It really feels like I should answer this with one of the more egregiously missing species, like an African rhino, a leopard species, meerkats, leopards, or sea lions... but I've just gotta go with my favorite animal not currently in the game, the tanuki or Japanese raccoon dog. They're so fat and fluffy and cute and entertaining, and I'm very fortunate to live relatively close to what I believe is the only Zoo in the US that currently has any. I've sat and watched them for what seems like hours before. They'd be such a great inclusion in PZ as well, as a canid species that looks and acts significantly different than any of the ones currently in the game. I mean, I'd trade both the arctic wolf and the dingo for them in a heartbeat... lol.....