Pets are animals that follow you. They can fight, search, and hunt. There are three pets in the game. As of v650, pets have their own management menu in the game. From this menu you can send them hunting or searching for resources and the loot will be better if your pet has a high level. They need to be fed in order to do anything. Each pet has its own abilities which you can use, both in and out of battle. If a pet takes damage or is "killed" during a battle, it will receive the "near-death" status. You then have to heal it in order for it to do anything again, or you can just let them heal by themselves over time.
You can only take two pets with you into battle at a time.
Pets gain experience from using abilities (see their individual pages) or by being taken to combat. This means that they do not get exp from crafting, quests, etc. Experience from a battle is divided evenly among all of the characters that were in it, meaning you (the player) as well as your pet(s). e.g. if you got 100 experience from a battle and had the raven pet with you, then you and your pet raven would both get 50 experience.
Raven: Raven can be obtained two ways: have premium when the 650 update came out, or start a new game in premium.
Wolf: If you had wolf before the update, you got wolf automatically. If you did not, then you can find it in a random encounter in the wasteland or in an Intact house. If it had a high level before the update, it will be a level 60 wolf. The wolf can also be obtained through the Wolf Cubs Quest as a reward.
Lil' Pum' kin: Can only be obtained through the 2019 Halloween event after defeating Pumpking and bring its head to the Hunter.