ZOOLOGICAL SOCIETY BULLETIN. 



BALANCING AT THE SURFACE. 



ment received an average of $38. ;M' for the raw 

 furs of the 1910 catch will serve to indicate what 

 a valuable asset is constituted by the seal herds. 

 Tlie herds are so diminished in size that only a 

 small fraction of the original numbers remains. 



Among the 

 interesting fea- 

 tures of the nat- 

 ural history of 

 the fur-seal may 

 b e mentioned, 

 their extremely 

 gregareous and 

 polygamous 

 habits ; the ex- 

 tremesexualdif- 

 ference in size 

 (the males at- 

 taining a weight 

 of -too to .500 

 pound.s and the 

 females 80 pounds) ; tlie fierce struggles of the 

 males to secure a well-filled harem; the driving 

 out of the unsuccessful males; and the long jour- 

 neys of the females for food. But the most in- 

 teresting and wonderful feature of their biology 

 is that of their long migration at sea for a 

 period of some seven or eight months, and the 

 unerring homing instinct that brings them back, 

 after a journey of several thousand miles, to the 

 obscure islets in the Behring Sea where the 

 rookeries are located. The return trip is not 

 even made over the same route as the outgoing 

 journey. On leaving the breeding grounds at 

 the approach of winter, the seals pursue a south- 

 erly course until the latitude of California is 

 reached ; then they turn rather abruptly east- 

 ward until off the California coast where they 

 turn northward and work their way back along 

 the Canadian and Alaskan shores until they ar- 

 rive at the Pribilof Islands in the Behring Sea. 



THE H:ND FlIPPERS SPREAD IN PRESERVING THE EQUILIBRIUM 



The adult males reach the breeding grounds 

 early in May, the young males next, and the 

 females, heavy with young, appear just before 

 the young are born in the latter part of June 

 and the first half of Jul}'. The young females 

 do not arrive until the last of July or August. 

 The female bears her first pup at the age of 

 three years and only one young is produced each 

 season. 



An interesting, because extremely mixed, ter- 

 minology has come into use about the islands 

 frequented bj' the seals. The adult male is 

 known as a bull and he wears a wig of longer 

 hair on the back of his neck; young males are 

 known as bachelors; the female is a coxa and her 

 offspring a ptip, and the society or aggregation 

 is a ]ierd and the breeding grounds are rooker- 

 ies. The bull collects as many cows as he can 

 secure (from 1 to 100) for his harem, while the 

 unattached males flock together on the hauling 

 grounds. Even the term seal is scarcely appli- 

 cable, as these 

 animals are but 

 distantly relat- 

 ed to the true 

 seals, and sea 

 bear would be 

 inueli more fit- 

 ting. 



Tliis particu- 

 lar species {Cal- 

 lorhinus a I a s - 

 caiius) occurs 

 on the Pribilof 

 Islands. The 

 Russian herd 

 on the Com- 

 mander Islands belongs to a slightly different 

 species {('. ursiiius). while a third species, now 

 nearlv extinct, is the ('. curileiisis of Robben and 



THEY SPEND MUCH OF THEIR TIME GROOMING THEM- 

 SELVES. 



