Calvin and Hobbes follows the humorous antics of the titular characters: Calvin, a precocious, mischievous and adventurous six-year-old boy; and Hobbes, his sardonic stuffed tiger. Set in the contemporary suburban United States, the strip depicts Calvin's frequent flights of fancy and friendship with Hobbes. It also examines Calvin's relationships with family and classmates, especially the love/hate relationship between him and his classmate Susie Derkins. Hobbes' dual nature is a defining motif for the strip: to Calvin, Hobbes is a living anthropomorphic tiger, while all the other characters see Hobbes as an inanimate stuffed toy. Though the series does not mention specific political figures or contemporary events, it does explore broad issues like environmentalism, public education, philosophical quandaries and the flaws of opinion polls.