Though 200 years have passed since the Great War, dogs have stayed generally unaltered by radiation. Dogs are a favored pet for traveling merchants, as they provide both companionship and protection. As a result of the radiation, most dogs have lost their fur and have slightly mottled skin, but some have retained their fur coats and appear completely normal.
Dogs are quadrupedal canines that can run at incredible speeds, allowing them to chase down prey. While running, they use their long tails to keep their balance. They are carnivorous, with sharp teeth designed to rip into the flesh of an animal.
Dogs are very compassionate and familial. They groom their pack members and protect them at all costs, even if it means their death. When threatened, they growl and bare low, ready to attack. If the intruder doesn't heed the warning, they will leap on the trespasser and attempt to rip out their throat.
Dogs are usually encountered in packs of four to six. To low level characters, this could mean trouble since they can easily overwhelm and surround them. To higher level characters, they are little more than a nuisance, yet can still be difficult to put down as a result of their erratic and quick running patterns. Vicious dogs (and their variants) are always hostile, unless the Lone Wanderer possesses the Animal Friend perk.
Raider guard dogs fight alongside their masters, the raiders. Since they're trained as guard dogs, they are very attentive and can spot the player character easier than many other creatures. Raider guard dogs will tend to run at targets they find hostile, alerting the raiders of their presence. They are still affected by the Animal Friend perk, but will not attack raiders.
These dogs are found around scavenger's encampments, and will be friendly to the Lone Wanderer as long as he/she doesn't act aggressively to them or their master. These dogs have slightly less Hit Points and attack damage than vicious dogs.
There is a Karma loss for killing the scavenger's dog, as well as the scavenger themselves and/or the scavenger's brahmin if they have one. Furthermore, scavenger dogs will attack if the Lone Wanderer continues to pursue the scavenger even after a warning is given.
While the scavengers' dogs share a model with Dogmeat, with the same breed and the same type of heterochromia, scavenger's dogs are significantly weaker than Dogmeat.
Scavengers' dogs will take back items that the player character steals from their master, even if their master is dead.
Identical to vicious dogs, these animals will often accompany Talon Company mercenaries. Much like the raider guard dogs, their Perception is high, they may spot hostiles faster than the mercs do. They are also affected by the Animal Friend perk, much like their other canine raider brethren.
Ruthless survivors of the wastes, these irradiated dogs will always be hostile, unless the player character has acquired the Animal Friend perk. They are almost always encountered in packs of 2-5, usually in open areas. Beware of these dogs as they can sometimes spawn in semi-random areas. Vicious dogs rarely use flanking tactics, but once they spot a target they will often encircle it in an attempt to stop it from escaping.
Used as guards by the Chinese soldiers in the Anchorage Reclamation simulation, these dogs have been unaffected by the Animal Friend perk, unlike raider, Talon company and vicious dogs. Guard dogs are only worth a single point of XP. Just like scavengers' dogs, they share a model with Dogmeat, with the same breed and the same type of heterochromia, while being significantly weaker. Once killed, like all characters in the simulation, they disappear from the game.