732 ZOOLOGICAL, 
BALANCING AT THE SURFACE. 
ment received an average of $38.34 for the raw 
furs of the 1910 catch will serve to indicate what 
a valuable asset is constituted by the seal herds. 
The herds are so diminished in size that only a 
small fraction of the original numbers remains. 
Among the 
interesting fea- 
tures of the nat- 
ural history of 
the fur-seal may 
be mentioned, 
their extremely 
and 
polygamous 
habits; the ex- 
treme sexual dif- 
ference in 
(the males at- 
taining a weight 
of 400 to 500 
pounds and the 
females 80 pounds); the fierce struggles of the 
males to secure a well-filled harem; the driving 
out of the unsuccessful males; and the long jour- 
neys of the females for food. But the most in- 
teresting and wonderful feature of their biology 
is that of their long migration at sea for a 
period of some seven or eight months, and the 
unerring homing instinct that brings them back, 
after a journey of several thousand miles, to the 
obscure islets in the Behring Sea where the 
rookeries are located. The return trip is not 
even made over the same route as the outgoing 
journey. On leaving the breeding grounds at 
the approach of winter, the seals pursue a south- 
erly course until the latitude of California is 
reached; then they turn rather abruptly east- 
ward until off the California coast where they 
turn northward and work their way back along 
the Canadian and Alaskan shores until they ar- 
rive at the Pribilof Islands in the Behring Sea. 
gregareous 
size 
THE HIND FLIPPERS SPREAD IN PRESERVING THE EQUILIBRIUM. 
SOCIETY BULLETIN. 
The adult males reach the breeding grounds 
early in May, the young males next, and the 
females, heavy with young, appear just before 
the young are born in the latter part of June 
and the first half of July. The young females 
do not arrive until the last of July or August. 
The female bears her first pup at the age of 
three years and only one young is produced each 
season. 
An interesting, because extremely mixed, ter- 
minology has come into use about the islands 
frequented by the seals. The adult male is 
known as a bull and he wears a wig of longer 
hair on the back of his neck; young males are 
known as bachelors; the female is a cow and her 
offspring a pup, and the society or aggregation 
is a herd and the breeding grounds are rooker- 
ies. The bull collects as many cows as he can 
secure (from 1 to 100) for his harem, while the 
unattached males flock together on the hauling 
grounds. Even the term seal is scarcely appli- 
cable, as these 
animals are but 
distantly relat- 
ed to the true 
seals, and sea 
bear would be 
much more fit- 
ting. 
This particu- 
lar species (Cal- 
lorhinus alas - 
canus) oceurs 
on the Pribilof 
Islands. The 
Russian herd 
on the Com- 
mander Islands belongs to a slightly different 
species (C. ursinus), while a third species, now 
nearly extinct, is the C. curilensis of Robben and 
THEY SPEND MUCH OF THEIR TIME GROOMING THEM- 
SELVES. 
