plain 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 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, giving it superior depth perception during a hunt.
12. One of the biggest differences between the museum's depiction of T. rex and the images in popular culture is that the real animal appears to be much svelter.
The new model shows a T. rex with even smaller forelimbs than previous ones and more prominent hind limbs.
According to museum paleontologists, an adult T. rex walked with fairly straight legs, much like an elephant. Walking with bent legs would have placed immense stress on its bones and joints, quickly exhausting its leg muscles.
13. 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, helping it reach speeds of 10 to 25 mph. 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.
14. There are still a few lingering mysteries about 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, leaving questions about differences between males and females unanswered as well.
15. Scientists aren't sure what 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, but most likely cooed, hooted, and made deep-throated booming sounds like the modern-day emu.
This article originally appeared on Business Insider.