Grass Snake (Natrix helvetica)
Grass Snakes are found throughout England and Wales but are absent from Scotland. They’re quite often seen in gardens, especially those with ponds which the snakes can hunt in. Grass Snakes are quite timid, often feigning death if disturbed; alternatively they may excrete a foul-smelling liquid. They are our longest native snake and can reach 150cm.
| Identification | Adults up to 150 cm in length. Grey-green in colour with a cream, yellow or light green belly. Distinctive yellow and black collar behind the head. Dark markings along the side and belly. Circular pupil. |
| Distribution | Native to the UK. Common in England and Wales but absent from Scotland and Ireland. Numbers thought to be declining. |
| Ecology | Non-venomous. Very good swimmers and may hunt in the water: often live around fresh water such as lakes, ponds or reservoirs. Also found in gardens, especially those with ponds or compost heaps. Feed on amphibians, small mammals, fish and birds. Search for prey using sight and sense of smell. |
| Predators and other threats | Grass snakes are eaten by badgers, foxes, domestic cats, and birds. Play dead if disturbed or produce a foul-smelling excretion from anal glands. |
A year in the life…
Spring
Adults emerge during March/April, with males appearing before females. Mating takes place in April.
Summer
Grass Snakes are the UK’s only egg-laying snake. Eggs are laid in June/July in rotting vegetation (including garden compost heaps), which acts as an incubator. The eggs hatch in late summer – the pencil-sized juveniles (around 15cm long) look exactly like miniature versions of the adults.
Autumn
The rest of the year is spent preparing for winter; Grass Snakes primarily hunt for amphibians or fish in ponds, canals and reservoirs (though they do not eat large meals very often).
Winter
The snakes hibernate between November and March.
In 2017, 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). Find more info here.
Studies and Actions from Conservation Evidence
The information below is from the Conservation Evidence website.
Studies and Actions from Conservation Evidence in detail
| Action | Effectiveness | Link | Froglife Advice |
| Create uncultivated margins around arable or pasture fields | Awaiting assessment | https://www.conservationevidence.com/actions/3518 | |
| Create or restore ponds | Awaiting assessment | https://www.conservationevidence.com/actions/3730 | Just Add Water |
| Use prescribed burning: grassland and shrubland | Awaiting assessment | https://www.conservationevidence.com/actions/3651 | |
| Protect brownfield or ex-industrial sites in urban areas | Awaiting assessment | https://www.conservationevidence.com/actions/3478 | |
| Manage vegetation using livestock grazing | Awaiting assessment | https://www.conservationevidence.com/actions/3711 | |
| Restore former mining or energy production sites | Awaiting assessment | https://www.conservationevidence.com/actions/3497 | |
| Cease livestock grazing: grassland and shrubland | Awaiting assessment | https://www.conservationevidence.com/actions/3498 | |
| Create or restore wetlands | Awaiting assessment | https://www.conservationevidence.com/actions/3755 | https://www.froglife.org/info-advice/land-management/ |
| Create artificial refuges, hibernacula, and aestivation sites | Awaiting assessment | https://www.conservationevidence.com/actions/3720 | https://www.froglife.org/learning-zone/wildlife-at-home/ |
| Translocate reptiles away from threats: snakes and lizards | Awaiting assessment | https://www.conservationevidence.com/actions/3731 | |
| Clear or open patches in forests | Awaiting assessment | https://www.conservationevidence.com/actions/3715 | |
| Install barriers and crossing structures along roads/ railways | Awaiting assessment | https://www.conservationevidence.com/actions/3507 | https://www.froglife.org/what-we-do/education/london-t-o-a-d/t-o-a-d-campaign/ |