While the proboscis of a burrowing spoon worm is on the surface it is at risk of predation by bottom-feeding fish. In some species, the proboscis will autotomise (break off) if attacked and the worm will regenerate a proboscis over the course of a few weeks. In a study in California, one of the most commonly found dietary items of the leopard shark was found to be the tube-dwelling innkeeper worm ("Urechis caupo") which it extracted from the sediment by suction.