When playing the “Raise Pups” game mode in co-op multiplayer, you and all other players in the session must find and settle at a den. As you progress through the missions, four pups will be generated based on the coats of the players currently in the session. Each player, if there are only two, will be able to name two pups. However with more than two players having enough Experience to name pups, the number goes down to correspond. For example, if there are 4 players, each gets to name a pup.
See Cooperative vs. Competitive Pup Raising if you have questions about "pup drowning" in multiplayer games.
When playing “Pack Life” there are no pups nor is there an option to change your wolf's age, however players often choose to roleplay as pups.