In a luminous top-floor workshop closed to the public at the American Museum of Natural History in New York, artists work with scientists to re-create scenes from lost or vanishing worlds. This is the birthing room for the museum’s elaborate dioramas, such as the brace of Northwest Indians who air-paddle their canoe through a fluorescent entrance hallway, or the 94-foot blue whale that swoops down from the duplex ceiling of the Ocean Life Hall, or the herd of elephants with fearsome tusks and windblown ears that charges through the Hall of African Mammals.
In recent months, artists in the workshop have been putting finishing touches on a special exhibit called Fighting Dinosaurs. In a diorama for the new exhibit a fierce velociraptor, looking like a thinned-down turkey with frighteningly large teeth, stalks a protoceratops. With a flanged crest and beaked mouth that make it look like a goat-sized version of its larger and more famous cousin, Triceratops, the protoceratops sees the predator coming and snarls. The scene is so vivid that some visitors may glance around nervously to be certain they haven’t been whisked back 80 million years by a hidden time machine. “When you come upon a diorama,” says David Harvey, the museum’s vice president of exhibitions, “it transcends all of the data. It becomes a real experience.”
Yet it is precisely that experience with which a growing number of scientists have a big problem: There is precious little data about dinosaurs to transcend. What the museum scientists know about Indians, whales, and elephants is more than enough to mimic real life. But when it comes to dinosaurs, all they really have to work with is an incomplete jumble of bones. Indeed, if the exhibits department were limited to just skeletal data for its dioramas and reconstructions, these halls would take on a most unromantic flavor. For instance, the Indians in the canoe would lack noses, ears, and breasts, and the diorama artists (ignoring for the moment that they are humans themselves) would be at a loss for what to cover them in—slick skin like a dolphin? Monkey fur? Gorilla hair? As for the blue whale, no one would know to make it blue. And the elephants are a special case. There’s a running joke among professional dinosaur artists that goes like this: Given just an elephant skeleton, they’d probably render a titanic hamster.
Does anyone know what dinosaurs really looked like? Sure we do. We see them everywhere, not just in the museums, but in magazines, movies, even in value meals at McDonald’s. But all of these lifelike renderings are mostly artistic interpretations based on very sparse scientific evidence. To begin with, dinosaur skeletons are rarely found intact, and figuring out how scattered bones fit together is not always clear. Then, making the leap of placing tissue and skin on those bones is a process fraught with unknowns. Some paleontologists trained in comparative anatomy are beginning to analyze microscopic marks that soft tissues make on bones in search of clues to what dinosaurs actually looked like. But taking a pile of bones and conjuring up what snarling dinosaurs about to battle each other really looked like involves at best equal parts educated guesswork and complete artistic fancy. As Mark Norell, curator of vertebrate paleontology at the museum, puts it, dinosaur artwork “is a fantastic leap from what we know.” And most scientists say we may never know a lot more than we do now.
If that seems discouraging, it’s good to know that scientists are also quick to say that asking what dinosaurs looked like is asking the wrong question anyway. Paleontology is a much broader endeavor than worrying about outward appearances. Those who study dinosaurs are more eager to know the life histories of the beasts: what particular adaptations they had, how they ate, how they raised their young, and what evolutionary relationships they might have had with one another and with modern-day animals. Time-traveling visual imagery grabs the public’s attention, but it’s not the point. “Dinosaur entertainment is healthy, sure,” says Luis Chiappe, a paleontologist with the Natural History Museum of Los Angeles County. “But we don’t look at Batman and think it’s a documentary about the LAPD.”
Further, to blame the artist is also to blame the messenger. Dinosaur art pervades our culture because we want it to. As fantastic creatures that really did exist, dinosaurs excite our imaginations. We want to explore their size and power and weirdness—and be glad they’re no longer around. Biologist Stephen Jay Gould describes dinosaurs as “big, fierce, extinct—in other words, alluringly scary, but sufficiently safe.” Randall Osborne, a social psychologist, contends that our need to imagine creatures vastly more powerful than we are is so strong that, “if we hadn’t discovered dinos yet, we would have invented them ourselves. We would have made them in our movies.” Or in our mythology: The Loch Ness Monster, Chessie the monster of Chesapeake Bay, and the various fire-breathing dragons that cropped up millennia ago in both Eastern and Western mythology are hardly accidental.
Our attraction to dinosaurs doesn’t spring from a scientific source, so the paleontological inability to say what they really looked like has no real power to drive dinosaur icons from our world. In fact, rather than wholly dismiss dinosaur art, many scientists use its popularity to their advantage. After all, it does win money for museums and field research. Some of the more media-savvy, like Paul Sereno at the University of Chicago, will wait to publicize a dinosaur discovery until they have a commissioned painting of the creature to show. By working with artists, scientists can at least inform them about what is known. “It’s great when [artists] try to be scientifically accurate,” says Scott Sampson, an officer of the Society of Vertebrate Paleontology. Thanks in part to efforts by his group to encourage relationships between professional dinosaur artists and scientists, most dinosaur images produced today, whether for movies or magazines or museums, are grounded in hard data, even though hard data can only be a starting point.
