Consider the normal daily rhythm
Giant African land snails are nocturnal. Check for overnight signs such as food rasping, movement trails, displaced substrate and fresh waste before concluding that the snail has not moved.
A newly arrived snail may also take time to settle after transport. Keep conditions stable, provide food and calcium, and avoid repeatedly waking it to check.
Check the environment with instruments
Read the thermometer and hygrometer, including recent minimum and maximum values. RVC guidance notes that conditions that are too hot, cold or dry can lead to inactivity or dormancy.
Check the substrate by touch, confirm the thermostat is operating and make sure the enclosure has not been moved into sunlight or a draught. Correct problems gradually rather than exposing the snail to sudden heat or heavy soaking.
Recognise dormancy without forcing the snail
A dormant snail may withdraw and form a thin seal across the shell opening. Do not peel the seal away or attempt to force the animal out. First confirm that temperature and humidity are appropriate for the species and that clean water and food are available.
If you cannot identify and correct a husbandry cause, ask an experienced exotics vet for advice.
Look for reasons to seek veterinary help
Deep withdrawal combined with unusual smell, discharge, tissue changes, shell collapse, injury or failure to respond after conditions are corrected is more concerning than ordinary daytime rest.
Keep notes and photographs. An exotics vet will benefit from the species name, temperature and humidity history, foods offered, waste production and any recent changes.
Good to know: Do not use this article to diagnose illness. If you are worried about your snail, contact an exotics veterinary practice.