We analysed several morphological characters of 84 road-killed D. caspius individuals from different areas of southern Romania. Most presented asymmetries in the total number of temporal scales, the temporal row and the periocular and labial scales. Almost a quarter of snakes had scars, located especially on the head and tail; many individuals had multiple injuries. The lowest rate of individuals with scars was found in the area with the least anthropogenic impact (Danube Gorge). This finding suggests that, in other areas in Romania, the species is threatened and lives in less optimal conditions. The number of individuals with asymmetries and scars differed according to the populated region, sex or size class. Most of the individuals were killed in August, due to the large number of road-killed juveniles.

Road mortality is one of the most obvious forms of anthropic impact upon fauna. The Iron Gates Natural Park is an area of great biodiversity, crossed by a 154 km long road running parallel to the Danube River. To estimate the impact of this road upon the fauna, between March 2019 and February 2020 we monitored road mortality on a monthly basis. We recorded 13,230 road-killed animals, belonging to 71 taxa. The greatest proportion of taxa was killed in early summer and the number of individuals killed peaked in autumn. A spring mortality peak was not observed. Cold-blooded animals were killed year-round, even though they should not have been active in winter in Romania. This is a consequence of the warmer climate of the region compared to the rest of Romania, but also the mild winter of 2019 / 2020. Mitigation measures such as stopping the construction of new roads would prevent the problem of animal road deaths being replicated in other areas. In addition to the ecological, zoogeographical and conservation value of its findings, our study also warns of a cause-effect link between global warming and an increase in road mortality.