Don't forget that MacPerl is a 'Classic' application, meant for MacOS 9.x and earlier. See the thread, MacPerl for more on the subject. MacOS X fits in with your Unix/Linux statement - it is BSD-based, and it ships with Perl 5.6.0 installed.
Don't get me wrong - MacPerl is great! Were it not for MacPerl a few years ago, I'd never have started learning Perl.