They may be one of the heartiest intertidal animals that you walk right past – except if you step on them the wrong way. Barnacles are like the armored soldiers of the sea, closing their six trapdoor plates tightly shut against the hot sun and the pounding waves. But, inside there is a tiny creature that is as weird as it is amazing. While barnacles might hurt your feet, their feet are one of the strange things about them. They are the only living part of the barnacle that you are likely to see – and even that is a rarity. Barnacles are arthropods, which means that they have jointed appendages like crabs and lobsters -theirs are just very small. When the conditions are right, they open up and stick out their specialized legs called cirri to catch food. These cirri are covered with tiny hairs that filter plankton out of the water as it flows by. Then, the food-laden legs come back into the buttoned-up volcano and provide nutrition for the barnacle. You can sometimes see this in a tidepool when the water is calm – their feathery whimsical legs waving back and forth as they collect food.

As the temperature cools and many animals go into a period of dormancy or head south for warmer conditions, I always appreciate the ones that stick around. And barnacles really are sticky. While their feet are waving around in the water, their heads are cemented in place. That could be to a rock, a pier, another animal’s shell or maybe even a whale. Because space is hard to come by in the ocean, an animal that can glue itself to anything is a clear winner. Try creating an adhesive that can pretty much stick to any surface and stay stuck when waves pummel it repeatedly. Scientists have tried to replicate barnacle glue and have yet to create anything as good as nature has. There’s a fascinating concept called biomimicry. Nature does this by copying itself – like a viceroy that looks like a poisonous monarch but isn’t actually poisonous. But sometimes humans try to copy nature’s innovation to solve our own conundrums. The book Biomimicry: Innovation Inspired by Nature has multiple examples, many of which are marine species like the barnacle.

Intertidal species face many survival challenges like staying stuck and not being crushed by wave action. Another is to be able to survive long periods between the tides with no moisture. Ever tried to pry open a barnacle? They are sealed up tight. Maybe you’ve tried a mussel, clam or oyster. All of these creatures are nearly impossible to open without a strong tool. This allows them to keep a tiny bit of liquid inside until the tide comes back in again and it is time to feed. It’s also obviously not easy for predators to get to them either.

You might not think that barnacles would be worth eating anyway because they are so tiny. But, in other parts of the world they can grow quite large. Across the Atlantic in Spain and Portugal, for example, gooseneck barnacles are a specialty and can be as long as 8 cm. Once cooked, you grab onto the foot and pull it out of the long “neck”. They’re pretty pricey due to how difficult and dangerous it is to scrape them off the rocks.

Barnacles are one of the oldest creatures on the planet and they haven’t changed much over millions of years. They are the sturdy troopers of many of the world’s oceans including here in Maine – their design helping them to survive some pretty tough conditions like a Maine winter.

However, since they might hurt your bare feet in the summer, perhaps fall and winter are the best times to look for barnacles. You can take a close look at their armored plates and imagine the odd creature within. Look up a picture of what they look like to help you envision what is hiding inside every sharp little volcano. And, when the spring comes, keep an eye on tidepools to see their hairy feet emerge at feeding time.

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