Animalia Stupendium: The Giant Clam

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Speaker 1: Welcome to Stuff to blow your mind, a production of iHeartRadio.

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Speaker 2: Welcome to Animalia Stupendium. My name is Argomandanes, former keeper of the Cauldron, current Quester of the Cauldron. I seem to have lost it and tireless creature chronicler, and as you know, mere monsters hold no mystery for me these days. Dracolitches, I'm sorry to say, are no longer dracolicious. Bore worms sadly live up to their name, but not in the way they should. So instead I turn my attention once more to the strange fauna of a land called Earth. Travel with me, gentle reader, as we consider.

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Speaker 3: The giant clam common name giant plan scientific classic occasion Tridacna geigis frequency and range. Coral reefs of the South Pacific and Indian Oceans size up to five hundred and fifty pounds or two hundred and fifty kilograms, diet filter feeding omnivores with symbiosis, treasure hoard Tridacna pearls challenge rating two.

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Speaker 4: Here in my home, realm giants are a diamond dozen, as are the gaping mass of underwater creatures. So, my fellow wizards and witches might think me quite mad for my latest terrestrial obsession. For the waters of Earth, particularly the shallow coral reefs of the South Pacific and Indian oceans, offer up a creature that is significantly smaller than a hill giant and completely incapable of swallowing a man whole. Ah, But that last fact has long eluded the people of Earth. Many are their tails of human divers whose arms become trapped in the rapidly closing shells of a giant clam, or of those jar like shells closing up over their entire bodies, swallowing them whole. Certainly, things of this nature occur every day in my own realm of the fantastic, but not so in the waters of Earth. For assuredly, while various folk traditions, tall tales, and Hollywood movies warness of such killer clams and man eating clams, there is no verified account of a giant clam ever, claiming a human life wisdom check success. For while various accounts speak of their shells closing on the human arm that reaches into steel their pearl, the fact of the matter is that a giant clam simply does not close its shell with enough speed to catch. Certainly, smaller clams may snap their shells closed with haste, but for Tridacna geigis, it's just too much mass to move in too short a time, and adults cannot even close their shells completely. Yet the stories persist, perhaps in large part because the clam shells a pair of calcareous shells or valves joined near a hinge with a flexible ligament simply remind us so much of a mouth, something these organisms don't exactly have. Instead, they have a pair of siphons, one for drawing in water and food, another for expelling waste. Furthermore, they are filter feeders and have no need for any jar like mechanics. They simply close or in this place nearly close their shells for protection. But alas perhaps human beings are just hardwired to see a gaping mar that might bite or swallow them. It is a matter of survival even when the threat does not actually exist. Oh and on the subject of their treasure, Yes, Tridacna pearls, they do in fact produce these. Like all pearls, they are products of abnormal growth, generally due to an infection, and as they can grow to quite large size, they can prove quite valuable, but only to humans, of course. The giant clam, however, is more than worthy of our attention, though regardless of its pearls or whatever tall tales may circulate about its purported bite. Again, it is nothing short of the largest bivalve mollusk in the ocean, and the tissue within their shells often takes on rather colorful hues blues, greens, and yellows that may seem to hypnotize the humble snorkeler and bring to mind fabrics of earthly wealth or other worldly splendor. The varied colorization of these mantle tissues is, of course, not a magical affair, but rather iriticide cells. It feed light to symbiotic single celled dinoflagellate algae or zoazanvella, and it acquires the sohasanthella via its constant filter feeding in the water, along with plectonic organisms that it actually eats. Thus, during the day, the clam opens wide and extends its mantle tissue to absorb the sunlight necessary for the algae to conduct photosynthesis. In return, the algae produced sugars and proteins that the clam needs to survive, along with its more traditional filtered diet, which it requires less of. Speaking of light, the giant clam also boasts thousands of pinhole eye spots along the mantle's head that allows it to detect changes in light, not only the cycles of night and day, but the tail tale shadows of approaching predators, of which it has many, and thus it may close or nearly close its shell, though again not with enough speed to capture a human being or a human limb. While Tradacna geigis is the largest, there are other species of giant clams as well, in the Tradacna genus, which stems from the Latin for three bites. Going back to the writings of Pliny the Elder and even the conquest of Alexander the Great, it was said that these clams supplied such meat as to require not one, not two, but three bites to consume. And humans certainly consume them, not merely for their meat, but also for their pearls and their enormous shells, and I've done so with enough gusto to make the organism critically endangered. This is, of course a threat not only to the giant clams, but to the robust and delicate coral reef environments, where they serve as reef builders, water filters, and ultimately sources of both food and shelter for other life forms in the reef. There are more mysteries concerning the giant clam to consider, but for now I must retire my wizard's quill and allow my familiars some respite. But I shall return with even more wonders of the natural world.

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Speaker 3: Hi, this is Robert Lamb. Thanks once more to the Wizard Argomnnines for joining us in this episode. Sources for this episode included The Secret Life of Clams by Anthony D. Fredericks twenty fourteen, the websites of the University of kane Bridge Museum of Zoology as well as the Florida Museum, and the writings of Plenty the Elder the Natural History and I'd also like to thank the guides and hosts at Missoul Resort in raja Ampat, Indonesia who introduced me to giant clams in the wild, including the specimen known informally there as Wu Tang clam. Thanks as always to the excellent JJ Possway for producing this episode. If you wish to contact Argomdines with recommendations for future episodes. You can send an email to contact at stuff to Blow your Mind dot com.

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Speaker 1: Stuff to Blow Your Mind is production of iHeartRadio. For more podcasts from my heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.