Grass Snake - Natrix natrix

The Grass Snake is a large thick-bodied snake with a distinctive yellow collar behind the head; they can often be seen basking in the sunshine on warm sunny days.

Habitat

Grass Snakes are normally found close to water bodies as well as woodlands with ponds. They are excellent swimmers and often only seen by the flash of the yellow collar when they are swimming. They prefer damp habitats including riverbanks and ditches, but also inhabit hedgerows and woodland margins.

Description

Grass Snakes are usually grey-green in colouring (although the colour can vary) with a distinctive yellow band around the neck. Black spots on the side (and sometimes some on the back) provide the typical pattern, while their underside has a checkering of black and white scales. Their heads are rounded in shape with black lines running from underneath their eyes, which are normally a golden colour, to their mouths. Their forked tongues are bluish in colour. The female is larger then the male, they normally grow between 70-120cm in length, but the female can occasionally reach 200cm in length.

Biology

They are active between March and October and are most likely to be seen basking in the sunshine in the early part of the day, or swimming as they hunt for food. They hunt in water (where they can stay submerged for up to half an hour) feeding mainly on tadpoles, newts, frogs and toads but will also take fish, small mammals and young birds which it grabs and then swallows whole and alive. When it is caught by predators the Grass Snake will hiss loudly and release a foul smelling substance whilst striking at its attackers head although they are not poisonous. One of the Grass Snakes most distinctive behaviour is when threatened it will play dead. They roll over onto their backs and stay very still allowing its whole body to go limp, mouth open and tongue hanging out for up to 15 minutes, or until the attacker loses interest; badgers, foxes and birds predate upon them.

The Grass Snake is Britain’s only egg laying snake and the female lays her eggs in August in compost heaps or under rotting logs, as they provide warmth for the eggs, after mating in the spring. The young hatch about 2 months after, but this is dependant on the temperature of the nest. Males reach sexual maturity at three, females at five. Grass Snakes live up to fifteen years.

When hibernating (between October and March) they search for frost-free places including compost heaps, wall crevices or old burrows. Grass Snakes hibernate as temperatures drop too low in winter for it to keep it’s body temperature high enough to be able to digest its food or function properly – they get their body warmth from the heat of the sun which is why early mornings are the best time to see Grass Snakes as they bask in the sun to raise their body temperatures.

Conservation

Grass Snakes are protected under the Wildlife and Countryside Act 1981 from being killed, injured or sold.