Grass snake - Natrix natrix - Family: Colubridae

• Add to Pick List
• Back to search results

Grass snake - Natrix natrix
© Peter Wakely/English Nature

This harmless (to humans) non-poisonous snake is Britain's largest and most abundant terrestrial reptile. Females are larger than males and can grow up to 1.2m. If you are fortunate enough to have a snake in your garden, it is far more likely to be a grass snake than either of the other two British species, the adder and the rare smooth snake. Its slender body has a background colour that may range from olive green to grey or brown, but a distinctive yellow and black collar is a diagnostic feature. The sides of the snake are marked with black bars or spots but it may easily be distinguished from the adder by the lack of a zigzag pattern on back.

Grass snakes can be found in a variety of dry and wet habitats: woodland edges, ditches, old pasture, heaths and chalk grassland. They spend much time in the water, from flooded gravel pits to garden ponds, hunting for frogs and other amphibians. In fact 'water snake' is an alternative name in some parts of the country. They can climb well, so you may even see a grass snake in a tree. They like warmth and can sometimes be found basking on compost heaps, which are favoured as egg-laying sites. Clutches of up to 40 eggs take up to 10 weeks to hatch.

Grass snake eat frogs, but not in vast numbers as some people imagine. They also take newts, lizards, fish, mice, birds' eggs and even nestlings. When threatened, they hiss, and if handled will spray urine, which has a foul and lingering smell! Grass snakes can live for as long as ten years. They hibernate, often en masse, waking in March or April. Warm spring days may be the best time to spot them, as they soak up the heat of the sun, sometimes on the top of compost heaps or a stack of grass cuttings.

Food

Frogs, newts, toads, lizards, fish, birds' eggs and small birds, rodents and insects. Young grass snakes eat tadpoles, worms and slugs.

Prey

Bank vole, Common frog, Common lizard, Common shrew, Common toad, Field grasshopper, Meadow grasshopper, Slugs and snails, Small fish, Smooth newt, Tadpoles, Water vole, Wood mouse, Worms, Yellow-necked mouse

Predators

Buzzard, Grey heron, Stoat