Animal Friend

Animal Friend is a Fallout, Fallout 3, and Fallout: New Vegas perk.

Fallout
With this perk, animals will not attack the PC, unless the animal is threatened or attacked first.

Deathclaws are not classified as animals for the purposes of this perk. Neither are any variety of arthropods such as radscorpions.

Fallout 3
After the player acquires the first rank of this perk, animals simply won’t attack the PC. After acquiring the second rank, these creatures will come to the PC's aid in combat, but never against other animals. This perk affects vicious dogs, Yao Guais, mole rats, and mad brahmin.

Additional Dialog

 * With this perk, a dialogue option becomes available when speaking to Tree Father Birch in Oasis. He will then explain to the Lone Wanderer why there are animals in Oasis, though this doesn't have any benefits.

Fallout New Vegas
This perk affects Bighorner, Geckos (not Fire geckos), Coyote, Legion mongrel, NCR guard dog, Fiend guard dog, Dog, Mole rat, Brahmin, Giant rat, and Nightstalker. It is is also more effective than in Fallout 3, as the second tier of the perk will now cause tamed animals to come to the aid of the Courier, whereas in Fallout 3 the only "neutral" animal type to all factions were Brahmin and few enemies used animals as attack pets.

Second Tier Uses

 * Goodsprings: Bighorn will attack the locals or Powder gangers during Ghost Town Gunfight and Run Goodsprings Run rather than fleeing.
 * Nipton: When attacking any Caesar's Legion members with Legion mongrels the animals will turn on their owners.