Tatonka!

Okay, so this is pretty incredible. (hat tip: Megan) It seems like conventional nature-film fare at first, but keep watching:

See web-only content:
http://www.theatlantic.com/personal/archive/2007/06/tatonka/54444/

This article available online at:

http://www.theatlantic.com/personal/archive/2007/06/tatonka/54444/