WHAT IS THIS?

At low water levels, long sandy beaches are often full of small, coiled worms scattered across the moist sand. They are sandworm excrements, or "casts".

The sandworms live in U-shaped burrows in the sand. They can grow up to 30 cm long, but are typically much smaller.

The worms' heads are located at one end of the burrow, swallowing sand and digesting organic material and tiny creatures located on/in between sand grains.

The sand grains pass through the worm and out of its rear end undigested. Surrounded by a slime layer, they keep their shapes, until they dry up or are touched.