Well, I guess I'll be the pedantic librarian on this thread:
For the record (or just as a point of interest), here are the names of big cats Apple has used so far:
Kodiak (the public beta -- not a cat at all! Hey, what th--??)
Cheetah (10.0)
Puma (10.1)
Jaguar (10.2)
Panther (10.3)
Tiger (10.4)
Leopard (10.5)
Snow Leopard (10.6)
Lion (10.7)
If they wanted to stick to "big cat" names, they still have Ocelot, Lynx and Cougar they could use. Ocelots and Lynxes are not technically big cats, but in the public's mind they are. Cougars are also called pumas, so technically Apple has already used that up.