Barnacles: living on a whale

Photo credit: Jim Scarff

Photo credit: Jim Scarff

Barnacles seem to have quite the life indeed. These crustaceans represent a diverse group that includes more than 1,000 species.

Some of these barnacles have adapted to living on marine mammals and tend to hang out on some of the baleen whales. My guess is that it’s easier to live and stay attached to a good sized whale moving steadily along like a large RV, compared to a dolphin, which would be like living on a roller coaster.

The lifestyle of a barnacle is pretty interesting. For starters, they are hermaphrodites, meaning each barnacle is decked out with both male and female reproductive set-ups allowing them to take care of their own business so to speak.

According to the Encyclopedia of Marine Mammals, “The barnacle’s life cycle usually includes six free-swimming plankton naupliar stages that feed while progressing by molts to the cypris or cyprid stage, which searches for a place to settle.” Cyprid is just an alien worthy name given to the last stage of larval development before a barnacle turns into a tiny shrimp-like creature.

While the barnacle is still in the cyprid stage, it “secretes cement from its antennules, from glands located in their base, and metamorphoses by molting into a juvenile, which begins to secrete adult cement and the calcareous plates that usually constitute its home.” So cool, this tiny ocean critter secretes cement to build it’s own home!

As adults, barnacles build their cement homes on various platforms in the ocean greedily straining plankton from passing water with “six pairs of feathery thoracic limbs.” These tiny limbs stick out from built in rooftop holes made for this exact purpose. And this is how they are able to survive by living on a marine mammal, the whale swims along while the barnacles snatch passing bits of food along the way.

Barnacles are not considered harmful to whales or other marine mammals, but are considered semiparisitic because they can cause drag, skin irritations and must be annoying. It’s definitely annoying on principle, having someone hitch a ride to your body without any benefits, not cool.

But without fingers to pick the barnacles off, the whales seem to have no choice and so the barnacles ride along in their finely constructed cement houses.

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