Are Barnacles Plants or Animals?

The barnacles that you see on the undersides of boats are animals with shells. They are part of the crustacean family, notes the Chesapeake Bay Program's Bay Field Guide.

Identification

• Barnacles are small in size, ranging from less than 1/2 inch to 1 inch in diameter. They come in colors that vary from gray to white, notes the Bay Field Guide.

Features

• Barnacles have six plates of shell, which are flat at the base and have an opening at the top. There are two valves at the top of the barnacle that open and close so that it can feed. Its diet consists primarily of plankton.

Features

• Like other crustaceans, barnacles go through a process known as molting. This involves shedding the shell, or exoskeleton, which grows when a barnacle adds calcium carbonate to its shell plates. Barnacles live in salty and nearly fresh water and attach themselves to rocks, pilings and other hard surfaces.