Greetings in that Divine and Most Precious Name of Our Lord and Savior Jesus Christ!
The problem with them being "dinosaurs" (as we think of them) is that the Scriptures seem to talk about these strange fellows in the present (and even future) tense (Job 41;Ps. 74:14; 104:26; Is. 27:1). That said, I still don't have a problem with them them being something akin to dinosaurs: it is for example interesting that the Scriptures and Fathers connect Leviathan with something akin to a dragon or sea monster, while the word dinosaur really means "Monstrous Lizard" or something like that; there seems to be a good bit of leeway in how we understand this creature (though it does seem to be an amphibian and not a reptile). It could be any of them in part, or all of them put together in some form or fashion, IMO. More importantly, I think, is the more "spiritual" side of what we should make of Leviathan. "For, behold, the Lord cometh out of his place to punish the inhabitants o fthe earth for their iniquity: the earth also shall disclose her blood, and shall no more cover her slain. In that day the Lord with his sore and great and strong sword shall punish leviathan the piercing serpent, even leviathan that crooked serpent; and he shall slay the dragon that is in the sea." (Is. 26:21-27:1) It is interesting to compare this with Rev. 20
I agree more with this. Looking for dinosaurs is silly, my mom used to laugh and say perhaps there never were any dinosaurs to begin with, as Baptists sternly believe that God created the Earth with the appearance of age, including all the geological features and fossils we find, and she got quite a kick out of just how much scientists made of all these fossil records. She often imagined how silly they looked to God, speculating the ages and eras of the earth based upon bones and rocks and theories and assumptions! In a deep way, that very much connects with the way you just interpreted these mythical beasts! The Devil and Serpent is the origin and source of deception, particular those "what if" deceptions that lead folks away from God in their hearts, like "what if I'm all alone in the world" or "what if the universe can be explained without the need for a Creator?"
I've been reading the Bible a Chapter A Day, for ten years nearly now, I am on my third run through, just finished Job last night as a matter of coincidence, and I was also meditating just on this very topic and on the spiritual nature of those beasts, the leviathan and the dragon. Standard, Orthodox rabbinical interpretations claim very confidently the inspiration for thethe Behemoth is the Hippopotamus and the Leviathan is the Nile Crocodile,
both of which were quite common in the swamps of the Jordan. When you reexamine the text in this context and in the light of historicity, that seems to be obviously a correct interpretation. But it is a parable, an allegory, and an allusion, as is most Hebrew and Biblical poetry.
I am less confident in how I feel the Behemoth represents, perhaps the stubborn, obstinant, hardheartedness that lies in the resistant nature of Humanity, which leads us to defiance, rebellion and sin.
There is a distinction made between the Behemoth and the Leviathan, as the it says that inevitably a man can catch with cords and rings the Behemoth, but that this can not be so with the Leviathan!
In our theology, humanity alone cannot conquer the Dragon, the Devil, Satan, only Christ through the power of the Resurrection, finally conquered Death and the Dragon, and finally with the purchase of His atoning Flesh and Blood put away the Wicked One. Humanity cannot conquer the Devil in its own power, that is why we need God in our midst, that is the saving miracle of Jesus Christ in our lives, to continually say, "Get ye behind me Satan, for you are not mindful of the things of God, but those of men!"
It seems clear that the Leviathan is the Devil, and to re-read in that context is far more edifying then to search for the material, physical, animal equivalents. I believe Joseph Campbell explained it best,
But to read a (religious) poem as a chronicle of fact is to say the least, to miss the point. To say a little more, it is to prove oneself a dolt, and to add to this, the men who put these (Holy) books together were not dolts but knew precisely what they were doing.."
Hero With a Thousand Faces