The Wolf is classified as an uncommon pet, and players have a 33% chance of hatching one out of a Christmas Egg.
Wolf
The Wolf is one of the six pets that were introduced to Adopt Me! on December 14, 2019, during the 2019 Christmas Event. The Wolf was obtainable through hatching Christmas Eggs, which were exclusive to the 2019 Christmas Event, and could not be obtained otherwise. Currently, the only way to obtain a Wolf is through trading with other players, or by hatching one from a Christmas Egg if you happen to still have one in your inventory.