Well, not as we know them. This isn’t an equine; if anything, the creature in this painting resembles a cross between a horse and a rhinoceros:
And it’s not as ancient as we thought, either:
For decades, scientists have estimated that the Siberian unicorn (Elasmotherium sibiricum) — a long-extinct species of mammal that looked more like a rhino than a horse — died out some 350,000 years ago, but a beautifully preserved skull found in Kazakhstan has completely overturned that assumption. Turns out, these incredible creatures were still around as recently as 29,000 years ago.
Not only were they incredible, they were incredibly big:
According to early descriptions, the Siberian unicorn stood at roughly 2 metres tall, was 4.5 metres long, and weighed about 4 tonnes. That’s closer to woolly mammoth-sized than horse-sized. Despite its very impressive stature, the unicorn probably was a grazer that ate mostly grass. So, if you want a correct image in your head, think of a fuzzy rhinoceros with one long, slender horn protruding from its face instead of a short, stubby one like today’s rhinos.
And if you saw something like this, you would not soon forget it — which may explain as well as anything else why stories of unicorns have persisted for so long.