Species of the Month

Between 90 and 180 cm long, the grass snake is Britain’s longest snake. Females are larger than males and can weigh up to 240g.  

Grass snakes have a distinctive yellow and black collar around the neck. They are typically grey/green with evenly spaced black bars along the flanks of the body. Although unlikely to be seen, their bellies are covered in black markings which are unique to each individual.  

Check out our website to see how grass snakes differ from the UK’s other reptiles. 

Frogs, toads and newts are a grass snake’s favoured prey, but they will also take fish, small mammals and birds. 

Grass snakes do not produce venom, so rely on the element of surprise to hunt. Striking out to grab the unsuspecting prey which is swallowed whole and often still alive! 

Feeding primarily on fish and amphibians, grass snakes occasionally venture into garden ponds in the summer months, particularly in rural or semi-rural parts of the south. 

Grass snakes are the UK’s only egg-laying snake. Eggs are normally laid in June or July, in a sheltered location within rotting vegetation. Compost heaps are often a favoured spot and act as a natural incubator. Up to 40 eggs may be laid and they hatch into miniature versions of the adults in late summer or early autumn. 

Grass snakes are non-venomous and are extremely shy, moving off quickly when disturbed. They are very good swimmers! 

Grass snakes are eaten by birds of prey, herons and mammalian carnivores. Camouflage is a great defence, but other tactics include producing a foul-smelling excretion or ‘playing dead’ (thanatosis behaviour) in an attempt to fool a would-be predator. 

Larger snakes may also hiss and feign strikes when attacked - flattening themselves out, to look bigger than they really are. 

• In 2017, the grass snakes found in Britain and western Europe were reclassified as a new species (Natrix helvetica) to separate them from those in central and eastern Europe (Natrix natrix). 
• The grass snake is one of three native snake species found in the UK and is our largest native terrestrial reptile. 
• Grass snakes are quite long-lived and can be 15–25 years old. 
• Your best chance of seeing one is to visit a suitable habitat early in the morning, when the snakes bask in the sun to generate warmth. Snakes frequently use the same ‘sunbathing’ locations. Approach quietly and please do not disturb them. 
• There currently isn’t enough data to understand how grass snake populations are doing in the UK. They are, however, fully protected by the Wildlife and Countryside Act (1981) meaning it is illegal to deliberately kill or harm them.  

Grass snakes are found across most of England and Wales but are absent from Scotland and Ireland. The species can occur in a variety of habitats such as wetland, farmland, grassland, and woodland, but they are usually found close to water. 

Grass snakes do visit gardens with ponds and plenty of vegetation. 

Being cold-blooded reptiles, grass snakes spend the coldest part of the year hibernating in warm, humid places such as tree root systems, fallen trees, compost heaps and rabbit warrens. Hibernation begins in October or November, and, depending on the weather, they will emerge in March or April. 

The grass snake is Britain’s only egg laying snake and the presence of suitable sites for eggs to incubate is vital for grass snake conservation. Factors like habitat loss and changes in land management have led to their decline. As grass snakes can use compost heaps and piles of grass clipping to lay their eggs, we can help provide suitable habitats in our gardens and allotments. Please see our webpage on tips for making your own compost. 

If you have space, try and leave some parts of your garden undisturbed. Areas of long grass or tall vegetation around a pond provide good places for grass snakes to shelter and hunt.  

Please let us know if you spot a grass snake. You can also share records throughout the year, with the Amphibian and Reptile Conservation Trust at www.recordpool.org.uk.