How does estivation help desert snails survive extreme drought?

Estivation is a vital survival strategy for desert snails, allowing them to endure extreme drought by entering a state of dormancy. During this period, the snails significantly reduce their metabolic activity, which helps them conserve energy and minimize their demands on the harsh desert environment.12

To protect themselves from desiccation while dormant, these snails employ several physical adaptations:

• Protective Seals: Many land snails secrete a mucous covering, known as an epiphragm, across the shell aperture. In particularly arid regions, this seal may be impregnated with calcium, making it nearly as thick as the shell itself.3
• Shell Withdrawal: By retreating into their shells, snails can effectively isolate themselves from the dry exterior. Some species, such as those in the genus Sonorella, can remain in this dormant state for years between rainfall events.3

By lowering their metabolic rate and sealing their shells, desert snails successfully bridge the gap between periods of moisture, ensuring their survival in an ecosystem defined by water scarcity.23