What central theme about human behavior does the "The Outcasts of Poker Flat" convey?

There are several themes developed in "The Outcasts of
Poker Flat." Perhaps the main theme is that of how fate--or, in Oakhurst's case, "a
streak of bad luck"--can control a person's destiny. But, in regards to human behavior,
the theme of heroism is dominant. Oakhurst at first appears to be the hero of the story,
showing his leadership ability during the first days of the outcasts' journey. However,
in the end, he takes the coward's way out, committing suicide rather than trying to ride
our his streak of misfortune. The true heroes are the least likely pair: Mother Shipton
and the Duchess. Mother Shipton starves herself to death, hording her food in the hopes
that it will eventually help the others. The Duchess shows a motherly touch with Piney,
keeping her spirits up to the end. Young Tom also shows a heroic streak, setting off in
the blizzard alone in search of help for the others.