EFFECT OF CLIMATIC INFLUENCES. 407 



tongues; lience the name Killer, applied to them by whalemen. 

 When the season arrives for the young Seals to enter the water 

 these animals are seen near the island, creating great conster- 

 nation among the Seals both young and old. They rarely ven- 

 ture near shore, but in three cases where they have been caught 

 young Seals have been found in their stomachs, leaving no 

 doubt of their object in ax^proaching the island. I have also 

 been informed by the natives of Bristol Bay that these same 

 animals are formidable enemies to the young Walruses and 

 Hair Seals. The Killers doubtless follow the Seals to their 

 winter feeding-grounds and prey upon them. During the time 

 the young Seals are absent from the island fidly 60 i^er cent, 

 of their number are destroyed by their enemies before they 

 arrive at the age of one year, and during the second year about 

 15 per cent, more are lost. Later they appear to be better 

 able to protect themselves, but before they arrive at maturity 

 at least 10 per cent, more are destroyed 5 so that if left entirely 

 to themselves only 10 or 15 per cent, of the annual product 

 would mature or reach the age of seven years. To what age 

 the males attain, there is no means of definitely ascertaining. 

 In the records of Shisenekoff, to which I have before alluded, 

 it is stated that he observed one male occujiy the same rock for 

 fourteen successive years. Only in five instances have I been 

 able to identify the same Seal as occupying the same place. 

 Four of these returned four years in succession, and the other, 

 five years. They were probably eight years old when first ob- 

 served, so that they attained at least to twelve years, which I 

 think may be considered as their average length of life. As I 

 have before stated, the large surplus of full-grown males exist- 

 ing in 1869 nearly all disappeared in about six years ; and when 

 we consider the fact of their severe labors during the breeding 

 season, when they pass from ninety to one hundred and twenty 

 days without food, engaged in a constant struggle for their 

 positions, and performing the most exhaustive function of phys- 

 ical life, six or seven years would seem to 'be the limit of the 

 active period of their lives. 



"Effect of climatic Influences. It remains now to 

 notice the effect of the climate on these animals. The climate is 

 very uniform at the islands during the period the Seals remain 

 here. The months of April, May, June, and July are the most 

 important portions of the year, as in August the Seals are all 

 in a condition to go in the water and avoid the influences most 



