The real T. rex looked nothing like the monster in 'Jurassic Park.' These 13 discoveries have upended our picture of the 'king of the dinosaurs.'
The first T. rex skeleton ever found was discovered in 1902 by paleontologist Barnum Brown of the AMNH.
Today, the institution boasts one of the only original T. rex skeletons on public display in the world.
Tyrannosaurus rex — from the Greek words for “tyrant” and “lizard” and the Latin word for “king” — lived between 68 and 66 million years ago, during the late Cretaceous period (just before the asteroid impact that ended the era of the dinosaurs).
The T. rex rocked a mullet of feathers on its head and neck, and some on its tail, too.
Feathers are rarely preserved in the fossil record, so they haven't been found yet on a T. rex specimen. But other dinosaur fossils, including other Tyrannosaur species and their relatives, do have preserved feathers.
That means paleontologist can "safely assume" T. rex had feathers as well, Norell said.
Although adult rexes were mostly covered in scales, scientists believe they had patches of feathers on attention-getting areas like the head and tail.
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 more than a 60% chance of succumbing to predators, disease, accidents, or starvation during its first year of life.
The 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," according to Gregory Erickson, a paleontologist from Florida State University who consulted on the museum's new exhibit.
The Hollywood actor — whose famous quote was, “Live fast, die young, 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. The bones have growth rings that correspond to the animal's age, much like trees. Experts can count the number of rings to determine a creature's age, and can also determine how fast the dinosaur was growing at different ages by comparing the spaces between the rings.
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 12-13 feet tall at the hip and was about 40-43 feet long.
The "king of the dinosaurs" evolved from a larger group of tyrannosaurs that were, comparatively, smaller and faster.
While the T. rex emerged about 68 million years ago, its tyrannosaur ancestors were 100 million years older than that.
The tyrannosaurioidea super-family consists of two dozens species that span more than 100 million years of evolution.
That evolutionary lineage might explain why the T. rex had tiny arms.
For earlier tyrannosaur relatives that had smaller bodies, these tiny arms were long enough to grasp prey or pull food into their mouths.
"The earliest tyrannosaur species had arms that were perfectly proportioned," Erickson 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 in an animal's body (kind of like a human's appendix or wisdom teeth).
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 that had been eroded by stomach acid.
The force of a T. rex bite was stronger than any other animal on Earth.
The T. rex had a bite force of 7,800 pounds, which is 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 a bite of 3,700 pounds.
No other known animal could bite with such force, according to museum paleontologists.
The T. rex was also a cannibal.
Scientists are pretty sure that the T. rex ate members of its own species, but they don't know whether the dinosaurs killed each other or just ate animals that were already dead.
Arguments about whether the dinosaur was a hunter versus 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."
The predator had a keen sense of smell, acute vision, and excellent hearing, which made it hard for prey to avoid detection.
When "Jurassic Park" came out in 1993, scientists really only knew that the T. rex was big, carnivorous, and had a small brain, Erickson said.
But now paleontologists know that the dinosaur had some of the largest eyes of any land animal ever. About the size of oranges, T. rex eyes faced forward like a hawk's, and were spread farther apart on its face than most other dinosaurs' eyes.
This gave the T. rex superior depth perception during a hunt.
One of the biggest differences between the museum's depiction of the T. rex and the images in popular culture is that the real animal appears to be much skinnier and svelter.
The new model shows a T. rex with even smaller fore-limbs than previous ones, and more prominent hind-limbs. According to museum paleontologists, an adult T. rex walked with its legs fairly straight, much like an elephant.
Walking with bent legs would have placed immense stress on its bones and joints, quickly exhausting the animal's leg muscles.
So, unlike the creature in "Jurassic Park," the real T. rex couldn't run. It just walked quickly.
An adult T. rex had a long stride, which helped it reach speeds of between 10 and 25 miles an hour. But the dinosaur never reached a suspended gait, since it always had at least one leg on the ground at all times.
Juvenile T. rexes, which weighed less than an adult, could run.
There are still a few lingering mysteries about the T. Rex, including what color it was.
In movies and illustrations, the animal is often depicted in drab colors, similar to those of a crocodile. But the new museum exhibit suggests that, since reptiles come in every color, the T. rex could have been brightly colored.
It's also challenging for experts to determine the sex of the T. rex skeletons they dig up, which leaves questions about differences between males and females unanswered as well.
Scientists are not sure what the T. rex sounded like, but the best guesses are based on the dinosaur's closest living relatives: crocodiles and birds.
A 2016 study suggested that T. rex probably didn't roar; instead, the animal likely cooed, hooted, and made deep-throated booming sounds like the modern-day emu.
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