When the larva has decided where it will dwell, it attaches itself to the rock with the help of a glue like substance from its entenn glands, throws off its larva shell, twists itself into place so its feet point outwards from the rock and starts building a new shell. The shell plates are seperated by living tissue so that growth is accomplished along these seams. For the cirria and the rest of the body to be to grow, the barnacles must be able to change parts of their exterior that is not composed of shell plates, which under ideal circumstances, can be as many as 15 times a year. It is not uncommon to see large amounts of "barnacle-skin" floating in the water during the summer. It is not uncommon for the Northern rock barnacle to be as old as 3 years.

Three generations of barnacles. The smallest individuals attach themselves to the rocks during the spring. On the older individuals, the years growth can be seen as new white shells.

Kicks in its food