Bild på S. balanoides

Builds kilometre long belts

On exposed cliffs and rocks, the barnacle is among the most important organisms that filter plankton out of the water. It is often mussels and barnacles that are the organisms that are mostly seen on wave exposed beaches in temperate areas around the globe. In many places along the northern coasts of the Atlantic and the Pacific, the Northern rock barnacle is found.

Has a long penis to reach its neighbour
who is both male and female


Many organisms in the sea release eggs and sperms into the water and let fertilization take place externally, but for barnacles to reproduce they have to mate with each other. Because they are stationary and attached to the rocks, they have to mate with their closest neighbour. This is accomplished by having a strong and stretchable penis, and that all individuals are hermaphrodites, that is, they are both male and female at the same time.
    Barnacles seldom fertilize themselves, because their offspring would not recieve a combinations of new genes. Because all sexually mature neighbours have both eggs and sperm, the chances of successful mating increases amongst the neighbours it can reach with its penis.
    The picture above depicts mating northern rock barnacles.

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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