How long can a pond snail stay underwater?

The pond snail is always active. Usually crawls among thickets, feeding on algae and small animals from the lower part of the leaves. The maximum crawling speed is 20 cm / min. Breathes air, the reserves of which are constantly replenished, rising to the surface (6-9 times per hour). Pond snails that live in deep lakes at considerable depths breathe air that is dissolved in water. When the reservoir dries up, it closes the mouth of the shell with a film.