Fat innkeeper worm

Animal Facts

  • Scientific Name

    Urechis caupo

  • Animal Type


  • Diet

    plankton, food particles

  • Size

    to 7 inches (17 cm)

  • Relatives

    Phylum: Echiura

Natural History

Innkeeper worms build U-shaped burrows in the muddy sand of low-zone mudflats. These fine "innkeepers" maintain lodgings for their buddies in the mud. Food, shelter and running water pumped by the innkeeper worm attract a motley crew of guests to this burrow. Some, like the arrow goby, check in and out quickly; others, like pea crabs and scale worms, take up permanent residency. The innkeeper isn't bothered by these guests, but doesn't benefit, either.


Many kinds of plants, birds and fishes depend on the special mix of fresh and salt water found in wetlands. When we protect wetlands against development, we protect the homes of many animals.

Cool Facts

Innkeeper worms eat by creating a "slime net" that traps tiny bits of food drifting in the water. When the net's full of food, the innkeper swallows its meal—net and all.

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