Profile of the Sea Mouse Ocean Worm

Sea Mouse (Aphrodita aculeata) in sand

Marevision/age fotostock/Getty Images

Despite its name, the sea mouse is not a type of vertebrate, but a type of worm. These bristled worms live in muddy ocean bottoms. Here you can learn more about these interesting ocean animals.


The sea mouse is a wide worm—it grows to about 6 inches long and 3 inches wide. It is a segmented worm (so, it's related to earthworms you'd find in your yard). The sea mouse has 40 segments. Looking at its dorsal (upper) side, it is hard to see these segments as they are covered with long bristles (setae, or chaetae) that resemble fur, one characteristic that gives this worm its name (there's another, more racy one, described below).

The sea mouse has several types of setae—these bristles are made of chitin and are hollow. Some of the finest bristles on the back of a sea mouse are much smaller in width than a human hair. Despite its drab appearance in some situations, the setae of a sea mouse are capable of producing spectacular iridescence.

On the worm's underside, its segments are clearly visible. The segments have leg-like appendages on each side called parapodia. Sea mice propel themselves by swinging the parapodia back and forth.

The sea mouse may be brown, bronze, black or yellow in appearance, and may appear iridescent in certain light.


  • Kingdom: Animalia
  • Phylum: Annelida
  • Class: Polychaeta
  • Subclass: Aciculata
  • Order: Phyllodocida
  • Suborder: Aphroditiformia
  • Family: Aphroditidae
  • Genus: Aphroditella
  • Species: hastata

The species described here, Aphroditella hastata, was previously known as Aphrodita hastata.

There is another sea mouse species, Aphrodita aculeata, that lives in the eastern Atlantic along the coast of Europe and the Mediterranean Sea.

It is said that the genus name Aphroditella is a reference to the goddess Aphrodite. Why this name for such a strange-looking animal? The reference is supposed because of the resemblance of a sea mouse (particularly the underside) to a female human's genitalia.


The sea mouse eats polychaete worms and small crustaceans, including crabs.


Sea mice have separate sexes (there are males and females). These animals reproduce sexually by releasing eggs and sperm into the water.

Habitat and Distribution

The sea mouse species Aphroditella hastata is found in temperate waters from the Gulf of St. Lawrence to the Chesapeake Bay.

The bristles are covered with mud and mucus - this worm likes to live in muddy bottoms, and can be found in water from 6 feet to over 6000 feet deep. Since they usually live in muddy bottoms, they are not easy to find, and are usually only observed if dragged up with fishing gear or if they are thrown on the shore in storms.

The Sea Mouse and Science

Back to the sea mouse's setae - the setae of sea mice may be paving the way for new developments in tiny technology. In an experiment reported by New Scientist in 2010, researchers at Norwegian University of Science and Technology plucked fine setae from dead sea mice, and then placed a charged gold electrode at one end. Into the other end, they passed charged copper or nickel atoms, which were attracted to the gold on the opposite end. This filled the setae with charged atoms and created a nanowire—the largest nanowire yet produced.

Nanowires can be used for linking parts of electronic circuits, and for making tiny health sensors used within the human body, so this experiment could have important applications.

Sources and Further Information

mla apa chicago
Your Citation
Kennedy, Jennifer. "Profile of the Sea Mouse Ocean Worm." ThoughtCo, Oct. 29, 2020, Kennedy, Jennifer. (2020, October 29). Profile of the Sea Mouse Ocean Worm. Retrieved from Kennedy, Jennifer. "Profile of the Sea Mouse Ocean Worm." ThoughtCo. (accessed March 29, 2023).