Smooth snake
The UK’s rarest and most secretive reptile
Many of the staff at GWCT have their “out of office” on and our office buildings have fallen a bit quieter, as most of the researchers and advisors are out and about conducting fieldwork, rather than being at our desks. However, recently we all put down our quadrats, binoculars, bird ringing pliers and satellite equipment for a few hours to come together for our annual GWCT staff summer BBQ at HQ, Burgate Manor, which is rare respite at this time of year. It gives us a good opportunity to hear how other projects are going and discuss highlights of fieldwork – who has had a good sighting or seen something unusual.
A conversation led to smooth snakes (Coronella austriaca), the UK’s rarest reptile, which got me thinking that this might be a good species for this month’s edition, so here we go. Fingers crossed you are not scared of snakes like my mother-in-law – the mere mention of them puts her on edge!
The rare smooth snake can only be found in a few places on sandy heathlands in Dorset, Hampshire, Surrey, Devon and West Sussex – the latter three being assisted by reintroduction projects, often found alongside the rare sand lizard because as they both favour the same habitat.
Identification
In appearance it is similar to an adder, but smaller and sleeker and lacking the distinctive zig-zag pattern along its back. The smooth snake is a dull grey or dark brown in colour and has black markings arranged in bars or two rows of dots down the back and nearly always possess a heart-shaped ‘crown’ marking, which covers the top of its head. They also have round pupil, and usually have an eye stripe extending from the eyes along the side of the head. Smooth snakes grow 60 to 70cm in length and weigh approximately 100g.
When to see
April to October
Lifecycle
As with other reptiles, smooth snakes are ectotherms (their body temperature depends on the temperature of their environment) and live quite secretive lives, keeping out of sight, generally found in dense, mature heather on dry, sandy or gravely heathland sites, often hiding under stones, logs and other debris in sunny spots rather than basking in the open like adders and grass snakes. They also are good climbers, entwining themselves amongst the stems of heather, where they are superbly camouflaged but can still make the most of the heat of the day.
When the season change, smooth snakes retreat from the colder weather; they do not technically hibernate but undergo a similar process called brumation to conserve energy and avoid exposure to harsh winter conditions between October/November to April, when they would struggle to warm up enough to be active and hunt. During brumation, snakes become less active and slow down their metabolism, heart rate, and breathing as they lower their body temperature to match the environment.
They are quite particular about where they retreat, and will choose a place underground that is dry, frost-free, and safe from predators, and they tend to favour unused mammal burrows, stumps of dead or rotten trees and root holes, or even large grass tussocks if it is thick enough. Suitable ‘hibernation’ sites (known as hibernacula) tend to have a southerly aspect, and are usually in full or partial sun, whilst being on well-drained substrate to ensure they don’t get flooded.
In spring, they usually emerge in April-early May, when the males compete to win females, who incubate their eggs internally and ‘give birth’ to 4 to 15 live young in September, which look like miniature versions of the adults.
Bite or squeeze?
The smooth snake is a non-venomous constrictor, coiling up around its prey to subdue it and often crush it to death. Smooth snake prey on sand lizards, slow-worms, insects and nestlings – being a good climber comes in handy! Don’t worry, it is basically harmless to humans as it is so shy and uncommon to see, and if it did strike in defence, it won’t be life-threatening.
Conservation status
Protected in the UK under the Wildlife and Countryside Act 1981. This means smooth snakes have full legal protection under UK law making it an offence to kill, injure, capture, disturb or sell them, or to damage or destroy their habitats. This applies to all life stages.
Priority Species under the UK Post-2010 Biodiversity Framework. Listed as a European Protected Species under Annex IV of the European Habitats Directive.
Did you know?
- The smooth snake’s name comes from the fact that its scales are flat and smooth, unlike those of the grass snake and adder, which have a ridge (or ‘keel’) down the middle.
- Smooth snakes are long-lived, and females tend not to breed every year, with an average lifespan of up to 20 years.
- Despite its superb camouflage, the smooth snake does have predators: birds, such as pheasants, carrion crows and birds of prey, and mammals, such as red foxes, badgers and weasels. When caught, the smooth snake will strike, but its bite is not venomous, so this is just a deterrent.
The GWCT has been project partners to Amphibian and Reptile Conservation’s Snakes in the Heather project, to help conserve the smooth snake, through monitoring, habitat management and engagement.
Megan Lock
Advisory
Image credit: Der Irbis