Physical Description

  • Large sea star with fifteen to twenty-four arms.
  • They have 15,000 tube feet.
  • Coloration of their soft skin can be orange, pinkish, yellow, brown, and purplish with white spines.
  • They can weigh up to 13.5 pounds and have a diameter over 3 feet
  • Juvenile sunflower stars start life with just five arms and can have 24 by maturity.


  • Unalaska Island, Alaska to Baja California, Mexico.
  • Less common south of Monterey Bay, California.


  • Live in sand, gravel, mud, or rocky substrates.
  • Commonly found from the intertidal zone to 390 feet depth.
  • Can be found as deep as 1,430 feet.


  • When they spawn, they stand on their ray tips and release sperm and eggs over the substrate.
  • The fertilized eggs become bilaterally symmetric larvae (foldable on one line of symmetry) until they are 7 weeks old, when they have metamorphosed into three-legged larvae.
  • Those larvae drop onto the substrate and becomes a miniature pentaradially symmetric (foldable on five lines of symmetry) star..


  • Sea urchins the majority of its diet.
  • Also eat fish, mussels, barnacles, crabs, clams, sea cucumbers, gastropods, octopuses, sand dollars, abalone, snails, chitons, dead squid, occasionally sponges and algae.


  • Alaskan king crabs, sea otters, gulls.

Interesting Facts

  • This is the heaviest and fastest known sea star, able to move at 3.5 feet per minute!
  • Unlike most sea stars with a rigid, one-piece skeleton, sunflower stars have a unique disjointed skeleton and rely on fluid pressure to maintain their form. 
  • When attacking food, they use their leading eight arms to grab the food and pull it into their stomach. 

Sources: Aquarium of the Pacific; Monterey Bay Aquarium;; University of Puget Sound

Photo: Matthew Meier