Home » Plants & Animals » Snails and Shells » Mucus trails help snails find their way back home

Mucus trails help snails find their way back home

© Esther Wullschleger

Although they can move over amazingly great distances, snails often have their preferred habitat range. To some extent, they might even be able to orientate themselves within this habitat, knowing where to find food and where to find shelter. Garden snails, for example, use to rest in sheltered places during hot summer days, and at night, they move towards cultivated plants to enjoy their meal. Why not return to the same hiding place proven worthwhile, instead of erring around and die on a 'desert' of a tarred street? Some snails indeed use to go back to the same places where they came from, and probably they use their own mucus trails as an aid in orientation.

'Homing' is even more crucial for survival in limpet snails (Patellidae or Acmaeidae) living on rocky marine shores. Every limpet occupies his very own place on the rock, and while growing up, it adheres so firmly to the ground that its shell adapts to all irregularities in the rock structure. That means, the shell grows so that it completely covers the animal on an uneven piece of rock, and isolates it hermetically from its environment. Not a single drop of water could enter the space between the shell and the rock, and in times of strong wave action or other threats, the animal can keep itself tight to the ground with a sucking force of about 15kg. This hermetic sheltering is particularly important in times of low tide, when the marine shore snails are exposed to intense sun.

But still, limpet snails have to move around from time to time in order to find suitable places to graze for food. They do this at times of high tide when they are submerged, given that the waves are calm enough. Under such calm conditions, each limpet starts to wander around, moving in a small circle up to a distance of about 1 metre. It seems that the snails miss their home place only extremely rarely, although suitable rocks are mostly inhabited by a considerable density of limpet individuals. This is because limpets mark their personal place, as well as their mucus trail around it, with certain chemical substances. These chemical markers are very stable and won't be washed away easily by the sea. Each individual follows only its own trace and tends to avoid the traces of other individuals.

Mucus trail following seems to occur amazingly frequently in snails. However, it does not only seem to be of importance in homing and orientation. By following mucus trails of conspecifics, snails do also find mating partners or, in snail species which tend to live in social aggregations, a group of conspecifics. And, less nicely, some predatory snails also follow the mucus trails of their prey species.

The copyright of the article Mucus trails help snails find their way back home in Snails and Shells is owned by . Permission to republish Mucus trails help snails find their way back home in print or online must be granted by the author in writing.