Proportions of different prey in the diet vary with age of seals. Foods of male and female seals are similar.
Young seals eat proportionally more shrimps than do older animals.
Recently, clams were important in the diet only in Norton Sound and near Wainwright, and only during late spring and summer. Greatest quantities of food were found in stomachs of seals which had eaten mostly clams. In Bering Strait, seals taken in spring 1958 and 1967 had consumed large quantities of clams, but this item was only a minor fraction of foods in 1975-79. Walruses, Odobenus rosmarus , have increased steadily in numbers since 1960. Whereas Bering Strait was mainly a route through which walruses migrated in spring and autumn.