Programme Coordinator – Sergey Ryabov, Moscow Zoo, Russia
The Dione’s ratsnake Elaphe dione has one of the largest range among all snake species, spreading from the western borders of Russia to Mongolia and the Russian Far East and from the Middle Volga, Lake Baikal and the Chita Oblast in the north to Iran and Central China in the south. The Dione’s ratsnake range states include Russia (from the western to eastern border), China (northern territories), Mongolia, Kazakhstan, North Korea, Kyrgyzstan, Uzbekistan, Tajikistan, Turkmenistan, Azerbaijan, Eastern Ukraine, Iran, and Afghanistan.
This species is highly variable in coloration, featuring dozens of natural colour patterns that are sometimes utterly different from each other. Elaphe dione has the largest number of coloration pattern forms among all snakes of Eurasia.
Goals of the programme
1. Fundamental research into reproductive biology and genetic mechanisms of trait inheritance and a comprehensive revision of the taxonomy of the Dione’s ratsnake Elaphe dione, a widespread Eurasian snake species with a huge number of variations and an unclear taxonomic status.
2. Creating a collection of the Dione’s ratsnakes represented by individuals from all populations distributed across the species’ vast range (total population size –300-400 snakes), detailed study of morphology, ethology, all aspects of reproductive biology, and genetic variability for the comprehensive revision of the taxonomic status of the species. Exploring the potential of natural variability of the snakes from various habitats and controlled selective breeding for obtaining new forms.
Objectives and methods
1) Establishing contacts with colleagues in the species range states and regions and making arrangements for obtaining live rat snakes from various regions;
2) Adaptation of wild caught snakes to laboratory conditions, treatment of snakes against internal and external parasites and possible diseases;
3) Selection of optimal housing and feeding regimes;
4) The species life cycle modelling based on the geographical latitude and climatic features of the habitats of the source populations and selection of methods stimulating breeding of the species under laboratory conditions;
5) Daily registration of data on each individual (data on feeding, ecdysis, mating, changes of temperature, humidity and duration of daylight, health problems, dehelmintization, vitamin therapy, weighing, etc.);
6) Detailed study of reproductive biology of individuals from each population (the length of copulation and gestation, selection of optimal egg incubation regimes, measuring the egg length and weight and weight of the females, monitoring egg growth processes, study of incubation duration, selection of initial diet, developing methods of neonate rearing, determination of the age of sexual maturity, photo recording of all stages of the work);
7) Using the long-term data for the comprehensive revision of the taxonomy of this species;
8) Exploring the potential of natural variability of each population and selection of rare variants through selective breeding;
9) Organizing temporary public exhibitions at interested zoos, with the demonstration of all available natural colour variations of the Dione’s ratsnakes, as well as of the new colour forms resulting from the activity under the programme;
10) Active promotion of the work under the programme among EARAZA members.