Most organisms go through many adaptations in order to survive, however, barnacles are thought to have little adaptations since their discovery. (a-z-animals 2008) Three adaptations of the barnacle Cthamalus fragilis include: their glue-like adhesion, their outer protective shell, and their ability to close their valves in order to avoid drying out.

One feature that many barnacles have that is unique to them is the glue-like substance that they create that allows them to attach to hard substrates. Their ability for underwater adhesion gives them a better opportunity to reach food and survive, as well as spread all around. The substance formed by barnacles through cement polymerization is hypothesized to be relatively comparable to blood clotting. This cement like fluid contains many proteins and is produced by special glands. (Multi-Agency Rocky Intertidal Network 20 Oct 2008) This is the fluid that permanently attaches them to ship hulls, animals, and debris. Currently, this substance is of particular interest to scientists and doctors, because there is potential use of this sticky substance for medical reasons. The interactions page explores this glue in further detail.

Originally testing this glue-like substance proved to be more difficult than initially expected. Actually obtaining the material needed to be done carefully. Instead of just cutting dissolving the glue after cutting off the bottom of the barnacle, researchers learned how to collect the glue as it was formed and secreted from the glands. (Bourton J 2009) Upon deconstruction of the glue, it was found that it works similar to the clotting of blood.

Another adaptation found in C. fragilis is their protective shell. Their hard outer layer often times gives the misconception that it is a mollusk, however we know that they are actually under the subphylum crustacea. By combining calcium from the water, and carbon dioxide, barnacles make calcium carbonate carina. This is what protects them from predators and their environment.

Avoiding desiccation is another feature associated with barnacles. Desiccation can be problematic for barnacles. Chthamalus are well adapted to drying out, giving them an advantage to their competitors. Because barnacles are incapable of moving freely and spend most of their life in one location, it is important for them to be able to adapt to a changing environment, especially in the intertidal zone where C. fragilis is found. C. fragilis is able to adjust to the new environment though a patterned behavior. Long periods of exposure to high temperature or air can greatly affect barnacles. Within their respiratory activity, barnacles use atmospheric oxygen to keep up (Barnes, H and Barnes, M 1957). Their ability to close their valves in order to not dry out is an important process that has been demonstrated.

Overall, barnacles have been around for a very long time, and their adaptations to their environments as well as to their predators has given them the ability to stay around and continue to migrate and evolve.


"Competition and Resource Scarcity." Global Change. 02 Nov. 2005. University of Michigan. 20 Oct. 2008>.

Knight, K. 2009. Super sticky barnacle glue cures like blood clots. Journal of Experimental Biology.

Dougherty, W.J. 1990. Barnacle adhesion: reattachment of the adult barnacle chthamalus fragilis Darwin to polystyrene surfaces followed by centrifugational shearing. Journal of Crustacean Biology 10:469-478.

Oceanic Research Group 2013. <URL:>. Accessed 23 March 2014.

A-z-animals 2013. <URL:>. Accessed 23 March 2014 

Bourton, J. 2009. Barnacles’ sticky secret revealed. Earth News Reporter. BBC Earth News Reporting Life on Earth 2013.

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