Cirripedia - Arthropod


attach to rocks, grasses, shells of crabs, clams, mussels, marine turtles, fins or other body parts of whales, floating timber, buoys, piers, even the bottom of boats some in low tide, some in the spray zone

Usually live crowded together


Barnacles = filter feeders, their legs stick out like tentacles from an opening at the top of their shell, at their tips are cirris (feathery appendages that sweep plankton and other food into their mouth, slides 2 of 6 plates across to let water in (to filter feed) then closes again which prevents barnacle from being exposed to dirty water


whelks, snails, sea stars, cancer crab, sargo fish, owl limpets


Plankton & other small debris like food


Barnacles float through the water until they stick to something suitable & stay there for the rest of their lives

Special Body Adaptations

-attach themselves to animals when young (larvae stage) once effectively glued to something suitable, a thin layer of flesh wraps around the barnacle thus the ot=uter shell is produced


Has both male and female reproductive organs

Usually cross fertilization, but in desperate times they can also self-fertilize

Babies hatch from eggs, secrete glue-like substance & attach themselves to a suitable surface

Special Facts

Because attached to and rarely move from their perch, they've developed a special way to reproduce without a mate


When they close up to feed, they can inhale, but not exhale
By Carly Bell p.1