Seasonal Nature Trackers: Slime Search

a snail, on moss, looking directly at the camera

You can find many different species of slugs and snails in your garden or local green spaces (image © Andrey Armyagov/Shutterstock)

At a glance

Record sightings of 10 different species of slugs and snails across the UK

Type of activity: Outdoors

Who can take part? Everyone

When? 11 Feb - 4 March 2022

How long will it take? A few minutes per slug or snail


Join our slug- and snail-spotting team this February and build our understanding of how some mollusc species are faring in the UK.

Slugs and snails can be found at almost any time of year. As the threat of frost recedes they begin to become more active. Empty shells can be a clue to the presence of living snails, which will have spent the winter hidden in cracks, or as eggs in the soil.

As part of our Urban Nature Project, we are particularly keen to improve our knowledge of molluscs in towns and cities. Having a better baseline of distribution means that we can monitor any changes that are happening.

In partnership with

Why slugs and snails are important

There’s more to slugs and snails than you might think. The UK has over 100 species of land snails, and over 40 species of slugs.

A small urban area or garden can host well over a dozen species, some of which will be non-native. Some arrived recently and are being spread across the UK remarkably quickly. Meanwhile some of our native species are getting rarer due to urbanisation and pollution. These trends can be monitored by carefully mapping where and when species are found.

Only a few of the species are plant pests. Most others eat decaying plants and organic matter, providing a useful cleaning and composting service. A few species are even predators. In turn, snails and slugs are part of the diet of many garden insects, birds and mammals.

How to take part

For Slime Search we’re asking you to spend a couple of minutes looking for snails and slugs in gardens or other safe urban areas.

There are ten species of slugs and snails we are particularly interested in. See the list below for more on these.

  1. Download. You can download the free iNaturalist app onto your smartphone, either from the Google Play store for Android phones or the Apple App store for iPhones.
    If you’d rather use your camera and a browser, then you can sign up on the iNaturalistUK website, then upload your photos later.
  2. Register. On the iNaturalist app, create an account and join the NHM Slime Search project so that your results can count and that you can see other people's entries.
  3. See it. Find a slug or snail between 11 Feb - 4 March 2022. Please see the list below for the 10 species we are particularly interested in.
    You will often need to look to look beneath stones, slabs, pieces of wood or other objects lying on the ground or soil. Most prefer damp, sheltered areas that are at less risk of frost. In milder weather and at night, slugs and snails often climb up bushes, tree trunks and walls.
  4. Snap it. Take a picture of the creature you've found.
    Many snails are smaller than people expect them to be. You may need to get quite close to the ground to get a good look, or a useful photo.
    Please note: Roman snails are a protected species and it is illegal to handle them. If you spot one, please do not move or disturb them.
    For slugs, to help with identification, get three photos if possible: a top down, a right side and view of the sole of the foot (see the photos of slugs on this page as examples). 
  5. Record it. Record what you find by uploading a picture onto the iNaturalist app or at iNaturalistUK.
  6. Log your location. Please note: it's important that you log the location of where you saw the slug or snail. If you take the photo through the iNaturalist app, please ensure that your phone location information is turned on.
    If you upload a picture later onto the app from your phone's photo gallery, or upload via a web browser, then you may have to add the location manually.

Mollusc species to look out for and record

Working with the Conchological Society of Great Britain and Ireland, we've selected ten species of particular interest. They are a mixture of native and non-native snails and slugs found in urban and suburban areas. They should be relatively easy to record and identify using iNaturalist, at any time of year.

No garden will have them all (some are quite rare) but all the species are slightly under-recorded. So every record counts!

We've paired the species: each pair look similar, but one has been recorded in more locations than the other.

Turkish escargot

Helix lucorum (© bjerrum, via iNaturalist (CC BY-NC 4.0))

Huge (up to 45 mm wide), almost spherical, rich brown, striped shell. Reported from a few gardens in London and as far away as Lancashire and South Wales. Introduced from Europe relatively recently, in the last 50 years.

