Snails have shells the moment they're born, but it's kind of hard to tell. In fact, it's hard to even see a baby snail. Some are nearly microscopic, such as Angustopila psammion, whose adult-sized ...

Snails live all over the world, even in the ocean and in freshwater streams, lakes, and marshes. They’re known both for their extreme slowness and for the houses (shells) they carry on their backs.