That's not completely true. Here is the desciption of the behemoth as found in the writings of Job:
"Look at the behemoth, which I made along with you and which feeds on grass like an ox. What strength he has in his loins, what power in the muscles of his belly! His tail sways like a cedar; the sinews of his thighs are close-knit. His bones are tubes of bronze, his limbs like rods of iron. He ranks first among the works of God, yet his Maker can approach him with his sword."
You need to understand the language. "tail sways like a cedar" does not mean a "tail". "Tail" was used in King James' time as a euphemism for penis. The text is saying that behemoth has a big dick.
Behemoth is also found in Babylonian literature (which the writers of Job would be familiar with) and is a mythical creature.
Also, we need to look at the
context. The context is an argument with Job over whether God was just to cause all the misfortunes to befall Job. Job says not. God says yes. In context God is claiming to knowledge of a beast that Job has never seen (and never will).
Notice also that God tells Job that he created this behemoth along with man.
But again, that's for the argument. God's Creation says that humans and dinos never co-existed. Why are
you forcing God into a lie?