Some paleontologists think the T. rex hunted by ambush.
Others believe it was too large to have been an active hunter, and suggest that T. rex was a scavenger. Ate other dinosaurs and animals. Lived at the end of the Cretaceous Period, about 67 million years ago. Measured up to 40 feet as adults, as long as 6 polar bears. Discovered in Montana in 1902 by Barnum Brown and named by Henry Fairfield Osborn in 1905.