The boots are made of sealskin and the soles of whale skin.
“The Islanders usually go barefoot both summer and winter, but sometimes wear boots made from seal or sea lion skin, but they are somewhat different, resembling sacks with soles of whale skin sewn to them. The wealthy, especially women, wear warm boots made from ground squirrel or marmot skins.” (Davydov 1812: 18—19)