How do land snails avoid drying out in dry conditions?

Land snails employ several physiological and behavioral strategies to prevent desiccation (drying out) in arid conditions:

• Shell Protection and Sealing: Prosobranch snails retreat into their shells and use an operculum to seal the opening. Pulmonates, which lack an operculum, secrete a protective membrane called an epiphragm across the shell aperture. In particularly arid environments, this seal may be reinforced with calcium to become thick and highly resistant to water loss.12
• Behavioral Adjustments: Most land snails primarily rely on behavior to manage moisture levels. They typically remain active in areas with high humidity, retreat into damp niches during dry spells, or burrow into the soil.1
• Dormancy: During prolonged periods of drought or cold, snails may enter a state of dormancy. Some species, such as Sonorella, can remain dormant for years between rainfall events, often reducing their reproductive structures to conserve energy.12
• Specialized Adaptations: In tropical regions, some land operculates have evolved breathing tubes that facilitate gas exchange while minimizing water loss during dry periods.1