The grass snake represents one of the three native species of snake which exist in Britain – the smooth snake, adder and grass snake.
The grass snake is non-venomous and could be described as a semi-aquatic species, frequently occurring where there are good populations of amphibians.
Most commonly identifiable by the black and yellow collar markings which form a ring around the base of the head, it is the only one of our snakes which lays eggs. Nesting sites are most commonly decomposing organic matter such as heaps of vegetation or compost, which create a warm and dry environment, but also paradoxically one with the humidity to encourage the growth of the eggs. The importance of the conditions required to create ideal nesting sites is one of the reasons attributed to the lack of grass snakes in highland areas of England, Wales and Scotland.
The grass snake is often in the shadow of the adder (Vipera berus) when it comes to the British press. However, herpetologists and nature lovers across the country last week were informed that we had a new species of grass snake, meaning that we have four, and not three, native species of snake across the land. This news was greeted with great interest and enthusiasm, however, the story was slightly misleading. In short, we continue to have three species of native snake, including the grass snake. What has in fact happened, is that the scientific classification of our grass snake has changed.
The news story was based around an excellent new research paper from Germany (Kinder et al, 2017). It suggested a revision of the taxonomy (classification of organisms) of grass snake across Europe. Previously it was widely considered that there were two species of grass snake, one of which being ‘Natrix natrix’ and the other being “Natrix astreptophora’. The ‘Natrix natrix’ was further divided into subspecies (taxonomic category that ranks below species) which included ‘Natrix natrix helvetica’ which was considered Britain’s native grass snake.
From recent genetic analysis, the researchers in Germany have suggested that there are actually three full species of grass snake in Europe, Natrix natrix, Natrix astreptophora and Natrix helvetica, with Natrix helvetica being the ‘new species’. According to the study, our grass snake should be amended from Natrix natrix to Natrix helvetica, or indeed Natrix helvetica helvetica, if discussed
as a subspecies.
Reference: Kindler, C, Chevre, M, Ursenbacher, S, Bohme, W, Hillie, A, D, Vamberger, M and Fritz, U (2017): Hybridization patterns in two contact zones
of grass snake reveal a new Central European snake species. Scientific Reports 7. DOI: 10.1038/s41598-017-078447-9