Cnn Go recommends Travel All Russia's winter tour as one of the top 24 things to do this winter. Extract from CNN article:
Get to know the Siberian Tiger, Vladivostok, Russia
The Siberian tiger remains elusive to visitors hoping to catch a glimpse of the beautiful big cat. Eco-tours offer visitors a holistic experience, and possibly even a sighting or two of the Siberian tiger. Try the “Realm of Amur Tiger” package offered by U.S.-based Travel all Russia, which adheres to ecotourism principles.
Links:CNN Go story: Travel Advent Calendar: 24 Christmas travel ideas
The Realm of Amur Tiger: tour details
Winter Treasures of Two Capitals Tour