In the southern Appalachian Mountains, multiple species of large salamanders in the genus Plethodon occur within the same niche, with different species dominating high and low elevations and engaging in interspecific competition where they overlap. Some high-elevation species are more aggressive than their low-elevation competitors, which may prevent the latter from ascending the mountain and potentially eradicating the high-elevation species over time. In the Cheoah Mountains, this interaction may occur between the Cheoah Bald salamander (Plethodon cheoah) as the high-elevation species and the southern Appalachian salamander (P. teyahalee) as the low-elevation species. Plethodon teyahalee is not limited to low elevations by physiological restrictions, so I wanted to examine if interspecific aggression may be contributing to the dominance of P. cheoah at high elevations. I ran aggression trials with P. cheoah and P. teyahalee in a lab setting to compare both species’ interspecific and intraspecific aggression. Aggression was defined as acts of a salamander looking towards, approaching, snapping, lunging, chasing, or biting the other salamander. Plethodon cheoah was found to be more aggressive than P. teyahalee in both intraspecific and interspecific trials, and larger individuals of both species committed more aggressive acts. However, smaller P. cheoah did show aggression toward larger P. teyahalee. Another factor that may contribute to the elevational distribution of these salamanders is their evaporative water loss rates through their skin. As P. cheoah is restricted to high elevations, I hypothesized that they cannot retain water as well as P. teyahalee and do not live at lower, drier elevations due to risk of desiccation. I measured the evaporative water loss rate of salamanders of both species using a LiCor gas analyzer. Both species had similar mass-adjusted water loss rates per individual and per cm2 of skin area. However, P. cheoah did have higher average water loss rates per cm2 of skin area and per gram of salamander than did P. teyahalee. This was because P. cheoah was smaller on average than P. teyahalee and had a higher surface-to-volume ratio. These results suggest that aggressive interactions and physiological constraints play roles in the elevational distributions of P. teyahalee and P. cheoah as in other montane Plethodon.