Snails are soft-bodied gastropods, similar to slugs, that have a hard shell on their back that they can completely retract into as a form of defence. There have been many fossils found of snails dating their existence back nearly 500 million years. Most are herbivores, using a band of microscopic teeth to rip into plant matter. They have both sex organs allowing them to self-fertilise if needed, laying eggs. Snails are famously part of French cuisine and they’re also eaten in other cultures.