Feral ghouls are similar in appearance to sapient ghouls but are skinnier and do not walk or run normally. Due to exposure to high levels of radiation, they have lost the ability to reason and will become hostile towards everyone but their own kind. This has caused much discrimination towards sane ghouls.
The brain structure of a feral ghoul indicates that the regenerative ability of the neurological system that affords "normal" necrotic post-humans their longevity does not extend into the higher reasoning functions of the brain itself. This condition is referred to as "ferocious post-necrotic dystrophy", according to the ghoul physician Barrows. Despite the apparent lack of the higher reasoning they once had as humans, some are capable of semi-intelligible speech, as the Vault 34 security officers will occasionally growl out understandable phrases similar to the trogs of The Pitt, meaning that their vocal chords are still relatively intact, as is the part of the brain which controls speech.
As the reasoning and critical thinking portions of a ghoul's brain deteriorate, the ghoul subject becomes increasingly hostile, giving in to a carnal need to feed. It remains unclear exactly what precipitates this change in neurobiology and psychology, but anecdotal evidence seems to indicate that non-social ghouls, or those in isolation, are more prone to the condition.
It is also quite possible that this is a gradual process, meaning that eventually all ghouls will succumb to this condition. However, considering the existence of ghouls that have been born prior to the Great War two centuries ago, it is quite possible that this theory is bunk, or that the rate of degeneration is dependent on the individual affected and surrounding environmental factors.
As with normal ghouls, ferals are not only extremely resistant to radiation, they are actually healed by it, as can be seen when a glowing one uses its' radiation blast nearby other ghouls. M.A.R.Go.T. also states that feral ghouls have no internal body heat.
Feral ghouls are the basic feral ghoul variant in Fallout: New Vegas; wearing only a pair of tattered shorts and noticeably weaker than standard human opponents, they are easily dispatched with one or two headshots from any decent ranged weapon or a solid hit from a decent melee or unarmed weapon.
Despite their shrill noise and remarkable speed, they are only truly a threat when they have the advantage of numbers, or when the Courier is at a low level. Feral ghouls usually retain the skin color they had when they were human.
The feral ghoul roamer is more dangerous than the regular feral ghoul. Though it is not as strong as the feral ghoul reaver, it is far more common. Unlike their Fallout 3counterparts, they do not wear the remnants of combat armor. Instead, they may be void of clothing or only wear a sleeveless shirt.
The feral ghoul reaver returns in Fallout: New Vegas, but it is nowhere near the potent combatant as the Fallout 3 version. Instead, New Vegas reavers are more comparable to the other feral ghoul variants, as they no longer possess the radioactive gore grenade attack, their lunges do not cause much knockback and they no longer emit radiation.
Their HP in this game can vary; at lower levels, they are merely slightly stronger than a feral ghoul roamer, but are weaker than a glowing one. They wear what appears to be the remnants of metal armor. Some can be found at the old nuclear test site and one will always spawn inside the sealed sewers, regardless of the Courier's level.
Feral trooper ghouls are former NCR troopers that have become feral. They are similar, but not identical, to normal feral ghouls, the difference being that they still wear their NCR trooper armor, indicating that they were on duty when the radiation was released from inside Camp Searchlight by Legion soldiers.
The ghoul troopers that attack with combat knives are not actually feral ghouls, but normal ghouls that are set to be hostile. As such, their knives and NCR armor are lootable. There are a total of nine of these, and killing them is part of the quest We Will All Go Together.
These ghouls are found often at higher levels, and at locations where the concentration of radiation is strongest. They have significantly more health and damage than the average ghoul. This variant on death (and while attacking) gives off a small amount of radiation. Its secondary attack is when it stretches its arms to the sky then gives off a burst of radiation. In some cases the ghoul might kill any ghoul in his close proximity to regenerate health to his own.
Glowing trooper ghouls are NCR troopers that have turned into glowing ones, affected by the local radiation levels after the Legion's assault on Camp Searchlight. As with regular glowing ones, they have the ability to emit harmful radiation waves. Removing the head of a glowing trooper ghoul will cause red blood to erupt from their neck, unlike the other limbs on their bodies where the blood glows green.
The Overseer is a unique orange-colored reaver, encountered in Vault 34. Its armor and facial structure are similar to that of a feral ghoul reaver's, but it has the same glow effect and radiation blast as a glowing one, albeit a different color.
Like the majority of the vault's population, the overseer has become a feral ghoul due to radiation poisoning. The Overseer stands on a raised platform in the Overseer's office, and on the bottom of this platform are two Vault-Tec turrets, which defend the Overseer. Of all the enemies in the Mojave Wasteland, it has the highest amount of HP amongst ghouls, thus making it a "boss" character.
Vault dwellers are a variant of feral ghouls found exclusively inside Vault 34. They are the remains of the population of Vault 34 following the reactor leak. They are completely feral and will attack any human on sight though they sometimes utter human phrases. The Courier will first encounter one at the end of the access tunnel, directly inside of the main entrance. They can also be found scattered throughout the rest of the vault, although at higher levels the Courier will encounter the more dangerous vault security guards and vault security officers.
They are the remains of the Vault 34 security team, and are clad in the rotting remains of Vault 34 security armor. They were members of the security team before and during the population control riots, and eventually they became feral ghouls along with the majority of the vault's remaining population after the reactor leak, becoming hostile creatures who will attack any human on sight.
Like the vault security guard, they are the remains of the Vault 34 security team. However, they have become glowing ones which are notably stronger. While in combat they may produce a pulse of radioactive energy.
Vault technicians are former technicians in Vault 34, who have since become ghouls due to the radiation leaks. Simply called vault technicians in game, they share a model with the standard glowing one, along with the same strengths and weaknesses. They are found dead in flooded chambers inside of the main section of the vault, in both cases under desks. Also in both cases, the Courier must retrieve a password from their corpse to progress further into the vault. They are found alive in the flooded reactor level accessed under the desk of the Vault 34 Overseer. One wanders the halls, while the rest wait, only breaking through a window and attacking the player when he/she is actually inside the reactor itself.
xbox360pcps3 Sometimes whilst targeting the head of a glowing trooper ghoul in V.A.T.S. with the Ratslayer, Dinner Bell/hunting shotgun or lever-action shotgun, the player will run backwards and not fire, letting the ghoul attack the player until death or until the bug ends. [verified]
ps3xbox360 When the Overseer is killed with an energy weapon, the ash pile remains may not appear. [verified]
pcxbox360ps3 Sometimes the Overseer doesn't attack you, not even when his turrets are destroyed, which is made worse (but in some regards better for the player) by the fact he cannot move from his podium/desk. [verified]