Well this prompted me to look up some verses in the King James and I think I must conclude that the "unicorn" in the Bible isn't referring to an ox or wild ox, but to a rhinoceros.
The word "unicorn" didn't always mean what we now portray as this magical horse with only one horn. In the first edition of Webster's Dictionary 1828 here are the two descriptions given for a "unicorn":
1. An animal with one horn; the monoceros. The name is often applied to the rhinoceros
2. The sea unicorn is fish of the whale kind, called narwal, remarkable for a horn growing out at his nose.
Notice how there is no mention of a horse or a fantastical being. The word "unicorn" meant just that. An animal with one horn.
So if the Bible says that it is speaking of an animal that has "one horn", there is no reason for us to think it is speaking of an animal with two equal sized horns. Just because we today have a connotation with the word "unicorn" it doesn't mean they did back then. Look at the word "gay". The word "gay" in the 1950's meant happy. The word "gay" in the 1990's and now means "homosexual". And even now I hear teens use the word "gay" to reference something that's "lame" or "silly" with no reference to sexuality. And that is just in a span of 60 years - much less 400 years!
There are two types of rhinoceroses. One with one horn and one with two horns. In Deutoronomy 33:17 the two-horned rhinoceros is the unicorn that the writer (probably Moses) is talking about: His glory is like the firstling of his bullock, and his horns are like the horns of unicorns: with them he shall push the people together to the ends of the earth: and they are the ten thousands of Ephraim, and they are the thousands of Manasseh.(emphasis added). Manasseh and Ephraim were brothers and later where tribal names of the children of Israel. And one of the tribes was much larger than the other! Just like the horns of the two-horned rhinoceros.
I believe a rhinoceros is referred to a unicorn because it has just that, one horn. An ox or a waterbuffalo on the other hand, have two large horns of equal size.
Look at the verse in Job 39:9-10 which says: Will the unicorn be willing to serve thee, or abide by thy crib?
Canst thou bind the unicorn with his band in the furrow? or will he harrow the valleys after thee? This verse speaks about the inability to tame a unicorn. You can tame an ox, but try taming a rhinoceros!
There are other verses in the KJV Bible that could interchangeably use "rhinoceros" or "wild ox" for "unicorn", but this is just an example of just how awesome God's Word is. It is vast and deep. You cannot skim through the Bible and expect it to fill you, it is not fast food!
Answers in Genesis is getting a lot of ridicule for what they stand for - that the earth is young and that God made this beautiful earth in literally 6 days and rested on the 7th and not millions of years. The people at AIG are creating a new theme park called The Ark Encounter. And because of this, some skeptics were asking if the "unicorn" would be included since it's in the Bible. Yes! I do believe the unicorn will be included, but not the ones these people think!