Snails have developed behavioral and physiological adaptations through the years. The once exclusive marine and freshwater snails formed gills and developed lungs in order to survive on land, while terrestrial snails formed gills in order to thrive in wet biotopes. Some, like the golden snails, formed both gills and lungs.
The snails' shells serve as their homes and act as a protective barrier from predators, such as crabs and birds. Cone snails have large, pointy shells that prevent crabs from grasping the cone's length. Some snails have patterned shells that camouflage them from predators. A terrestrial snail excretes slime which attracts water from its nearby surroundings, helping the land snail to move easier and avoid water loss.