The UK's Native reptiles

Reptiles are found in a wide range of places, from sandy heaths and woodland ridges to garden compost heaps. Some of Britain’s six species of reptiles are now very rare, meaning that The Wildlife Trust’s work to restore and protect vital habitats has never been so important. Reptiles are fascinating animals that are often sadly forgotten about when talking about interesting UK wildlife. Most lay eggs, but some give birth to live young, they live in an array of habitats and, contrary to general expectations, are often quite shy.

Adder

The adder is a greyish snake, with a dark and very distinct zig-zag pattern down its back, and a red eye. Males tend to be more silvery-grey in colour, while females are more light or reddish-brown. Black (melanistic) forms are sometimes spotted.

The adder is a relatively small, stocky snake that prefers woodland, heathland and moorland habitats. It hunts lizards and small mammals, as well as ground-nesting birds, such as skylark and meadow pipit. In spring, male adders perform a 'dance' during which they duel to fend off competition to mate. Females incubate the eggs internally, 'giving birth' to three to twenty live young. Adders hibernate from October, emerging in the first warm days of March, which is the easiest time of year to find them basking on a log or under a warm rock.

Latin: Vipera berus

Common lizard

The common lizard is variable in colour, but is usually brownish-grey, often with rows of darker spots or stripes down the back and sides. Males have bright yellow or orange undersides with spots, while females have paler, plain bellies.

Living up to its name, the common lizard is the UK's most common and widespread reptile; it is the only reptile native to Ireland. It is found across many habitats, including heathland, moorland, woodland and grassland, where it can be seen basking in sunny spots.

Also known as the 'viviparous lizard', the common lizard is unusual among reptiles as it incubates its eggs inside its body and 'gives birth' to live young rather than laying eggs. Adults emerge from hibernation in spring, mating in April and May, and producing three to eleven young in July.

Latin: Zootoca vivipara

Grass snake

The grass snake is usually greenish in colour, with a yellow and black collar, pale belly, and dark markings down the sides. Females are bigger than males.

Our largest snake, the grass snake, is particularly fond of wetland habitats, but can also be found in dry grasslands and in gardens, especially those with a pond nearby. During the summer, grass snake can be spotted basking in the sun near their favourite ponds or swimming in the water.

They hunt amphibians, fish, small mammals and birds. Females lay 10 to 40 eggs in rotting vegetation, such as compost heaps, incubating them until they hatch in early Autumn. Like all reptiles, grass snake hibernate, usually from October to April.

Note: The British population of grass snake belongs to the distinct subspecies Natrix natrix helvetica, but new research published in August 2017 proposed that it should be elevated to full species status, with the name barred grass snake.

Latin: Natrix helvetica

Sand lizard

Female sand lizards are a sandy-brown colour, with rows of dark blotches along the back; males have green flanks that are at their brightest during the breeding season, making them easy to spot.

The sand lizard is one of the UK's rarest reptiles. It favours sandy heathland habitats and sand dunes, and can be spotted basking on bare patches of sand. Sand lizards are confined to a few sites as destruction of their habitat has reduced their range.

Males emerge from hibernation in spring, turning a bright green colour as they get ready to mate. Females lay their eggs in the sand in June and July, and the young hatch one to two months later.

Latin: Lacerta agilis

Slow worm

The slow worm is much smaller than a snake and has smooth, golden-grey skin. Males are paler in colour and sometimes sport blue spots, while females are larger, with dark sides and a dark stripe down the back.

The slow worm is neither a worm nor a snake, but is, in fact, a legless lizard - its identity is given away by its abilities to shed its tail and blink with its eyelids.

Slow worms can be found in heathland, tussocky grassland, woodland edges and rides where they can find invertebrates to eat and a sunny patch in which to sunbathe. They are often found in mature gardens and allotments, where they like hunting around the compost heap. However, if you have a cat, you are unlikely to find them in your garden as cats predate them. Like other reptiles, slow worms hibernate, usually from October to March.

Latin: Anguis fragilis

Smooth-snake

Similar in appearance to the adder, the smooth snake can be distinguished by its more slender body, round pupil and less well-formed dark pattern on its back. It is usually grey or dark brown in colour.

The rare smooth snake can only be found in a few places, often alongside the rare sand lizard because they both favour the same kind of sandy heathland habitat. As with other reptiles, smooth snakes are ectotherms (their body temperature depends on the temperature of their environment), so bask in the sun during the day and hibernate from October to April when they would struggle to warm up enough to be active and hunt. In spring, males compete to win females who incubate their eggs internally and 'give birth' to 4 to 15 young in September.

Latin: Coronella austriaca

Non-native reptiles in the UK

Along with the native species, there are several non-native species that have escaped from captivity or introduced into the wild. On the UK Mainland one particular species of European lizard has gained a firm foothold. While we know some populations have been introduced, the origin of others is uncertain. It may, indeed, be native in some areas. This is the wall lizard.

One further lizard species, the green lizard, is most unlikely to be native although there have been repeated introduction attempts in the past (now, of course, illegal), many of which have survived for a great many years. There is certainly one current breeding colony known in the south of England.

Both of these species are native to Jersey in the Channel Islands.

Aesculapian snake

A colony of unknown origin occurs in and around the grounds of the Welsh Mountain Zoo in Colwyn Bay, north Wales, and has existed there for 30-40 years. Numbers are unknown, but the colony is likely to contain at least several dozen individuals. Reproduction appears to occur regularly, as specimens of all size classes can be found, but at present, there is no indication that the species has spread beyond the immediate vicinity of the zoo. Adults are unmistakable, being more or less uniformly olive or brownish, often with light stipples on some scales. Juveniles can be confused with juvenile grass snakes. However, they differ in having a well-defined dark stripe from the eye backwards along the sides of the head, which is not present in grass snakes, and in lacking dark edges to most upper lip scales, which are conspicuous in grass snakes.

Latin: Zamenis longissimus

European pond terrapin

This terrapin used to be native c. 8,000 years ago. It was presumed to have become extinct due to climate deterioration. However, odd individuals have been found in this country in recent years although we are uncertain if they are breeding. It can only be conjectured whether these constitute a remnant of the original population or are escapees from captivity.

Latin: Emys orbicularis

Green lizard

This is far and away the largest lizard you are likely to see in this country. It can reach a total length in excess of 35cms. It is another bulky lizard rather like the sand lizard in build but unlikely to be confused with this or any other species because of its size and the overall green colouration. Some females and juveniles have two noticeable white lines on each side of the back and in the latter case, the base colour is brown rather than green. Mature males often develop blue cheeks during the breeding season. Although the adult animals appear to have no difficulty in surviving in our climate, historically the summers have not been good enough to allow egg incubation over sufficient years to allow colonies to become truly established. With global warming this situation is changing and we certainly have at least one population which has now been established and growing over a number of years.

Latin: Lacerta bilineata

Red-eared slider

The Red-eared slider is another terrapin species which has become distressingly common in the wild in the UK. It is not however, native, originating from North America. All the individuals in the wild in the UK are the result of escapes or deliberate releases. There is some suggestion that they may represent a threat to wildfowl chicks and fish but there is little evidence to substantiate this.

Latin: Trachemys scripta elegans

Wall lizard

The wall lizard can grow to about 20cms in total length, up to two-thirds of which might be tail. It is a little larger than the viviparous lizard. Pattern and markings are very variable but can be very similar to the viviparous lizard's. It can also be differentiated from the latter species by its rather pointed head as against the bullet-shaped head of the latter. Both male and female can often be coloured quite a bright green - not to be confused with the occasional green tint in the viviparous lizard.

Latin: Podarcis muralis