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.
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/
We use cookies to improve your experience and see how our guests are navigating the website. If this is alright by you, hit 'Accept All', or 'Settings' to customize and learn more.
Read our cookie policy
