Though adult T. rexes were mostly covered in scales, scientists think they had patches of feathers on attention-getting areas like the head and tail.
3. T. rex hatchlings looked more like fluffy turkeys than terrifying predators.
T. rex hatchlings were covered in peach fuzz, much like a duckling. As they aged, they lost most of their feathers, keeping just the ones on the head, neck, and tail.
Most hatchlings didn't survive past infancy. A baby T. rex had a more than 60% chance of succumbing to predators, disease, accidents, or starvation during its first year of life.
4. T. rex had a fairly short lifespan by human standards. No known T. rex lived past the age of 30.
The T. rex was like "the James Dean of the dinosaurs," said Gregory Erickson, a paleontologist from Florida State University who consulted on the museum's new exhibit.
The Hollywood actor, often connected to the famous quote "Live fast, die young, and leave a good-looking corpse," died in a fiery car crash at the age of 24. T. rexes, similarly, were spectacular but died quite young.
Paleontologists can estimate the age that a dinosaur was when it died by analyzing its fossilized bones, which have growth rings that correspond to its age, much like trees. Experts can count the number of rings to determine its age, as well as compare the spaces between rings to find out how fast the dinosaur was growing at different ages.
5. A T. rex grew from a tiny hatchling to a 9-ton predator in about 18 to 20 years, gaining an unbelievable 1,700 pounds per year.
A full-grown Tyrannosaurus rex weighed about 6 to 9 tons. It stood about 12 to 13 feet tall at the hip and was about 40 to 43 feet long.
6. The "king of the dinosaurs" evolved from a larger group of tyrannosaurs that were smaller and faster.
While the T. rex emerged about 68 million years ago, its tyrannosaur ancestors were 100 million years older than that.
The tyrannosauroidea superfamily consists of two dozen species spanning more than 100 million years of evolution.
7. That evolutionary lineage might explain why T. rex had tiny arms.
For earlier tyrannosaur relatives with smaller bodies, these tiny arms were long enough to grasp prey or pull food into their mouth.
"The earliest tyrannosaur species had arms that were perfectly proportioned," Erickson said.
He said he thinks T. rex's puny arms were vestigial — a body part or organ that no longer serves a function but is nevertheless retained (kind of like a human's appendix or wisdom teeth).
8. An adult T. rex didn't need its arms to hunt — its massive jaws, filled with sharp teeth that constantly grew back, were enough.
"T. rex was a head hunter," Norell said. The predator had the rare ability to bite through solid bone and digest it.
Paleontologists know this from the dinosaur's fossilized poop; they've discovered T. rex feces containing tiny chunks of bone eroded by stomach acid.
9. The force of a T. rex bite was stronger than that of any other animal.
T. rex had a bite force of 7,800 pounds, equivalent to the crushing weight of about three Mini Cooper cars. By comparison, the massive saltwater crocodile of northern Australia — which grows to 17 feet and can weigh more than a ton — chomps down with 3,700 pounds of force.
No other known animal could bite with such force, according to museum paleontologists.
10. T. rex was also a cannibal.
Scientists are pretty sure that T. rex ate members of its own species, but they don't know whether the dinosaurs killed one another or just ate ones that were already dead.
Arguments about whether the dinosaur was a hunter or a scavenger have raged over the years, but "a bulk of the evidence points to T. rex being a predator, not a scavenger," Erickson said. "It was a hunter, day in and day out."
11. The predator had a keen sense of smell, acute vision, and excellent hearing, making it hard for prey to avoid detection.
When "Jurassic Park" came out in 1993, scientists knew only that the T. rex was big and carnivorous and had a small brain, Erickson said.
But now paleontologists know that the dinosaur had some of the largest ey