Mat 12, 1922] 



SCIENCE 



505 



foundation is an evolutionary process. Man 

 has never yet interfered very successfully with 

 the great scheme of organic evolution, and 

 there is no reason to suppose that he can pro- 

 pose a superior substitute for the evolutionary 

 process in the development of science. Selec- 

 tionists have practically abandoned the belief 

 that they can create new things at will, and are 

 content now to discover, preserve, and combine 

 what already exists or what may come into ex- 

 istence without their aid. Practical scientists 

 may well take their cue from the selectionists, 

 permit investigation to take its own course, 

 and choose from among its products such as 

 seem capable of application. 



A. Frankun Shull 

 Univeksity of Michigan 



WHAT BECOMES OF THE FUR 

 SEALS 



The census of Alaska fur seals in 1921 as 

 computed by Mr. Edward C. Johnston, of the 

 U. S. Bureau of Fisheries, amounted to a total 

 of 581,457 animals, exclusive of 22,546 surplus 

 males which were killed for commercial pur- 

 poses. This is a low but substantial increase 

 of 5.2 per cent, over the figures for 1920. The 

 annual percentages of increase of the class of 

 breeding cows since 1912 have been as follows : 



1913 12.54 



1914 1.06 



1915 11.02 



1916 12.99 



1917 9.44 



1918 11.63 



1919 9.97 



1920 6.59 



1921 5.22 



Since it is this class which is the controlling 

 element of the herd it will be instructive to 

 examine these figures with considerable care. 

 In the first place, the great variation from year 

 to year in the rate of increase is most notice- 

 able; but it is no greater than that which is 

 found to exist on the several rookeries, as an 

 examination of the complete reports published 

 by the Bureau of Fisheries will show. 



To some persons the above figures may ap- 

 pear satisfactoi-y. Every year since the cessa- 

 tion of pelagic sealing in 1911 a gain has been 



shown, whereas a loss was sustained from 1886 

 to that date. It was during this last period 

 that uncontrolled slaughter of the females de- 

 veloped and threatened the very existence of 

 the species before it could be checked through 

 diplomatic channels. 



Others will doubtless ask, "Why have the 

 increases been so low?" A species of animal 

 the female of which brings forth one young 

 each year and approximately ten in a lifetime 

 should increase annually more than 8.98 per 

 cent, on the average. But that is all that an 

 average of the above percentages will show. 



Several facts have been learned the past few 

 years which throw some light on this important 

 subject. For instance, it has been found in 

 several successive years that only one half of 

 the females which are born live to be three 

 years old. The loss of the class on the islands 

 before the pups learn to swim is about one per 

 cent. It varies from three fourths of one per 

 cent, to one and one half, depending entirely 

 upon how many bulls more than necessary are 

 present on the rookeries. The annual loss of 

 females through actual killing on the islands 

 does not exceed 75, or less than five hundi'edths 

 of one per cent.; all such deaths are purely 

 accidental and largely unavoidable in the con- 

 duct of commercial work. 



Therefore, the loss can take place in but one 

 other place and that is in the sea. The figure 

 of 50 per cent, loss the first three years was 

 obtained in the following manner : The loss of 

 breeding females, due to old age, is about 10 

 per cent, each year because the average breed- 

 ing age is about 10 years. If this 10 per cent. 

 be deducted from the number of breeding 

 females in any year, say 1915, the remainder 

 will represent the breeders of that year which 

 remained alive in 1916. If this be taken from 

 the total number of breeders in 1916, the last 

 remainder will represent the increment of new 

 three-year-old cows that year because the first 

 young are born the third year. In several 

 seasons this increment has been only about 50 

 per cent, of the number of female pups born 

 three years previously. In other words, the 

 loss amounts to one fourth the total number of 

 births in any one year. Out of the females 

 born during the last nine years, therefore, the 

 following losses have been suffered : 



