Bat Star

Bat Star Patiria miniata

Type of Animal:
Valvatid Starfish

Rocks, rocky/sandy bottoms, crevices, surfgrass areas, seafloors covered w/ rocks/shells/gravel/ sand/algae, kelp forest, exposed coastlines, broken shells, sandy areas, muddy areas, shallow exposed bays, rocky/sandy shore bays, continental shelves, exposed/protected rocky shores, exposed/protected sandy beaches, wharf pilings, found from intertidal/subtidal zones all the way to 984.252 ft deep

Found from SE Alaska to Baja California

Usually has 5 arms (sometimes as many as 9 arms) w/ center disk being wider than stubby arms are in length, color ranges from green to purple to red to orange to yellow to mottled brown to solid brown, webbing between arms looks like bat’s wings

Other sea stars, tunicates, marine worms, dead/live algae, carrion, detritus, dead/live plant matter, surfgrass, bryozoans, sea urchins, sponges

Status in Wild:

Monitoring of collection. Those used for embryological studies put back where found.

Found in colonies of different sizes as well as alone sometimes

Additional Info:

Young: Bipinnaria
Group: Colony
8 in

1 month

Life Span:
5-30 years

Main predators are other sea stars, crabs, fish, gulls, sharks, otters, snails, & nudibranchs.
Spawning occurs by male discharging sperm & female releasing eggs. Sperm/eggs unite at sea being carried away by ocean currents.
Eggs hatch into planktonic bipinnaria, later metamorphosing into pentamerous juveniles, eventually becoming young sea stars.
Also called sea bats, webbed stars, broad-disk stars, purple sea stars, yellow sea stars, red sea stars, & bat starfish.
Can breed all year round.
Mouth located on underside & extends stomach out of mouth, digesting food externally.
Have commensal relationship w/ Bat Star Commensal Worm-worms live on sea star’s surface w/ worms eating food scraps & sea star neither being benefited nor harmed.
Tube-feet allow them to move & hold on to surfaces.
At larger carcasses, they’ll have slow-motion feeding frenzies.
1 defense mechanism is secreting chemicals used to stimulate escape responses in other animals.
To eat food, they cover it w/ stomach & ooze digestive juices over it, liquefying food.
Fights over space involve pushing/laying arms over each other.

Fun Fact(s):
Scientific name means “vermillion dish.”
Like most sea stars, they can regenerate lost limbs.
Like all sea stars, they can right themselves up by using tube feet/arms if upside down.
Due to long breeding period, scientists use these sea stars for embryological studies.

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