Which ones? I asked a veterinarian I knew. – In the upper or lower jaw?
He gave me a very expressive look, well, very expressive, so that I immediately felt like an old resident of a psychiatric hospital… for the hopeless.
Then, somewhat slowly and carefully choosing his words, he asked me a counter question:
Have you, Esprit, decided to add the specialty of crocodile dentist to your many hobbies?
Commendable!
The toothache in both in the equal way!
But first of all, prepare strong steel struts or, better, order a lattice ball, like a bathysphere, so that, being inside it, you can freely roll into the open mouth, and there you can safely engage in professional activities. Keep in mind that the jaw compression force of a crocodile is 17-30 times greater than that of a human!
I recommend starting with the design and construction of such a “working” bathysphere!! Safety is above all!
The history of my question is long-standing: I once asked my good friend, a dentist, which jaw is more likely to suffer from various dental diseases?
He immediately replied: Lower!
Why? I asked, surprised.
Have you ever heard of the Law of Universal Gravitation? Instead of answering, he asked with friendly irony.
Yeaaaah, – I replied uncertainly, straining my memory,
Well, understand that because of the weight, food remains more in the lower jaw than in the upper one. And they are a breeding ground for microorganisms that cause all kinds of gum and dental diseases!
This answer seemed unconvincing to me, so I came up with another one:
The lower jaw is MOVABLE, unlike the upper one. This means that its blood supply is carried out through the arteries, which are constantly subjected to bends and compression. And the outflow of blood, generally through the veins, is extremely low. This is a partial stagnation of blood in the venous bed! When the jaws are clenched, the muscles also probably contract and, greatly increasing in diameter, constrict the arteries and veins of the lower jaw. In a sleep, too, the mouth is usually closed!
That is, its blood supply, on average, is WORSE than the upper one, and therefore diseases are more common in it!
But how do I prove this case?
And I thought that we need to find living creatures that have both movable jaws, not the lower one!
Then if their dental diseases are the same in frequency and nature in both, then I’m right.
If the lower one suffers more anyway, the dentist friend is right.
This is the background of my question to the vet!
In general, it’s strange why reptiles have movable TWO jaws, while mammals have only the lower one.
Reptiles are biologically closer to fish, for example, to the family of carcharodons, sharks (the species has existed for three hundred million years). And they also have movable both jaws!
Snakes and crocodiles too. Crocodiles, for example, in order to spread BOTH JAWS, tilt their heads back!
Why did mammals suddenly acquire only one movable jaw, contrary to their biological history?
Possible answer:
Breathing air. The respiratory tract, trachea and bronchi SHOULD NOT be squeezed by movements of the jaws, but ALWAYS remain open! Evolution has “decided to sacrifice” the blood supply a little for the sake of breathing, since the blood is supplied under sufficient pressure, and the air is drawn into the lungs due to the weak discharge in them! If we VERTICALLY lower a long tube into the water and try to draw it in, what is the maximum length of the tube so that we can draw water through it? I don’t think it’s more than a meter, even less! One tenth of the atmosphere or less. (Ten meters of water column creates pressure on the bottom of one atmosphere.) And the blood pressure (systolic) of 120 mmHg is one sixth of atmospheric pressure.
Marine mammals – seals, whales, dolphins and others – all need to breathe air, while reptiles turned out to be a TRANSITIONAL link from fish to mammals and did not have time to adapt so well to breathing air. That’s probably why most of them died out.: Suffocated in constant lack of oxygen!?
Just think how just choosing MOVABLE and IMMOBILE JAWS can decide the million-year fate of entire species of creatures!
(Stronger than the famous horror movie “Jaws”).
Does it turn out that the abandonment of the mobility of the upper jaw for the benefit of breathing with the lungs, rather than with the gills, turned out to be a kind of biological PROGRESS?
More precisely, by adapting to the ecological niche in which the creatures found themselves.
In general, I see: Is it a direct road for me to a crocodile pond or a serpentarium?
Anyway, I’ve been living in them for so long…
20 X 2026
