In territorial salamanders and lizards, tail loss may immediately reduce the resource holding power (RHP) of residents, making defense of territories more difficult. Residents of the Red-Backed Salamander, Plethodon cinereus, defend territories using scent marks and agonistic displays. We examined (1) the marking behavior of tailed and tailless residents when establishing new territories, and (2) the behavioral responses of intruders to chemical cues produced by tailed and tailless residents. In the first experiment, we counted the number of postcloacal presses (PCP: a scent-marking behavior) by tailed and tailless salamanders (future residents) placed into unmarked test chambers. Tailless salamanders performed significantly more PCPs than tailed salamanders. Increased marking may have provided a benefit for tailless residents: tailed intruders, when placed in chambers marked by tailless residents, showed significantly less aggression when the residents performed more PCPs. In the second experiment, we observed the agonistic behavior of intruders placed into test chambers previously occupied by tailed or tailless residents. Tailed, but not tailless, intruders were significantly less aggressive in chambers marked by tailed residents than in chambers marked by tailless residents. Our results suggest that scent marks, in the absence of visual cues, provide intruders with information associated with tail condition (e.g., RHP) of residents.