Molluscs

Most molluscs have shells, which is how you spot them. If you find shells, make sure the creature isn’t still living inside! If it is, put it back again! Here are some of the molluscs you can find on the Quantocks.

On Land

Slugs

Slugs don’t have a shell but are still molluscs! Instead they are covered in a layer of slippery slime. It protects their skin and stops them from drying out. It also makes it harder for birds to pick them up! During the day, slugs hide in dark, moist places. At night time they feed on soft leaves, fruit, rotting plants and dead insects. Slugs mate in the autumn, and lay about 40 eggs which hatch into tiny slugs in the spring. Grass snakes eat slugs.

Snail

  • Snail

Snails. Snails protect their soft, moist bodies by growing a spiral shell. The shells come in different shapes, sizes and patterns. Snails close off the entrance to the shell with a layer of hard slime. In the daytime, they hide in dark cracks and corners. They come out at night to eat live or dead plants. Some snails also feed on other small invertebrates. Thrushes eat snails by breaking open the shells on stones.

On the seashore

Sea snails

Sea snails with their spiral shells are common here. Most of them feed on seaweed, so you will find them in or under seaweed especially where it drapes over rock faces. You can see where the sea snails have been because they leave a slimy trail. Here are three sea snails you might spot:

Winkles & Top shells

  • Winkles
  • Top shells

Winkles and top shells have strong shells. Their shells protect them even if they are knocked off the rock. If this happens they close up the end of the shell with a shelly cover so they don’t dry out.

Whelks

  • Whelks

Whelks have a large whitish shell and feed on other sea snails. They use their rough, flexible tongue to bore through the other snails’ shells and eat them.

Other Sea Molluscs

Limpet

  • Limpet

The limpet has a very strong foot like a sucker. It makes a smooth, shell-sized patch for itself and then holds on firmly with its foot. There are no gaps left for water to get out of the shell, so it doesn’t dry out at low tide.

When the limpet is hungry it moves about on the rock to feed on the slimy algae. It scrapes the algae off with its long, flexible tongue and leaves a zig-zag pattern of scrape marks. Sometimes people think these are fossil markings!

Barnacle shells

  • Barnacle shells

Barnacle shells stay stuck to the rock all the time. When the tide is in, the creature inside opens the top plates of its shell and pushes out its feathery legs. Then it sweeps tiny bits of food down into its mouth!

Chitton

The Chitton (‘Coat-of-mail’) shell feeds in the same way as the limpet. If it gets knocked off the rock, it rolls up its shell into a ball, like a woodlouse. It looks a bit like a woodlouse too but it is about twice the size.

Piddocks

Have you ever found a stone that has lots of small holes in? They might have been made by a piddock. The piddock has a cylindrical shell with sharp edges. It drills its home in the rock by twisting its body from side to side to make a tunnel. As it grows, the piddock has to keep making its home bigger. Quite often one of the tunnels will contain the empty white shell left by a dead piddock.

Mussel

The mussel has a dark blue shell with two parts that can open and close. It fixes itself to the rock with time threads. Most of the time the mussel stays tightly shut so it doesn’t dry out. When the tide comes in, it opens the shell slightly to collect small food particles.

Extinct Molluscs

Ammonites (‘Saint Keyna’s Serpents’)

  • Ammonites
  • Ammonites

Ammonites are the main fossils found in the rocks of Kilve beach. You can easily recognise them by their round, flatly coiled shape. This shows that they were molluscs, like snails.

People used to think that they were made when St. Keyna of Keynsham turned a plague of snakes to stone (‘snake-stones’)! In fact they were tube-shaped sea shells with an octopus-like creature living in the outer, widest part of the coil.