
He hath as it were the strength of an unicorn. (Numbers 23:22 KJV)
The King James Bible mentions unicorns in six verses. It doesn't give much detail about the creature except to say that it noted for having great strength. To the western mind, unicorns are mythical creatures that now only exist in fantasy novels and Dungeons & Dragons but the Bible talks about them as though they are real creatures. Many people pounce on this fact as an opportunity to label the Bible as a work of fiction. Even liberal Christians use the mention of unicorns as an excuse to say the Bible shouldn't be taken literally.
In response to such criticisms, we must first acknowledge them for what they are – straw man criticisms that don't accurately represent what the Bible says. Many critics aren't intentionally making a straw man. Instead, they are committing the exegetical fallacy of reverse etymology. That is, they are forcing the modern meaning of a word onto its original meaning. When the Bible was written in Hebrew, the Medieval concepts of unicorns did not even exist. The writers of the Bible certainly did not have the western image of unicorns in mind when the original text was penned.
My understanding of Hebrew is next to nothing but, according to Brown-Driver-Brigg's Hebrew Definitions the word translated as “unicorn” in Numbers 23:22 above is the Hebrew word “rêm” (ראם). BDB defines it as “wild bulls which are now extinct.” There's nothing about that definition that suggests the Hebrew writers specifically understood this beast to have a single horn. It could be a description of an animal using terminology similar to our name for the modern breed of cattle, the “long horn.”
Since I'm more comfortable reading Greek, I looked up the verse in the Septuagint where I found it is rendered as monokerōtos (μονοκέρωτος) which literally means “only horn” or “one horn.” So, even long before the KJV translation, it seems the idea of a one-horned animal was already understood. What we have then, is the Bible mentions a one-horned animal renowned for having great strength. Do such animals exist? Of course they do!

Even today there exists a species of rhinoceros with one horn. Interestingly, the Latin name for the animal is Rhinoceros unicornis. Did you see that, “unicornis”? It's the word unicorn! So even according to modern taxonomy, there are true unicorns alive today. Rhinos also possess great strength so a one-horned rhino would definitely fit the bill of the biblical unicorn.

Now, there are many other horned animals that have lived throughout history. For example, there is a group of horned animals called, ceratopsians. The most famous critter belonging to this group is the triceratops. The triceratops, of course, has three horns but another member of this club is monoclonius. Would you care to guess how many horns the monoclonius had? I don't know exactly how strong the monoclonius was but given the fact it about the size of a car, I would suspect it was likely impressive.
I'm sure there are still other candidates that would fit the description of the biblical unicorns. It's not my objective to prove exactly what species of creature it was. My objective is demonstrate what it was not – it was not the horned horse of European folklore.

