Goose barnacles are marine crustaceans but, unlike many other members of their class, they are hermaphrodites, meaning that the animal has both male and female sexual organs. Fertilization is internal and the young are brooded in the mantle cavity before they are released. Their eggs hatch into free-swimming larvae, which drift with the ocean currents as one of the immense number of animals that comprise zooplankton. As they develop, the larvae attach themselves to an object by way of a strong stalk or 'peduncle'.

Average gestation period: 1 weeks.