“I’ve worked with marine mammals for a long time, and with many different species of pinniped, but I’ve never experienced anything like walruses,” said Colleen Reichmuth of the Long Marine Laboratory at the University of California, Santa Cruz. “They are fantastic.”

Yet she and her colleagues despair for the walrus’s future. Like the polar bear, which last week was granted protection under the Endangered Species Act, the walrus depends on the seasonal rhythms of the polar ice cap for every phase of its life, which means it is particularly vulnerable to the warming of the earth’s climate and the retreat of the ice.

The walrus might well be a match for any famously eggheaded animal of any nonhuman order: for Flipper, for Willy, for Alex the gray parrot, for Kanzi the bonobo chimpanzee. As researchers have lately determined, the walrus shares with other big-brained species an unusually extended childhood. Walrus calves remain with their mothers for several years, compared with several weeks or months for the young of other pinnipeds, and that sustained dependency “could very well provide an opportunity for learning,” said Dr. Reichmuth, particularly about walrus civics.

Evidence suggests that the bonds between walruses are exceptionally strong: the animals share food, come to one another’s aid when under attack and nurse one another’s young, a particularly noteworthy behavior given the cost in energy of synthesizing a pinniped’s calorically rich, fatty milk.

“Walruses are very gregarious, and they like to be near other walruses,” said Chad Jay, who heads the walrus research program for the United States Geological Survey’s Alaska Science Center in Anchorage. “They like hanging out together, touching each other, socializing. Even when it’s hot and they have plenty of space, they prefer to clamber on top of each other and huddle together.”

Walruses want so much to be with other walruses that if there are no other walruses around, they will make do with the next available large object.

Image LIFE ON THE RINK The walrus, with its stiff, sensitive whiskers called vibrissae, depends on the seasonal rhythms of the polar ice cap for every phase of its life. Credit... Cary Anderson/Aurora Photos

Lee Cooper of the University of Maryland Center for Environmental Science recounted his 2004 expedition aboard a research vessel in the Bering Strait, when the crew came upon a number of calves that had somehow gotten separated from their mothers, and, oh, how excited the calves were to spot the ship and its staff, and how desperately they sought to climb aboard.