This is the best I could find:
Mac OS X versions are named after big cats. Prior to its release, version 10.0 was code named "Cheetah" internally at Apple, and version 10.1 was code named internally as "Puma". After the immense buzz surrounding Version 10.2, codenamed "Jaguar", Apple's product marketing began openly using the code name to promote the operating system. 10.3 was similarly marketed as "Panther". Version 10.4 is marketed as "Tiger". "Leopard" has been announced as the name for the next release of the operating system. Apple has also registered "Lynx" and "Cougar" as trademarks.
What about you?