Bat Sea Star

Patiria miniata

Bat Sea Star

Patiria miniata

Other Common Names
Sea bat, webbed star, broad-disk star

Sandy Coast, Rocky Coast

Other Common Names

Sea bat, webbed star, broad-disk star

At the Aquarium

Sandy Coast, Rocky Coast

Appearance

Bat stars reach up to 8 inches across and come in a variety of colors. They can have 4 to 9 arms, but usually have 5. They are named for the webbing that spans between the arms.

Habitat

Kelp forests, rocky bottoms, sandy bottoms, or among surf grass. Lower intertidal zone to depths of 984 feet.

Diet

Scavenger; often eats algae, sponges, worms, and colonial tunicates

Life History

Bat stars reproduce by broadcast spawning year-round, with a peak in late summer. Females release millions of eggs that will join with sperm to create an embryo. A bat star larva is transparent and planktonic and over ~30 days undergoes several metamorphoses until reaching the adult stage. Bat stars can also reproduce asexually. If part of a parent star breaks off, it can result in a new individual that is a genetic clone of the parent. Bat stars can live up to 35 years.

IUCN Status

Not Evaluated

Ecosystem & Cultural Importance

As scavengers, bat stars remove dead animals and algae, keeping their ecosystem clean. As prey, bat stars serve as food to other sea stars, mollusks, and crustaceans.

Alaska to Baja California, Mexico

Though found in Oregon, the bat star is considered uncommon here. Look for it in shallow, exposed bays.

A bat star can have as many as 20 worms (Ophiodromus pugettensis) living in the grooves by its tube feet. This is considered a commensal symbiosis because the worms neither help nor hurt the star. The worm benefits because they are sheltered and can eat leftover bat star food. Bat stars feed by bringing their stomach out through their mouth and pressing it against the food. The stomach then releases digestive juices onto the prey, dissolving it for consumption.

Citations & Other Resources

Aquarium of the Pacific website: https://www.aquariumofpacific.org/onlinelearningcenter/species/bat_star
Biodiversity of the Central Coast website: https://www.centralcoastbiodiversity.org/bat-star-bull-asterina-miniata.html
Invertebrates of the Salish Sea website: https://inverts.wallawalla.edu/Echinodermata/Class%20Asteroidea/Asterina_miniata.html
Monterey Bay Aquarium website: https://www.montereybayaquarium.org/animals/animals-a-to-z/bat-star
National Marine Sanctuary Foundation website: https://marinesanctuary.org/blog/sea-wonder-bat-star/

Bat Sea Star

Bat Sea Star

Other Common Names

At the Aquarium

Appearance

Habitat

Diet

Life History

IUCN Status

Ecosystem & Cultural Importance

Citations & Other Resources

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