Subspecies are a special class of animals which cannot be bred in habitats or purchased from the Zoo Shop. Instead, they can be bred via the Breeding Lab. They are also available as prize animals from the Wheel of Fortune and the Traveling Circus, and the Black Zebra subspecies can be obtained on Safari. Each subspecies differs from the base species and from other subspecies on several points:
- They each have a unique appearance.
- They cannot be placed in the same habitat as one another.
- Some of their stats differ, including different star ratings, attractiveness points, and resale values.
When breeding a pair of adults in the Breeding Lab, the resulting baby may turn out to be the same subspecies or a higher ranking subspecies, and never lower than the lowest breeding parent involved. Typically, the baby produced is equal or +1 degree higher. Subspecies' degrees are ordered by their star rating, which coincides with their resale value and attractiveness. The highest star-rated (and final) subspecies of an animal type is also the most difficult to obtain, because typically, players have to "build" towards achieving these animals.
Consider the parrot animal type, which consists of the base animal plus four additional subspecies:
- Scarlet Macaw (Base Animal)
- Military Macaw (2nd Degree)
- Blue-Throated Macaw (3rd Degree)
- Gray Parrot (4th Degree)
- Sun Parakeet (5th Degree) *The highest rated subspecies cannot be bred
Since breeding in the lab usually results in either the same subspecies or the next highest degree subspecies, and since both parents are consumed as a result of breeding in the lab, obtaining the highest degree subspecies often takes some considerable effort. Even if every breeding attempt was favorable, and produced a +1 degree baby, to obtain one Sun Parakeet, sixteen Scarlet Macaws and fifteen separate breedings would be necessary.