In almost every zombie narrative, the boundaries between the human and the monster is blurred. One of the most significant of these boundaries is between the monsters and the monstrous behavior of the living.
The zombies certainly represent a serious external menace, but they cease to be much of a danger once the living humans have taken up a defensive position and fortified it. The real threat comes from the other human survivors on the inside of the barricades—“those who still think, plot, and act” (Bishop 39). As Dillard points out, “The living people are dangerous to each other . . . because they are human with all of the ordinary human failings.” Because “emotions such as fear, anger, hatred, and jealousy . . . are expressed only by the living,” these things come to seem “quintessentially human” ([American Horror] 22).
In his films, Romero clearly asserts that “the living have a certain propensity for murderous violence, territorialism, and irrationality—qualities that immediately surface during a crisis” (Waller 281). The zombies do not exhibit these negative human characteristics, but they always rise to the surface within the survival group. While the zombies attempt to consume the living, the flaws within human nature threaten to do the same from within the barricades.
The threat of the living is not only from within the survivor group, but outside it as well. Besides the zombie and the “hero”—the monster and the human, Romero’s movies include a third group in his films—the monstrous human. In these characters we see the worst and most inhuman behavior—again showing that the living are not that much different from the undead.
In Night of the Living Dead, this group is McClelland and his posse. Although engaged in a grizzly task, they do so with a heartless carelessness that ends in the unintentional murder of Ben. In Dawn of the Dead, the survival group is beset by lawless renegades on motorcycles, for whom “the only real sport left is slavery, torture, rape, and murder, the enactment of base appetites.” The zombies are shown to be less of a threat since they “don’t think or plan or scheme, they are mere animals to be avoided; other survivors, however, are more calculating and dangerous” (Bishop 24). Romero is showing us that “the true monster threatening civilization [is] humanity itself” (95).