Centaur

Centaurs (so named for its many malformed legs) are mutated creatures. They are a by-product of infection by the Forced Evolutionary Virus.

West Coast
Centaurs encountered in New California and Mojave Wasteland were created by the Master. The creation process involved tossing a varied mix of humans, dogs, and other types of animals into a FEV vat to be infected by the virus, Fallout Bible 0: "3. Are the radscorpions a product of the FEV virus? When you talk to the doctor, Razlo, in Shady Sands, he tells you that they were once American Emperor Scorpions but that he has no idea how they mutated because radiation alone couldn't have done it.  For that matter, what about all of the other creatures of the wasteland?  Which ones have been mutated by FEV and which ones haven't?  Maybe in the bestiary each creature could have a stat that shows it's level of FEV infection." "Answer:
 * The radscorpions are a result of a combination of radiation and the FEV virus, and Razlo in Shady Sands is correct - they were originally Emperor Scorpions that have grown... big.
 * FEV-Infected Critters in the wasteland include almost all the ones you've seen in F1 and F2: Mantises. Most species of rats. Gecko lizards. Brahmin Scorpions Ants Various varieties of plants, including the Venus Flytrap. Rumor has it some dogs were affected, but no one's seen any, so for now that's just rumor. Of course, the centaurs are a mash of human, dog, and various other parts... but hey, who knows how that mutation came about. Grey was probably messing around in one of his labs.
 * Creatures not mutated by FEV probably did not survive the aftermath of the Great War, with the possible exception of cockroaches... and perhaps normal ants, though there are FEV-infected versions of these species.
 * No one knows where those bird noises in Vault City came from.
 * I'll try to include a chart of FEV-infected creatures in future additions as well as other critters that you may not have seen in F1 and F2. Most likely a great majority of insects were affected (they tend to breed much faster, and their mutations tend to become evident pretty quickly as the generations advance), possibly beetles, some spiders, cockroaches, and other creatures." and then seeing what mutant chimera emerged as the virus produced rapid and unpredictable mutations. The resultant centaurs can differ quite radically in physical appearance from one another. However, all known centaurs are somewhat humanoid in appearance. Despite this consuming them is not an uncommon practice; such as with Mom's Diner of The Den.

Capital Wasteland
Like their western counterparts, the Capital Wasteland centaurs are created by infection with FEV along with the local breed of super mutants; their birthplace being Vault 87. They often accompany the super mutants, serving as watchdogs and alert their masters to danger. Despite their prevalence of tongues they are not able to speak.

Variations
Centaurs of all known varieties are not harmed by radiation, but seem drawn to it, as they are often found in heavily irradiated environments.

Two-headed centaur


Physically, these centaurs are around the size of a bear, with a large, misshapen torso and six humanoid arms that serve as legs. A cluster of wriggling fleshy tentacles bloom out from their underside, scrabbling at the ground around them. Branching from their front halves are a pair of long, thick necks, with a canine head on the left and a humanoid one on the right. The canine head has a thick metal collar around its neck, adorned with spikes, not unlike an ordinary dog collar. The two heads seem to realize that they are still two different creatures as the dog head can be seen trying to gnaw on the humanoid head.

So far, the two-headed centaurs have only been encountered on the West Coast, in the Core Region.

One-headed centaur


In this type of centaur only the human-like head remains, and the feelers on the back are replaced by three long, tentacle-like tongues. Unlike its two-headed "cousins", this kind of centaur uses a ranged attack: a high-arcing, slow-moving saliva projectile that can carry lethal doses of radiation. Oddly enough, it is capable of igniting lingering gas vapors as well. In close quarters it utilizes a long, three-pronged tongue to whip and slash at any intruders.

This kind of centaur can be encountered both in the West and the East of the former United States.

Evolved centaur


As the name suggests, they are a bigger and stronger variant of a centaur. Having been exposed to much more radiation than regular centaurs, they have significantly more muscle mass as well as thick clusters of tumors growing from their backs.

Giant evolved centaur
An even bigger variety of the evolved centaur, the giant evolved centaur is the largest and most dangerous variation of centaur to be discovered to date.

Gallery
''Concept art by Adam Adamowicz