Garden snails can come in a variety of different colours depending on the species. The most common garden snail in many parts of the world is the brown garden snail (Cornu aspersum), also known as the common garden snail or European brown garden snail. These snails have brownish-grey shells with faint vertical stripes. Their bodies are typically greyish in colour with a distinct black band that runs across the body towards the head.
Why are garden snails different colours?
The colour of a snail’s shell is determined by its genetics and diet. The base colour of the shell comes from pigments derived from foods the snail eats. For example, snails that eat carrots frequently may have more of an orange tint to their shells. Then the patterns and stripes come from genetic variations within that species of snail.
Different species of snails have evolved with different colourings that help them blend in to their environments and avoid predators. Garden snails tend to have shells that are shades of brown, black, or white – earthy colours that don’t stand out against soil, rocks and plants. Some species have stripes that break up the outline of the shell and provide camouflage.
Common garden snail shell colours
Here are some of the most common colours and patterns seen on the shells of popular garden snail species:
- Brown garden snail – Shades of brown, tan, grey, with faint vertical striping
- White garden snail – Pure white or off-white shells, sometimes with brown banding
- Black Portuguese snail – Very dark black or blackish-brown shells
- Marbled garden snail – Swirled brown and white banding
- Striped garden snail – Distinct yellowish vertical stripes on a dark base
- Glass snails – Completely translucent shells showing the snail’s soft body underneath
The colour variations help distinguish between the many species when identifying snails in the garden. Even within the same species, there can be a fair bit of diversity in colour depending on what foods are locally available.
What affects the colour of garden snail shells?
Several factors contribute to the colour and patterning of garden snails’ shells:
Genetics
The basic colour and pattern a snail’s shell will develop is determined by the snail’s genetics. Each species has its own typical colours and markings coded into its DNA. Some, like the white garden snail, are more uniform, while others can vary quite a bit.
Diet
The foods a snail eats can have a subtle effect on its shell colouring. Carotenoids from foods like carrots, tomatoes, and green leaves can impart an orange/reddish tone. Calcium from eggshells or cuttlebone makes for a whiter, stronger shell. A nutritious diet typically results in more vivid and attractive shell colours.
Environment
Exposure to dirt, pollution, or other environmental factors can sometimes dull or stain a snail’s shell from its natural colour. For example, acidic soil may leach some of the colour out, while algae growth can turn some shells greenish.
Health and age
An older or unhealthy snail may have a faded, cracked, or discoloured shell compared to a young healthy snail of the same species. As the snail secretes shell material over its life, the oldest layers of shell are the most weathered.
Do garden snails change colour?
For the most part, garden snails remain the same colour throughout their lifespan. The shell colour and pattern they are born with is fixed based on their genetics. However, there are a few instances where a snail’s shell colour may change slightly over time:
- As a snail ages, its shell colour often fades gradually.
- Poor diet or health can make shells paler and less vibrant.
- Injury or shell damage may scar the shell and cause discolouration.
- Algae or soil staining can add darker patches or a greenish tinge.
While minor changes are possible, the snail cannot alter its shell colour or pattern dramatically. A brown-shelled snail cannot suddenly become white or striped for example. Any changes would occur slowly over the snail’s life and appear as weathering or dulling of the original colour.
What colour are garden snail bodies?
While snail shells show the most prominent colour, the bodies of garden snails also have some pigmentation:
- Brown garden snail – Greyish-yellow body with dark grey bands around the tentacles.
- White garden snail – Whitish-grey body, sometimes with brown smudges or dots.
- Black Portuguese snail – Very dark grey to black body colour.
- Marbled garden snail – Grey body with dark mottling that matches the shell.
Unlike their shells, snails can actually change their body colour slightly to match their surroundings. Special pigment cells under the skin called chromatophores allow the snail to lighten or darken its skin for camouflage or temperature regulation.
Are brightly coloured snails common?
While many people think of snails as having dull, earthy shells, there are some species with very bright, vivid shell colouring. These include:
- Grove snails – Deep reddish-brown or orange shells.
- Turkish snails – Pink, white, and brown striped shells.
- Madagascar chromadopsis snails – Pastel blue, yellow, or green shells.
- Tiger snails – Dark shells with bright yellow swirls or spots.
However, these more brightly coloured species are less common in home gardens. They tend to originate from specific regions and require more care when kept as pets. The subdued colours of brown garden snails provide them good camouflage and have become dominant among wild snail populations around the world.
Conclusion
While garden snails may seem drab in colour at first glance, a closer inspection reveals a diverse array of shells. Shades of brown, white, black, striped, and marbled are just some of the possibilities. Genetics play a key role in determining the shell colour, but diet, environment, age and health can alter it slightly over the snail’s lifetime. The colour provides camouflage from predators and helps distinguish the hundreds of land snail species from each other. With proper care, the shells of garden snails can remain vivid and beautiful for many years as these fascinating creatures slowly traverse gardens, yards and sidewalks.
