Ultrafierce Tyrannosaurus rex is an icon. But the “tyrant lizard king,” which lived between 68 million and 66 million years ago, is just the youngest member of a family of dinosaurs that went back to about 167 million years ago. The earliest tyrannosaurs were quick and small. So how did T. rex become so big and bad?
That’s one of the questions at the heart of “T. rex: The Ultimate Predator,” an exhibit now open at the American Museum of Natural History in New York City. The exhibit takes a deep, multisensory dive into what we know about this most famous of dinosaurs. It is a fitting centerpiece for the museum’s 150th anniversary: The very first T. rex specimen was unearthed in Montana in 1905 by Barnum Brown, a paleontologist at the museum.
In 1908, Brown and his team dug up a second T. rex skeleton — this one nearly perfect. The new exhibit includes a reproduction of this skeleton but goes beyond that static representation, drawing on cutting-edge research over the last 10 years or so to illustrate how scientists now think the animals grew, moved, ate and perceived the world.
For instance, cranial analyses suggest that T. rex had excellent vision and a very good sense of smell. The dinosaur also had a bone-crushing bite force (SN: 11/10/18, p. 13). Perhaps reassuringly, the exhibit also notes that while a juvenile T. rex could run — defined as lifting one foot fully off the ground followed by the other — adult T. rexes were too heavy for a running gait. Their skeletons would have buckled under such a weighty load.
Life-size models of T. rex at various life stages help illustrate the animal’s astoundingly rapid rate of growth. Fluffy hatchlings were perhaps the size of chickens (and only about 40 percent of them survived their first year). By age 4, the animals were already 4 meters tall, and by age 20, they had reached their full height, about 13 meters. A T. rex that lived to age 28 was essentially a senior citizen; no known T. rex specimens are thought to be older than that.There’s a lot we still don’t know about T. rex : what it sounded like, how to tell apart males from females and how the species got to be so giant ( SN: 3/16/19, p. 11 ). For clues to lingering puzzles, researchers have often turned to the other two dozen or so known members of the tyrannosaur family. As described in the exhibit, fossilized feathers found with several of T. rex ’s close relatives are the reason scientists suspect the king had feathers too. And tyrannosaurs with sensitive facial skin could mean that T. rex was similarly sensitive to touch and temperature ( SN: 4/29/17, p. 5 ).
Happily, the exhibit gives some of these other members of the tyrannosaur family tree a moment in the spotlight. These dinos include little-yet-fierce tyrannosaurs such as the wolf-sized Proceratosaurus bradleyi, which lived about 167 million years ago, and hollow-boned, long-armed and feathered Dilong paradoxus, which lived about 126 million years ago.
Although there’s a lot of information to take in, the exhibit also aims to be highly interactive. There are touchable fossils and fossil casts, a “roar mixer” that allows people to imagine the voice of a T. rex by blending other animals’ sounds, and a virtual reality station where visitors can piece together a skeleton. The pièce de résistance comes at the end of the exhibit: A life-size animated T. rex projected onto a screen that tracks passersby; stand in front of it long enough and it might take a snap at you.