Tail autotomy is a major defensive strategy to escape from predation in many species of lizards. Although tail loss provides an immediate survival benefit, it may entail substantial costs. A total of 117 blue-tailed skinks (Eumeces elegans) were collected from a population in Lishui to evaluate energetic and locomotor costs of tail loss. Of the 117 skinks, 81 (c. 69%) had autotomized some portion of the tail at least once. The blue-tailed skink in this population showed a high tail-break frequency, and therefore may be subjected to intense predation pressure. The proportions of individuals with tail breaks located in the proximal (except for the extreme base,<10% original tail length), middle and distal portions of tails were 47%, 36% and 11%, respectively. The frequency distribution of locations of the tail break did not differ between the sexes. Three tail segments were successively removed from each of the 17 experimental skinks (14 males, 3 females) initially having intact tails. Locomotor performance of each skink at the body temperature of 30℃ before and after each tail-removing treatment was measured by chasing them down the length of a 2 m racetrack with one side transparent, which allows lateral filmation with a digital video camera. The recorded tapes were later examined for three locomotor variables (the maximal distance, number of stops and sprint speed). All removed tail segment and body components were individually weighed and determined for the amount of lipids in each sample. Another independent sample of 15 individuals (12 males, 3 females) with intact tails was measured for locomotor performance to serve as controls for successive measurements taken at the time for the experimental skinks. The tail is an important storage organ for lipids in E. elegans. The amount of caudal lipid represented approximately 39% of the total body lipid, and was positively correlated with tailbase width, indicating that thicker tails contained relatively more lipids than did thinner tails. Caudal lipids were disproportionately stored along the length of the tail, with most lipids being concentrated in its proximal portion. Locomotor performance was almost unaffected by tail loss in this species, with a slight decrease in sprint speed until most of the tail was removed, and no significantly changes in the maximal length and number of stops after each tail-removing treatment. The degree of locomotor impairment associated with tail loss in this study (reduced by approximately 19% of the mean speed of skinks with intact tails) falls within the values reported for other species of lizards, thus E. elegans is among species of lizards whose tails play an important functional role in locomotion. The results from this study show that partial tail loss due to predatory encounters or other factors may not severely affect energy stores or locomotor performance in E. elegans. As tail breaks occurred more frequently in the proximal and middle portion of the tails in E. elegans collected from the field, it can be concluded that tail autotomy occurring in nature often incurs substantial energetic and locomotor costs in E. elegans.