Ritual Combat of Elaphe quadrivirgata Observed Outside the Mating Season

Abstract: Males of a Japanese colubrid snake, Elaphe quadrivirgata, have been reported to exhibit ritual combat during the mating season between April and May to gain access to females. I observed ritual combat by wild E. quadrivirgata in mid-June, which is considered outside the normal mating season. This observation suggests that the mating period of E. quadrivirgata extends beyond May, at least to late June, or that E. quadrivirgata exhibits ritual combat not only in competition for mating but also for food or other things. In addition, by the analysis of the video recording, I confirmed that E. quadrivirgata exhibited topping behavior, which is a characteristic of combat in viperids.