In the Bible Behemoth is a great land-creature named only in Job 40, described by God in his speech to Job as a plant-eating animal of enormous strength.
Job 40:15-16 in the King James Version reads:
15 Behold now behemoth, which I made with thee; he eateth grass as an ox. 16 Lo now, his strength is in his loins, and his force is in the navel of his belly.
These verses appear in Job 40, in the section where God begins to describe Behemoth to Job. Read it in context at Job 40:15-16, or the full chapter at Job 40. Encyclopedia entry: en.wikipedia.org/wiki/Behemoth.