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Inkeeper worm burrows its way through silt

Fat innkeeper worm

Urechis caupo

Animal type
Invertebrates
Ecosystem
Coastal wetlands
Relatives
Phylum: Echiura
Diet
Plankton, food particles
Range
California coast
Size
Up to 7 inches (17 cm)

Meet the fat innkeeper worm

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 from them, either.

Conservation

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 is full of food, the innkeeper swallows its meal—net and all.

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