Small Shelly Fauna

Speaking in Tongues

A couple entries ago, I made mention of the candiru, Vandellia cirrhosa, one of my all-time favorite parasites. Pretty close to it on the list of “things too cool and horrifying to possibly be real” is the parasitic isopod Cymothoa exigua. This small crustacean feeds on the tongue of the rose snapper, Lutjanus guttatus. It sucks the tongue down until it is a bloody nub, rendering the fish tongueless. So far, this is not particularly out of the ordinary for a pernicious parasite. What makes Cymothoa incredible, however, is that once the tongue is eaten off, it just hunkers down, clamps onto the tongue-stump, and takes over the job of “tongue” for the fish. (See the central picture on the Tree of Life's Isopoda page or this lateral view of the infection.) The fish, long ago having dulled to the sensation of having its tongue gradually chewed off, is no doubt oblivious to its lingual functions having been taken over by some chitinous interloper. And so it lives on, doing fishy masticatory things as per usual, except for the fact that its tongue is a now a living, breathing separate organism. I have long pondered this creature and got to thinking about my own tongue. Could it, perhaps, be something equally alien to me as the isopod to its host? Years of tooth-brushery have left me knowing my tongue pretty well. It seems to respond to my nervous command, it moves where I want it to move, it helps me process food, and I feel pain when it is injured. Yet lingering doubts concerning its organismal autonomy remain. My own tongue, or my original tongue, at least, is (was?) connected to the base of my mouth by a series of connective tissues and nerves, the latter forms being various ramifications of the glossopharyngeal persuasion. Were I to have lost my tongue, the impotent terminals of these nerves would doubtless still fire when I have “move tongue” thoughts. Is it too incredible to imagine, then, that perhaps this saliva-clad doppelganger that styles itself as my tongue can sense the nervous pulses coming up from its feeding-stump and move accordingly? Like Cymothoa, doing what I physically need the tongue to do? But then there’s the matter of the pain when I hurt my “tongue.” If it were an independent creature, I should feel nothing when it is injured. But it is in the best interests of the tongue-beast, as in all beasts, to not be injured at all. To prevent such activities, it would surely take instructive action against the source of its own pain (invariably myself, with my careless bicuspids). The point would be clear: if I do not want a hurtful stimulus applied to my lingual nerve-endings by some unfathomable proboscis, I would do well to take care of what I believe to be my tongue. My last hope against my internal logical barrage against the long-held orthodoxy that my tongue is my own is the fact that a whole sense, taste, emanates from this organ. Capable as it is of stimulating, with frightening believability, the nerve endings in my mouth, certainly the tongue-beast would not be capable of registering the vast array of flavors that a gourmand such as myself has sampled over the years. Even this hope is easily compromised, unfortunately. Taste and smell are such closely linked senses, after all. The broad spectrum of sabor (ranging in volume from mere microliters to the full dos litros) could perhaps be the result of neurological intermingling between my own nasal apparatus and the hateful chemoreceptors of the beast. Only a fool would think that such a diabolical parasite as the human tongue-beast would not have been crafted by natural selection to maximize its own gain. Parasites routinely change the behavior of their host to suit their own ends (most terrifyingly in the rhizocephalan barnacles, which transform their crab hosts into zombified slaves, devoted only to the proper care of barnacle larvae). I guess what I’m try to say here is that of course the tongue-beast would have some sort of taste control, in order to ensure that I eat the foods that best serve the tongue-beast! Don’t you see? Why do I cherish the flavor of foods that I know are bad for me? The beast commands me! It demands nourishing sucrose flowing through the tongue-stump, and high fat food-particles collecting at dental bases that it can collect while I sleep! It needs these if it hopes to foster a brood of little tonguelings of its own. As a final horrific view into the world of the tongue-beast, have you ever really looked at your so-called taste buds? I mean, really looked at them? Don’t they remind you of…eyelids? Of course, the beast would never give itself away by flashing its peepers to you when you’re watching. I’m sure it’s extremely photosensitive, and only opens them when it’s dark. One might question the utility of optical receptors inside someone’s mouth, and here I have no biological explanation other than to say that it might be a vestige of some kind, and that plenty of parasites (Cymothoa among them) bear seemingly useless eyes. But I just know that they’re there, and it fills me with revulsion. Sometimes, late at night, when my breathing has slowed and I am near sleep, I will creep as if somnambulistic to the mirror and flash the lights as I open my mouth, hoping to catch the innumerable turquoise, scallop-like eyes of the beast peering back at me. Just like when you catch the split-second pupil dilation during a major change of light intensity. Of course, I have never been successful in catching the beast. But I know that right now, it is inspecting the edges of my gumline, perhaps searching for a place to begin hoarding its eggs. I’m not quite sure how it breeds, and perhaps, like tapeworms, it simply flushes them through the digestive tract. I sense that, drawn like all of us by a basic biological imperative, it longs to perpetuate its hated race across sentient mouths of the world. At times I consider what to do about it. Although cutting it out would doubtless be effective in terminating it, I am far too fond of its simulated benefits of taste and speech to risk such a procedure. After all, my original tongue would never grow back, even if the beast was exterminated. I can only go on living in symbiosis with it…and every so often checking in the mirror late at night. One of these days I will catch it.