Several species of fur seals are known, all of them limited to the
southern oceans or the coasts and islands of the North Pacific. All
are strongly gregarious and formerly sought their island breeding
grounds in vast numbers. At one period, soon after the purchase of
Alaska, it was estimated that several million fur seals were on the
Pribilof Islands in one season. During the height of their abundance
the southern fur seals were equally numerous.
The value of their skins and the facility with which these animals may
be slaughtered have resulted in the practical extermination of all but
those which breed under governmental protection on the Russian islands
off the coast of Kamchatka and on the Pribilof Islands in Alaska. Owing
mainly to wasteful pelagic sealing prior to the recent international
treaty, the numbers on both these groups of islands were much reduced.
The Alaska fur seal is a migratory species, wintering down the Pacific
coast as far as northern California. The migrations of these seals
are of remarkable interest. In spring they leave the northwest coast
and many of them travel steadily across more than two thousand miles
of the North Pacific. For days at a time they swim through a roaring
gale-swept sea, under dense, low-hanging clouds, and with unerring
certainty strike certain passages in the Aleutian Islands, through
which they press to their breeding grounds, more than 100 miles beyond,
on the small, fog-hidden Pribilof Islands.
Fur seals are extremely polygamous and the old males, which weigh from
400 to 500 pounds, “haul up” first on the breeding beaches. Each bull
holds a certain area, and as the females, only one-fifth his size, come
ashore they are appropriated by the nearest bulls until each “beach
master” gathers a harem, sometimes containing more than 100 members.
Here the young are born, and after the mating season the seals, which
have remained ashore without food from four to six weeks, return to the
water. The mothers go and come, and each is able to find her young with
certainty among thousands of apparently identical woolly black “pups.”
From the ages of one to four years fur seals are extremely playful.
They are marvelous swimmers and frolic about in pursuit of one another,
now diving deep and then, one after the other, suddenly leaping high
above the surface in graceful curves, like porpoises. Squids and fish
of various species are their main food. Their chief natural enemy is
the killer whale, which follows their migrations and haunts the sea
about their breeding grounds, taking heavy toll among them.
Since the discovery of the Pribilof Islands by the Russians the fur
seal herds there have yielded more than five million recorded skins.
A census of the herds in 1914 gave these islands nearly three hundred
thousand seals. Now that pelagic sealing has been suppressed and the
herds are being protected, there is every reason to expect that the
seals will increase rapidly to something like their former numbers.