How We Elected T. rex to Be Our Tyrant Lizard King
Story by Brian Switek
From snout to tail tip, T. rex was certainly a superlative animal. It lived between 68 and 66 million years ago in western North America, the range of the species extending from what’s now southern Canada through New Mexico. And yes, it was a giant: The largest and last member of its family, a fully-grown T. rex could grow to be 40 feet long and weigh over 9 tons. The ’saur had a jaw powerful enough to crush the bones of other dinosaurs – and, while contested, calculations based on skeletal anatomy and muscle mass suggest that a T. rex in a hurry could have moved at speeds of 17 miles an hour or more.
Few would think to question the generation-defying popularity of our king, Tyrannosaurus rex. In academic journals, galleries of paleoart, and even the now-25-year-old Jurassic Park franchise, T. rex has come to represent the ultimate epitome of dinosaurness. University of Nevada, Reno historian of science Jane Davidson puts it this way: “If you say ‘dinosaur’ to most people, I would bet you that the mental image they have first is of T. rex.” The tyrant even reigns on Twitter, where Sue the T. rex has amassed nearly 41,000 followers.
Paleontologists were on the trail of T. rex before they even knew it. In the late 19th century, teeth and isolated bones carried back from western expeditions during this time would, ultimately, turn out to be T. rex scraps. These were glimmerings of something fierce, during a time when only a handful of dinosaurs were known and each new discovery had the potential to not only reveal new species but entire families of dinosaurs. The two skeletons that revealed tyrant’s full glory were excavated by famed fossil hunter Barnum Brown in 1900 and 1902, respectively, and later described by paleontologist Henry Fairfield Osborn in 1905.
There was a bit of initial confusion. Osborn called the first skeleton by the (also catchy) name of Dynamosaurus imperiosus, even accidentally including some ankylosaur armor in his vision of the dinosaur, while dubbing the second, better skeleton Tyrannosaurus rex. He soon realized his mistake, however, and in a follow-up paper said both skeletons should be called Tyrannosaurus rex.
The first, less-complete skeleton went on to the Carnegie Museum of Natural History in Pittsburgh – where it can still be seen today – and the better skeleton was reassembled in the dinosaur halls of the American Museum of Natural History in New York, where it was known as AMNH 5027. Decades before the discoveries of soon-to-be celebrity rexes “Sue,” “Stan,” “Jane,” “the Wankel Rex,” and others, AMNH 5027 became the most famous dinosaur of them all. Casts and reproductions of this dinosaur can still be seen at museums around the world.
Why? Tyrannosaurus was far larger than any other predatory dinosaur found so far (there’s still plenty of debate over whether it still holds the title for the heftiest Cretaceous heavyweight). Moreover, compared to most dinosaur discoveries of the time, including other predatory dinosaurs, the first two Tyrannosaurus skeletons were relatively complete. As if this wasn’t enough to prime Tyrannosaurusfor the big time, it turned out Osborn was the ideal promoter for the dinosaur.
“Henry Osborn was a wonderful publicist,” Davidson says. The paleontologist was thinking big from the start; at one point he even considered mounting both original T. rex skeletons in a single scene, facing off over a carcass. That idea was scrapped in favor of a single mount of the better skeleton, which the local press immediately enthused over. Even when only the hips and legs of the museum’s favored T. rex were up, the New York Times declared the dino “the prize fighter of antiquity.”
Osborn had the bones, the facilities, the funding, and the press attention to make T. rex a star, notes University of Maryland paleontologist and T. rex expert Thomas Holtz, Jr. The dinosaur even appeared as the villain in the 1918 movie The Ghost of Slumber Mountain, one of the earliest dinosaur flicks. The name was surely part of the dinosaur’s appeal, too. “Calling it the king of the tyrant lizards was genius,” Davidson says – a name that was simple, evocative, and immediately told you exactly the kind of dinosaur you were looking at.
But the familiarity of T. rex slightly can obscure the true nature of the dinosaur. “If T. rex had been discovered in the last 20 years or so, we would consider it a weird or extreme dinosaur,” says Holtz. T. rex has extremely large and thick teeth for its skull size, an extraordinarily deep and wide skull, and lumpy ornamentation around the eyes that are more prominent than those of its relatives. Despite being the name-bearer for an entire family of dinosaurs, Tyrannosaurus is among the strangest of its kind.
Nevertheless, T. rex has become an ambassador dinosaur, known from over 50 partial skeletons and with a paper trail longer than the carnivore’s body. “But fame comes at a price,” Holtz notes. The huge bulk of literature gives us the impression that we know T. rex well, when, in reality, we’re still getting to know the basics. In other words, Holtz notes, “T. rex has become the Drosophila melanogaster of vertebrate paleontology” — the very measure of almost any question you could think to ask about the Cretaceous period — whether it’s the best study subject or not.
The king is also prone to generating controversy. In the early 90s, when paleontologist Jack Horner proposed that T. rex only scavenged for food rather than hunted, the outcry from other experts and the public alike was louder than a cinematic dinosaur’s roar. (There’s evidence T. rex both hunted and scavenged, like most modern carnivores, with the real question being how much of the dinosaur’s diet was fresh versus carrion.)
More recently, a 2016 conference presentation suggested dinosaurs like T. rex had fleshy lips covering their teeth and spurred debate among T. rex fans; the description of a different tyrannosaur by Thomas Carr and colleagues proposed that these predators had more crocodile-like faces with exposed choppers. Soon thereafter a 2017 study suggesting that T. rex was primarily scaly drew critique from those who think T. rex had at least a partial covering of fuzzy protofeathers. And don’t even get started on the long-running, vociferous argument over whether small tyrannosaur specimens from the same haunts as T. rex should be relabeled “Nanotyrannus.” (Spoiler: they shouldn’t.)
This kind of attention isn’t unique to T. rex. Popular icons tend to stay that way, often following a concept called the 80/20 rule – that is, about 80 percent of the effects come from 20 percent of the causes. In Davidson’s other field, the history of art, she says, “one gets more attention for example if you find a new Leonardo, or a purported new Leonardo, than if you find yet another painting by David Teniers II.” The same goes for T. rex: far more attention is given to a minor revision about the tyrant king than, say, Camarasaurus, or another dinosaur that doesn’t have nearly the same cultural cachet.
In the century since Osborn’s announcement, T. rex has continued to metamorphose. New ideas about the species, as well as dinosaurs in general, have created an entire continuum of T. rex visions, from tail-dragging sluggards to supercharged hypercarnivores covered in fuzz. Even this month’s release of Jurassic World II – which stars a T. rex that was accurate by 1993 standards but needs a few updates – helps highlight how our perceptions of those old bones keep shifting with the times.
Even after all those years, it’s hard for those who study the king to resist its appeal. “T. rex has always been my favorite dinosaur, since I was three years old,” Holtz says. “Originally it was just because it was, in the literal sense of the word, awesome. But as time went by and I began to learn more about anatomy and biology and the nature of science, I got to appreciate the species in new ways.” T. rexappeals to both the high-minded and the visceral parts of ourselves, and, Holtz says, the poetry of the species has a persistent draw.
Think of it, says Holtz: “The giant predator in a wonderful ecosystem which ended in fire and darkness. Who wouldn’t love that?
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