Wednesday, June 24, 2009

What's That Stuff?

Some people mistake these things for garbage on the beach. Actually, these rubbery-looking objects are live egg casings of the large, carnivorous Moon Snail (Polinices lewisii).

On a recent tidepool animal collecting trip Pacific Science Center Life Sciences staff brought back a few Moon Snail Collars for our visitors to handle and examine. During the spring and summer, female Moon Snails extrude sheaths of hardened mucus and sand filled with fertilized eggs. Although there are thousands of eggs living in a sand collar, the eggs will never produce young in our tidepool. The excellent filtration system of our Puget Sound Salt Water Tidepool will strain the eggs out of the water before they become viable.

Because clams are a dietary staple of the Moon Snail, this gastropod is unfairly maligned by some clam diggers. The prized butter clams of shell fishers are often too difficult for this snail’s drill.

Because of their size (up to 5 inches with a 12 inch foot) and destructiveness, we don’t collect Moon Snails - just their egg casings. Stop by to see and feel these fascinating organisms. They won’t be around long!

Want to learn more about Moon Snails? Go to

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