# Periwinkle Snails (*Littorinidae*)

Periwinkle snails are small, colorful snails that live on rocky shores. They have spiral shells that can be blue, gray, or brown, and they love to munch on algae!

- **Category:** [Invertebrate](https://www.snappit.app/explore/categories/invertebrate)
- **Rarity:** Common
- **Danger:** 1/5 · Very low
- **Habitat:** Coastal areas
- **Also known as:** Rock Snail

![Periwinkle Snails](https://commons.wikimedia.org/w/index.php?title=Special:Redirect/file/Littorina_littorina.jpg&width=800)

Photo: Amy Benson, U.S. Geological Survey, Public domain · [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Littorina_littorina.jpg)

## Appearance

The Periwinkle Snails has a sturdy, conical or turban-shaped shell that typically ranges from grey, brown, or black to olive green, sometimes featuring subtle banding. Its small size and smooth, often dull, exterior help it blend into rocky shorelines. This distinctively robust shell visually sets it apart from more delicate land snails.

## Taxonomy

- **Kingdom:** Animalia
- **Phylum:** Mollusca
- **Class:** Gastropoda
- **Order:** Littorinimorpha
- **Family:** Littorinidae

## Interesting facts

- Periwinkles can detect predators just by sensing chemicals in the water!
- Some periwinkle snails can live for five years or even longer in the wild!
- Their tongue, called a radula, is covered in thousands of tiny teeth for scraping algae!
- They leave a slimy trail wherever they go, like a secret map only they can follow!

## Special abilities

- **Rock Grippers:** Periwinkle Snails can hold onto rocks incredibly tightly because of their strong muscular foot that helps them resist crashing waves.
- **Tide Adapters:** Periwinkle Snails can seal their shell opening with a trapdoor (operculum) that helps them survive when the tide goes out.
- **Shell Shield:** Periwinkle Snails has a thick, calcified shell that helps them protect against predators and harsh environmental conditions.

## Measurements & details

- **Size:** 10-25 mm
- **Lifespan:** 365-1825 days
- **Leg Count:** 0

## Diet & Feeding

These tiny ocean grazers munch on microscopic algae and tiny plant matter found on rocks.

- **Primary Foods:** algae, diatoms, microscopic plant matter, biofilm
- **Foraging Method:** Grazing

## Ecological connections

- **Eaten by:** [Herring Gull](https://www.snappit.app/explore/herring-gull) (*Larus argentatus*) — Gulls drop periwinkles from height to crack their shells.
- **Eaten by:** Green Crab (*Carcinus maenas*) — Crabs use their strong claws to crush periwinkle shells.
- **Eats:** Sea Lettuce (*Ulva lactuca*) — Periwinkles graze on this common green algae on rocks.

## Traits

- [Solitary](https://www.snappit.app/explore/traits/solitary): Solitary animals live alone for most of their lives, only interacting with others for mating or parental care.
- [Colorful](https://www.snappit.app/explore/traits/colorful): Colorful describes organisms or objects displaying a wide range of bright and distinct colors.
- [Herbivorous](https://www.snappit.app/explore/traits/herbivorous): This trait characterizes organisms whose diet consists entirely or primarily of plant material.
- [Decomposer](https://www.snappit.app/explore/traits/decomposer): Describes organisms that break down dead organic material, recycling nutrients back into the ecosystem.
- [Coastal](https://www.snappit.app/explore/traits/coastal): Coastal habitats are dynamic environments located along the interface between land and sea, influenced by tides, waves, and saltwater.
- [Diurnal](https://www.snappit.app/explore/traits/diurnal): Diurnal animals are primarily active during daylight hours, typically resting or sleeping at night.
- [Marine](https://www.snappit.app/explore/traits/marine): Marine habitats encompass all saltwater environments of the Earth's oceans, supporting an immense diversity of aquatic life.

## Collections

- [Insects](https://www.snappit.app/explore/collections/insects)

## Safety

**Danger:** 1/5 · Very low

Don't touch snails you find outside; they need to stay in their homes!

## Frequently Asked Questions

### How to identify Periwinkle Snails?

Compare the overall shape, opening, spiral, ribs, hinge and surface sculpture. Beach shells often lose the colors and sharp edges they had on the living animal, so shape does most of the work. Seashell Identifier: upload a photo and compare the visible details.

### How big is Periwinkle Snails?

10-25 mm

### How long does Periwinkle Snails live?

365-1825 days

### What does Periwinkle Snails eat?

These tiny ocean grazers munch on microscopic algae and tiny plant matter found on rocks.

### Where is Periwinkle Snails usually found?

Coastal areas

### How does Periwinkle Snails hunt?

Grazing

### How many legs does Periwinkle Snails have?

0

## More Invertebrate

- [Coral](https://www.snappit.app/explore/coral)
- [Crab Spider](https://www.snappit.app/explore/crab-spider) (*Mecaphesa asperata*)
- [Garden Spider](https://www.snappit.app/explore/garden-spider) (*Araneus diadematus*)
- [Brown Recluse Spider](https://www.snappit.app/explore/brown-recluse-spider) (*Loxosceles reclusa*)

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Source: [Periwinkle Snails: Facts & Places to See — Snappit](https://www.snappit.app/explore/periwinkle-snails)