Smooth snake (Coronella austriaca)
|Size||Length: up to 60 cm (2)|
Listed under Appendix II of the Bern Convention (3), Annex IVa of the EC Habitats Directive, Schedule 5 of the Wildlife and Countryside Act 1981 (4), and Schedule 2 of the Conservation Regulations 1994 (5).
This non-venomous snake is very rare in the UK, and is superficially similar in appearance to the adder (Vipera berus), but can be distinguished by a number of features including a rounder head and longer, slender build. It is brown or grey in colour and has dark spots on the upper surface rather than the zig-zag patterning characteristic of the adder. The eye has a round golden iris and the head is brown with a black crown and eye stripes (6). The common name 'smooth snake' refers to the scales, which lack the keel of the other British snakes (2).
The smooth snake is widely distributed in Europe, but has a very restricted range in Britain, which reflects the distribution of southern heaths (7), and is found only in Dorset, Hampshire and Surrey (2), with a reintroduced population in West Sussex (7). In the last century the British range has decreased; the species has been lost from Wiltshire and Berkshire (2) and there are historic records from Devon (7).
In Britain the smooth snake is found in dense stands of mature heather on dry, sandy or gravely heathland sites (2). They also occur in humid heaths and bogs next to dry heath (7).
This snake is extremely secretive, spending much of its time in a variety of crevices and holes in the ground (7), under stones (6), in loose sand and soil (2) and concealed in litter and vegetation (7). When basking, they often wrap themselves around heather in order to camouflage themselves (6). The diet consists of lizards, small mammals, and snakes (including other smooth snakes), which are caught by a quick strike and subdued by being squeezed in coils of the body. Prey is then swallowed whilst alive. Juveniles feed entirely on reptile prey, and this factor may restrict the range of the species to areas where reptile densities are sufficiently high (2).
Very little is known about the reproduction of this species; it is thought that they breed every other year (7), and mating occurs in April, May and early June. Smooth snakes are ovoviviparous; eggs are produced but the young hatch out of these internally and are born live (6) in September and October (7). The young snakes may hibernate immediately after birth, emerging the following year usually in March (2).
The main cause of the decrease in the range of this snake has been the widespread loss of suitable heathland sites due to development and the creation of conifer plantations (2). On remaining heathland, major problems arise due to the small size of populations, which are unable to recover after fires and other sudden events (7). Neglect and inappropriate management such as over-grazing, or poor fire prevention can lead to scrub invasion and loss of habitat structure. It can take more than 15 years for a heath to recover the mature stands of heather required by the smooth snake (2).
The heathlands of southern England have been the focus of a concerted conservation effort since the 1970s. Volunteer groups organised by the British Herpetological Society and The Herpetological Conservation Trust's professional team have carried out appropriate management such as scrub clearance and the creation of bare sand patches and mown areas which act as fire breaks (7). A reversion to management by low-intensity grazing to maintain heathland is receiving much interest, but it is unknown how this will impact on the smooth snake (2). An action plan has been developed, although this snake is not an official UK Biodiversity Action Plan species.
A smooth snake 'action plan' prepared by the Herpetological Conservation Trust is available at
Information authenticated by The Herpetological Conservation Trust. For more information on The Herpetological Conservation Trust see:
- Keel: a structure that resembles the keel of a ship either in function or in shape. An example is the breastbone of flying birds, which have deep keels onto which the large breastbones attach.
- UNEP-WCMC (Feb 2002) http://quin.unep-wcmc.org/
- Beebee, T. and Griffiths, R. (2000) Amphibians and reptiles: A natural history of the British herpetofauna. The New Naturalist Series. HarperCollins, London.
- Bern Convention (Feb 2002) http://www.nature.coe.int/english/cadres/bern.htm
- Naturenet (Feb 2002) http://www.naturenet.net/law/sched5.html
- Conservation Regulations (Feb 2002) http://www.hmso.gov.uk/si/si1994/Uksi_19942716_en_1.htm
- The Herpetological Conservation Trust (Feb 2002) http://www.hcontrst.f9.co.uk/noframes/animals/smooth_snake.htm
- The Herpetological Conservation Trust (2002) Pers. Comm.