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Home > Research & Collections > News > Oh, Barnacles

Oh, Barnacles

These stationary animals sure get around

Gray whale breaching off the coast of San Diego, CA, boasting more than a few barnacles. Photo by Eric Neitzel.


“Those are barnacles on top,” said Jann Vendetti, Assistant Curator of Malacology. She was pointing to a snail shell covered in shells, rocks, and yes, barnacles. The snail is in the genus Xenophora, and it’s known for attaching objects to its shell as it grows, but it didn’t add the barnacles. Those just happened to land there and grow.

Barnacles belong to the enormous class (or subphylum) of animals called Crustacea, along with crabs, shrimps, and pill bugs, among many others. But unlike these very mobile crustacean cousins, barnacles are sessile — they stay in one place, anchoring themselves to a surface and filter feeding. They also hold a world record: they have the biggest penis-to-body-size ratio of any animal ever. Congratulations to them on that.

There are over 1,200 different species of barnacles, and many specialize in the type of surface they grow on. They pucker the sides of ships, docks, and all sorts of different of animals. Some barnacles don’t bother their animal hosts too much, but many are parasites, harming the animals they grow on. And the barnacles hitchhiking on the Xenophora snails got me thinking — how many collections at the Natural History Museum of Los Angeles County have stowaway barnacles?

I won’t keep you in suspense. To start, we have barnacles in Crustacea and Invertebrate Paleontology, where they most definitely belong. Crustacea has today’s barnacles, and Invertebrate Paleontology has fossil barnacles. But being the opportunists they are, barnacles have also found their way into Malacology, Echinoderms, Mammalogy, and possibly even Herpetology Collections.

See below for an account of the many barnacles scattered through our collections.

small barnacles dot the back of a big crab in a jar
In the Crustacea Collections, we have a crab with barnacles growing on its back, showing that barnacles grow on fellow crustaceans, too.
photo of 4 barnacles in trays. they're about the size of baseballs
Among some of the larger barnacles in our Crustacea Collections, we see a species originally described by famous naturalist Charles Darwin, who was fascinated with these creatures.
a drawer of large barnacles, which looks like big rocks with holes in them
In the Invertebrate Paleontology Collections, we have many examples of ancient (and often very large) barnacles. At times in the past, ocean water had higher concentrations of calcium and carbonate ions (construction materials) as well as elevated planktonic productivity (barnacle food), providing the means for these animals to grow bigger than they do today.
a swirly snail shell, about the size of a human hand, with barnacles growing on it, which look like roses made of stone.
This snail shell in the Malacology Collections is sporting some barnacles, which look a little bit like roses.
a pink barnacle on a sand dollar
In the Echinoderms Collections, this pink barnacle can be found on these delicate sand dollars.
barnacles on whale skin in jars
There are barnacles in our Mammalogy Collections because we often keep samples of whale skin with barnacles growing on it. The jar on the left has whale skin on the top, with a large white barnacle embedded in it, with barnacles growing on top of those barnacles below. It’s a many-layered barnacle party in there. On the right, there is another sample of whale skin with smaller barnacles growing on it. And for further intrigue, in between the barnacles, there are small whale lice, a different crustacean that calls whale skin home. And if you’re wondering whether or not these barnacles cause their host whales any discomfort, at this point we don’t know for sure, but as Mammalogy Collections Manager Jim Dines explains, “It’s possible one of the reasons whales breach and slap down on the water is to itch themselves.”
a photo of a sea turtle with barnacles growing on its neck and back
This sea turtle in Hawaii has many barnacles growing on its head, neck, and shell. Photo by Jöshua Barnett

Herpetology Collections Manager Neftali Camacho and I did a search through our sea turtle specimens in search of wayward barnacles, but we sadly didn’t find any. It’s possible there is one hiding out in our vast Herpetology Collections, though, as they do indeed grow on these marine reptiles, as you can see in the above picture.



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