A Marvel, A Madness

The Pribilofs are the most isolated of U.S. lands, two islands—St. George and St. Paul—lying in the cold Bering Sea 200 miles north of the Aleutians. Together, they hardly cover 60 square miles, and between them are 40 miles of sea. The residents (450 on St. Paul, 180 on St. George) are the descendants of Aleut slaves. And most Pribilof islanders of middle age or older were once de facto if not de jure slaves themselves. Slaves of the U.S.

Mist, drizzle, torrents and blizzards pour down some 300 days a year. But winters in the Pribilofs are not exceptionally cold, sub-zero readings being uncommon. Summers, if often gloomy, are mild, with temperatures ranging between 45 and 60. Because of the wet, mild climate, St. Paul and St. George are lush, carpeted with a bright green mat of alpinelike plants. The flowers are spectacular—lupines, poppies, lousewort—splashing patches of red, blue and yellow through treeless meadows.

There are a few upland birds, but only two native mammals in the interior: the Arctic fox, which is common and very visible, and the Pribilof shrew, which is uncommon and all but invisible. A few hundred reindeer, imported in recent times, roam St. Paul. In summer, millions of sea-birds—puffins, auklets, murres, cormorants, jaegers, kittiwakes—nest on the rocky perimeters of the islands. Clouds of them, like living mist, hover over the cliffs and beaches.

But these natural wonders are secondary. The marvel of the Pribilofs is the seals. For centuries the islands have served as the principal breeding, birthing and summering grounds for the northern fur seal (Callorhinus ursinus). About 80% of the world's northern fur seal population—1.3 million animals—gather here, most of them in rookeries on St. Paul.

Northern fur seals are nomadic. Throughout the winter they lead exclusively pelagic lives, wandering as far south as the waters of Southern California. In the spring the scattered herd begins to swim north, navigating the sea passes of the Aleutian chain and reaching the Pribilofs in ordered waves, the time of arrival determined by age and sex. In late May or early June the mature males, impressive creatures that have fed well all winter and weigh between 400 and 600 pounds, haul themselves up on the islands' rocks. When the bulls arrive their hormonal juices are flowing and they are aggressive and violent. They quarrel savagely, their jaws and teeth formidable weapons, the objective being to stake out a territory of some 200 square feet and defend it against encroachments by other males. Older bulls will occupy the same territories they held in previous summers, but they may be challenged and driven off by more vigorous animals. Generally it is the veterans, between 10 and 15 years of age, that succeed in establishing claims. These are descriptively and rightly called beachmasters. Inexperienced bulls, seven to 10 years of age, often end up stateless, hanging around favored areas, waiting for an opening and keeping beachmasters alert and provoked.

Several weeks later the pregnant females land. They are set upon by beachmasters bent on herding as many cows as possible (sometimes up to a hundred) into their territory. Usually within three days of her arrival the cow bears a pup (twins are rare). About six days later the cow is again impregnated by the harem bull; the fertility rate is between 60% and 80%. Females too young to have been bred the previous summer but receptive on their arrival land after the pregnant cows. Younger bulls often begin their careers as beachmasters by collecting these virgin females into small harems.

Once the birthing and breeding are completed, the females suckle their offspring and then return to sea to feed. They leave the pups sprawled on the beach for a week at a time, then return for two days to nurse them and rest. This cycle is continued for three months, during which time the pups, little more than large stomachs attached to small heads and flippers, remain on land. It is a mystery how a cow finds her pup out of the thousands of seemingly identical youngsters squirming about the rocks. There is no foster-feeding. Roger Gentry, a biologist studying seal behavior on the Pribilofs, believes identification is by voice. Returning to her harem area, the cow vocalizes and so does the pup. In the babble of crying and bleating, the cow is able to locate her offspring. Whatever the method, it works. As they drag themselves up on the beaches, cows roughly bat away all the other pups until they come upon their own.

The bulls linger in the rookeries for a month or so after the pups are born, continuing to defend their territories and trying to establish some internal order by snapping and bellowing at their mates and offspring. As the season progresses, cows and pups seem increasingly unimpressed by the posturing males, which appear more frenzied than frightening. The beachmasters, not having been to sea to feed since arriving on land two months earlier, are gaunt and worn down by sexual duties and social crises. In August they give up trying to exercise authority and go back for another nine months to the peace and bounty of the ocean.

While sexually mature and newborn animals are thus engaged, the migration continues. Immature bulls, 3-to-6-year-olds, arrive in late June and congregate at the edges of the rookeries in what are called bachelor hauling grounds. Immature females, 2-and 3-year-olds, beach after the young bulls, obeying, as do all the seals, some marvelous inner clock. A few yearlings of both sexes may come ashore briefly in September and October, but for the most part seals remain at sea until they are two years old. By December at the latest, all healthy seals have left the Pribilofs.

The northern fur seals followed this pattern undisturbed until 1786, when Gerassim Pribilof, a Russian adventurer, found them. Pribilof did not just stumble on the islands that now bear his name; he had been searching for them.