When you see a snail, it’s hard to miss the spindly little eyes that sit atop their heads. Some people find them quite disgusting, but these slimy creatures are actually pretty interesting!

Snails are molluscs, which means they have shells made of hard calcium carbonate. The shells are often drab, white, gray or brown in color. They can be shaped like bumps or ridges, and some even have spiraling traits.

They’re also pulmonates, which means they breathe air through a lunglike pulmonary cavity protected by their mantle. Most land snails are pulmonates, but some aquatic snails, called prosobranchs, have tubelike siphons that draw water in and out of their mantle cavities to extract oxygen from the water.

The shape of a snail’s eye is unique to the species, and can range from tiny pigment cup eyes found in limpets to concave mirror eyes found in scallops. Some molluscs, like conchs and conch-like sea snails, have large eyes, which are used to help them hunt prey or to detect danger.

These adapted to their environment, which makes them able to see more clearly than most other invertebrates on the planet. The eyes themselves are grouped together, which increases their sensitivity to light.

Snails have chemo- and mechanoreceptors all over their bodies, which are responsible for detecting touch and chemical signals. They also have nerves around their tentacles, which are important for navigating in their environment and making sure they stay safe from predators.