SEAL LIFE ON THE PRIBILOF ISLANDS. 109 
CAUSE OF THE DECREASE OF SEALS. 
It has been generally conceded that the decrease of the seals is due 
to human interference, and in view of the many known cases of extermi- 
nation by human agency there is no reason for dissent from this opinion. 
When we go a step further, however, and inquire what special form of 
interference is responsible for the results observed, we are met at once 
by diversity of opinion. Men have located and carried on the ordinary 
operations of life on the seal islands. They have killed seals on the 
islands. They have intruded upon the resorts of the seals and driven 
off certain classes of these animals. They have killed mature males and 
young on land, and both males and nursing and pregnant females at 
sea. Some of these operations ceased many years ago, and others are 
still carried on. Out of all these factors of destruction, old and new, 
we are called upon to select the one or ones which are responsible for 
the effects observed, and with whose cessation the decrease would like- 
wise cease. In the present state of knowledge I conceive that this can 
not be done in such a manner as to place the matter beyond dispute. 
Conclusions have to be based largely on opinions, rather than on facts, 
and as long as these opinions can be challenged the conclusions will 
fail to receive universal acceptance. 
Putting aside the effects of all past forms of interference, however, 
as intangible, we know what operations are going on to-day and what 
is the condition of the seal herds. Weknow that the seals of all classes 
have greatly decreased in number and have shown that the decrease is 
still going on. We know that considerable numbers of male and of 
nursing and pregnant female seals are killed at sea, and that considerable 
numbers of male seals are killed on land. Now, whether few or many 
males remain is of no consequence, so long as there are enough to 
fertilize the females. 
My observations during the past summer show that there are enough, 
and that they are desirous of taking part in reproduction. If this is 
not true, why are there always males hovering about the water’s edge 
and attempting to intercept the females as they leave the rookeries? 
Why are there small harems at the water’s edge (and even in the water) 
which are constantly being broken up by the stronger bulls near by? 
Why are there new harems formed at the back of the rookeries 
the cows with pups) at the close of the season? Why are the pups 
arassed? If there were not enough bulls to fertilize the females, or if 
the bulls lacked vigor, none of these things would occur. But they do 
occur, as [ witnessed with my own eyes. Hence, I do not hesitate to 
state that, in my opinion, the number of bulls is sufficient for present 
purposes of reproduction, and that the bulls are virile. It is not to be 
inferred, however, that the number of males has not decreased. This 
is conceded, but, as already stated, the fact is of no interest in the 
present connection if enough remain. 
When we turn to consider the female seals, we find that the question 
assumes a very different aspect. It is useless to inquire whether there 
are enough females. Even if the islands of St. Paul and St. George 
were covered completely with female seals, there still would not be too 
many, provided there were males enough to fertilize them. When, 
however, we find the females decreasing year by year, there is every 
cause for alarm. ‘Taking the condition regarding males as they are 
to-day, the question we are considering resolves itself to this: What is 
the cause of the decrease of female seals? If we can not find a cause 
