Mud Worms (Polydora ligni)
Color: Slightly reddish in color.
Size: 1 inch long, 1/4 inch wide.
Habitat: Intertidal and subtidal, rocky shores, soft mud or sand, oyster beds, and pilings.
Seasonal appearance: All year.
Mud worms are small, segmented, tube-building worms similar to clam worms. They are slender, cylindrical, and mostly transparent. Mud worms can be identified by two long, coiled organs, called palps, which extend from the head section and are used to sense and collect food. The fragile palps are often destroyed during collection of the worm, making identification difficult. Mud worms have bristles or paddles along each of the body segments, that are used for swimming and for extra traction when crawling along the mud. They have two long antennae, a forked lobe above the mouth, a forked tail, and four eyes positioned in a rectangular shape on the head.
Life History and Behavior
Mud worms are burrowing, tube-building worms. Unlike wandering worms that seek out prey, such as clam worms, mud worms capture food as it comes to them, using their specially modified palps. The fifth body segment is wide and has minute hooks and a suction-like tail that holds the worm in its tube. The palps can often be seen extending from the tube as the animal sweeps the bottom of the sea floor and the water to collect food.
Mud worms are among the most abundant worms in Rhode Island waters. Often forming large colonies, they can smother other benthic invertebrates in the area. They usually collect bits of sediment and mud and excrete the mud after separating out the food. This mud will build up around the worms, creating a several-inch deep layer of sediment around the worm colony.
Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.