I am pretty sure considering where it saves you would need Windows. HOWEVER it is possible to install Windows on a Mac as I have friends who have done it, personally I don't know how it is done.
There are ways, but they invariably involve you using some form of emulator like W.I.N.E. and a cursory glance tells me that nobody's had much luck from that angle. If you want to have a fiddle, this is probably the most likely to find success with: Home - PlayOnMac - Run your Windows applications on Mac easily! Your best bet is do as Matt says, install a copy of Windows onto your Mac. I have about an hour's worth of experience with Apple computers so don't know off the top of my head how to do so, but I believe the gist is to create a partition on your hard drive, install Windows to the partition, then use a piece of software to manage which OS you boot into on startup. The main drawback of this approach would likely be procuring a copy of Windows. If you're doing it for the purposes of playing Zoo Tycoon 2, you could look for a copy of Windows XP for maximum compatibility, but looking and finding are two different things, and if you do find one, installing XP to an online computer comes with some security risk. Quite minor these days, but there all the same. EDIT: I should have said, there are copies of Zoo Tycoon 2 for Mac out in the wild, but not Ultimate Collection, and I don't think the expansions came out for Mac originally, either. If that doesn't bother you, maybe getting one of these would be your lowest hassle route to Zoo Tycoon on your Mac.
