How many single horned creatures are there including real, mythical, extinct, etc. that you can name? Off the top of my head I can think of a few such as: unicorn, narwahl, rhinocerous, etc.
I don’t think there are any real one-horned animals. The rhinoceros’ “horn” is a hair-based growth; the narwhal’s “horn” is a tusk.
In the realm of delightful, enchanting myth, of course, there’s Princess Unicorn.
Not all rhinoceros are one-horned. Nor all narwhals, for that matter.
The prehistoric ceratopsian Monoclonius was single-horned (think of it as a triceratops without the two top horns)
The Ceratosaurus actually had two horns, like many rhinoceros do, but one is pretty small, so I can probably squeak it by.
Medieval bestiaries also included, besides the Unicorn, another one-horned beast called the Monoceras, which looks like it may just be a repeated case of the Unicorn, since the name means “one horn”.
Then there’s the Rhinoceros Beetle:
I’m sure there must be plenty of other dinosaurs and lizards that fall into this category. In addition, there are the artificially created unicorns, made by fusing the horn buds of an immature bull or goat, and the mistaken cases, like the re’em and some African antelopes. See Willy Ley’s essay on the unicorn, and Odell Shepherd’s claasic The Lore of the Unicorn. And search the internet
Flying purple people eater. He only had one eye also.
The Kirin which is somewhat Unicorn like.
There are the occasional goats with fused horns forming a single horn.
BTW: Just to get it out of the way, the narwhal actually has a long tooth and not a horn. It is an incisor tooth that projects from the left side of the upper jaw and forms a left-handed helix.
Many dragons over the years, especially more recently have a single horn and of course there is the relatively recent Pegacorn.
I believe Peter Cook had the horn, once.
Plus, the females often do not have a horn/tusk at all, which is what I think CalMeacham may have been referring to.
Boromir had one horn … oh, wait - you probably only wanted ones that were actually attached to their bodies. Never mind.
The two rhinos with single horns both belong to genus Rhinoceros: the Great Indian Rhinoceros, R. unicornis, and the rare Javan Rhinoceros, R. sondaicus. Both the Black and White Rhinos of Africa and the Sumatran Rhino have two horns, both on the midline of the snout, as did the Woolly Rhino of Ice Age Eurasia. Of all the variant extinct rhinos (quite a broad radiation), only Family Rhinocerotidae, the modern surviving forms and their closest extinct relatives, appear to have grown the medial collagen horns that gave the animals their name.
The extinct perissodactyl family Brontotheridae had a hammerhead-shaped medial nasal horn. The artiodactyl family Antilocapridae, represented today by the Pronghorn “antelope” of Western North America, also had medial horns, often bifurcating or producing even more complex shapes.
Whatever the Sirrush (Hebrew re’em) of Babylonian legend may have been, it’s depicted as a gracile ungulate with a long, straight single brow horn, the base appearing to be above and between the eyes. It’s worth noting that the legendary unicorn was not a horned horse, but an animal with cloven hooves and a “beard” on its chin, of horselike build but otherwise similar to a large goat. Very rarely, the horn cores of a goat will fuse and produce a single-horned goat that bears close resemblance to the medieval bestiaries’ pictures of unicorns.
There are a number of birds with single bony “horns” or hornlike ornaments on their heads or bills:
There are many species of hornbills.
There are several species of cassowary.
I have also seen some narwhals with two tusks. I thought he might have be talking about those. I did not know the females often don’t have the “horn”.
Here is a picture of one that was killed: Warning it is a bit bloody.
Here is a close up of the tooth. You’ll see why they use to sell narwhal “horns” as Unicorn horns.
It never hurts to sneak in a Tolkien reference, especially when talking myths.