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Trees- ShrubsGrass Snake (Natrix natrix)
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The grass snake usually grows to a length of 120 cm, including the tail; it has been recorded up to a length of 200 cm. It is a thick-bodied, large snake with a well defined head; its pupils are round and it has 19 keeled back-scales across the mid-body (1). The males and females are relatively similar in appearance, although the females are usually larger (2) and sometimes twice as long (1). Males can also be identified by the presence of swelling at the tail’s base (3).
The colouration of Natrix natrix is variable, but many have a characteristic yellow, black bordered collar just behind the head (1). The body is usually olive-grey, greenish, or olive-brown in colour (1) (2) with various dark blotches or sometimes light stripes. The underside is whitish or grey and marked with black (1) (2). Totally black (melanistic) forms and albinos occasionally arise (2).
Natrix natrix is one of four species in the genus Natrix; N. maura and N. tesselata are also found within Europe.
When disturbed, the Grass Snake will hiss and strike with its mouth closed, it very rarely bites (1). Adult males will usually shed its skin twice a year; females will shed it just once yearly before egg-laying. When handled, it will frequently expel a foul-smelling substance from its anal glands. Natrix natrix has also been observed to feign death, lying on its back with its mouth open and tongue hanging out (1).
During the winter months, October to March (3), the grass snake will hibernate in rock piles or deep leaf litter.
Mating takes place from March to June. Males will rub their chin against their potential mate and up to 22 males will form a ball around the female, wrestling with each other in their attempt to mate with the female (1). Copulation can last up to three hours; the females will mate just once. Two to five weeks later, the female will lay two to 105 white eggs, although around 30 is usual for a mature female (1). These will usually be around 20 to 40 mm; they tend to stick together and swell considerably. Males will reach sexual maturity at around three years old, the females breed once they are four to five years old (2).
Natrix natrix is usually found near water; over most of its distribution it is found in moist fields and woods, reaching an altitude of up to 2,400 m (1). In north Europe, it is a lowland species and less restricted in its habitat; it can be found in open woods, hedgerows, gardens, parks and rough grasslands (1) (3).
The Grass Snake is present in the majority of Europe up to approximately 67º N latitude (southern Scandinavia) (1). It is also found from north-west Africa to Lake Baikal, north-west China and Mongolia.
In most areas, the food is primarily toads and frogs; although fish, newts, tadpoles, small mammals, nestling birds and other snakes are taken occasionally with all prey eaten alive (1); juveniles eat tadpoles and invertebrates (2).
Protected in the UK by Schedule 5 of the Wildlife and Countryside Act, 1981
Listed under Appendix III of the Bern Convention (4).
Description written by Ben Harvey (2009)
(1) Arnold, E.N., 2004. A field guide to the reptiles and amphibians of Britain and Europe. 2nd ed. London: Harper Collins Publishers.
(2) ARKive, 2009. Grass Snake – Natrix natrix – Information – ARKive – facts and status. [Online] Available at: http://www.arkive.org/grass-snake/natrix-natrix/info.html [Accessed 2009 June 02].
(3) Beebee, T. & Griffiths, R. (2000) Amphibians and reptiles: a natural history of the British herpetofauna. Harper Collins Publishers Ltd., London.
(4) Europe, C.o., 2002. Convention on the conservation of European wildlife and natural habitats: Bern Convention. [Online] Available at: http://conventions.coe.int/Treaty/FR/Treaties/Html/104-3.htm [Accessed 23 July 2009]
