Bat Star (Patiria miniata)

Contributed by TPERP Clay Clifton

Where to find them: 1 to 3-inch diameter individuals are found in the rocky middle inter-tidal zone in crevices and under ledges or rocks, while 6-inch diameter specimens are found in deep water in the kelp bed community and on walls of submarine canyons. Range is from Sitka, Alaska to La Paz in Baja California Sur, Mexico. South of Point Conception, California, specimens are few, small, stunted and usually found under rocks. P. miniata is rare in the Rocky Intertidal at Cabrillo.

What do they eat: A great variety of attached animals (barnacles, limpets, etc.) or dead plants or animals.

Who eats them: Primary threats are souvenir harvesting/collection of these animals by people. 

Adaptations: Wide range of coloration including solid white, yellow, orange, brown, gray, red or purple; or pale and irregularly mottled or spotted with these colors. Usually five (but sometimes four up to nine) rays used to grasp and pry open shells of prey. Eyes are on tips of rays (arms) and respiration (breathing) is through the skin. Fossil records indicate this phylum has been on Earth for more than 500,000,000 years.

Reproduction: External by discharge of male and female sperm and eggs during late winter and spring, initially developing as minute, free swimming larvae, which the sea stars develop inside of, absorbing the larval form as they grow.

What’s their life like: An omnivore or scavenger, P. miniata, along with other sea stars are the most easily recognizable and familiar residents of southern California rocky inter-tidal. Suckers on tube feet allow them to cling to surf swept rocks and slowly cover the rocky inter-tidal in search of prey.

Interesting facts: Commonly used in embryological experimentation because of availability, long breeding season and tendency of males and females to extrude sexual products very readily. Feeds by extending its voluminous stomach out of its body over its prey.

Classification
Phylum: Echinodermata
Class: Asteroidea
Order: Spinulosida
Family: Asterinidae
Scientific Name: Patiria miniata
Common Name(s): Bat star , Sea bat, red, yellow or purple sea star

Source(s) of Information:

Edward F. Ricketts, Calvin, J., and Hedgpeth, J.W. Between Pacific Tides. Fifth Edition. 1939, renewed in 1985. Stanford University Press.

Jeffery L. Brandon, and Rokop, F. J. Life Between the Tides – The Natural History of the Common Seashore Life of Southern California. 1985. American Southwest Publishing Company of San Diego.

Last revised 17-Aug-13