Pacific Sand Dollar

Dendraster excentricus

Pacific Sand Dollar

Dendraster excentricus

Other Common Names

Eccentric Sand Dollar

Sandy Coast

Other Common Names

Eccentric Sand Dollar

At the Aquarium

Sandy Coast

Appearance

Pacific sand dollars are a disc shaped animal that can get up to 3 inches wide. They are covered in tiny spines ranging from purple to brown.

Habitat

Sandy bottomed subtidal and low intertidal areas.

Diet

Algae, micro plankton, and free-floating juvenile crustaceans

Life History

Pacific sand dollar eggs have a jelly-like coating that stops their progenitors from accidentally eating their own eggs. After hatching, the juveniles float in the water as microscopic plankton for several weeks. The juveniles eventually settle to the seafloor and become adult sand dollars. This settling can be triggered by pheromones made by adult sand dollars, ensuring that the juveniles settle down in an area where sand dollars can thrive. Once settled, sand dollars spend the rest of their lives–up to 13 years–on the seafloor.

IUCN Status

Not Evaluated

Ecosystem & Cultural Importance

The empty shell of the pacific sand dollar, known as its test, is an iconic seashell. Many may recognize this animal’s shell more easily than a living specimen. Pacific sand dollars carry nutrients up the food web of their environments. They eat small plankton drifting in the water and are then eaten by sea stars and fish species including the starry flounder.

Baja California to south eastern Alaska.

The Pacific Sand Dollar is the only sand dollar found in Oregon. The shells of the Pacific sand dollar can be found on sandy beaches across the coast.

The Pacific sand dollar eats by propping itself up on its side and catching plankton floating in the water. Pacific sand dollars also eat sand to weigh them down, preventing them from drifting away with the current.

Citations & Other Resources

Morris, R. H., A. P. Donald, H. C. Eugene. 1990. Intertidal Invertebrates of California. Stanford University Press, Stanford, CA, USA.
Meinkoth, N. A. 2011. National Audubon Society field guide to seashore creatures. Random House Inc., New York, NY, USA.
Encyclopedia of Puget Sound. 2024. Dendraster excentricus. University of Washington. https://www.eopugetsound.org/species/dendraster-excentricus
Burke, R. D. 1984. Pheromonal Control of Metamorphosis in the Pacific Sand Dollar, Dendraster excentricus. Science 225:442-443.

Pacific Sand Dollar

Pacific Sand Dollar

Other Common Names

At the Aquarium

Appearance

Habitat

Diet

Life History

IUCN Status

Ecosystem & Cultural Importance

Citations & Other Resources

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