Jason Brougham, a senior preparator at the American Museum of Natural History, sculpted the Fighting Dinosaurs’ protoceratops in the new diorama. To start with the science, Brougham studied protoceratops bones under the direction of paleontologist Norell. Brougham had a lot to go on because some 120 protoceratops skeletons have been found. For some dinosaur species, the fossil record contains only one skeleton, which is, more often than not, incomplete. Many dinosaur artists have faced the challenge of rendering a creature on the basis of half a skeleton. Mark Hallett, who has drawn and painted dinosaurs for museums, scientific publications, National Geographic, and movie studios, recently rendered a newly discovered dinosaur, Seismosaurus, on the basis of only 40 percent of its skeleton: “A few neck vertebrae, a complete pelvis, about a third of the tail, and no skull,” he says. To help get a better idea of what the creature looked like, Hallett studied its closest known relatives and made a plausible guess.
Even with complete skeletons, there is lots of room for interpretation on how the bones go together. One major controversy with ceratopsians (the family of Triceratops and Protoceratops) is whether they stood on straight legs like rhinos or crouched crook-legged like crocodiles. In most dinosaur art before the 1980s, ceratopsians dragged their bellies under legs crooked out to the sides. Since then, it has been more popular to render them straight up, as on rhinos. That is the way Brougham sculpted his protoceratops. But Peter Dodson, a ceratopsian expert at the University of Pennsylvania, argues the proper pose is crook-legged, not necessarily in the “extreme push-ups” pose of modern crocodiles, but certainly not in the straight pillar fashion of modern rhinos either. According to Dodson’s reading of bones, all straight-legged ceratopsian reconstructions suffer from painful shoulder dislocations.
With a working model of the skeleton, artists like Brougham must first think about muscles. The bones help in this regard. Muscle attachment points are sometimes obvious as scars on fossils, and the relationship between muscles and bone is fairly consistent for most vertebrates.
The process of laying muscles over the skeletal frame was vital to the success of Disney’s Dinosaur movie. Hallett put together some of the initial working illustrations of these imaginary dinosaurs. He sketched detailed skeletons of iguanodons, the herding, four-legged, long-necked, long-tailed dinosaurs that serve as the main characters in the movie. Over each skeleton, he drew a full set of muscles adapted from crocodile anatomy and complete with Latin names. Then, at the behest of Disney, Hallett modified the overall look of the creatures to be reminiscent, in a Mesozoic way, of horses. The muscle drawings became the basic set of instructions the animators used to move the dinosaurs around in a believable way.
Applying muscles to a skeleton can be error prone. While the upper arm bone and elbow of a human strongly suggest biceps, the abdominal cavity of a skeleton provides no information—in humans or dinosaurs. “There’s a lot of extrapolations involved,” says Hallett, but if you are a careful student of comparative anatomy, “you can be reasonably assured of the major groups.” If the artists render the muscles the way dinosaurs actually wore them, then their accuracy approaches that of, say, the musculature page in a human anatomy book: not a bad indication of what we look like on the outside, but still missing breasts, ears, noses, pot bellies, and all the other soft-tissue structures that define a creature’s shape but make no large marks on the bone.
Brougham mentions elephant trunks and ears, tapir snouts, and toucans as examples of creatures whose appearance one could never guess from their skeletons alone. “A toucan is preposterous,” he says. Its head seems too big to hold up and “it’s too extreme to be true.” Still, Brougham acknowledges that reminders of nature’s whimsy does not give him license to speculate as many illustrators have done, putting, for example, proboscises or caruncles on a variety of dinosaur body parts. If Brougham doesn’t have good information on soft tissues, he won’t add any—no hump on the protoceratops’s back, nor droopy wattles under its chin, nor a peacocky frill about its crest, even though all are as likely as the trunk on an elephant.
Brougham covered his protoceratops model with an ochre skin embossed with a scaly pattern suggested by fossilized skin impressions. What dinosaur skins actually looked like is one of the least-known elements of reconstruction. Brougham had to guess how the scales might have differed over the various parts of the body. He chose ochre as a neutral tone that might have blended well with the arid sands of the area, subtly camouflaging the creature from the eyes of a velociraptor. Most dinosaur colorations in recent years—and every year brings a wider range of patterns and pigments—are based on guesses about the landscape the creature lived in and its need for camouflage. By necessity, this reasoning makes unscientific assumptions about the ability of dinosaur eyes to distinguish colors and shapes. Eyes are a soft tissue that we will likely never have direct evidence for, paleontologists say. We do not know what dinosaurs saw, or if they saw in color, so we cannot know how they evolved to hide from each other.