Smooth snake

Latin name

Coronella austriaca

Class

Reptiles

Group

Snakes & Lizards

Size: Adults typically grow to 50-60 cm (20-24 in.), occasionally larger. Donald Street, for example, mentions a specimen from Russia that measured 92 cm (36 in.) in his 1979 The Reptiles of Northern and Central Europe. Adults weigh approx. 35-80 g (1-2.8 oz.), occasionally up to 100 g (3.5 oz.), varying with age, sex, and season.

Appearance: Smooth snakes are a moderately small species. The relatively small head, terminating in a somewhat pointed snout, joins the cylindrical body by way of an indistinct neck. The eyes are small with circular pupils and a brown or golden iris. The tongue is forked for about one-third of its length. Colouration is variable, ranging from the typical greyish brown through to pinkish or, occasionally, bronze/copper-coloured. The body is daubed with dark grey or brown (rust-coloured in bronze animals) blotches, with two lines of indistinct spots running the length of the animal's back. The markings may be more comprehensive and distinct on the head than elsewhere, and there's typically a darker line originating in front of the eye and extending just past the neck on each flank. Melanistic (i.e., dark/black) individuals have been occasionally reported in Europe. The scales of the smooth snake give the animal its name. The scales of other British snakes have a keel (ridge) running down the centre of each scale, the absence of which gives these animals a smooth "polished" texture. Pigmentation on the dorsal surface of the head appears distinct, allowing for identification of individuals over time. Skin is shed 4 to 6 times per year.

Distribution & Population: Despite being widely distributed across Europe, from France and Portugal in the west to Scandinavia and Russia in the east, Norway and Sweden in the north, and Sicily, Italy, and Greece in the south, the range in Britain is now highly restricted. The species is found only in some isolated pockets in Dorset, Hampshire, and Surrey; one reintroduced population also exists in Sussex and another in southern Devon. This restriction seems largely a reflection of southern England being the limit of the species' range, with summers only just long enough for breeding, although the species was historically much more widespread than it is today. No robust data exist for population size in Britain, but it is likely that it consists of no more than a couple of thousand animals.

Habitat: In England, the smooth snake is restricted to areas of well-drained, sandy heathland, particularly to south and south-east facing slopes, being only occasionally found in light woodland. In Europe more broadly, it's a dry-loving, but otherwise reasonably tolerant, species that also inhabits woodland, clearings, sandy quarries, rocky walls, meadows, grasslands, and even roadsides and cultivated fields. Throughout their range, there appear to be three key elements to a suitable habitat: substratum into which they can burrow; dense undergrowth for secluded basking, and an upper stratum in the vegetation to provide protection from extremes of heat and cold.

Longevity: Early captive data suggested this species was relatively short-lived (e.g., Major Stanley Flower gave 1.3 years as maximum longevity in his April 1925 paper to the Journal of Zoology), but field data suggest much greater ages may be attained. In March 2025, for example, Nick Dobbs recaptured a male in East Dorset estimated to be at least 15 years old. The most comprehensive dataset of which I'm aware is Chris Reading's 31-year study on Studland, Dorset, which suggested females at the site lived, on average, about 8 years, while males survived for 10 years; maximum ages were 15 and 25 years, respectively. Presumably, the secretive nature of this species promotes longevity.

Sexing: Males are often smaller than females, but with longer tails that have a slight bulge just below the vent. Indeed, individuals can be sexed based on the relationship between tail length and snout-vent length, and the presence/absence of this hemipenes swelling at the base of the tail. Donald Street considered there to be distinct colouration differences between males and females from their second year: the former being reddish-brown on top with dark brown/grey markings and an orange underside flecked with pink specs, while the latter is dark grey with dark brown or black markings on top and a vivid, uniform, shiny black belly. A Dutch study published in 1988 found this species could also be sexed based on the number of ventral body and tail scales.

Activity: A predominantly diurnal (day-active) species, but one that's less conspicuous than other British snakes. It often basks under cover and, while sometimes found in clearings, seems reluctant to cross large open areas in England (likely impeding colonisation). A semi-fossorial species, which spends time below ground hunting and hibernating. More likely to be found active on warm (20-27C / 68-81F), overcast days, sometimes warm nights, or during cooler times of the day. Radiotelemetry of New Forest snakes suggested a generally low median hourly movement rate of about 0.54 m per hour (1.8 ft. per hr), with the fastest recorded travelling at 167 m per hr (550 ft. per hr). Hibernation is typically October to April.

Territory/Home Range: Few data are available. Nicholas Arnold and Denys Ovenden, in A Field Guide to the Reptiles and Amphibians of Britain and Europe, gave home ranges between 0.5 and 3 ha (1.2-7.5 acres) in England, noting that the animals do not tend to move far in a day (e.g., 13-100 m / 43-330 ft.), while Chris Reading's 2012 study on ranging behaviour and home range size in southern England estimated males and females to range over 4 and 2.4 ha (10 and 6 acres), respectively. Donald Street described individuals leaving regular sites for days, weeks, or even years, before returning. May return repeatedly to favoured resting/basking spots, even very quickly after having been disturbed.

