Nature Notebook – Lunged Snail

“If the opening is on the left, then it is a lunged snail.” The students learned the difference between lunged and gilled snails using this identification technique. They then determined that the snails in our collecting tray were all lunged, or pulmonated, snails.

Lunged snails have a body cavity surrounded by thin tissue. Atmospheric oxygen (versus oxygen dissolved in the water) is collected and stored in the space. The oxygen moves through the tissue into the snail’s body. When the supply is depleted, the snail must return to the surface to “breathe” and gather more oxygen.

Although this seems like a lot of work, the adaptation is advantageous to the snail. It allows the snail to inhabit many more bodies of water (even those that are not particularly clean) than its gilled cousin.

A population of one lunged snail can quickly become many. They are hermaphroditic so they can self-fertilize their eggs and rapidly increase their numbers.