Biljana Oklopčić emphasizes the portrayal of race in Tarzan of the Apes. She claims that Tarzan represents white, male opposition to the "black rapist" stereotype which was prevalent in the Southern U.S. at the time of its publication because the language which describes apes parallels propaganda against people of Sub-Saharan African descent. Catherine Jurca similarly analyzes Tarzan as opposed to tolerating the presence of people of other races and classes in favor of preserving his own culture. The way that Tarzan defends his corner of civilization, his parents’ home, from the "savages" who want to destroy it, reflects an early twentieth-century American attitude; as darker-skinned immigrants flooded the country, especially urban areas, white Americans feared that their culture would be destroyed by newcomers who did not understand or care about it, and tried to protect the suburbs in the same way that Tarzan tries to protect his home. Though Burroughs’ admirers have tried to downplay claims of racism, or to explain that it was a common stereotype at the time the book was written, John Newsinger examines the extent to which Burroughs unfavorably described black characters. He wrote that Tarzan is the story of the "whiteman’s conquest of black savagery", where the native Sub-Saharan Africans are portrayed as brutes whom Tarzan enjoys taunting and killing. Civilization Tarzan's jungle upbringing and eventual exposure to Western civilization form another common theme in literary criticism of the novel. Berglund notes that Tarzan's ability to read and write sets him apart from the apes, the African villagers, and the lower-class sailors in the novel, and culminates in Tarzan recognizing himself as a human for the first time; moreover, he sees himself as a man who is superior to others unlike himself. Jeff Berglund argues that this realization exemplifies Burroughs' portrayal of whiteness and literacy as fundamental to civilization through implying that Tarzan's growth into a perfectly civilized person stems from his Western, white heritage and ability to read and write. However, Mikko Tuhkanen claims that the apparently civilized qualities of Tarzan, such as his interest in reading, threaten his survival as a human in the jungle. For Tuhkanen, Tarzan represents the fluidity with which humans should define themselves. He asserts, "[T]he human and the nonhuman become grotesquely indistinguishable" in the novel. Humans mistake apes for other humans, an ape tries to rape Jane, Tarzan finds a surrogate ape mother when he cries out like