Whenever I read this passage in Job, I think of a brachiosaur (brontosaurus). Although according to modern paleontology brachiosaurs did not eat grass, the Lord made everything within a few days, and they would just as easily eat grass as anything else. One species of brachiosaur is the largest dinosaur known, either ultrasaurus or supersaurus (I cant remember which of the recent discoveries is the largest). Early on in my Christian life, when I still beleived in evolution, I tried hard to see this as an elephant, or anything else, but I cant.