“Today we see that many big mammals — like elephants, rhinos, hippos, and Cape buffalo — have greatly reduced their covering of hair,” he explained. “As big bulky animals living in warm environments, these mammals are more concerned with the risk of overheating than the challenge of staying warm, so they are better off with little to no hair. The same explanation probably explains, at least in part, why big tyrannosaurids had little to no feathers.”
T. rex, which could grow to about 40 feet long and 20 feet tall, had very long legs and strong leg bones. These indicate that it could move quickly when it wanted to do so.
“In a sprint, it could probably out-run any other large dinosaur,” Persons said.
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T. rex, as well as other tyrannosaurs, lived in a range of habitats, from swamps to open floodplains. During the day, these regions could become very hot. A large animal with an active lifestyle living in an often-hot environment was then “better off not wearing a down jacket,” Persons said.
Exchanging such a feathery covering for a scaly hide meant that T. rex and its kind were covered in skin that was tough and resistant to abrasion, the researchers believe.
Persons is currently investing still more new T. rex fossils, this time from Saskatchewan, Canada. Instead of focusing on the skin, he is examining the enormous dinosaur’s skull, and what it reveals about the carnivore’s face.
“One cool thing about T. rex that isn’t well known is that the dinosaur actually had small horns on its cheeks, and this new material gives us clues to how those little horns grew,” Persons said.
Taken together, the horns, T. rex’s tough skin and the dinosaur’s enormous size help to explain why this animal was one of the most formidable terrestrial predators of all time.
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