Slugs and Snails

Slugs and snails are among the most common wildlife found in British gardens, yet many people know surprisingly little about them. These fascinating molluscs play an important role in the ecosystem by recycling nutrients, feeding wildlife and helping maintain healthy soils.

For months now I have been getting up early in the morning to pick these slimy creatures off my garden plants. I have learnt where they hide and I catch them crawling back over the garden wall after I have thrown them into the park beyond. They really are quite amazing creatures!

Slugs Evolved from Snails

Although they look quite different, slugs evolved from snails. Some slug species still retain a tiny internal shell hidden beneath their mantle, while others have lost it completely through evolution. Slugs also tend to have asymmetrical internal organs, a result of their evolutionary history.

In England there are around 100 species of land snail and approximately 46 species of slug, each adapted to different habitats and food sources.

How Slugs and Snails Sense the World

Most land slugs and snails have four tentacles. The two longer upper tentacles carry their eyes at the tips and can be retracted for protection. The two shorter lower tentacles are used for smelling, tasting and feeling their surroundings.

The Amazing Snail Shell

A snail’s shell is not simply a home—it is part of its body. As the snail grows, it continuously enlarges its shell by adding new material around the opening. This allows the shell to grow throughout the snail’s lifetime while providing protection from predators and harsh weather.

What Do Slugs and Snails Eat?

Instead of jaws, slugs and snails use a ribbon-like tongue called a radula, which is covered with thousands of microscopic teeth. These tiny teeth scrape (rasp) food from leaves, fungi and other surfaces.

Most species feed on decaying plant material and fungi, making them valuable decomposers that help recycle nutrients back into the ecosystem. While some species will feed on living plants, many play an important role in breaking down dead organic matter.

Some slugsclimb trees to reach food. Certain species are capable of lowering themselves from branches using a strand of mucus.

Why Is Slug and Snail Blood Blue?

Unlike humans and other mammals, slugs and snails use copper rather than iron to transport oxygen around their bodies. This gives their blood a blue or grey appearance instead of red.

How Slugs and Snails Reproduce

Most slugs and snails are hermaphrodites, each individual possesses both male and female reproductive organs. However, they usually mate with another individual, after which both partners may lay eggs.

How Fast Can a Garden Snail Move?

A typical garden snail travels at around 0.03 mph (0.05 km/h). At that speed, it would take approximately 33 hours of continuous movement to cover one mile (1.6 kilometres).

Natural Predators

Slugs and snails are an important food source for many animals. Their natural predators include birds, frogs, toads, beetles, snakes, hedgehogs, and even other species of slugs and snails. By supporting these predators, slugs and snails form an essential part of the food chain.

Why is Slug Slime so Special?

Slug and snail mucus is made mostly of water, but it has amazing properties. During gentle movement it remains thin and slippery, allowing the animal to glide effortlessly across rough surfaces. When subjected to sudden force, however, the mucus becomes thicker and stickier, making it resistant to stretching and pulling.

This remarkable slime helps slugs and snails move over rough ground, climb walls, hang upside down, conserve moisture, protect themselves from injury, leave chemical trails to find food and mates, and defend against harmful microbes commonly found in damp environments.

How Scientists are Using Snail Slime

The unique properties of snail slime have attracted considerable scientific interest. Researchers are studying its potential for medical adhesives and wound healing, while snail mucus is already widely used in skincare and cosmetic products because of its moisturising and skin-conditioning properties.

Why Slugs and Snails Matter

Although gardeners often view slugs and snails as pests, many species are beneficial. They help recycle dead plant material, support wildlife by providing food for predators, and contribute to healthy ecosystems. Understanding their role in nature reveals that these remarkable molluscs are far more fascinating—and far more important—than they are often given credit for.