A slug’s body is composed of approximately 80% to 90% water. As a result, it is susceptible to desiccation (extreme dryness), which is worsened by the fact that slugs have little or no shells.

RHS SLUG FACTS . Amazing slug facts from the RHS. Slug blood is blue. They have 2000-8000 teeth; They can mate with themselves; The fastest travels at 17.6 metres an hour. They poop from their heads; ...