Hybridization in Vipers—A Case Study on Mating Between Vipera ammodytes transcaucasiana and V. a. ammodytes in Captivity

In the present study, we examine the possibilities of planned generation in snakes by controlling the two most important factors for their estrus—ambient temperature and daylight hours. As a result of controlling these environmental parameters in an increasing gradient until reaching optimal values for the species, we observed copulations in late March and early April between a female Vipera ammodytes transcaucasiana and a male V. a. ammodytes. After three months of “pregnancy”, we obtained viable offspring in early July, which is about two months earlier compared to wild populations. The species used in the experimental setup, in natural conditions, usually produce offspring in late August to early October. Another aspect considered in the publication and followed in the experimental setup was to possibly test if in evolutionary and developmental aspect, both subspecies are closely related and interspecies breeding is possible (which might indicate mutual ancestry). The hybrid individuals were monitored during their entire development from newborns to subadults for pathological traits during development to roll-out crossbreeding incompatibility. In our pilot investigation, no acquired or inherited pathological traits have been observed. The individuals were consistent with feeding and exhibited excellent individual development. Future research coupled with genetic investigation can give valuable insight in the field, whether it is valid to regard the genera as a Vipera ammodytes complex or as different subspecies groups.