Widespread but only found in localised pockets.

Roman snail

Helix pomatia (© jeremydclark, via iNaturalist (CC BY-NC 4.0))

Huge (up to 45 mm wide), almost spherical, pale and wrinkled shell. Found on chalk soils in southern England; very occasionally elsewhere. Probably introduced to Britain in Roman times, 2000 years ago.

Please note: Roman snails are a protected species and it is illegal to handle them. If you spot one, please do not move or disturb it.

Widespread in South and South East England.

Kentish snail

Monacha cantiana (© kayakernz, via iNaturalist (CC BY-NC 4.0))

Up to 15 mm wide, usually white or transparent, with a red-brown tinge around the shell opening. Likes road verges and waste ground. A Mediterranean species common in the southeast, and spreading in northern and western Britain.

Widespread but rarer in the north and west.

Girdled snail

Hygromia cinctella (© joeholt, via iNaturalist (CC BY-NC 4.0))

10 mm wide, with a sharp, pale keel running round the edge. The dark or light-coloured body shows through the shell. A Mediterranean species that has spread rapidly across urban Britain during the 21st century.


Thames door snail

Balea biplicata (© Ben Rowson)

16-18 mm long. Slender, brown or grey, and finely wrinkled. A rare species recorded only from around the Thames floodplain in London and Essex, but could be found elsewhere.

Currently only seen around the Thames floodplain.

Two-toothed door snail

Clausilia bidentata (© Dai Herbert)

10 mm long. Slender, brown or grey, and finely wrinkled. Habitually climbs trees and walls to feed on lichens and algae. Common in woods and parks, perhaps especially in areas with less air pollution.


Ghost slug

Selenochlamys ysbryda (© James Turner)

50 - 75 mm long. Body white, sometimes slightly translucent. No saddle shaped -mantle' towards the head. New to science when discovered in Wales in the 2000s, but originates from Crimea. Found in south Wales and spreading into England.

Mainly found in south Wales but in localised pockets elsewhere.

Worm slug

Boettgerilla pallens (Top image © Ben Rowson, bottom © James Turner)

35 - 55 mm long. Very slender white to grey body, with a saddle shaped 'mantle' towards the head. Thin and worm-like when crawling. Lives underground. First discovered in Britain in 1972, but now widespread across the country.


Crimean keeled slug

Tandonia cristata (Top image © Imogen Cavadino, bottom © James Turner)

25 - 35 mm long. Grey body with dark net-like pigments and light-coloured keel along centre of the back. Uniformly pale sole of the foot. First noticed in 2014 and scattered in Wales and southern England, mostly in gardens and disturbed habitats.

Found in a few sites in Wales and southern England, but may occur elsewhere.

Budapest keeled slug

Tandonia budapestensis (image © James Turner)

50 - 70 mm long. Grey to brown body with a contrasting orange keel along centre of back. Dark pigment strip along the centre of the sole of the foot. Widespread across Britain, common in gardens.


How we'll use your observations

Observations added to iNaturalistUK may be shared to the National Biodiversity Network Trust’s NBN Atlas, which amalgamates and shares biodiversity data for the whole of the UK. Any iNaturalistUK observations that reach research grade will be shared with the Global Biodiversity Information Facility (GBIF). This enables them to be analysed and researched widely, to better understand the UK's rich biodiversity.

Experts from the Conchological Society, Ben Rowson and Imogen Cavadino are working with us on Slime Search. They will check the photos you submit and help identify the species.

About the Conchological Society 

The Conchological Society of Great Britain and Ireland has run the national recording schemes for molluscs since 1876. Anyone can join the Society to learn more about slugs and snails. Their specialists are working with us on Slime Search to check the photos you submit and to add the data to their database, which is accessible via the National Biodiversity Network


We thank all funders to the Urban Nature Project campaign so far, including those who wish to remain anonymous, for their generous support. We recognise the following funders for their exceptional contributions to the campaign:

Explore urban nature funders logos