Sea mouse
The sea mouse is a unique marine polychaete worm known for its distinctive fur-like bristles and large, flattened body, which can range from three to twelve inches in length. Found primarily in shallow coastal waters along Europe’s coasts, it inhabits sand and mud environments below the low tide line, where it burrows and feeds on carrion—dead animal matter. Its body features fifteen pairs of scales covered in dense, iridescent bristles that can display a spectrum of colors, including gold, red, and violet. The bristles not only assist in locomotion but also provide protection against predators, as they can be poisonous if they puncture skin. Sea mice possess gills for respiration and may use their tentacles to help gather food from the seabed. Although much about their reproductive habits remains unclear, it is believed that fertilization occurs externally, with young potentially existing as free-swimming larvae before settling on the ocean floor. The typical lifespan of a sea mouse ranges from six to ten years.
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Sea mouse
The sea mouse is a large worm with fur that lives in the ocean just below the water's low tide level. It burrows through the sand and mud for carrion, or dead animal flesh.
Kingdom: Animalia
Phylum: Annelida
Class: Polychaetae
Order: Phyllodocida
Family: Aphroditidae
Genus: Aphrodite
Species: Aculeata
Among the species of polychaete worms is the sea mouse. Polychaete worms are a class of worms with segmented bodies in the same phylum as earthworms and leeches. As a polychaete worm, each segment of the sea mouse's body is separated from the one on either side of it by tissues called septa. The side of each segment has a pair of muscular extensions called parapodia. Each parapodium has a bundle of bristly hairs called chaetae which are made from a material called chitin. Polychaetae means many bristles and refers to these bundles of bristles. Tiny hairs called cirri also grow from each segment and help the sea mouse sense its surroundings.
The sea mouse lives in shallow coastal waters worldwide, but it is found primarily along the coasts of Europe. It lives under rocks and in burrows in the sand and mud below the low tide line. As it crawls and plows slowly through the seabed, it feeds on carrion, or dead animal flesh.
The sea mouse has a flattened, oval-shaped body three to six inches (7 1/2 to 15 centimeters) across and up to 12 inches (30 centimeters) long. Fifteen pairs of large scales cover the back of the sea mouse, and a layer of dense, thick bristles covers these scales and looks like fur. The bristles are gray over the body’s center but iridescent along the edges. Iridescent means they reflect light in such a way as to turn several colors. Along the edges, the bristles shift between gold, red, yellow, orange, scarlet, crimson, lilac, and other colors.
The underside of the sea mouse shows the ring-like segments of its body. Bristles on the sides of each segment help the sea mouse move on the sea bottom. These bristles are poisonous and can cause severe irritation if they puncture the skin. These bristles and those on their backs may protect them from predators, like fish. The sea mouse can scurry quickly when in danger.
Like fish, the sea mouse has gills to breathe. The sea mouse lies in its burrow in the sea bottom with its head pointed downward and its tail pointed upward. It moves its tail and body to pull water into the burrow and over its gills. The bristles keep out the sand, and the scales protect the gills. Its body may also absorb oxygen from the water.
The two eyes of the sea mouse are at the tips of two little stalks so that the eyes stick out from the head. The head also has two short tentacles. How the sea mouse feeds is uncertain. It may use these tentacles and the many cilia, or tiny hairs, on them to collect food from the bottom of the water. The sea mouse may have a pharynx, or throat, that can turn inside out to swallow larger food.
Little is known of the reproductive habits of the sea mouse, but they are likely to be similar to those of other polychaete worms. Fertilization of the female's eggs by the male's sperm most likely occurs outside the body. The young may have a brief period as free-swimming larvae, or young, before they settle to the bottom, or they may hatch from the eggs and live on the bottom.
The life span of the sea mouse is 6 to 10 years.
Bibliography
Baker, Nick. "Sea Mouse: A Guide to the Aphrodita Aculeata." Discover Wildlife, 16 Feb. 2023, www.discoverwildlife.com/animal-facts/insects-invertebrates/sea-mouse-aphrodita-aculeata. Accessed 1 May 2024.
"Sea Mouse." The Wildlife Trusts, www.wildlifetrusts.org/wildlife-explorer/marine/worms/sea-mouse. Accessed 1 May 2024.