Job 40:17

Modern

His tail sways like a cedar; the sinews of his thighs are tightly knit.

Traditional

He moveth his tail like a cedar: the sinews of his stones are wrapped together.

Literal

He bends his tail like a cedar; the sinews of his thighs are tightly knit.

Latin

Stringit caudam suam quasi cedrum; nervi testiculorum ejus perplexi sunt.

Hebrew

English

His tail sways like a cedar; the sinews of his thighs are tightly knit.

After listing natural animals, God described Behemoth and "Leviathan" as creatures humans cannot control (39:1–30; 40:15–24; 41:1–34). Job could not control the wild donkey or ox (39:5–12; 40:15–24). However, God created and could control them, and Job had to accept this fact (41:2).
Here, Behemoth appears to be a natural creature:

It is an animal God made, just as he made Job (40:15).
It is not a fierce predator but eats grass like an ox (40:15).
It is in a poem about God’s creation of the natural world, not in a myth about the world's formation. Most commentators think Behemoth is the hippopotamus, a large, grass-eating animal (40:15–19). It rests in the river among lotus plants and reeds (40:21). Like the wild ox, Behemoth is strong (40:16–18, 24; 39:11). Yet it is mostly peaceful (40:20–23).