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Wolves, reintroduced to Yellowstone in 1995 and 1996, have made a well-documented—and, to some, controversial—comeback in the park. From just a few dozen released back then, their numbers have swollen to include roughly 480 wolves in 75 packs across the greater Yellowstone ecosystem. Still, canis lupus can be pretty elusive from spring through autumn. But bare trees and a permanent blanket of snow make winter the best time for spotting the top dog, especially in Slough Creek and the Lamar Valley. Wildlife biologists Nathan Varley and Linda Thurston—aka The Wild Side—offer a full day of wolf trekking, including transportation, entrance fees, hot drinks and breakfast, from $480 (1 to 5 people) to $680 (6 to 14 people).
And, If the wolf watching isn't too hot, there are always bubbling mud pots, erupting geysers and gem-colored mineral pools, which, set against the white canvas of winter snow, look all the more spectacular.