Connell's famous barnacle experiment was initiated to learn more about competitive exclusion and distribution of branacle species. Barnacle species are distributed in distinct zones on the rocky shores of the Atlantic coast. The Chthamalus in upper intertidal zone; is a smaller species and the semibalanus in low intertidal zone which is a larger species. Chthamalus found in the higher physical stress and higher temperatures because the low tide levels causes them to be exposed to the extreme outside environment for longer periods of time than the semibalanus. Additionally barnacles can only feed while submerged and the higher up shore a barnacle is, the less it can feed and grow. The experiment wanted to understand why they lived this way.