What was the last macOS release named after a big cat?

What was the last macOS release named after a big cat? Mountain Lion. OS X Mountain Lion, version 10.8, was Apple's final major Mac operating-system release to use a big-cat name.

Released on July 25, 2012, Mountain Lion followed OS X Lion and continued Apple's sequence of feline names. Earlier releases included Cheetah, Puma, Jaguar, Panther, Tiger, Leopard, Snow Leopard, and Lion. The naming tradition began as an internal-code-name practice and later became prominent marketing branding.

Mountain Lion also marked Apple's increasingly annual release rhythm and its effort to bring iPad-inspired features to the Mac. It added Notification Center, Gatekeeper, Messages, Notes, Reminders, Game Center, and deeper iCloud integration. It was distributed through the Mac App Store rather than on physical installation media.

The next major release, OS X Mavericks, changed the naming pattern completely. Announced in 2013, it was named for a California surfing location, beginning Apple's long-running California place-name era. Sierra, El Capitan, and Yosemite therefore came after the big-cat period, not before it.