Snails

• Phylulm Mollusca
• Class Gastropoda (Belly-Footed Animals)
• Family Pulmonates (Lung-Breathing Snails)
• Family Prosobranchia (Gill-Breathing Snails)

Other Names

• Snails are referred to as gastropods
• Pond, pouch or lunged snails are called Pulmonates
• Gilled snails are called Prosobranchs

Appearance

• Light-sensitive "eyes" located on the ends of "antennae"
• Shell is a single piece
• Lung-breathing snails have shells coiled like a tuba or spiral shells opening on the left side without a door. Lung = Left
• Gill-breathing snails have spiral shells opening on the right side with a door

Behavior

• Move by means of wavelike muscular contractions along their "foot".
• Movement is aided by cilia hairs and a track of slime.
• Withdraws into its shell for protection against predators or drying.
• Lung-breathing snails trap a pocket of air in the space between the shell and the body. Oxygen is taken directly from that air.

Aquatic Habitat

• Live in still or quiet water.
• Found in vegetation.

Reproduction

• Hermaphroditic - both sexual organs in one individual.
• Lay eggs in a jelly clump under rocks and leaves.
• Lunged snails are short-lived and can complete their life cycle in a year.
• Gilled snails may live 3-5 years.

Feeding Type

• Herbivores that feed on algae scraped from stones and leaves.
• Detritivores that feed on decaying matter.
• Browses by means of a radula - a ribbon-like tongue embedded with thousands of "teeth" - drawn along rocks or leaves.

Predation

• Food for fish, ducks and leeches.

Pollution Tolerance

• Only count live snails when sampling invertebrate numbers.
• Lunged snails are not dependent on dissolved oxygen because they have lungs and breathe air. Because they obtain air from above the water's surface they are not as sensitive to pollution and are not really good indicators of water quality.
• Gilled snails rely on oxygen dissolved in the water and may be susceptible to pollution.
• Pollution tolerant.
• Large numbers may indicate poor water quality and organic enrichment.