Common cockles live buried in muddy and sandy shores, between the high and low tide marks. Their rounded, domed shells have distinctive ridges radiating from the centre. Cockles filter tiny plankton and other food from the water and are an important meal for oystercatchers, shore crabs and flatfish. 

There are several species of scallop, and they can be tricky to tell apart. The variegated scallop is one you are most likely to find washed up on the beach. Its shell can be white, pink, red, orange, yellow or purple, sometimes with beautiful patterns. 

The common whelk lives on sandy seabeds below the low tide mark. It is the largest sea snail found in our seas and therefore the largest snail shell you are likely to find on our beaches. The common whelk is carnivorous and feeds on worms and other molluscs, often using the edge of its own shell to prize open other shells. It also scavenges for carrion, which it finds by smell.

Piddocks are unusual clam-like shellfish that spend their lives hidden inside burrows in soft rocks such as clay and sandstone. They slowly make their burrows bigger as they grow and use their siphons to filter food from the water. Their long, oval shells look a little like wings, giving them the nickname Angelwings. When a piddock dies, its empty burrow can become a home for other marine creatures.

Slipper limpets arrived in the UK from America during the 19th century and are now widespread around our coasts. They often form stacks, with one shell sitting on top of another. Turn one upside down and you'll see where their name comes from – it looks just like a tiny slipper! They are now considered a serious pest of oyster and mussel beds.

Oyster drills are whelks, living below the low tide mark down to depths of 150m. The oyster drill is unmistakeable, being much rougher and more jagged in outline than any other whelk. The oyster drill is also known as the 'sting winkle' or 'rough tingle'. The common name ‘oyster drill’ comes from the fact that they prey on young oyster spat, using their tongue to drill through the oyster shell, before slurping the insides up like a smoothie!

A non-native species, the American oyster drill, has also been recorded along the Kent and Essex coasts, where it feeds on native oyster beds.

The Arctic cowrie is one of the UK's smallest and most delicate sea snails and an absolute favourite find for avid shell collectors when washed upon the shore empty! 

Hornwrack might look like dried seaweed, but it is actually a colony of tiny animals! Look closely and you'll see a network of little boxes, each home to an individual zooid. Hornwrack grows in bushy clumps on shells, stones and rocky seabed. The tiny zooids filter food from the water using special feeding tentacles. Despite its unusual appearance, hornwrack is a tasty snack for sea urchins, sea slugs and even sea spiders!

The shore crab is one of the UK's most familiar crabs. If you've been rockpooling or crabbing, you may well have met one! They are usually greenish but can also be orange or red. The different colourations are related to the crab's age and whether it is breeding season. It is medium sized and can be identified by the pattern of spikes on its shell (carapace). The shore crab has five upturned spikes on each side of the carapace and 3 rounded lobes between the eyes. 

The common starfish is found all around the UK, from rockpools to depths of at least 600 metres. Despite its name, it isn't a fish at all – it is an echinoderm, meaning “spiny skinned”. Starfish are predators that love to eat mussels and other shellfish. They pull open their prey's shell, push their stomach inside and digest their meal before sucking it back up! They can even gather in huge groups when food is plentiful, using special receptors in their skin to sniff out dinner.

The green sea urchin is a small, round, spiny creature found around rocky UK shores. It often hides among seaweed, kelp and seagrass and can live down to around 100 metres. It feeds mainly on seaweed and other marine life, including sponges, barnacles and mussels. Its short spines can have bright purple tips, earning it the nickname purple-tipped urchin. Like starfish, sea urchins are echinoderms. If you find an empty, delicate urchin skeleton on the beach, you've found its test – the hard structure left behind.

When sharks and true skates reproduce, they lay eggs inside tough, leathery cases. These protective capsules allow the embryo to safely develop until, after several months, it is ready to hatch. Eventually, a fully formed young shark or skate emerges, leaving the empty eggcase behind.

The empty cases, often called “mermaid’s purses”, can then be carried by the sea onto beaches. They are particularly easy to spot along the strandline. Each species produces an eggcase with its own distinctive size, shape and features. By examining these differences, we can work out which species the eggcase came from.