Life on the Mid Shore

The easy life

Life in the middle of the shore is considerably easier than it is for those living higher up, though it is still a harsh environment for marine creatures, with regular and prolonged periods of exposure to air.

Coping with extreme conditions

Animals have developed many ways of coping with the extreme conditions encountered during the low water period - from the risk of drying out and overheating during the summer to the possibility of freezing during a hard winter. The methods of overcoming these problems vary, but generally fall into one of two categories:

Shut up tight and sit it out
Take refuge somewhere cool and damp

Limpets & Barnacles

The best examples of the more stoic approach are limpets and barnacles - two very different animals that look superficially alike because of their similar approach to solving the problems of prolonged exposure to air.

The limpet's attachment seems permanent but when covered by the sea, or on a cool, damp night, the grip is relaxed and the limpet crawls over the rock surface, grazing as it goes on an almost microscopic layer of algae covering the rocks.

Scratch marks left by the limpet's file-tongue can be clearly seen on the rock surface, betraying its extensive feeding range. Before the returning tide covers it, the limpet is able to find its way "home" - the one spot where its shell perfectly fits the underlying rock, thereby reducing the risk of it drying out on a hot day or being dislodged. Frequently scars can be seen on the rocks marking the position of old limpet "homes".

Limpets