Unicorns

Unicorns

Original lineart by kokamo77

Unicorns have captured our imaginations for centuries. A beautiful horse-like animal hiding in the dark forest in the moon light, but could the unicorn really exist? Due to Baron Georges Cuvier's clam that a cloven hoofed animal must have a cloven skull (meaning two horns) it seems unlikely, but a professor named Dr. W. Franklin Dove artificially moved the horn buds of a calf so they were placed side by side creating a one horn like appearance when the horns grew.

Deer with only one antler

(he also did the same for goats) A similar phenomenon happens naturally with a deers antlers sometimes, though extremely rare. Another animal that also conflicts with Baron's clam is the rhino. A rhino's horns are made of modified hair and the rhino is also a relative of the horse, another fact is that a rhino's two horns are in the center of the head and not on the sides. But this is due to the fact that the rhino is an odd-towed ungulate (meaning an odd number of toes on each foot) and it has three toes on each foot, making the horn(s) work (an animal with three toes has an even skull). And some of the horses ancestors had three toes on each foot as well.

Dr. Dove's Cow and Goat

Body Structure:

Image by: Unicorns-of-the-Vale

Horn:

Now that we have an answer to the horn (two horn buds growing beside each other) we can answer the question: What about a unicorns magic? Well lets start with how the horn works in the first place. The inside of a cow horn is hallow so lets say that our unicorns horn is also hallow, now we have a space where special tissue can go. That special spongy tissue is the answer to the unicorns mysterious magic. The brain sends two special chemicals to the tissue of the horn that then gets stored for later use. Those chemicals are Luciferin which is a chemical that emits light when exposed to oxygen and Luciferase which determines the color of the light (this is how fireflies and some scorpions glow). The colors depend on how the two chemicals mix which can result in colors like red, blue, green, yellow, and even purple. For the unicorn its horn will glow mostly at dusk and at night. The color is normally yellow or green but during the day if the horn glows it will normally be red. The chemicals get to the surface of the horn through special pores in the horn that allow the chemicals to travel to the surface by getting squeezed out of the tissue at the center of the horn by muscles (much like how the muscles around our pours in our skin squeeze water out of the skin to cool us off). The unicorn evolved bioluminescence as a form of communication since the unicorn is a cathemeral animal which is an animal that is active both day and night. The glowing horn is used to frighten predators to make it look like the unicorn is poisonous (though they are not). The unicorn will also rub its horn on trees, rocks, and grass to mark its territory leaving a glowing smudge on the objects. But the unicorn horn is not magic at all. Just like its cousin the rhino the unicorns horn it just like a cows horn that possess no magical power at all.

Mane:
Now that the horn is settled lets get to the body and why the unicorn has certain features. First is the mane, just like the mane on a horse or lion it's to help protect the neck from the sharp hooves and teeth of an opponent.

Feathers:
The hair behind the legs is a different matter. The hair is called feathers and it is not truly known what purpose they serve. Most argue that it's to help keep warm, though this may make sense to some it is not the answer. If an animal had to keep warm they would have shorter legs, bodies, neck, and tail. Not simply more fur, also horses don't loose vary much heat through their legs making the Maintain Body Heat theory completely wrong. Another theory is that it acts like a leafs edge (called the Margin) and keeps the lower leg and hoof dry, which in turn will help keep infection at bay and will help prevent Rain Rot which is the rotting of the skin when exposed to the elements to long. This theory makes more sense then the last so lets go with that.

Beard:
It is unknown if the beard of a unicorn serves a purpose or not, but it is estimated that it helps the animal to attract mates, though both male and female unicorns have beards that are roughly the same length which  disproves the theory. A better explanation is that it determines a unicorn's health and age. A shorter beard means that the unicorn is young or sick, while a long one means that the unicorn is older or healthy.

Ear Tufts:
The ear tufts are another mystery it is thought that they help the unicorn hear better (like a lynx's ear tufts) or help protect the ears from frostbite. The answer is most likely both. It is proven that the ear tufts do help to improve hearing in lynx, bobcats, and caracals, so why not unicorns as well? In colder climates though the ear tufts can have an additional use by helping to keep the ears warm so the animal doesn't suffer from frostbite in cold winters or rain.

Lion-like Tail: 
The tail on every animal (except us) is used for balance, and communication. The lion-like tail of a unicorn is no exception. The unicorn just like horses also use their tails to swat away flies and other harmful bugs from it's body.

Cloven Hooves:
The cloven hoof is unique to the unicorn in the horse family since no other equine has an even number of toes on each foot. The advantage is that the cloven hoof provides more traction then the single hoof. This helps unicorns clime up rocks, hills, and mountains much easier then with a single hoof. 

Diet: 
The diet of the unicorn is mainly grasses, flower buds, and in times of desperation small branches, leaves, and bark.

Colour:

Original lineart by kokamo77

A Unicorn's colour is determined by location and season. The fabled white (light grey in horse terms) unicorn is only found during the winter or in a Tundra biome, where as the black unicorn is commonly found in dense forests with little sunlight. Grey unicorns are found in mountains, bay unicorns are found in forests, and dun unicorns are found in plains and deserts.
Season plays a big factor and like many animals their colour is determined by season. Buckskin unicorns for example are found in mostly plains biomes but change colour during winter to white for better camouflage. The only things that don't change colour are the hooves, horn, eyes, and skin (hence a black or dark brown muzzle).