Sand Dollar
WILDLIFE ADVENTURES – SAND DOLLAR
KELLI BECTON – ADVENTURES IN CHILDREARING
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Sand Dollar
The term sand dollar refers to species of extremely flattened, burrowing sea
urchins belonging to the order Clypeasteroida. Some species within the order, not
quite as flat, are known as sea biscuits. ~ Wikipedia
Sand dollars are of the class Echinoidea of the phylum Echinodermata.
When you hear the term sand dollar, you most likely think of a round, flat, white or grey
colored disk found in the sea or along the sea shore.
While these are indeed sand dollars, they are actually the exoskeleton of the animal and no
longer alive. It is made of calcium carbonate. The live animal is covered with a brown skin with
tiny hairs, cilia, and tiny spines on both front and back.
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The sand dollars found washed up on the beach are usually already dead, because they cannot
live on the shore. Their habitat is the sandy ocean bottom, usually in fairly shallow waters.
Do you see the flower shape in the center of the sand dollar? It is where many of the tube feet
are located.
Tube feet- how sand dollars breathe
They are echinoderms, which means spiny skinned. There are fuzzy, tiny spines (cilia) with tube
feet on the underside of the sand dollar which are used to crawl around, and grab food. Tiny
organisms are sifted by the tube feet through the sand and then passed along ridges to the
animal’s mouth. Where the spines come together in a cone shape underneath the sand dollar
body, is a place where food, like crab larvae is held and then passed to the mouth. They have
five teeth-like parts to chew or grind up food. Tiny organisms such as plant material or
plankton, and larvae make up the bulk of sand dollar diet. The chewing process takes about 15
minutes, and the digestion takes up to two days.
Most sand dollars have five sets of pores. They move sea water into the sand dollar's body,
which is then pumped to where it's needed to aid in movement or other internal functions.
These are the gills of the animal and are located on top (Pictured above).
The sand dollar is an invertebrate. See a list of other marine invertebrates here.
An invertebrate is an animal without a backbone. The sand dollar has a skeleton, but no spine/
backbone.
They live on average from 6 – 10 years. The age of a sand dollar is determined by the rings
around the exoskeleton plates – much like the age of a tree.
Predators: Sand Dollars are eaten by starfish, mollusks, some fish, and skates.
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Sand Dollar Facts
SCIENTIFIC NAME
Dendraster excentricus
HABITAT
Sandy Seafloor
ANIMAL TYPE
Invertebrates
DIET
crustacean larvae, small copepods, detritus, diatoms, algae
SIZE
to 3 inches across (7.6 cm)
RANGE
low intertidal to about 130 feet (40 m) from Alaska to Baja California
RELATIVES
sea urchins, sea stars, sea cucumbers; Phylum: Echinodermata
Information on Sand Dollar Facts from - http://www.montereybayaquarium.org/
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Mouth
5 branches of tube feet
5 sets of petalloids – each
with 2 feet acting as gills
Which carry food to the mouth
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Credit this photo: State Archives of Florida, Florida Memory,
http://floridamemory.com/items/show/161114
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Micah 7:19
He will again have
compassion on us;
He will tread our
iniquities under foot.
Yes, You will cast all
their sins into the
depths of the sea.
ADVENTURESINCHILDREARING – WWW.HOMESCHOOLINGADVENTUREZ.COM
Micah 7:19
He will again have
compassion on us; He
will tread our iniquities
under foot. Yes, You will
cast all their sins into
the depths of the sea.
ADVENTURESINCHILDREARING – WWW.HOMESCHOOLINGADVENTUREZ.COM
Sand Dollar video: Click on the video photo to watch a sand dollar
in action! Or go here- http://youtu.be/O3uKWy5Vljs
Sand Dollar craft video: Click on the photo of the video or go
here- http://youtu.be/6B-79m_MQ3k
ADVENTURESINCHILDREARING – WWW.HOMESCHOOLINGADVENTUREZ.COM
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