Job chapter 39 lists a number of animals including wild goats, wild asses, unicorns, peacocks, ostriches, horses, hawks, and eagles. Isaiah 34:7 prophesied a time when the blood of unicorns would be shed--probably at the time of the destruction of the Northern Kingdom of Israel by Assyria in 722 B.C. There is no sound reason to assume the references described anything other than a real, flesh-and-blood, one-horned animal.
Related to the rhinoceros, the unicorn above lived in Siberia. It stood about 6.7 feet tall and was approximately 15 feet in length. 18th century reports from Africa, including rock drawings and eyewitness accounts, describe a single-horned, aggressive, horse-like animal; so unicorns were found far from Siberia.
Actually I'm not all that concerned about unicorns. Like so many other things in the Bible that have been mocked and eventually proven to be correct, unicorns are but one in a long and growing list. For example, early 19th century archaeologists laughed at the Biblical mention of the Hittites. Not only did they insist the Hittites never existed, but that mention of their iron chariots would have been an impossibility because the time period in which their empire existed was the bronze age when iron smelting hadn't yet been discovered. Archaeological discoveries later in the same century proved not only the existence of the Hittites, but the fact that they did indeed use iron for their chariots and weaponry. Big 'Whoops!' Other nations said not to have existed include the Horites and the Edomites. Archaeological evidence ultimately proved otherwise. Many people argued that Pontius Pilate never ruled over Palestine when it was a part of the Roman Empire, if he existed at all; however, a stone column discovered near the Mediterranean had his name carved into its surface. More than 40 kings of various nations mentioned in the Bible, but whose existence was long questioned, have all been proven to have existed through the evidence of contemporary documents and inscriptions unearthed by archaeologists.
Two 20th century archaeologists, Nelson Glueck and William Albright, credited the Bible as being the single most important source document from ancient history. Interestingly, neither man was a Christian.
While the account of creation will probably never be proven scientifically--no one was there except the Creator Himself, and it isn't something that can be re-created in a controlled scientific experiment (you'll just have to take His word for it)--we can rest assured that the Bible is just as true in its early chapters as in its references to unicorns and the Hittites' iron chariots. Jesus Himself accepted the creation account: "Have you not read that He who made them at the beginning made them male and female, and said, 'For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh'?" That quotation is found in Matthew 19:4-5, where Jesus was quoting Genesis 2:24.
As Peter wrote in chapter one, verses 19-21, of his second epistle, "We have the prophetic word confirmed, which you do well to heed as a light that shines in a dark place, until the day dawns and the morning star rises in your hearts...for prophecy never came by the will of man, but holy men of God spoke as they were moved by the Holy Spirit."