Microsoft Game Studios today announced that Zoo Tycoon 2, the game developed by Blue Fang Games, is now available in North American retail stores for $39.99 (U.S.). Don't forget to check out the recently released demo where you can adopt four different animals: the Bengal tiger, the Thomson's gazelle, the dromedary camel, and the common peafowl. The demo also featurs the Freeform game mode, which allows you to build zoos using an unlimited budget, and a limited number of buildings, guest amenities, fences, scenery objects, plants, trees, and rocks.