Walrus

The walrus (Odobenus rosmarus) is a large Arctic pinniped divided into two subspecies: the Atlantic walrus (Odobenus rosmarus rosmarus) and the larger Pacific walrus (Odobenus rosmarus divergens). Adults of both sexes carry elongated ivory tusks, which are used to haul out onto ice, establish dominance, and maintain breathing holes. They feed primarily on benthic invertebrates, especially bivalve mollusks, which they locate using their sensitive, whisker-like vibrissae on the seafloor. Walruses are listed as Vulnerable on the IUCN Red List, with the Pacific population numbering in the hundreds of thousands and the Atlantic population significantly smaller and more fragmented.

The walrus is a keystone species in Arctic coastal systems, turning over sediment as it forages and making nutrients available to other organisms. Its dependence on sea ice for resting, giving birth, and nursing calves makes it acutely sensitive to climate-driven ice loss. As summer sea ice retreats, walruses are increasingly forced onto crowded shoreline haul-outs, where stampedes caused by disturbance can kill large numbers of animals, particularly calves. Additional pressures include historical commercial hunting, which reduced populations sharply before protections were introduced, and ongoing subsistence hunting, shipping traffic, and oil and gas development in Arctic waters.