New Defender's Study Bible Notes
39:9 unicorn. The unicorn is supposedly a mythological animal; actually the creature referred to here is the extinct aurochs, or wild ox, a fierce animal that once inhabited this region. Many of the animals mentioned in this chapter, as well as other parts of the Old Testament, are of very uncertain identity, and various translators have tied them to a considerable diversity of modern animals. The probable reason for this uncertainty is that many of the animals, like the “unicorn,” are now extinct, because they could not long survive the drastically changed environments following the great Flood. Modern Bible scholars, however, for the most part, accept the standard system of evolutionary geological ages, and never consider the very real possibility that the many now-extinct animals of the past still existed on the earth in Old Testament times.
39:13 wings and feathers. There is a question whether or not the bird described in Job 39:13-18 is really an ostrich, or some extinct bird. In the other three occurrences of this word (Hebrew notsah) it is translated “feathers,” in no case referring to ostriches. The characteristics of the bird described in these verses correspond only in part to those of the modern ostrich. The reference to “wings” would seem pointless, for the ostrich is flightless.