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Tyrannosaurus Rex is the most widely known and iconic Dinosaur in history. Discovered by paleontologist Barnum Brown in 1902 in Wyoming and Montana, and dubbed the Tyrant Lizard King by Henry Fairfield Osborn in 1906. T-Rex was approximately 46 feet long and 15 feet high. It weighed between 7-14 tons. Many people believe T-Rex was an insatiable predator that devoured anything in it's path. However recent research conducted by paleontologist Jack Horner paints a very different picture of the beast. Horner believes T-Rex was a gigantic scavenger, stealing already killed meals from smaller predators like Dromaeosaurus.
Robert Bakker and the T-rex
Hunter or scavenger?
The big debate about T-Rex is whether it was a hunter or a scavenger. First we need to take a look at animals that have a similar skull and jaw to T-Rex. Alligators are a good example. An American Alligator's bite force could range from between 2,000 PSI(pound per square inch) and 3,000 PSI. According to expert Dr. Greg Erickson a professor of paleontology at
Florida state University the estimated bite force of T-Rex would have been between 3,000 and 6,000 PSI.That's enough force to pulverize bone and fossil evidence shows that T-Rex' jaws were perfectly capable of the job. Bones of Hadrosaurs and Triceratops have been discovered with Tyrannosaur tooth marks embedded in them. So based on this evidence we know that T-Rex' jaws were capable of crushing the bones of other large Dinosaurs. But this isn't enough evidence to prove that T-Rex was a hunter. Jack Horner cites the fact that T-Rex has a very sensitive and well developed sense of smell based on the shape of it's brain-case, and the region dedicated to smell. Horner says this is a trademark of scavengers like Jackals, Vultures and Hyenas. Another reason Horner doesn't buy the carnivore idea is the fact that the Rex has such tiny arms for a predator and he wouldn't be able to grab things. Horner's last argument for T-Rex as the scavenger, is that it's legs were not designed for running, but walking at speeds of up to ten to fifteen miles per hour. This Horner states is because the thigh bone is longer than the shin bone.
It is safe to say that there is enough evidence based on the anatomy of T-Rex, that it wasn't suited for active pursuit. Let's face it if a fully grown Tyrannosaurus Rex exceeded more than twenty miles per hour, and tripped, the results would be fatal with all that tonnage. But what about ambush? Lying in wait for some poor Hadrosaur to come to close to a thick group of trees T-Rex is hiding in, or better yet, chasing a group of Hadrosaurs into the waiting jaws of another T-Rex. There has been evidence found of other Dinosaurs with yet more bite marks from none other than T-Rex on their bones; However these cases also show that the wounds healed. One such case was an Edmontosaurus, a common Hadrosaur with Tyrannosaur bite marks in it's tail that healed indicating the animal somehow survived a vicious attack from a T-Rex. A Triceratops has also been found with T-Rex bite marks on it's neck frill and they were also healed. So now we have evidence that Tyrannosaurus did in fact attack live Dinosaurs on occasion.
Territoriality and cannibalism
Many Tyrannosaurus skulls have been discovered with severe, and sometimes fatal looking injuries. The cause of some of these wounds appear to be from other Tyrannosaurs suggesting territorial battles and even cannibalism. Paleontologist Nick Longrich of Yale University looked at some T-Rex toe bones from Montana and noticed large tooth marks embedded in the bone. Longrich came to the conclusion that these tooth marks were definitely from another T-Rex because T-Rex was the only large theropod living in North America at that time according to the fossil record. There are plenty of examples of Tyrannosaurs leaving facial bite marks on each other as well suggesting that perhaps they fought over carcasses. Longrich and other paleontologists hypothesize the giant predators may have participated in cannibalism habitually—but it's unknown whether the Dinosaurs fought to the death or simply scavenged other T. rex carcasses. Longrich told Discovery News, "They're equipped to kill and eat large animals, and if you're hungry enough, fellow members of your species are just one more kind of large animal."
How fast was T-Rex?
Paleontologists that understand the criteria of bio mechanics (physics of organisms) believe that Tyrannosaurs could move fairly fast, possibly 10-20 mph, but not as fast as other smaller theropod dinosaurs. Smaller Tyrannosaurs like Albertosaurus, or younger individuals might have ran faster than the larger adult T-Rex. Yet there is still no clear evidence that Tyrannosaurs could even have run; some paleontologists think that their body size confined them to only a fast walk, like an Elephant. According to Jack Horner T-Rex couldn't run because it's thigh bone was slightly longer than the shin bone. Horner says that this is a characteristic of a walker not a runner. Trackways that specifically were made by an adult Tyrannosaurs would shed light on the matter, but so far none have been discovered.
Was T-rex a hunter or a scavenger?
10 facts about Tyrannosaurus Rex
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Profile of T-Rex at NatGeo
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- Walking with Dinosaurs - Fact File: Tyrannosaurus
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