June 7, 2013 1:27:03 PM
Dinosaurs aren't what they used to be. Oh, they got wiped out sixty-five million years ago, except for the line that brought us birds, so their fossil remains remain unchanged, but our understanding of what they looked like and how they lived are vastly different from before. Richard Owen, who coined the term dinosaur, arranged for models of Megalosaurus and others to be shown at the Crystal Palace in 1852, models that looked like squat hippos with crocodile skin. That wasn't the way they looked when I was a kid in my dinosaur phase; they were lumbering, drab-colored, pea-brained monsters. At that time, every kid's favorite dinosaur was the Brontosaurus, and Brontosauruses not only are long dead, they never existed, or at least they aren't called that now. The differences in our understanding of dinosaurs are a big part of the show in My Beloved Brontosaurus: On the Road with Old Bones, New Science, and Our Favorite Dinosaurs (Scientific American / Farrar, Straus, and Giroux) by Brian Switek. Switek is a gifted science writer and amateur paleontologist who (unlike the rest of us) never grew out of his love of dinosaurs, and conveys his enthusiasm with good humor and a lot of details about our current scientific understanding of our long-gone dino friends.
Switek's Brontosaurus is beloved because it is the old-style dinosaur from his youth. The name means "thunder lizard," which is a lot more memorable than "deceptive lizard," the etymological origin of Apatosaurus, so named because the finder thought the ribs resembled those of other fossils. Maybe this is part of the reason Brontosaurus was so well remembered through Switek's generation. The Apatosaurus has priority; it was named by one of the giants of fossil-digging, Othniel Charles Marsh, before 1880, but Marsh also thought he perceived subtle differences in another specimen, and named that specimen Brontosaurus. There are still the same difficulties these days in telling what bones constitute a different species, especially if one set of bones are from a juvenile and one is from an adult. But by 1903, paleontologists were fully aware that the two names were being applied to one species, and the rules are that the earlier name takes precedence. That would have been the end of the matter if the world consisted of nothing but paleontologists. Inexplicably, museums were slow to make the change, even at Switek's beloved American Museum of Natural History. "Maybe," he offers, "they thought the old name sounded better, or were unsure about rebranding one of the most famous dinosaurs in their halls." Switek doesn't mention it, but even the US Post Office got into the act, issuing a stamp featuring the dinosaur in 1989, wrongly labeling it Brontosaurus and refusing to correct the mistake. Pedants had fun accusing the Post Office of promoting scientific illiteracy.
It's not just that Brontosaurus has had its name erased. It is a vastly different dinosaur now than it was when I learned about it over fifty years ago, and that's why Switek has his title; Brontosaurus stands for an old idea, one that has been corrected by closer scientific study. It used to be that the great beast was a sluggish, gigantic, dim, gray-green lizard, and it had to live in swamps because its huge bulk could not otherwise be well supported. It would be out of place on land, and when it did happen to wander onto the flats, its enormous, heavy tail would drag behind it on the ground. Maybe we human mammals initially looked at these alien lizards in this way out of a certain victor's pride; the teensy mammals that were our ancestors lived while those dodo dinosaurs died.
Switek has great fun distinguishing for us the concepts of dinosaurs fifty years ago and the way paleontologists see them now, with updates even on the "Dinosaur Renaissance" that started in the sixties. "Plodding Mesozoic idiots on television and in my library books were gradually being replaced by colorful, clever dinosaurs that looked limber enough to turn cartwheels over the ancient landscape." Not only were these dinosaurs active, they were hot-blooded, and the paleontologists had data to back up the revolutionary new concepts. This meant a lot of changes for museums. Most of them did not update the murals in the dinosaur halls, which will probably always show Brontosauruses as big swampy lizards. Many have, however, updated the way the skeletons are put together. The metal framework of holding the bones was modified, to reflect that dinosaurs were efficient runners who held their tails out behind them. Evolution had millions of years to work on these creatures, and until the disaster that ended their line 65 million years ago, they were extremely successful; their speed and agility certainly played into that success.
The way dinosaur skin looked, too, has gone through changes, and Switek looks at its color history by means of dinosaurs in the movies. There wasn't any problem with the gray-scaled Brontosaurus in King Kong; that gray could have stood for anything, probably the olive green or mud brown that media with more color capability were using at the time. When Technicolor came in, dinosaurs were specifically dull greenish, like Ray Harryhausen's creatures in One Million Years B.C. It is surprising that Jurassic Park (1993) did not take advantage of a couple of decades of the Dinosaur Renaissance, but its dinosaurs were drab. "Apparently Steven Spielberg wanted classic Hollywood monsters rather than the most accurate dinosaurs science could offer." Living dinosaurs, the birds we see every day, have colorful plumage, and there is no reason to think that their ancestors did not, also. In fact, more dinosaurs are being seen as feathered. They probably evolved feathers for insulation and mating display (their descendants modified them for flight), and microscopes and chemical analyses have teased out that the ancient feathers had colors. If you really want to think about how much our picture of dinosaurs has changed, imagine that Tyrannosaurus rex had feathers. A beplumed Tyrannosaurus just seems a lot less rexy, but he probably did have the downy coat.
My Beloved Brontosaurus serves as an agreeable summary of changes in paleontological thinking and is a wonderful update for those of us who dropped our enthusiasm for the big beasts as we grew up. Besides being packed with scientific lore, though, it is a cheerful personal document about a subject Switek obviously loves. He reveals, for instance, that he asked a tattoo artist to install an Allosaurus on his right arm, and tells us where the artist went to look at a museum specimen to get it right. When Switek is at the Natural History Museum of Utah, in the paleontology lab cleaning fossils, he is amused by kids going by. His workspace is enclosed in glass so visitors can see what paleontologists do. "They're so excited - until they realize that cleaning dead dinosaurs is a real pain in the ass, a war of millimeters between you and the matrix that surrounds the fossil bone." As he drives in this tour between different digs and museums, he is amused to see dinosaurs on the road, many of them grotesque and weatherworn: "If you want to get a driver's attention, put out a dinosaur." There is deeper philosophy, too: "Pick any dinosaur you like, and that ancient creature is undeniable proof that our planet has a history so deep that we can barely comprehend it, that life has changed dramatically over time, and that extinction is the ultimate fate of all species." Reading about the better ways we have of understanding these strange and distant beasts, and the changes we have put them through, it's hard to avoid his conclusion: "Dinosaurs are better than ever."