If it’s ever discovered that barnacles have language, I suspect the first words we’ll hear will be, “woo hoo!!” and they will be squealed by a “manatee barnacle,” one of that special brotherhood of barnacles that arrive in Crystal River every autumn clinging to the backs of returning manatees. These are not a unique species, just ordinary barnacles in extraordinary circumstances. They are the lucky few whom fate delivered onto the back of a resting manatee at the most critical moment of their life.
Barnacles enter the world as one-eyed, six-legged, spiny-tailed, larvae called nauplius. Life for nauplius is that of care-free and unattached plankton, a not-so-exclusive category of aquatic organisms whose only defining trait is that they have little control of their own movements. Their lives are led at the pleasure of the ocean’s currents; they go with the flow, sipping fine brine and feasting on the endless supply of even smaller plankton. Theirs is the implied promise of all plankton—a life of freedom. It’s right there in the name, plankton, which comes from a Greek word for “wanderer.”
But, even the best laid plans of barnacles go often askew. A half year into its life’s journey, things begin to change for the carefree nauplii. Joints stiffen and it begins to morph into a creature that looks surprisingly like a tiny mollusk (surprising, because barnacles are not mollusks, they are crustaceans). In this new “cyprid” stage of life, the would-be barnacle foregoes feeding as it noses around looking for a suitable place to call home. It’s not choosey; oyster shells, clams, driftwood, human garbage, any solid object with enough space to do a head-stand will do. Once a place is found, the cyprid rolls over and cements its head to the surface with a dollop of brown goo exuded from its neck. This glue is powerful stuff. Dentists study it with a mind toward attaching dentures to the more storied regions of their patient’s smiles. In a strange twist, this glue which nature concocted to bind barnacles permanently in place is used by humans for added freedom—freedom to gnaw an ear of corn, freedom to smirk at less clever creatures. Having secured a home site, the barnacle encases itself in hard, calcareous shell plates. The “wanderer” has become the ultimate home-body. The only thing missing is a family.
Success, as barnacles calculate it, consists of just two things; finding a good home-site where the plankton flows like wine, and at least one barnacle neighbor with whom it can occasionally have sex. But, there’s a problem—they’re barnacles. As you can imagine, being glued to the floor by their head and being encased in a hard shell presents a challenge to the horn-fraught barnacle. But, as their half-billion year ancestry would imply, they have worked this problem out admirably.
As with many immobile sea creatures, barnacles are hermaphrodites. Each individual has both ovaries and a penis (the latter deserving honorable mention as being proportionally largest in the animal kingdom—nearly 10 times the animal’s body length). Generally speaking, barnacles spend most of their time in male mode, eating, resting and occasionally probing around with their penis for a receptive neighbor. But, once in a while, they are surprised to find themselves on the receiving end of a neighbor’s penis. Voila, they are a female—and pregnant. (this is where we might hear the second utterance—shriek?—heard from a barnacle).
For most barnacles, life is fairly predictable. But for some, opportunity knocks when they are in the critical final moments of their cyprid stage. For them, good timing, favorable currents and dumb luck come together perfectly to deliver them onto the back of a mobile sea creature such as a sea turtle, a whale or a resting manatee. It’s a life-defining moment. For the first time in its life, and probably the last, it owns its fate. In this singular instant, the soon-to-be barnacle will make the only consequential decision of its life. It has two simple choices, hesitate or roll over and attach that head…and be quick about it! One gust of water current; one shutter of the whale’s skin; one sudden notion in the mind of a manatee to move to a nearby clump of eelgrass, and all hope for becoming a true “wanderer” is gone. For the lucky few that hit their mark, it’s off to the adventurous life of a manatee barnacle.
Manatee barnacles must surely be the outlaw bikers of barnacle society when they glide into Crystal River in the autumn, riding their “hogs” with their long cirri blowing in the currents. And, while they aren’t so much riding as clinging for dear life, they do go fast. When their hog is sufficiently motivated, a manatee barnacle might top 20 mph—an unimaginable speed for the posers attached to the bridge pilings that pretend they are going fast in the rushing tidal currents. Manatee barnacles are the real deal; the 1%ers.
But the free-wheeling lifestyle comes with a price. Persistent gnawing of buck-toothed sheepshead fish and the constant sloughing of dead skin from the manatee’s thick hide take a toll on manatee barnacles. Their motto should be live fast and die young. For the next few weeks—months if they’re lucky—they’ll cruise the coves and eelgrass meadows of King’s Bay, flaunting the rules of civilized barnacle society. But by the spring warm-up, most will be dead.
Crystal River, 11/22/11: A marine biologist leans toward the reciever, closes his eyes tight and listens. He has been using this equipment for several years studying manatee vocalizations and knows most of the aquatic sounds that hum King’s Bay; but not this one. His brow furrows as he strains to hear the faint, unidentified squealing. He’s only heard it a few times before, and always when the manatees are arriving from their summer feeding grounds. He makes a puzzled notation in his field journal, “sound appears to be coming from the vicinity of some barnacles on the manatees back and sounds like....woo hoo ???”