Hello everyone, thank you for stopping by. Today we’re going to be talking about a fish, well, rather a mollusk- the squid! So, to start with, I’ll remind you of what Blathers has to say about it.
“Well, first off, squids are members of the mollusk family, just like the octopus. Many mollusks like snails and clams have shells, but the squid’s body is almost completely soft. The exception is a long, narrow bit of hard material going through its main body - the last remnant of its shell. Of course, having your shell INSIDE is not a best practice. Perhaps they lost the owner’s manual!”
Allow us to expand upon this particular factoid and discuss the skeleton and beak briefly. The cephalopod- this is the class that contains octopus and squid- beak evolved from their shells, slowly over time, of course, and has a very unique structure. As Blathers told us, the squid is nearly entirely soft, gelatinous tissue, they are able to conform to any number of shapes and squeeze through extremely narrow openings, provided the small rod skeleton and beak fit, contrast them to octopus who have only the beak. The beak is quite similar to that of a parrot in shape and strength, but it’s flexibility depends on what part of the beak we’re speaking off. It’s not entirely rigid, as one might expect, and this allows it to be useful to the squid.
For humans, and indeed all creatures with endoskeletons, that is, those who keep their bones inside, movement is created by muscle pulling against bone, for the most part. There needs to be a rigid anchor to pull against for the movements to work as they do. But for squid, the beak is the only really rigid part, as the skeleton and it are effectively one piece, and in order to wield it effectively, this needs to work a little differently. As the muscles need to move the beak itself, pulling solely against an entirely rigid appendage would be clumsy, thus the tip of the beak is very solid and, indeed, sharp, a precise weapon, but the base has more water, and flexes with the surrounding tissue. The beak is made of chitin, as are many exoskeletons of various types of bugs, and it’s chitin sensitivity which can make a person allergic to dust mites and the like, especially when inhaled.
Pictured is the beak of the giant squid, I’ve chosen the largest sample to show detail. Where the beak contains more chitin, it has darker pigment.
Squid can be a rather sophisticated creature and one that science is still learning some basic principles of. Most squid are pelagic, that is that they live in open water, and all are actively hunting predators. They trap their prey in their arms, then cut them into pieces with their beaks, in order to swallow them. If I may raise a pedantic point, squid generally have eight arms and two tentacles, the difference being that tentacles have suckers only on the end, and arms have them all along them.
To continue to contrast them to octopus, we can see a wonderful example of how biological structure and behavior go together. As I said, most squid are pelagic, but most octopus are benthic, meaning they live closer to the sea floor. A key difference in their anatomy is responsible for this habitat difference. The small skeleton I mentioned previously, also called the pen, allows the squid to swim more effectively as it has more developed muscles. The octopus, while capable of swimming, relies more on crawling about with the arms, thus being more comfortable when it has something to attach to.
Squid are known for spraying ink, which impairs the vision and chemoreceptors of their predators, allowing them to escape. Chemoreceptors allow animals to detect chemical differences in their environment, such as amount of oxygen or pH level. They’re also quite adept at changing color, which allows for a wide array of communication strategies, as well as simply hiding from both predators and prey. As with many animals that change color, they’re quite sensitive to light, and shining a focused beam of light on them can be a way to be able to see the change as it occurs, though it’s important not to distress them when studying this.
While we don’t understand all of their social relationships, we do know that squid have them. They have the most highly developed nervous system of any invertebrate and their brain is a ring of nerves that encircles the esophagus. Their mating tends to involve complex courtship displays involving changing color and positioning, some species lock their beaks together for the dance.
The range of squid size is quite enormous, from less than an inch, to more than 40 feet, with the average being less than two feet. The giant squid has the largest eyes in the animal kingdom, larger than footballs, by some accounts.
One wonders what this might suggest about their souls, having such grand windows… Ah, forgive the romanticized digression.
Giant squid have inspired many great works of mythology and fiction and were known, in some form, from the time of Aristotle, the 4th century, B.C. They spawned myths of the Kraken, Scylla of the Odessey, perhaps the Leviathan as well.
To think we have been aware of such creatures for well over 2,000 years, but we only got to see them living and well in 2004, and that was only a photograph. The first video of them in their natural habitat was captured in 2012. Ancient peoples considered them frightening monsters … I suppose it’s really only that we define monsters as things that aren’t real that means we don’t… But would the giant squid have seemed more or less frightening if they’d gotten to see them? The deep sea contains wonders for sure, captivating and horrifying, and the giant squid is no exception.
Here is a preserved specimen from the Melbourne Aquarium.
Here is one of the first images recorded in 2004, by Kubodera and Mori.
To close, perhaps we’ll take a look at some of the smaller varieties, more similar to what you can catch on your islands, hm?
Here’s a Hawaiian Bobtail squid, which moves by undulating, or moving back and forth, the small fins on the head. This particularly cute image was captured by Chris Frazee and Margaret McFall.
Here’s a Humboldt squid, similar in appearance to ours, and unfortunately known to be rather aggressive to humans, it’s probably best to observe this one from a distance.
Thank you for listening and I hope you stop by again soon!