444 EXTINCT AND VANISHING MAMMALS 



females and their young. On Stejneger's second visit in 1896, 

 the result of this was plainly evident in the depletion of some 

 of the rookeries that had formerly been well populated. It was 

 not until pelagic sealing was stopped by international agree- 

 ment in 1911 that this danger was removed. At the present 

 time the colonies are apparently in flourishing condition on the 

 Commander Islands, although the great yields of their palmy 

 days are no longer taken. According to Barabash-Nikiforov 

 (1938) the seals "spend only the summer period on the Com- 

 mander Islands. They begin to arrive at the end of April or 

 the beginning of May but are present in their greatest numbers 

 at the beginning of August. The first new-born young appear 

 in the middle of June, 2 or 3 days after their mothers arrive at 

 the island. Soon after this the fertilization of mothers occurs. 

 Moulting takes place from the middle of August until the 

 middle of September, and about the middle of October the 

 animals begin to leave the island. Fish is the chief food of the 

 fur seal . . . Infection with endoparasites, chiefly Uncin- 

 aria, is especially great among the young fur seals." 



The fur-seal rookeries of the Kurile Islands, the home of C. 

 ur sinus mimicus, were not discovered until 1881, or 11 years 

 after the islands were ceded to'Japan by Russia in exchange for 

 the southern half of Sakhalin Island. There were four islands 

 on which rookeries occurred, and these totaled a population of 

 about 22,000 seals as then estimated. They were so speedily 

 decimated by Japanese sealers that by 1898 Stejneger on 

 careful inquiry concluded that a possible 30 animals might 

 still remain. The race may already be extinct. 



It is believed that both the Commander Islands and the 

 Kurile Islands fur seals at the close of the breeding season moved 

 southward into somewhat warmer waters for the winter season, 

 but the extent of this migration is not clear. Sowerby (1923) 

 writes that they are said to occur off Chefoo, in northern 

 Shantung Province, China, and even perhaps to Shanghai, but 

 the evidence is not very definite. 



ALASKAN FUR SEAL 

 CALLORHINUS TJRSINUS CYNOCEPHALUS CWalbaum) 



Siren cynocephala Walbaum, Artedi, Genera Pise., p. 560, 1792. 

 SYNONYMS: Trichechvs ? hydropithecus Shaw, Gen. Zool., vol. 1, pt. 1, p. 247, 1800; 

 Manatus ? simia Illiger, Abh. Akad. Wiss. Berlin, Phys. Kl., 1804-11, pp. 64, 68, 



