When the temperature drops in autumn, a wild garden snail will enter a state of dormancy to protect itself. Cornu aspersum can survive the cold but a hard frost will kill it by forming ice crystals in its soft inner tissues. The wily snail will therefore seek out sheltered places, huddle together with other snails to prevent water loss and/or burrow into the soil. Much as it does in aestivation (the summer procedure) it forms a membrane of dried mucus, often hardened with calcium, to seal off its shell - apart from tiny pores to allow it to breathe. It might hang upside down to keep the rain out of its shell.
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I must confess that I am guessing that this is the epiphragm. |
During this period it will live off energy stored in its hepatopancreas or digestive gland and its metabolism slows down. Its heart rate and oxygen use fall dramatically. In the Spring, when temperatures and moisture levels rise, the snail breaks through its own epiphragm and may even eat the seal for the calcium it contains.
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We are both pleased to greet each other in the Spring. |
From then on, we have our usual lovable mollusc, either as a pet or in the wild, happily rasping at our young lettuces.