Smooth Snake

Overview

The Smooth Snake (Coronella austriaca) is an exceptionally secretive, non-venomous colubrid snake native to the temperate and Mediterranean regions of Europe and Western Asia, ranging from the British Isles across Central Europe to the Caucasus and northern Iran. Characterized by glassy, completely unkeeled scales that feel silky smooth to the touch, this slender constrictor is one of Europe’s most specialized and elusive reptiles, frequently overlooked due to its cryptic coloration and subterranean basking habits.

Inhabiting warm, sandy lowland heathlands, dry rocky slopes, and open sunny woodland borders, Coronella austriaca functions as an obligate reptile specialist, preying primarily upon lizards and slow worms. While globally secure across its core continental range, it represents one of the rarest native reptiles in the United Kingdom, where it is strictly restricted to isolated southern heathland fragments.

Biology and Physical Characteristics

Coronella austriaca is a slender-bodied snake with a narrow head barely distinct from the neck and a relatively short, tapered tail. Unlike the European adder (Vipera berus) and grass snake (Natrix helvetica), whose dorsal scales are raised with longitudinal ridges (keels), the scales of the smooth snake are perfectly flat, glossy, and unkeeled, giving the body an iridescent, silky texture. The pupils are round, indicating diurnal and crepuscular activity.

The ground color ranges from greyish-brown to warm reddish-brown or bronze, with two parallel rows of small, dark brown or blackish spots running along the spine, which often fuse into irregular bars. A prominent dark brown or black stripe extends from each nostril, passing directly through the eye and across the temple to the neck. A dark, heart-shaped or crown-like blotch adorns the top of the head (the origin of the generic name Coronella, meaning ‘little crown’).

Behavior and Ecology

Smooth snakes are secretive, highly cryptic animals that rarely bask in full open view. Instead, they practice ‘thigmothermy’—basking cryptically beneath warm corrugated metal, flat stones, discarded debris, or woven under deep heather canopies that absorb solar radiation. When foraging, the smooth snake stalks slowly through dense ground cover, ambushing resting common lizards, sand lizards, and slow worms.

Upon seizing a lizard with its sharp teeth, the smooth snake instantly throws two to three tight muscular coils around the prey, suffocating it like a miniature python before swallowing it whole, typically headfirst. Mating takes place in April and May, during which males engage in vigorous courtship. Females exhibit viviparity (ovoviviparity): after a gestation of three to four months, they give birth in late August or September to four to fifteen fully formed, active young that break free from their delicate transparent membrane sacs immediately upon birth.

Conservation and Human Impact

The Smooth Snake is classified as Least Concern on the IUCN Red List, supported by widespread distribution across Central and Eastern Europe. However, in several northern European countries, including the United Kingdom, Netherlands, and Belgium, populations are critically endangered due to historical destruction of over eighty-five percent of lowland heathlands for urban expansion, agriculture, and commercial forestry.

In Britain, the species is protected under the Wildlife and Countryside Act and designated as a European Protected Species under the Conservation of Habitats and Species Regulations. Intensive conservation efforts focus on heathland restoration, removal of invasive pine and rhododendron scrub, construction of artificial sand basking banks, and creation of connected habitat corridors between isolated heathland fragments.

Interesting Factoid

Smooth snakes are immune to the venom of the European adder (Vipera berus) and have been documented successfully overpowering, constricting, and consuming juvenile adders in overlapping heathland habitats.