On the dominance scale they are the most dominant, being followed by the Aquus. In practice this means a pure felidae without a recessive will always breed felidae dominant offspring regardless of the other parent's genes.
Felidae eggs look red with a black cracked outer shell. They are sold in the egg shop for one orb each and are not limited in quantity so they can always be bought.When a new user joins FF their account comes with six engineered Felidae eggs, three male and three female. Commonly known as 'Original 6' or O6, these customs are special in that they are bound to your account once created and cannot be bought, sold, traded or given away through other means. If you move accounts your 06, can travel with you.
When a user reaches a Breeding Score of 50 they can use the Lab Changer feature to turn an engineered egg into a felidae egg for 1,000 energy, and at breeding score 100 an unborn baby can be turned into a felidae for 2,000 energy.
They are fairly plain, closely resembling ordinary housecats with wings. Being among the feli, along with the Zerda, that have the least surface area, most markings look more compact on them than other larger breeds such as the Xano.