Investigation into the habituation of snails
Introduction
Snails have eye stalks that once touched are retracted inside. Relative to a snail’s speed when
performing other actions, the retractions of the snail’s eye stalks happen very rapidly. This suggests
that this action is very important to the survival of the snail. I will be testing whether successive
stimuli on the snail’s eye stalks will dull this reaction.
Hypothesis
Successive stimuli on the eye stalks of the snail will increase the retraction as the snail will adapt to
the fact that the stimuli are not threatening.
Variables
Independent – Number of pokes
Dependent – Time taken for stalks to re-emerge
Control – Age and size of snails.
Risk assessment and ethical considerations
Disinfect surfaces after snails have been on them as snails could carry harmful bacteria.
It is more acceptable to perform experiments on invertebrates as they have simpler nervous system
and do not process pain the same way as vertebrates. That being said It is important to still treat the
snails with respect and to prevent unnecessary pain and discomfort. Some may still consider the
experiment to still be unethical as the touching of eye stalks evidently causes some level of
discomfort to the snail.
Method
1. Collect a land snail and place it on a clean firm surface, wait a few minutes for the snail to
emerge from its shell and get used to the environment.
2. Dampen a cotton wool bud with water.
3. Gently touch the snail between the eye stalks with the cotton wool bud and start the
stopwatch recording the amount of time it takes for the stalks to return to its originally
extended position.
4. Repeat step 3 for a total of 10 touches. Recording how long it takes for the stalks to re-
emerge each time.
Results
