446 EXTINCT AND VANISHING MAMMALS 



the birth of the young the females are ready for mating and 

 are occupied with the care of the pup, going and coming freely 

 to and from the feeding grounds in the adjacent seas. The 

 nonbreeding immature males or "bachelors" consort by them- 

 selves in a separate part of the shore. It is from this group 

 that killings are best made, since the polygamous habits of the 

 species result in the production of many more males than are 

 needed for propagation, assuming that the ratio of the sexes is 

 approximately the same among the young pups. Parker (1917) 

 records that in 1914, he found "the number of cows associated 

 with one bull varied by actual count from 1 to 106," with an 

 average of about 60, a number probably "somewhat too high 

 for the best condition of the herd." In August the harems 

 begin to break up, and the pugnacity of the adult males relaxes. 

 By November the rookeries are nearly deserted, and the herds 

 put to sea once more on their southward migration. 



The rookeries on the Pribilof Islands were under the adminis- 

 tration of the government of Russia until 1867, when Alaska 

 was purchased by the United States. Up to that time the 

 collecting of pelts was under the monopoly of the Russian- 

 American Co. Since the discovery of the islands in 1786, more 

 than 5,000,000 sealskins have been taken, and with proper 

 management there is no reason why the yield should not con- 

 tinue indefinitely. 



But the exploitation of these resources in the decades after 

 the purchase of Alaska by the United States soon began to 

 show in the decline of the herds. Investigations proved that 

 the chief cause was "pelagic" sealing. For while the breeding 

 colonies were managed with a certain degree of discretion 

 ashore, and the poaching of sealing crews was more or less 

 stopped, it developed during the eighties that an increasing 

 number of sealers made a practice of lying offshore outside of 

 territorial limits and shooting the females that came out to 

 their feeding areas. The resulting reduction of the females 

 thus involved the loss of their new-born young through starva- 

 tion on the rookeries. This abuse was eventually stopped by 

 international agreement in 1911 between the United States, 

 Great Britain, Russia, and Japan. At that time, in 1912, it 

 was estimated that the colony of fur seals on the Pribilof 

 Islands had been reduced to some 130,000, a number far 

 smaller than the population that can be carried by the available 



