When we look at a gorgeous beach strewn with beautiful sea shells, like West Gulf Drive on Sanibel Island, on the Gulf of Mexico, it is a soothing sight of great beauty to us humans. It seems peaceful and lovely, clean and fresh.
However... all those lovely mollusk shells are telling a different story if you look a little more closely, and think a little more deeply.
Every empty mollusk shell represents a death. Here are untold millions of deaths. Vast infant mortality. Countless juveniles that never made it to adulthood. Countless young adults that never had the chance to live a long life.
Yes, a few of these external skeletons represent snails or clams that made it to adulthood, reproduced, and presumably died peacefully of old age in their sandy bed.
But SO MANY of the snails and clams died what we would consider to be horrible deaths at the "hands" of predators.
So many clams were drilled by moon snails or murex predators! So many clams were crunched into pieces by sting rays!
So many gastropods, seemingly secure in their strong shells with apertures guarded by a strong operculum, had their castle systematically ripped open by a box crab or torn to pieces by who knows what skillful and ruthless predator!
Of course I am not trying to suggest that the clam or snail suffered agonies of anxiety as the end approached and it felt its defenses being breached for the final time.
And it is true that many gastropods shells show successful repairs after predation attempts that did not prove fatal.
It's not all death and destruction.
Or is it?
A shell pile from the distance. All of the whitish deposits are shells.
Some of the drift at Blind Pass, Captiva side.
Hand-picked very small shells from the drift line at Blind Pass, Turner Beach, Captiva.
The round white bivalve near the middle is about 12 mm in diameter.
Here is an overview of some of the tremendous predation efforts that take place here below the waves.
The shells of these species are strong and not at all easy to break!
If I had to break a whole one of any of these, I would need a hammer -- they are too strong to crush underfoot, even with hard shoes on!
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This way of thinking as a kid was what let me rationalize collecting and displaying bones and skulls as a kid. If sea shells, "gastropod bones", can be kept and displayed for their beauty, why not skulls? At least most of those dead critters meant life for another, likely one of those numerous fighting conchs.
Ahhh... sounds like you're having a blast! All this death and destruction sure is fun to look at. ;)
@gcwarbler visited Sanibel recently and documented some really cool shells there. With your added observations, Susan, I'm dying to go! :)
I went there as a kid in the mid 80s and it was like a dream to a kid that had never before seen so many beautiful shells; especially all the tiny ones! I later learned that we had been there after a big storm, but those beaches are still etched into my memories. Returning about 15 years later, there were many fewer shells and everything seemed much more 'touristy', but perhaps that because all I cared about on the first trip was collecting all the shells I could! :-)
@mrfish33 -- I agree with you that bones and skulls are as lovely as shells of mollusks, although people have a different set of associations with those objects! And the colors of internal skeletons are usually not as spectacular as the colors and patterns of external skeletons.
I guess I should explain that fighting conchs are vegetarians, despite their pugilistic common name. None of the true conchs (family Strombidae) are predatory.
@sambiology -- it is glorious here, although it is expensive to stay on the island, and expensive to park here and there are only a few beaches that have public parking (at $4 an hour!) and you are not allowed to park anywhere else other than those few public beaches.
@beschwar -- I expect there were quite a lot more cool shells on the beaches back in the mid 80s, because there were FAR fewer shellers here back then. But the key thing, as you said yourself is: "after a big storm". :)
It is amazing how many shellers are out on the beaches searching -- day or night. That is true even now when it is low season still and we are staying at the quiet end of the island. I can't imagine what high season is like.
I shoulda though that through, musta been whelk or moon snails. Moon snails, now they are predators!
Yes one of the main predators of mollusks here that are also mollusks are indeed the moon snails (I call them the tigers of the sand flats) and the murex species, as well as the Florida Horse Conch, the Tulip Snails and the big Whelks.
But the crabs and sting rays are everywhere too. I wish I knew what other animals are strong enough and skilled enough to break into a thick, well-defended shell.
On minus tides I understand that raccoons go down on the beach and eat mollusks. And gulls will eat clams if they can drop them on a hard surface to break them open.
I remember a friend of mine saw pigs in the Philippines go down the beach at low tide and root up some clams and eat them -- pigs are smart!
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