Aesop never penned a fable about a snail. If he had written about a certain freshwater mollusk, the moral might have been Boldness comes from a strong shell or maybe Careless snails get chomped. But because the snail and its variable shell are real, their lesson has more to do with the the weird workings of evolution.
Individual Radix balthica snails can have differently shaped shells. They also have varying “personalities,” at least as far as you can measure such a thing in a mollusk. To