Mating System and Behavior of Steppe Rat Snake (Elaphe dione) in South Korea

The mating system affects the animal’s mating behavior, operational sex ratio (OSR), and the genetic information of paternity. It is generally known that many species in the order Serpent accept polyandry. We observed the mating behavior of steppe rat snakes three times from April 1 until September 30, 2020. In all cases, the sex ratio participating in mating was one female and two or more males. Moreover, in two cases, two males were observed to insert their hemipenes into one female’s cloaca at the same time, which was a unique finding. It was concluded that steppe rat snakes would be highly likely to adopt polyandry, a common mating system of snakes. It will be possible to understand the exact mating system of steppe rat snakes by conducting behavioral genetic studies on them.