Watch the full-length episode at http://video.pbs.org/video/2332594879 (US Only) Breathtaking footage of a wolf pack going after a herd of bison in Canada's Wood Buffalo National Park. "Cold Warriors: Wolves and Buffalo" premieres Wednesday, February 13 at 8/7 (check local listings) and is part of the 31st season of the Peabody and Emmy award-winning series produced by Thirteen in association with WNET for PBS. Major support provided by Canon U.S.A. Inc.