The common name snail is also applied to most of the members of the molluscan class Gastropoda that have a coiled shell that is large enough for the animal to retract completely into. When the word snail is used in this most general sense, it includes not just land snails but also thousands of species of sea snails and freshwater snails. They do not have a great reputation but the story goes that if a snail climbs a plant or post, rain is coming, research led by the University of York goes one better: it shows snails can provide a wealth of information about the prevailing weather conditions thousands of years ago. The researchers, including scientists from the Scottish Universities Environmental Research Center (SUERC), analyzed the chemistry of snail shells dating back 9,000 to 2,500 years recovered from Mediterranean caves, looking at humidity at different times in the past.