Debunking Dinosaur Myths

By Frederic Golden

An expert on the "terrible lizard" separates fact from fiction

Nothing irks Edwin Colbert more than the widespread notion that dinosaurs were lumbering dimwits too big and clumsy to cope with their environment. "A canard," snaps Colbert. "Dinosaurs were not failures. They were enormously successful. They dominated the planet for 135 million years." By contrast, man is only a few million years old. Declares Colbert: "I doubt if we'll be around as long as the dinosaurs."

At 78, Colbert may be the world's premier authority on the ancient reptiles. He has devoted more than half a century to tracking down, examining and reconstructing their fossilized remains. His quest has taken him to sites as distant as the frozen wastes of Antarctica. Curator of fossil reptiles and amphibians at New York City's American Museum of Natural History for 35 years, he directed the construction of its famed dinosaur galleries. Though Colbert retired in 1970, he continues to write and lecture, showing a rare gift for bringing to life a long-dead world. Nowhere is this talent better displayed than in his latest book, Dinosaurs: An Illustrated History (Hammond; $30), which does much to separate paleontological fact from popular fiction.

Contrary to the public image of dinosaurs as the Edsels of evolution, says Colbert, they were extraordinarily well-adapted creatures. They inhabited every corner of the world and ranged in bulk from the chicken-size Compsognathus to the 100-ton Brachiosaurus, the largest creature ever to trod the earth. Though they plodded through swamps and shallow coastal waters, they were essentially land bound. Some ambled on all fours; others scampered after prey on their lower limbs. Some may have lived a century or more.

When these terrestrial reptiles first appeared 200 million years ago near the end of what geologists call the Triassic Period, tropical or subtropical forests covered much of the landscape. The continents were gathered in a single primordial landmass called Pangaea. Initially, the dinosaurs were relatively small and vulnerable, about the size of ponies. Many of them undoubtedly fell victim to voracious, crocodile-like reptiles called phytosaurs. But by using almost every evolutionary stratagem, they proliferated in number and diversity. Some developed thick protective plating, comparable to that of modern-day armadillos. Ankylosaurus had armor on its skull, knobby stubs over its back and legs, and possessed a tail that ended in a huge bony club. Perhaps to shed excess body heat, Stegosaurus sprouted triangular-shaped fins on its back. Thanks to such biological cunning, within only a few million years, the dinosaurs became the overlords of their antediluvian domain.

The most fearsome of these creatures were carnivores, like the ferocious Tyrannosaurus, which seems to have feasted on its fellow dinosaurs. Others, like the long-necked Brontosaurus, the archetypal dinosaur of cartoons, were gentle, browsing vegetarians. In spite of their comparatively small brains, dinosaurs were not dumb, floundering brutes. Deinonychus, for instance, was a fleet, two-footed creature with scimitar-like claws on its hind legs, grasping hands and dagger-sharp teeth. It apparently hunted in packs, in the manner of wolves. Stegoceras perhaps employed the thick dome on its skull in sexual combat, as an elk uses its horns. Dinosaurs may even have had nurturing, maternal instincts. The recent discovery in Montana of the fossilized remains of tiny baby dinosaurs only twelve inches long, near an adult of the same species, suggests that females hovered protectively over their young offspring.

It was in 1822 that an English fossil hunter first identified some newly discovered teeth as the detritus of extinct reptiles. (Dinosaur means "terrible lizard" in Greek.) Ever since that time, experts have been squabbling almost as furiously as did the reptiles themselves. In the 19th century, Yale's Othniel Charles Marsh and Edward Drinker Cope of Philadelphia, the leading collectors in the U.S., feuded so bitterly over fossil sites in the badlands of Wyoming that their teams came close to combat. Today the skirmishing is more genteel, although no less forceful. Some experts, for example, have contended vigorously that dinosaurs must have been warm-blooded, like mammals and birds, in order to have mustered the internal heat, or energy, for an active, land-based life. Colbert disagrees. He explains that their bulk alone would have enabled large dinosaurs to retain body heat.

Still another debate has centered on the creatures' demise, which took place 65 million years ago. Numerous explanations have been offered for the mysterious extinction: radiation from an exploding star, a reversal of the earth's magnetic field, a global epidemic, even the destruction of eggs by small mammals. Colbert, skeptical of all the theories, is especially critical of the latest and most popular explanation: the earth, struck by a giant asteroid, kicked up a huge volume of dust, reducing sunlight and killing off the plants that dinosaurs ate. Colbert points out that new finds in Montana show that the animals were dying well before the asteroid hit. Says he: "We probably shall never know why these fabulous reptiles, so long the masters of the continents, should have disappeared completely from the earth." It is the only really pessimistic, and perhaps questionable, note in this splendid retrospective account.

--By Frederic Golden This file is automatically generated by a robot program, so viewer discretion is required.