| Scientific Name | Sistrurus tergeminus |
| Category | I |
| Taxon | Reptiles |
| Climate Change Vulnerability Score | Less Vulnerable |
The Western Massasauga (Sistrurus tergeminus) is a small (0.5 m [2 ft] total length) rattlesnake that is found across the southwestern US and northern Mexico. It is typically found in desert grassland habitats. It is predominantly nocturnal, especially during the hot summer months. The Western Massasauga will experience a high degree of climate exposure and has a high adaptive capacity. Overall, it has a Climate Change Vulnerability Index ranking of Less Vulnerable under both Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 Scenarios. The Western Massasauga’s climate change vulnerability is impacted by factors related to movement, demography, and abiotic niche, which influence its ability to shift in space, persist in place, and respond to climate change impacts. It is impacted by barriers, land-use changes, and other anthropogenic factors that could increase the effects of climate change.


