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This is an octopus resting on a reef.
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Windows Original, adapted from Corel Photography

Molluscs

A variety of animals, including snails, octopi and squid, are called molluscs. Over 90,000 species of molluscs are called gastropods. The beautiful shells you see when walking along the beach are probably from one of these animals. They are rather simple creatures, feasting on sponges or other small animals. Some live near reefs, while others prefer the mud or even sandy shores.

Oysters, scallops and clams are called bivalves because they have two shell halves. Bivalves enjoy tiny organisms like plankton and sometimes algae. They aren't as pretty as the gastropods, but they make a much better dinner!

Finally, there are the cephalopods, probably the most famous molluscs and the most intelligent. Squids and octopi are the most common the largest ones. Some giant squids can reach lengths of 50 feet! These larger animals, like the octopus in the image, eat fish, crustaceans and other molluscs.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA