As with many of London's works, the overriding theme is man's relationship with nature. Here, as elsewhere, he presents this as something of a one-sided relationship in which man must always respect his natural environment. If he doesn't, then he will invariably come to grief.

The Eskimo tribe of which Koskoosh was the former chief needs to live according to the dictates and rhythms of nature if it is to survive. With the change of season, the tribe must move on and head north to search for new hunting grounds. As Koskoosh is dying, he will be left behind. The tribe has a completely unsentimental attitude towards illness and death. Once someone has become a burden, no matter how old or young, infirm or helpless, they are left to die in the icy wastes. As well as Koskoosh, a young child called Koo-tee is also sick. Koskoosh contemplates his imminent death, as well as the child's, with complete equanimity.

London's sympathetic portrayal of the Eskimos' customs indicates that he feels they have the correct attitude in their relationship with nature. They don't try to fight the forces of nature, as many unfortunate characters in London's stories often do; one thinks of the protagonist in "To Build a Fire," for example. Instead, they live in accordance with nature, paying it the appropriate level of respect, though red in tooth and claw it often is. Individuals will die, but the species must live on. And to preserve the species, one must look to nature in all its harshness for a shining example of how society's weaker elements should be weeded out.