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Snails (Mollusca: Gastropoda)

General Information about Snails (Mollusca: Gastropoda)
Life History Freshwater snails lay a mass of eggs in the spring. Immature snails look like adult snails except they have fewer coils on their shells. Most kinds of freshwater snails live for 2-5 years.
Diversity There are about 15 families of freshwater snails in North America. The families are divided into two major groups: gilled and lunged snails.
Distinguishing characteristics Snails have a single shell; most kinds have a spiral shaped shell.
Habitat & Feeding Freshwater snails may be found in lakes, ponds, marshes, swamps, streams and rivers. Freshwater snails are generally scrapers; they use a tongue-like structure covered with tiny small, sharp teeth to scrape food particles from the substrate.
Water quality indicator status Freshwater snails that have gills are intolerant of low dissolved oxygen levels. Lunged snails are somewhat tolerant of low dissolved oxygen levels. High numbers of lunged snails may indicate poor water quality.
Fun facts
  • Freshwater snails are eaten by fish, waterfowl, amphibians and many aquatic invertebrates.
  • Some kinds of freshwater snails are hermaphroditic.