Snail fact sheet | Field of Mars EEC

What are snails?

Snails are soft-bodied invertebrates called gastropods. Gastropods are the largest group of molluscs and include land snails, freshwater snails, sea snails and slugs. Most snails have a single shell for protection, a soft body, tentacles, and a broad muscular foot that helps them glide slowly over surfaces. They feed using a rasping tongue-like structure called a radula.

Sydney has both native and introduced snails. Native snails are often small, hidden animals that live in moist bushland places such as leaf litter, under bark, under logs, around rocks and in damp soil. Introduced snails are more often noticed in gardens, farms, nurseries and other places changed by people. A Sydney-focused study recorded more than 80 native land snails and slugs, as well as at least 28 introduced species, from Sydney and nearby areas.

A snail.

Snails have soft bodies, tentacles and a shell that helps protect them.

Where do snails live?

Snails need moisture because their soft bodies can dry out easily. In bushland, many native snails shelter under leaf litter, fallen bark, logs, rocks and loose soil. These places stay cooler and damper than open ground, especially during hot or dry weather.

At Field of Mars Reserve, Lane Cove National Park and bushland reserves, good snail habitat may include shaded gullies, creek edges, leaf litter, rotting logs, loose bark, fungi and dense native ground cover.

Leaf litter, bark and fallen leaves create damp shelter for snails and other invertebrates.

Native snails of Sydney

Sydney’s native snails are not all the same. Some are tiny, some have bristly shells, some are flat-shelled, and some are only found in particular parts of Sydney. Many are difficult to identify without expert knowledge, so it is best to describe them carefully rather than guessing the exact species.

The Sydney carnivorous snail (Vitellidelos dulcis) is a small native snail recorded from the Lane Cove National Park area. Unlike many snails that feed mostly on fungi, algae or decaying material, carnivorous snails may feed on other tiny invertebrates.

The Sydney carnivorous snail is a native snail listed from the Lane Cove National Park area.

The Sydney bristle snail (Austrochloritis sydneyensis) is another native Sydney land snail. Bristle snails have fine hair-like bristles on the shell. A Willoughby bushland inventory lists Austrochloritis sydneyensis among native molluscs recorded from Lane Cove River bushland, and the Atlas of Living Australia uses the common name Sydney Bristle Snail.

The Sydney bristle snail is a native land snail found in the Sydney region.

The Mona Vale woodland snail, also known in some older sources as the midden snail, is listed by the Atlas of Living Australia as Sauroconcha middenense. Some local and government sources still use the older name Meridolum middenense. The Dural Land Snail profile notes that snails from the northern side of Sydney, between Parramatta and Port Jackson and east of Berowra Creek, are identified as Meridolum middenense.

Empty shell of a Mona Vale woodland snail, also known as a midden snail.

The Dural land snail (Pommerhelix duralensis) is an endangered native snail from north-western Sydney. It is a shale-influenced habitat specialist and is found in low densities along shale-sandstone transitional landscapes. It should not be presented as a Lane Cove National Park species, but it is a useful wider Sydney example of a threatened native snail.

The Dural land snail is an endangered native snail from north-western Sydney.

The Cumberland Plain land snail (Meridolum corneovirens) is an endangered native snail from western Sydney. It lives in small isolated patches of Cumberland Plain Woodland and nearby habitats. Unlike the introduced garden snail, it does not eat green plants and feeds mainly on fungus.

The Cumberland Plain land snail is an endangered native snail from western Sydney.

Introduced snails in Sydney

Introduced snails arrived in Australia from overseas, often accidentally on plants, soil, packing materials and shipping containers. The Australian Museum notes that more than 65 land and freshwater snails and slugs have been introduced to Australia, although only some have become pests.

The most familiar introduced species is the common garden snail (Cornu aspersum, previously often called Helix aspersa). It was introduced from Europe and is usually associated with people, gardens and urban areas. It can feed on living plants and may damage seedlings, vegetables and garden plants.

The common garden snail is an introduced species often found near people.

Other introduced garden snails recorded in Australia include the white Italian snail (Theba pisana) and the green garden snail (Cantareus apertus). These species are mostly important as agricultural or horticultural pests rather than bushland animals.

The white Italian snail is an introduced snail species recorded in Australia.

What do snails eat?

Snails use their radula like a tiny file to scrape food from surfaces. Some scrape algae from rocks, bark, walls or plant surfaces. Others eat fungi, lichens, soft decaying leaves and dead organic matter. Bristle snails feed mainly on decaying leaves, bark, microalgae, fungi and lichens.

Not all snails are garden pests. Many native snails help recycle nutrients by feeding on fungi and decaying material. The Cumberland Plain land snail, for example, is a fungus specialist and does not eat green plants. Introduced garden snails are more likely to be noticed because they can damage living garden plants.

Snails use a radula to scrape food from surfaces, leaving tiny feeding tracks.

What is the life cycle of a snail?

Most land snails lay small round eggs in damp, sheltered places such as soil, leaf litter or under logs. The eggs hatch into tiny young snails. Young snails grow slowly and add new shell material as their bodies get larger.

The Cumberland Plain land snail lays clutches of small white eggs in moist, dark areas such as under logs, and the eggs take about two to three weeks to hatch. Pest snail eggs are also often laid in soil or other damp protected places.

Snail eggs are laid in damp, sheltered places such as soil, leaf litter or dead wood.

What adaptations do snails have to help them survive?

Snails have a shell that protects their soft body and helps reduce water loss. When a snail is disturbed or conditions become too dry, it can pull its head and foot back inside the shell. Some snails seal the shell opening with a layer of dried mucus during dry periods.

Snails move on a muscular foot and produce mucus that helps them glide over rough surfaces. This mucus also helps protect the soft body from drying out. Many land snails are most active at night, after rain or on cool overcast days when conditions are damper.

Some Sydney native snails are adapted to very specific habitats. The Cumberland Plain land snail can dig into soil during drought, while the Dural land snail is linked to shale-sandstone transition habitats in north-western Sydney.

A snail’s mucus helps it glide across rough surfaces and reduces water loss.

Why are snails important?

Snails are part of bushland food webs. They help break down fungi, algae, lichens and decaying plant material, returning nutrients to the soil. They are also food for animals such as birds, reptiles, frogs, beetles and other predators.

Native snails can also tell us something about habitat condition. A bushland area with leaf litter, fallen bark, logs, fungi, shaded soil and native ground cover is more likely to support native snails and many other invertebrates. Small patches of remnant native vegetation can be important refuges for Sydney’s native land snails.

Broken snail shells can show where birds or other predators have eaten snails.

Snails and snail relatives

Slugs and semi-slugs are close relatives of snails. Slugs usually have no visible shell, while semi-slugs have a small shell that is too small for the animal to fully withdraw into.

The semi-slug Helicarion mastersi has been recorded from the Lane Cove area near Blue Gum Creek. The red triangle slug is another native gastropod sometimes seen in Sydney bushland and gardens. These animals are not snails in the everyday sense, but they belong in the same larger gastropod group.

Semi-slugs are close relatives of snails but have a much smaller shell.

How can you help snails?

You can help native snails by protecting damp microhabitats. Leave leaf litter, fallen bark, rotting logs and rocks in place where it is safe to do so. These habitats provide shelter for native snails, slugs, worms, slaters, beetles and many other invertebrates.

Avoid using snail baits and pesticides unnecessarily, especially near bushland, waterways, habitat gardens and outdoor learning spaces. These products can affect non-target animals as well as pest species.

If you find a native snail, observe it carefully and leave it where it is. Do not move snails between bushland areas, gardens or reserves. Moving animals can spread disease, change local populations and place snails in unsuitable habitats.

Leaf litter, bark, logs and native plants provide shelter for snails and their predators.

Related fact sheets

More invertebrate fact sheets

• Invertebrate fact sheets – overview
• Gastropod fact sheet – learn more about the mollusc group that includes snails and slugs.
• Leopard slug fact sheet – an introduced slug often found in damp urban habitats.
• Red triangle slug fact sheet – a large native slug that feeds on algae and is sometimes seen in moist bushland.
• Common rough slater fact sheet – another damp-habitat invertebrate found under logs, bark and leaf litter.

Habitats and ecosystems

• Leaf litter habitat fact sheet – explains the damp ground-layer habitat used by many snails and other invertebrates.
• Rock and log habitats fact sheet – logs and rocks create cool, moist shelters for small animals.
• Eucalypt forest fact sheet – learn about the bushland environment that supports many snail species.
• Field of Mars Reserve fact sheet – learn about the reserve and the habitats found there.

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