Zynga hinted at the release of a Private Zoo in Mafia Wars for a short while, but has finally come through with releasing this new property in the game. The Private Zoo can be thought of like the Armory and Weapons Depot, both of which are found under your New York set of properties, except that instead of producing Armor (defensive items) and Weapons (offensive items), respectively, you'll now be able to "acquire" animals from around the world that will help fight on your side.
You can find your new Private Zoo by heading into your Properties bar while visiting Mafia Wars New York. As you might expect, the Zoo has a level, and yours starts out at just level 1. You'll need to collect various items to level up your Private Zoo and subsequently unlock better animals, so meet us behind the break for all of the details on how to go about that.