Fallout 3 creatures

General information
All Fallout 3 creatures when in proximity of others will fight each other, so long as they are not in the same faction as grouped below. (For example, Deathclaws will attack Mirelurks, while Feral Ghouls will not attack Glowing Ones.) The exception to this is that Humans are always willing to fight Ghouls and vice versa.

Humanoid

 * Aliens (Mothership Zeta): Abomination, Alien, Alien Captain, Alien Worker
 * Human: Brotherhood of Steel, Enclave, Outcast, Raider, Talon Company, Wastelander, Wildmen (The Pitt), Regulators, Slavers, Hunters, Scavengers, Tribals (Point Lookout), Smuggler (Point Lookout), Pitt Raider (The Pitt)
 * Ghouls (sentient): Ghoul, Chinese Remnant Soldier, Ghoul Guard (Broken Steel), Wastelander
 * Ghouls (feral): Feral Ghoul, Feral Ghoul Roamer, Glowing One, Feral Ghoul Reaver (Broken Steel), Swamp Ghoul (Point Lookout)
 * Trogs: Trog (The Pitt)
 * Swampfolk: (Point Lookout): Scrappers, Trackers, Creepers, Brawlers, Bruisers

FEV Experiments

 * Super Mutants: Super Mutant, Super Mutant Brute, Super Mutant Master, Super Mutant Overlord (Broken Steel), Super Mutant Behemoth
 * Centaur

Non-Humanoid

 * Brahmin, Mad Brahmin
 * Mole Rat
 * Yao Guai
 * Dogs: Vicious Dog, Raider Guard Dog, Scavenger's Dog, Talon Company Guard Dog ,Dogmeat, Dogmeat's Pup (Broken Steel)

Reptiles

 * Deathclaw
 * Mirelurk King
 * Swamplurk Queen (Point Lookout)

Crustaceans
(Point Lookout)
 * Mirelurks: Mirelurk, Mirelurk Hunter, NukaLurk, Swamplurk, Mirelurk King

Insects and arachnids

 * Fire ants: Fire Ant Worker, Fire Ant Soldier, Fire Ant Warrior, Fire Ant Nest Protector, Marigold Ant Queen
 * Giant ants: Giant Worker Ant, Giant Soldier Ant, Giant Ant Queen, Mutated Forager Ant
 * Bloatfly
 * Radroach
 * Radscorpion, Giant Radscorpion, Albino Radscorpion (Broken Steel)