Cabrillo Marine Aquarium

Whale Barnacle

Cryptolepas rhachianecti


Fun Facts

    Whale barnacles live attached to the skin of whales.

    The whale barnacle uses their feathery feet, called cirri, to both feed and breathe.



  The whale barnacle is a filter-feeding crustacean that lives attached to the bodies of baleen whales, typically gray whales. The body is flattened and causes less drag than their upright rocky intertidal relatives. Whale barnacles feed on plankton. Though often described as parasites, the relationship is an example of obligate commensalism, as the barnacles neither harm, nor benefit, their host. Barnacles are hermaphroditic (they have both female and male sex organs) and the life-cycle is synchronized with the migration of the gray whale. The barnacle reproduces in the winter when the whales are inside the lagoons in Mexico. By reproducing in the enclosed lagoon, the free swimming barnacle larvae have a greater chance of locating a host. If reproduction occurred in the summer while the whales are spread out in the open ocean near Alaska, the larvae would have a harder time finding a host and would likely be eaten by filter feeding organisms.

To learn more about whale barnacles and marine mammals, visit the Whales & Dolphins Room and the Courtyard at the Aquarium.