 

 the food supply become uusuited to their needs ; and that wherever the home of a spe- 

 cies is so situated as to provide a suitable climate and food supply throughout the 

 year, such species do not migrate. This is the explanation of the fact that the 

 northern fur-seals are migrants, while the fur-seals of tropical and warm temperate 

 latitudes do not migrate. 



