Job (40:15 onwards)

"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.

The hills bring him their produce, and all the wild animals play nearby.

Under the lotus plants he lies, hidden among the reeds in the marsh.

The lotuses conceal him in their shadow; the poplars by the stream surround him.

When the river rages, he is not alarmed; he is secure, though the Jordan should surge against his mouth.

Can anyone capture him by the eyes, or trap him and pierce his nose?"

So, from this we gather:

This specific animal Job is referring to is the greatest animal God has made. His tail alone is like a cedar tree. His bones are like tubes of bronze in terms of their strength, and his loins are like tubes of iron. Also a herbivore.