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The Secret of the Heathlands
- Madeleine H
- Oct 20, 2020
- 5 min read
The heathlands of Southern England are home to Britain’s most shy and secretive reptile, the smooth snake (Coronella austriaca). In the last century, smooth snake populations have decreased by 90%, driving this species into the shadows. But we are here to shed some light into the ecology of this beautiful rare reptile.
Distribution & Habitat
Despite being widespread across Europe, in the UK they are limited to the lowland heathlands of Dorset, Hampshire, Surrey and West Sussex, and populations have since been reintroduced in Devon. The smooth snake is a heathland specialist, dependent on well managed lowland heathland with mature vegetation. Habitats can range from dry slops to humid heathland. Populations in Surrey have a preference for dry lowland heathland comprised of a mosaic of mature heather and deep moss. Smooth snakes will typically seek refuge under stones, logs, and other debris in the sun. Although usually ground dwelling, smooth snakes have also been observed climbing bushy vegetation. 85% of smooth snake habitat has been lost since the 1800, contributing to their declining populations.
Identification
Adults grow to 60-70cm in length, with females often being larger than the males. The smooth snake, as its name would suggest, have smooth shiny scales that lack a keel. The body is slender and the head is round. The smooth snake typically has muted colouration varying from dark grey to dull brown. Brick red variations have also been observed. Males are typically more reddish in colouration, whilst females are usually more grey. The underbelly is pale in females, and more orange in males. Dark markings, forming dots, bars or dashed lines, can be seen along the back, from head to tail. Although, these markings can sometimes be undefined. Occasionally, there is a second pair of lines running the along the flanks, however these aren't always as obvious as the dorsal markings. The smooth snake also sports a dark heart-shaped crown on its head. This crow is also sometimes described as being shaped like a butterfly! The head is further characterised by a dark line running across the eye, along the side of the head. The pupils of the smooth snake are round, distinguishing it from the adder- another snake native to Great Britain.
Juvenile smooth snakes have the same markings as adults but are darker in colour. Their heads appear large in proportion to their body, but they'll grow into it. They are shorter and slimmer than adults, being roughly the size and thickness of a pencil when born (15cm).
Diet
The smooth snake is not a fussy eater and will eat anything it can fit its chops around. That being said, the smooth snake does have a preference for other reptiles, such as the common lizard, slow worms, sand lizards, and juvenile snakes, including juveniles of their own kind. The smooth snake is also known to eat small rodents and fledgling birds. The smooth snake will stalk its prey before attacking. Upon striking, the smooth snake will grasp its prey in its mouth and coil its body tightly around it. The smooth snake's backwards facing teeth and constricting behaviour prevent its prey from escaping. Although not a true constrictor, smooth snakes use constriction as a method to subdue large prey and orientate it into its mouth head first, before swallowing it whole, and sometimes, still alive. While this may sound horrific, the smooth snake is not venomous and is completely harmless... unless you are a lizard. Juvenile smooth snakes predate mostly on juvenile common lizards. As the snake matures, the diet becomes broader, and the snake exhibits more generalist feeding, predating on small mammals, such as shrews and voles.
Reproduction & Lifestyle
Smooth snakes go into hibernation in October, and will emerge again in Mid-April, with Males typically emerging before females. Smooth snakes hibernate in dry frost-free underground shelters, as well as old disused mammal burrows. Shortly after emerging male smooth snakes will start their search for a female to mate with. During this time males are aggressive and will fight rival males. When the male finds a suitable mate, they will intertwine their bodies. Females refrain from breeding every year, as generating offspring is very demanding on them and takes two to three years to recover. Female smooth snakes are ovoviviparous, meaning they incubate their eggs internally and then give birth to live young. A female will typically birth between four and fifteen young in August and September. Juveniles will stay with their mother for a few days after birth before dispersing. Although, it’s not uncommon for the juveniles to remain in a group after dispersal, and are often seen basking together in a ball. Juveniles will go into hibernation soon after being born, gaining their first life experiences in the next Spring. Smooth snakes finally reach sexual maturity after four years.
Predators
Birds, such as pheasants, crows and birds of prey, are common predators of the smooth snake. Foxes, Badgers and Weasels are also known to savour the flavour of smooth snake. Likewise, to adult smooth snakes, juveniles are at risk of predation from the same list of predators. In addition to this, juveniles also suffer predation from other adult smooth snakes. The smooth snake relies on its excellent camouflage to avoid predation. If caught, the smooth snake will bite in defence, however as a non-venomous snake, this does not serve much as a deterrent. Similar to the grass snake, the smooth sometimes will release a foul-smelling discharge from its anal glands, called musk, as a defence mechanism. However, the musk of the smooth snake is less pungent than the grass snake's.
Smooth Snake Conservation and How You Can Help
Smooth snake populations are facing monumental declines due to habitat loss, fragmentation and degradation. Uncontrolled fires, scrub and tree incursion and lack of suitable breeding sites are also contributing factors in the smooth snake's decline.
Much of the smooth snake's habitat was also destroyed in the 1940s due to the conversion of heathland to military training grounds during World War II. A relationship between smooth snake population declines and cattle grazing has also been observed, suggesting the introduction of grazing cattle alters the heathland making it less favourable for the smooth snake, and its prey, such as the common lizard
The smooth snake is protected in the UK by the Wildlife and Countryside Act 1981, meaning it is an offence to kill, injure, capture, disturb or sell them, and to damage or destroy their habitat. The smooth snake is also listed as a priority species under the UK Post-2010 Biodiversity Framework. Internationally, the smooth snake is further protected under Annex IV of the European Habitats Directive.
Conservation work is being done to protect existing habitat and populations, and to enhance degraded habitat. Monitoring populations and habitat is vital for their conservation as it provides insight into how the species is doing nationally and locally. NGOs, like the Amphibian and Reptile Conservation Trust (ARC) are working hard alongside agencies, other NGOs, the Amphibian and Reptile Group (ARG), conservation land managers and volunteers, to promote national habitat and species monitorisation. They are additionally working on re-introductions of smooth snakes to restore the historic range of the species. So far ten successful reintroductions have taken place. The Wildlife Trusts are also working to restore and protect heathland habitats by promoting proper management, clearing encroaching scrub and implementing beneficial grazing schemes, which are all vital actions necessary to maintain and enhance these habitats for smooth snake populations.
If you are passionate about smooth snakes and conservation, and wish to get involved, you can volunteer with ARC, ARG and the Wildlife Trusts to assist with their conservation projects. Additionally, you can donate to ARC and sponsor a smooth snake! Check out the links below to learn more:
Sponsor a smooth snake with ARC- https://www.arc-trust.org/donate/sponsor-smooth-snakes/5/credit-card
Volunteer with ARC: https://www.arc-trust.org/Listing/Category/volunteer
Find your local ARG to volunteer with: https://www.arguk.org/get-involved/local-groups
Volunteer with the Wildlife Trust: https://www.wildlifetrusts.org/closer-to-nature/volunteer
Become a member of the Wildlife Trust: https://www.wildlifetrusts.org/join
Sources:
Reading C, Jofré G (2020) Smooth snake population decline and its link with prey availability. Amphibia-Reptilia, 41: 43-48. https://doi.org/10.1163/15685381-20191237
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