Regular animals, which can also be called rare animals (despite some being fairly common) are animals which are not the base animal, or the normal species of that animal, but can only be found in the stampede through normal play. All regular animals give animal mastery XP.
Regular animals are essentially 'normal' animals, or animals found in a normal way and do not require any special requirements apart from riding past a certain distance. Players can find regular animals randomly in the stampede, with animals of a higher tier appearing less often. If the player is unable to find animals, they can purchase regular animals from the Zoo Transfer Program with real money, however, this is not recommended.
In the Space Zoo, regular animals are unlocked progressively as the player upgrades their habitat, which differs from the Sky Zoo, where all regular animals are already unlocked once the base animal has been tamed.