Homage to the American Frontier
The novel is a clear homage to spirit of the American Frontier bearing many similarities Westerns such as a desert location, the damsel in distress, and the climactic face-off with the antagonist. Mars may be treated as a sci-fi nod to the Wild West and John Carter, a soldier turned Martian Messiah is your classic frontiersman. He initially comes into conflict with the Green Martians, the novel’s nod to the Native Americans. A Princess of Mars is written quite possibility as an expression of pining for a sentimentalized forgotten world of wide-open spaces, adventure, and interactions with noble savages.
Race
Race and interracial interactions are a frequently encountered theme in A Princess of Mars. Mars, or Barsoom as its natives know it is divided not just by racial borders but also by unique cultural distinctions and appearance of each race. The Green Martians, or Tharks in native Barsoomian, are a savage, green-skinned race that holds strength as the highest ideal. They live in a primitive tribal society and raiding other Thark communities the only economic activity that they busy themselves with. Tars Tarkas, chieftain of the Green Martians, seems to be the exception to the general savagery of the Tharks as he seems to be the only one exhibiting noble qualities such as living by a clear code of ethics and exercises some restraint with regard to violence. The Tharks are contrasted by the Red Martians, who are the other dominant sapient species of the planet. The Red Martians live in cities and make use of bizarre technology such as energy pistols and flying machines. It is later on revealed that they are the result of the interbreeding of the white, yellow, and black Martians---their precursors---who decided to pool both their scientific knowledge and genetic strengths to produce a hardy race that would survive the planet’s failing ecosystem. These two races have their representative characters interacting with one another without undue conflict. In fact over time some of the most enduring bonds of friendship form between these most unlikely of friends serving as in-novel argument that “nobility transcends race.”
Ecological Cautionary Tale
The novel is full of images of ruins of the grand cities and canals that the precursor Martian races built. In narrating these details there is both a sense of wonder and a nostalgic sadness that is communicated that despite the immense technological achievements of the ancient Martians there was nothing they could do to stop the slow but gradual decline of their world. Thus an underlying theme of the novel is a warning against unhindered exploitation of the environment, a reproof against the heedless development of technology, and the unchecked expansion of human habitation.