Bat Sea Star

The bat sea star Patiria miniata. Photo credit: Conor Gearin
The bat sea star (Patiria miniata). Photo credit: Conor Gearin

Bat stars (Patiria miniata) are named for the thick webbing between their arms that gives them a more “bat-like” appearance than other sea stars. These colorful echinoderms are most commonly seen in some shade of red or orange, but are also found in a variety of mottled colors including yellow, brown, green, pink, and purple. Like most sea stars, bat stars typically have five arms, but are sometimes born with between four to nine arms.

When a bat star finds a food item, it extends one of its two stomachs outside of its mouth cavity and using digestive enzymes, begins breaking down its prey. Eventually, the bat star pulls its stomach and partially digested prey back into its body to complete digestion.

Scientific Name: Patiria miniata

Type: Echinoderm
Habitat: Inter-tidal zones
Range: Pacific coast of North America
Life Span in the Wild: unknown for certain, but at least several decades!
Size: Usually 4-5 inches but can reach up to 8 inches
Weight: 250 grams on average
Diet: Omnivore and a scavenger
Status: Not Evaluated

Bat stars have an unusually long breeding season. Males and females discharge fertile sperm or eggs all year long, but more abundantly during the late winter and spring. Females release millions of eggs into the ocean through the pores between their arms and the males release a cloud of sperm. Once fertilized, bat star eggs quickly develop into embryos and then tiny free-swimming planktonic larvae. These larvae have strong regenerative capabilities, such as regrowing missing body parts if cut in half.

Bat star bipinnaria at fourth day of development Photographed using confocal microscopy. Histones are labeled in blue, actin filaments in orange. Credit: N. Carrigan via cc license
Bat star bipinnaria at fourth day of development Photographed using confocal microscopy. Histones are labeled in blue, actin filaments in orange. Credit: Natalie Carrigan via CC license
Bat Sea Stars and the MBL

Scientists at the MBL and around the world study bat stars to learn more about embryonic development, reproduction, and regeneration. The Swartz Lab at the 91鶹 studies sexual reproduction and development in P. miniata, and its relatives as a window into understanding human health and fertility.

Learn more about the Swartz Lab Learn more about the MBL's New Research Organism Strategic Initiative
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