Invasion by alien species has become a major problem that threatens the security of our ecological environment. It is one of the three major environmental problems in the world today. Preventing alien invasions has become a focus for both government and public sectors, and a focal topic within academic circles. Of the many of invasive species, the Red-eared turtle (Trachemys scripta elegans) poses a particularly serious threat. As one of the 100 most dangerous invasive species in the world, Red-eared turtles have caused irreversible effects on the ecosystems they invade. Previous studies have shown that the Red-eared turtle is able to cause such extensive damage because of its ability to adapt to its environment. Some of their physiological and behavioral indicators show an advantage, but there is still insufficient data to explain their competitive advantage overall. This paper examines the body temperature, dependence of locomotion on temperature, compensatory growth, and the immunity of hatchling Red-eared turtles and Chinese pond turtles (Chinemys reevesii). We found that Red-eared turtles could significantly influence the thermoregulatory behavior of the Chinese pond turtle. The Red-eared turtle exhibited a wider range of body temperatures and thermal tolerance, better locomotor performance, and innate immunity in comparison to its counterpart; indicating a more stable compensatory growth mechanism. When exposed to a thermal gradient, Red-eared turtles that were bred together with Chinese pond turtles selected lower body temperatures and had larger coefficient of variation of body temperatures than those bred separately. The upper (CT_Max) and lower (CT_Min) limits of thermal tolerance were 41.2℃ and 3.6℃ for the Red-eared turtle, and 37.2℃ and 4.5℃ for the Chinese pond turtle, respectively. We therefore concluded that Red-eared turtles have an advantage in the thermal resource competition in a polyculture environment. The locomotor performance of the two species was measured when the body temperature was held at three different levels: 20, 28℃ and 36℃. Sprint speed and maximal distance increased with body temperature of both species and the locomotor performance of the Red-eared turtle was better than that of the Chinese pond turtle when compared at the same body temperature. Therefore, the Red-eared turtle exhibited better movement potential and likely has more advantages in the field during competition for food and predator evasion. Compensatory growth was observed in the two turtles following starvation. The change in body mass of the two species increased evenly under the five-day starvation treatment. Body mass increased more rapidly in the Red-eared turtle than in the Chinese pond turtle when subjected to the 10-day-long starvation treatment and more slowly when under the 15-day starvation treatment. The coefficient of variation for body mass was larger in the Chinese pond turtle than in the Red-eared turtle. Both species showed immunoreactivity to phytohemagglutinin; with the immunoreactivity of the Red-eared turtle taking six hours to reach its maximum level-significantly faster than that of the Chinese pond turtle. These results indicate that the Red-eared turtle can adapt to new environments quickly and therefore threaten the native turtles as an alien species. This adaption could be ascribed to the potential advantages in their locomotor and physiological characteristics.