The Sunflower Star, Pycnopodia helianthoides, is a one of the fastest sea stars. They can move over 40 inches in one minute. One of the reasons they can move so fast is their tube feet. Tube feet are flexible, hollow appendages operated by hydraulic pressure and are used for movement, anchoring, and trapping prey. Sunflower stars have over 20,000 attached to the undersides of 20-plus arms. This star does not always start with so many arms. As a juvenile they have 5 arms and continue to grow more. The arms are mobile soft and flexible, allowing them to feed on variety of prey such as urchins, clams and other sea stars.
Even though Sunflower Stars have an insatiable appetite, there are some species that can be difficult to feed on. Mollusks, like abalones, will twist back and forth until they escape the grip of the sunflower star. Urchins will gnaw at the sunflower star with its many pedicellariae (pinchers). These animals put up a fight! Even so, most of the time purple urchins are not able to escape and the sunflower star will be able to digest the urchin whole and then spit out the test (skeletal structure) of the urchin.
Sunflower stars are beautiful to look at because they come in a variety of colors, ranging from purple to brown to yellow. Like most animals living along the coast, urban run-off like oil from cars or soaps can harm these creatures.
Talk with your family and see if there are ways to help keep the waters healthy for these magnificent creatures!
References: Edited by: KC O’Shea Photos: MSI http://echinoblog.blogspot.com/2012/07/what-are-fastest-known-starfish.html http://www.seastarsofthepacificnorthwest.info/species/sunflower_star.html http://www.montereybayaquarium.org/animal-guide/invertebrates/sunflower-star