Diet: Appears to have relatively poor eyesight and hunts prey by scent, mostly during the late afternoon and evening. It is a constrictor and may coil its body around larger prey items, although it does not appear to kill prey by suffocation. Feeds primarily on other reptiles, and Christopher Reading and Gabriela Jofré's 2013 paper on the diet of snakes in southern England suggested the bulk of the diet (48%) was lizards, followed by shrews (35%) and mice (13%) – mammals were taken predominantly in spring, reptiles during the summer and autumn. Frogs, toads, and other snakes may also be taken on occasion. Indeed, there's at least one report of a smooth snake eating a grass snake (Natrix helvetica) of equivalent size in Romania during 2019, although it's unknown whether this represents scavenging or active predation. Donald Street recounted observations of smooth snakes eating slowworms, adders, and even Aesculapian snakes. He also referenced reports of this species taking spiders, insects, and earthworms, although noted that, among his captive snakes, lizards were the only prey eaten. Juvenile snakes may tackle adult lizards. Arnold and Ovenden mentioned reptile eggs and nestling birds being taken, and young snakes feeding on insects. Street noted that prey is typically swallowed within 10 to 15 minutes, while large items may take up to five hours. Cannibalism and maternal cannibalism (i.e., mother eating young) has been recorded.

Classed as non-venomous and harmless to humans, although Street described a small venom gland in the roof of the mouth producing a strong neurotoxic venom that causes respiratory paralysis in small prey animals.

Reproduction: The breeding season runs from mid-March to May, with some suggestion of matings during the autumn. Males presumably locate females by scent, following her closely while she's in oestrous, and may fight among one another for mating rights, with some "dances" reported to have lasted hours. The male coils around the female in a "mating embrace" that may last several hours while passing sperm and during which he may bite her head/neck. Smooth snakes are ovoviviparous (i.e., retain the eggs, which hatch inside the female, resulting in live births) and females gestate for 4 or 5 months before giving birth to, typically, 3 to 9 young (range in Europe appears to be 2 to 19) between late July and late September (occasionally into October). Based on studies in Norway, gestation is heavily dependent on summer temperature, with hot summers yielding earlier births than cool ones. There are very occasional reports of pregnant snakes hibernating, which may result in early/spring births. Young measuring 12 to 21 cm (5-8 in.) and weighing 1.5-2.5 g (0.05-0.09 oz.) are born in a transparent sac from which they struggle free within a few hours postpartum. Neither parent shows any interest in the young, which shed their skin 10 to 12 days after birth and reach sexual maturity at 3 or 4 years old - males breed earlier/younger than females.

Predators: Adults are elusive and spend some of their time underground, which reduces the threat from predators. They are, nonetheless, still at risk from corvids, birds of prey, and larger gamebirds such as pheasants, the latter of which are well known to take juvenile adders and young grass snakes and presumably represent the same threat to neonatal smooth snakes. As with other snakes, hedgehogs, foxes, and badgers may take them opportunistically as might small mustelids (stoats and weasels).

Behaviour and Sociality: Behaviour is poorly understood. While they may be found basking in close proximity, they are do not appear generally gregarious and are ordinarily encountered solitarily outside of courtship. One report of a smooth and grass snake basking together, intertwined. One chemoreception study found neonates could differentiate related from unrelated individuals, with the latter apparently eliciting more interest. Many authors have noted an intriguing male bias at their survey sites (e.g., an m:f sex ratio of as high as 3:1), although the reason(s) for this is(are) not understood, although non-breeding females may emerge later and move away earlier than breeding females, being less visible thereafter. Street postulated a "more or less complex hierarchical system", but there is a paucity of data on this. Will sometimes release a mildly odorous secretion from the vent if handled (under license in England) and occasionally bites, although the teeth are small and of no risk to humans.

Threats: Britain's rarest native reptile, the smooth snake is protected under English law by the Wildlife and Countryside Act (1981), listed as a "Priority Species" on the UK Post-2010 Biodiversity Framework, and a "European Protected Species" per Annex IV of the European Habitats Directive. Overall, it's illegal to kill, harm, or even disturb the animals, and a license is required to catch and handle them for research purposes. Their preferred habitat in England of dry heathland makes them vulnerable to fires (including controlled burning), and high grazing pressure may degrade the habitat (i.e., simplify vegetation structure and remove ground cover) below a threshold where the species can persist.

Smooth snake in detail

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Bibliography

Amphibians and Reptiles: A Natural History of the British Herpetofauna - by Trevor Beebee & Richard Griffiths
HarperCollins Publishers -- 2000 -- ISBN: 978-0002200837

Britain’s Reptiles & Amphibians - by Howard Inns
WildGuides Ltd. -- 2011 -- ISBN: 978-1903657256

Collins Field Guide: Reptiles & Amphibians of Britain & Europe - by Nicholas Arnold & Denys Ovenden
HarperCollins -- 2004 -- ISBN: 978-0002199643

Field Guide to the Amphibians & Reptiles of Britain & Europe - by Jeroen Speybroeck, Wouter Beukema, Bobby Bok & Jan Van Der Voort
Bloomsbury Natural History -- 2016 -- ISBN: 978-1472935335

Herpetology: An Introductory Biology of Amphibians and Reptiles - by Laurie Vitt & George Zug
Academic Press Inc -- 1993 -- ISBN: 978-0127826202

RSPB Spotlight Snakes - by Jules Howard
Bloomsbury Wildlife -- 2020 -- ISBN: 978-1472971692

Snakes of Europe, North Africa and the Middle East – A Photographic Guide - by Philippe Geniez & Tony Williams
Princeton University Press -- 2018 -- ISBN: 978-0806988276

The British Amphibians and Reptiles - by Malcolm Smith
HarperCollins Publishers -- 1969 -- ISBN: 978-0002130295

The New Encyclopedia of Reptiles and Amphibians - by Tim Halliday & Kraig Alder (eds)
Oxford University Press -- 2004 -- ISBN: 978-0198525073

The Reptiles of Northern and Central Europe - by Donald Street
Batsford Books, London -- 1979 -- ISBN: 978-0713413748