How to identify UK animals

UK's native reptiles

How well do you know your native reptiles? Can you tell the difference between a slow worm and a smooth snake, or spot a common lizard from a sand lizard? If not, our handy table should help you identify these cold-blooded animals this summer.

Once you think you know them why not try identifying our mystery reptile using our cunning clues at the bottom of the page, and even tell us what you have seen while out and about.

The United Kingdom has six native reptile species: three snake and three lizard. Our guide is for observation only and we do not recommend handling any wild reptile. Please be cautious around adders as they are venomous and, although bites are extremely rare, they do require medical attention.

Our waters are inhabited by a number of sea turtles, of which the leatherback is the most frequently recorded and can be regarded as a native species.

There are also established populations of introduced and alien reptiles across the UK (more info on alien species below table).

What did you see? Where did you see it? I could be a... Watch
  • A long snake capable of reaching well over a metre in length.
  • Grey-green to dark olive in colour.
  • Black bars down the sides of the body.
  • Yellow and black collar around the neck.
  • Common throughout England and Wales.
  • Near water in heathland, meadows and open woodland.
  • Swimming in rivers, ponds and marshes.
Grass snake

Grass snake (Natrix natrix)

  • A slender snake reaching lengths up to 70 cm.
  • Smooth flat scales.
  • Males usually brown and females grey.
  • Dark butterfly shape on top of head with black bars or rows of dots down the back.
  • Incredibly rare in England.
  • Restricted to heathlands with mature vegetation in Dorset, Hampshire and Surrey.
  • Hidden under stones, logs and other debris exposed to the sun.
Smooth snake

Smooth snake (Coronella austriaca)

  • A stocky snake up to 70 cm long.
  • Males are grey with black zig-zag stripe.
  • Females are light brown with dark brown zig zag stripe.
  • There is a "V" or "X" shaped marking on head and a row of dark spots on each side.
  • Widely distributed throughout mainland Britain.
  • In specific habitats such as heathland, moorland, meadows and open woodland.
  • On road and rail embankments and very rarely in gardens.
Adder

Adder (Vipera berus)

  • Lizard approximately 15 cm from nose to tail.
  • Variable colour from shades of brown, through to anything from yellow to red and green to black.
  • Variable patterns of spots or stripes along back and sides.
  • The UK's commonest lizard is widely distributed.
  • Occupying a wide range of habitats from heaths and woods to ditches, hedgerow and gardens.
  • Hibernating under logs or stones.
Common lizard

Common (viviparous) lizard (Zootoca vivipara)

  • Stocky lizard attaining lengths up to 20 cm from nose to tail.
  • Brownish colour with varied patterns of dark patches with light centres (eyespots) and two back stripes.
  • Males often show vivid green sides during breeding season.
  • Very rare in England.
  • Confined to sandy heathland in Dorset, Hampshire and Surrey; also sand dunes on the Mersey Coast.
  • Dependent on managed habitats, occupying mature vegetation that provides cover.
Sand lizard

Sand lizard (Lacerta agilis)

  • Legless lizard up to 40 cm long, often mistaken for a snake.
  • Generally grey/brown colour with shiny looking scales.
  • Females have dark sides with black back stripe.
  • Males sometimes sport blue spots.
  • Very common throughout mainland Britain.
  • In moist grassy areas with scrub including wild gardens, open woodland and wasteland.
  • Mostly underground or underneath objects or in compost heaps.
Slow worm

Slow worm (Anguis fragilis)

Alien reptiles

The United Kingdom has populations of reptiles that have either gained a foothold from Europe, were deliberately released or have escaped from captivity. Here are some you may encounter:

Common wall lizard (Podarcis muralis) - similar to the common (viviparous) lizard but has a more pointed head.

Western green lizard (Lacerta bilineata) - large at around 35 cm and is a overall green colour.

Aesculapian snake (Zamenis longissimus) - a uniform olive-yellow to brownish-green colour, lengths of 150 cm are possible. Only found around the grounds of the Welsh Mountain Zoo in Colwyn Bay, North Wales.

European pond terrapin (Emys orbicularis) - lengths of up to 40 cm with a brown shell that has some yellow and green, possibly escapees from captivity.

Red-eared slider (terrapin) (Trachemys scripta elegans) - around 30 cm in length, look out for red stripe on each side of the head.

Want to know more about alien and introduced animals and plants and whether they are good or bad for our native species? Then read our feature.

Quick tips to take with you

Reptiles are cold-blooded, obtaining heat from the environment to operate normally. So a good time to observe them is when they are either basking in the sun to warm up in the morning or when the cold has slowed them down.

Although difficult to spot up close, the scales can be quite characteristic, having a granular, smooth or keeled appearance.

Another clue to identification is in the eye - many lizards (like our natives) have moveable eyelids whereas our snakes don't. The colour of the iris and the shape of the pupil are also really good quick guides - an adder's vertical slit of a pupil can be a very good early warning sign that you're near a venomous snake!

There can be a lot of variation in colour, patterning and structure within a reptile species due to geographical separation, seasons and the sexes, all of which can make identification difficult. Remember males in the breeding season are usually more colourful.

If you have a camera or phone with you, then these handy tips and tricks will help you to get the best out of your photographic equipment, whatever your level of expertise.

Been inspired and want to help?

There are some wonderfully visual online guides to help you identifying Britain's reptiles. The Amphibian and Reptile Conservation have a very comprehensive guide to reptile identification (pdf) that can also be downloaded from The Amphibian and Reptile Groups of the UK. There are also detailed pages for each species of reptile. There is another excellent guide to identifying the reptiles found in the UK from Reptiles and Amphibians of the UK. If it is just snakes you are interested in then have a look at this picture guide to identifying the UK's snakes.

Once you have identified what you have seen, you can submit sightings of both native and alien reptiles to the Amphibian and Reptile Groups of the UK, who also have links to local recording groups. The National Amphibian and Reptile Recording Scheme run various surveys for you to sign up to and take part in, and for unusual and exotic looking reptiles, sightings can be submitted to Alien Encounters. There is also the latest observations of amphibians and reptiles from iSpot, an online resource for identifying and sharing nature.

Test yourself

Now you are armed with all the facts, can you identify this reptile from the clues?

smooth skin

I have smooth flat scales.

black bars

I have black bars or spots.

heathland

I can be found in heathland.

Click here for the answer and to find out more about our mystery reptile.

Love your reptiles? Then tell us about any you have seen and join the conversation with BBC Nature on Facebook and Twitter @BBCNature. You can also share your photos on the Springwatch Flickr group.

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