Over the years, researchers have found ample evidence proving that the horned Triceratops and the Tyrannosaurus Rex (T. rex), which roamed western North America in the late Cretaceous period — some 69 million years ago — were mortal enemies. However, finding perfectly-preserved fossils of the prey and predator locked in combat was something they only dreamed of until the 2006 discovery of the "Dueling Dinosaurs" at a private Montana farm by commercial fossil hunters Clayton Phipps and his team.