The time has come, the walrus said …

Nobody knows how many walruses the world holds.

But researchers have little doubt that the figure is on a downward slide, as the polar ice sheet on which the mammal depends for every stage of its life thins and retreats from beneath its flippered feet.

“The ice is melting three weeks earlier in the spring than it did 20 years ago, and it’s re-forming a month later in the fall,” said Carleton Ray of the University of Virginia, who has studied walruses since the 1950s.

“There’s no question that these changes are very bad for walruses,” Dr. Ray added, as they are for other ice dwellers like polar bears and four species of the walrus’s pinniped kin: the ribbon, ringed, spotted and bearded seals. New York Times, 20 May 2008