Bild på S. balanoides

Can holds its breath for a long time

It is tough sitting high up above the waterline. The Northern rock barnacle, that often sits high up on the beach and unable to move, must find other ways to survive hardships, e.g. heat, cold, variatians in salinity and drought. The barnacle must also have the ability to breath in air, but at the same time keep its shell closed to prevent evaporation and dehydration, which is accomplished by occasionally by opening its shell and changing air. If too much water evaporates, the salt content within the barnacle can increase and have a negative effect. The cold also has the same effect: when the water around the tissues freezes, salt content will also increase in the unfrozen water.
    Because of the barnacles protective calcareous shell and tight skin, they are able to survive out of the water at least a couple of weeks - even when it is warm and dry during the summer. When conditions became critical, the barnacle goes over to an anerobic way of life, meaning that it can keep its shell closed tightly all the time and can survive without oxygen.
    It is not only high salt concentrations that cause problems for the Northern rock barnacle, even brackish water effects the barnacle negatively. Even then the barnacle closes its shell and goes over to an anerobic life style when it rains at low water.

Ice and the dogwhelk kill

The dogwhelk can be quite common in certain areas, where it kills and eats barnacles. To assault the barnacle, the dogwhelk has to wait patiently until the barnacle has opened its shell. At that time the dogwhelk inserts its rasp furnished trunk and scapes up the softer parts of the barnacle. Occasionally, the dogwhelk uses this trunk to bore a hole through the barnacles shell.

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Kicks in its food

White belts

Long penis

Dwelling place

Can hold its breath

The dogwhelk kills


Other specie

Northern rock barnacle    More facts     Other names
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Bo Johannesson | Martin Larsvik | Lars-Ove Loo | Helena Samuelsson