168 
ZOOLOGY: G. H. PARKER 
THE GROWTH OF THE ALASKAN FUR SEAL HERD BETWEEN 
1912 AND 1917 
By G. H. Parker 
United States Seal Investigation, 1914 
Read before the Academy, April 23, 1918 
The apprehension with which the condition of the Alaskan fur seal herd 
was viewed some half decade a^o has disappeared in consequence of the 
steady growth of the herd. Few animals have been more closely watched 
and counted from year to year than the Alaskan fur seals and their remark- 
able habits of breeding exclusively on the Pribilof Islands and of assembling 
there each summer in one immense complex family render these counts of no 
small biological interest. It is probable that in late July and early August 
of each year every living Alaskan fur seal (Callorhinus alascanus) is either 
on one of the Pribilof Islands or in the immediately adjacent sea. Thus an 
annual complete rendezvous of this species takes place in an almost unique 
way, and this rendezvous gives opportunity for a census of the fui seal such 
as is possible in scarcely any other undomesticated animal. 
Table I exhibits in several particulars the numerical conditions of the herd 
from the summer of 1912, when detailed counting was begun, to that of 1917. 
The numbers in this table are taken from the successive reports on the state 
of the herd as given out in the publications of the United States Bureau of 
Fisheries (Osgood, Preble, and Parker, 1915; Bowers and Allen, 1917; Smith, 
1917; Fisheries Service Bulletin, No. 30). The counts in the years 1912 and 
1913 were made under G. A. Clark; those in 1914 under a group of six in- 
vestigators, B. W. Harmon, T. Kitahara, J. M. Macoun, W. H. Osgood, 
G. H. Parker, and E. A. Preble; and those of 1915, 1916, and 1917 under 
G. D. Hanna. 
Table 1 opens with an enumeration of the new-born pups for the seasons 
under consideration. From 1912 to 1916 inclusive these enumerations were 
made as direct counts of the numbers of pups on the beaches by methods 
well established on the islands. In 1916, owing to the increase in the num- 
ber of pups, direct counting was accomplished only with difficulty, and in 
1917, in consequence of still greater increases, it was found necessary to re- 
sort in part to a method of estimates. Hence it is believed that the num- 
bers for 1916 and particularly for 1917 are not so accurate as those for the 
preceding years. 
In no feature is the growth of the herd indicated more clearly than in the 
yearly increase in pups. This increase ranges in a progressive series from 
81,984 in 1912 to 128,024 in 1917. The nature of this increase can be appre- 
ciated best when the numbers are plotted in some such way as in Graph 1 
in which the abscissas represent years and the ordinates numbers of pups in 
