|Image: Mal B via Flickr|
|Image: Nick Hobgood via Flickr|
The biggest species of all is Tridacna gigas, one of which was recorded at 1.37 metres (4.5 ft) across. Its shell weighed in at 230 kilograms (510 lb), suggesting a live weight of about 250 kilograms (550 lb).
Another one was even heavier. Despite being a mere 1.15 metres (3.8 ft) across, the live weight was estimated at 340 kilograms (750 lb)!
I think they call it "heavy kissing".
Like most other bivalves, the Giant Clam is a filter feeder. They open up their huge, calcium carbonate shell to expose the beautifully coloured mantle within.
|Image: Boogies with Fish via Flickr|
Inhalant siphon open wide enough to see the gills within.
This is Tridacna maxima, the "Large Giant Clam". Which is hilarious.
Exhalent siphon of Tridacna squamosa, the Fluted Giant Clam
Giant Clams have to keep their shell open for another reason: there's the garden to think about! Dotted around the mantle are clear windows that allow sunlight to get through. This isn't for their own immediate benefit; they're not trying to warm the cockles of their heart. It's actually for the huge amount of single-celled algae that live in their tissue.
|Image: richard ling via Flickr|
Symbiotic algae provide yet more colour to their cheeks
|Image: Phil Camill via Flickr|
But just imagine if cows had a special bit of intestine where they could grow their own grass. All that manure could be stored in there and used as plant fertilizer! Isn't that fantastic? Shouldn't we all stop using the bathroom and instead grow tiny apple trees in transparent segments of our large intestine? Is this not our inevitable future? I wonder if we could have tiny cows in there, too?
|Image: richard ling via Flickr|
It's true that Giant Clams can shut their shell pretty well, but they can't do it quickly. Someone would have to be an utter buffoon to sit there as a Giant Clam slowly closed its giant shell over an arm or leg. That'd be like spending tens of millions of dollars on an incredibly ugly pearl.
Biggest pearl in the world, mind.
Big enough and ugly enough
to take care of itself
And, since clams don't use mother of pearl (more like one of the three ugly sisters of pearl), it lacks the shiny iridescence we expect from pearls and ridiculously expensive things in general.
This pearl is almost like one of those diamonds you get in murder mysteries. The ones with 2,000 years of murder and bloodshed, going from king to queen to the stomach of a goose to yet another king. You know the story.
Unfortunately it appears that most of the stories surrounding this pearl are a fiction concocted to increase its perceived value. Including the one where Osama bin Laden was going to buy it for Saddam Hussein.
Probably for the best; it would've been a bit much for a first date.
|Image: brian.gratwicke via Flickr|
Clearly a big decision, so these youngsters may spend weeks going from place to place until they make up their mind. They'll start capturing the symbiotic algae at this point too, providing them with a comfortable bed and breakfast
This all occurs after broadcast spawning. That exhalent siphon is used to cast eggs and sperm into the sea and what will be, will be. They may look like a huge pair of puckered lips, but that doesn't mean they'll get up off the floor for a kiss. They're far too comfortable for that kind of effort.