Grass snake(Natrix natrix)

Brian Marston of Little Thetford tells us he recently saw a five–six foot (1.5–2 m) grass snake (Natrix natrix) swimming in the catch-water drain at the back of his house.

The grass snake, one of only three snakes native to the United Kingdom, lives near water and feeds on amphibians. It can be identified by its distinctive yellow, white or cream collar around its neck. The pupil is round which distinguishes it from the poisonous adder (Vipera berus) which has a vertical slit pupil. The grass snake is harmless to humans as it is not poisonous. If cornered, it can hiss and snap at you without opening its mouth. It may also play dead. Predators include some birds of prey, foxes and even the domestic cat. The grass snake hibernates from October through to April. The female lays up to forty eggs during June and July in a warm spot, such as within a compost heap. The eggs hatch in the autumn.

Growing to as much as six foot three inches (~2 m), grass snakes are, in fact, the largest reptile in the UK. They are protected by the Wildlife and Countryside Act 1981 and included in the UK Biodiversity Action Plan (2007) as a priority species in need of conservation and protection.

Update: 7 June 2011 – BBC Nature, Grass snake