Grass snake fact file
- Common name – grass snake.
- Scientific name – natrix natrix helvetica.
- Size – adult grass snakes can grow to lengths of 120cm, but 80-100cm is average.
- Identification tips – the body is an olive-green colour with subtle black spots or lines regularly spaced along the back and flanks. The snake’s most distinguishing feature is its pale yellow collar immediately behind the head.
- Preferred habitat – dense undergrowth and as close to fresh water as possible, such as ponds and streams.
- Diet – grass snakes feed mainly on frogs and small fish if available. Newts will also be readily eaten. Land food includes bird eggs and small mammals such as mice.
- Breeding – mating happens between late April to May, soon after the snakes emerge from their winter hibernation. Between 5 and 40 eggs are laid in August / September and hatch after around 10 weeks.
Small patches of rotting vegetation make ideal grass snake nests, as the decomposition of the vegetation provides the required heat for the eggs to develop properly.
- Other points – the grass snake is Britain’s largest reptile and the most common snake. Widespread throughout the New Forest and surrounding countryside, especially around fresh water. They are very strong swimmers and are equally at home in the water as on land.
Grass snakes are non-venomous; under threat they may release a pungent odour or, on occasion, remain motionless in an attempt to play dead.