Wonderful Wacky Water Critters
Orb, Gilled, and Pouch Snails
Think how hard it would be to carry your house on your back! That's what a snail does. Each kind of snail has a unique shape or color to its shell. How many kinds did you find? There are two major types of snails. The lunged and the gilled snails. The pouch snail, one of the lunged snails, lives in ponds and pools where oxygen is low. It can be found in slow, polluted rivers too. The orb snail, also one of the lunged snails, lives in clean, quiet waters. Gilled snails have a shell "door" (Operculum) which they can close when they go into their shell. This type of snail is typically found in clean rivers. They need more oxygen than the pouch snails. The snail's shell provides protection from enemies. It also is a handy oxygen container. When a snail is seen crawling upside down on the surface of the pond it is gathering fresh air into its shell. When a snail is threatened it pulls its "foot" into its shell and is safe from most predators. A snail has both its eyes and mouth on its foot! Watch how it uses its eyes like periscopes as it moves along, scraping and feeding on algae. The snail is very sensitive to acid in the water which can dissolve its limey shell. Where do you think the acid might come from?
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