Squid Empire - The Rise and Fall of the Cephalopods

[cranefly]

Squid Empire - The Rise and Fall of the Cephalopods (2017) by Danna Staaf

A wonderful book on the evolution of cephalopods, from their lowly beginnings on the sea bottom living within shells, to buoyancy tactics to rise up into a whole new realm, to transformations into shell-less forms, most notably squid and octopus, to improve their maneuverability and make them less visible to the echo-location whales.

Along the way there's all kinds of facts.  The giant squid was long known about from dead carcasses washed up on shore.  But it wasn't until 2004 that it was filmed alive in its natural deep habitat.  Many people think it is extremely rare.  In fact, there has never been a sperm whale cut open that doesn't contain lots of giant squid beaks.  While the beaks of squid we eat in a restaurant are pea-sized, these are the size of a hand.

Marine biologists believe that sperm whales eat 3.6 million giant squid every day.  That puts their numbers beyond comprehension.  The ocean deep is indeed a tentacled realm.

Lots of other remarkable facts.  Highly recommended.

[Drunk Monk]

Is the squid intelligent?  I stopped eating octopus because it's obviously a sentient being but I don't consider squid that sentient.  I mean there's the anemone, then the hydra, and then it breaks off the reef and becomes the squid, right?  It's really just a swimming plant, right?  

Say it's not sentient because I don't want to give up calamari.

[cranefly]

Well, the squid hasn't proven itself to be as ornery smart as an octopus.  On the other hand, squid are very gregarious animals (unlike solidary octopuses) and their social intelligence appears to be high.  They have very sophisticated ways of communicating with each other.

For instance, a bunch of squid can camouflage themselves and maintain that camouflage while communicating with each other with pulses of polarized light -- which they can see but predators and prey can't.  Oh, and they manage their camouflage (every part of their body is capable of multiple color changes per second, enabling swift and high-res patterns) despite being color blind.

They also adjust their buoyancy by changing the salt water in their bodies from a sodium chloride base to an ammonium chloride base, which is lighter than salt water, making it easier for them to rise up for night feeding.

Still, I think it's fine to think of squids as fully tricked-out lamborghinis driven by some dumb scrap of kelp.

P.S. Squid have the barest remnant of their ancestral shell inside their elongated mantel.  It's like a sliver of flexible cartilage, called a pen, which is used for muscle attachment -- and squid are pretty much all muscle.  In fact, squid are like protein bars for predators, which is why they are highly sought after by whales, sharks, seals, etc.

Anyway, the scientific name for this pen is gladius (meaning swordlike, which is its shape).  [Gladiator has the same root.]  So every time you eat a squid, you're eating a sword.  Which begs the question: How could you possibly give up something like that?

.

[Drunk Monk]

This isn’t going the direction of some sword swallowing hentai, is it? Cuz I don’t eat that cuttlebone - those are fed to budgies, I think.

[cranefly]

This isn’t going the direction of some sword swallowing hentai, is it? Cuz I don’t eat that cuttlebone - those are fed to budgies, I think.

Cuttlefish have cuttlebones, squid have pens.  But you're right, and I'm wrong.  Whichever you eat, the cuttlebone/pen has been removed during preparation.

Cuttlebones are what you see in bird cages.  They are  porous and fragile, easy for birds to pick apart for the calcium.  In fact, cuttlefish can't go very deep or their cuttlebones will implode.

Squid have no such problem and are the rulers of the deep.

As for octopus, their intelligence is overrated.  This came about from tall tales told about Fred Astaire and his pet octopus named Popeye.  Rumors spread that Popeye was actually composing all the dance routines and even stepping in as Astaire's dance partner during practice.  But that's a bunch of hogwash.  Amazing what some people will believe.  The most that Popeye ever did was to crawl out of his tank when Astaire wasn't around and paint the bottoms of his tap-dance shoes a fluorescent orange.  Astaire wouldn't notice this right away, such that directors were always shouting, "Cut!" and pulling at their hair, pleading with Astaire to get rid of that damned octopus.  Not that he ever did.

The point being, I hardly think this bit of sophomoric humor serves as evidence for true sentience.

[Drunk Monk]

The point being, I hardly think this bit of sophomoric humor serves as evidence for true sentience.

I first read that as 'sentence' instead of 'sentience'.  I was going to retort 'sentence schmentence' and just post some gifs.  Doesn't work as well with sentience but I'm still posting those gifs.

[King Bob]

Don't forget the related Ammonites, who pretty much ruled the seas for millions of years, although most died out during the Permian extinction. (I may have the wrong extinction event there.) Many nice fossils of them, particularly the pyritized specimens.