Snails eat both dead and living plant material. They feed by scraping with a special tongue-like organ called a radula. The radula, with many tooth-like structures on it, is used very much like a wood file. Both land and water snails breathe with a lung, not a gill. Every so often water snails must come to the surface to expose the lung opening to the air for gas exchange.
Snails often have parasites that affect man and other animals.