There’s a recent AP article Squid beaks may have medical application that sounds like a non-discovery.
“…That deadly beak may be a surprise to many people, and has long posed a puzzle for scientists. They wonder how a creature without any bones can operate it without hurting itself…
The beak, made of hard chitin and other materials, changes density gradually from the hard tip to a softer, more flexible base where it attaches to the muscle around the squid’s mouth, the researchers found.”
Ok, having cut open squid only a few times to prepare calamari, I knew without any research just where the beak connected, and that it was not about to cut the animal itself.
And, it’s not that rare a trick. Most chicken bones have both hard parts and softer parts where things attach.
So was there any real discovery, or just a writer that was amazed at ordinary information?
Here’s the original article, but you can’t have access to more than just the synopsis without a subscription.
I’m with you: I don’t understand the mystery. I think it might be because the transition is pretty severe (apparently the tip of the beak is harder than most polymer compounds) and that it is accomplished without a change in component parts. I might be reading too much into the synopsis, but it seems like the authors are saying that the tip of the beak is made from the same stuff as the rest of the critter, and the difference in hardness is had by varying the ratios of the components. That would be remarkable. In other critters, the transition between hard and soft tissues is achieved by making entirely different out of different molecules. Tendon is made (mostly) from different stuff than bone, and soft tissue is different again. If a squid can go from hard as rock to squishy gelatin using all the same compounds, then that would be cool. And would be an easier thing to mimic in replacement joints, like they said.
I think the big deal is that the physical properties of the beak are so radically different at each end while still being the same physical part.
Imagine a pencil. It has an eraser attached on one end and the writing tip extends from the center of the barrel on the other. However, in this case, instead of the eraser being held onto the end of the pencil with a crushed metal ring, and the graphite being encased in wood, the entire eraser was all the same piece of the same material.
The writing tip is the same material as the part you hold, but with a minor difference in the way the material is formed. The eraser end just kind of fades into the barrel of the pencil. and the writing tip just kind of fades in the barrel from the other end.
I don’t ever recall encountering a single chicken bone that was as hard as a tooth at one end and the consistency of cartilage at the other, with a smooth and seamless transition from one to the other. Maybe we’re eating different kinds of chicken.
There aren’t any bones in a chicken that are as hard as a tooth, period. (Except, of course Hen’s teeth, but those aren’t common)
There are some bits that are distinctly rubbery at one end and distinctly bony at the other - although I’m not sure (without actually taking apart a chicken right now) whether this is achieved by a blended transition from bone to cartilage, or just a bone with a cartilage sheath that extends off to pure cartilage. I suspect the latter though.
Why is it unusual? Because a squid is an invertebrate with no exoskeleton. Soft all over, and with no joints – yet it has a hard, sharp beak. For an animal with a boney skeleton (or chitinous exoskeleton), anchoring and controlling a hard beak isn’t too much of a design challenge, but try putting one on something as soft and pliable as a squid. So, yes, it’s an unusual feature, and a good illustration of the great variety of evolutionary adaptations.
How is this significantly different from my fingernails, which are hard, keratiinous structures that are attached to my soft parts (not to my underlying bone)?
Yet I can scratch with them, pry things off, and pick my nose, usually without any worry that they’ll come loose.
Squids don’t just have hard beaks. May of them have barbs on their tentacles, as well. These, too, must be tenaciously rooted in the relatively soft squidflesh for them to function (and they do act more like my fingernails).
Heck, the animal world is full of instances of hard, rigid things attached to soft tissues. Look at porcupine quills. Oh, you say, those aren’t attached strongly – they’re supposed to pull off. But they also aren’t supposed to go the other way – being driven into the porcupine’s own flesh. Ditto for hedgehogs. Sea urchin quills. Snail’s teeth. (Yes, they do have hard teeth, with which they bite things. Snails strike me as even wobblier than squid)
Squid and octopus beaks (and cuttlefish, and nautiloids) don’t strike me as all that unusual.
The fingernail probably isn’t a good comparison seeing that it can use the underlying finger bone as a brace against the rest of the nail and as a rigid structure to add force. A fingernail, with the help of the bone underneath as a means of delivering sufficient force, can scratch a 2x4. Now, if one had a fingernail growing out of his flaccid dick, there’s no way he’d be able to provide enough force to scratch the 2x4. In fact, he’d probably end up pulling splinters out of his junk and all his friends calling him woodpecker.
