Brushing up on dinosaurs; when art and science combine, the result can be a remarkable vivid and accurate glimpse into prehistoric life.

Brushing Up On Dinosaurs

Robert Bakker met his first dinosaurs in the spring of 1955 in his grandfather's sun room, and he fell in love. There on the coffee table, a terrifying Tyrannosaurus rex glowered at a longnecked Apatosaurus supping in a swamp -- both surrounded by a menagerie of wonderfully exotic creatures that roamed the prehistoric landscape hundreds of millions of years ago. Ten-year-old Bakker had discovered Rudolph Zallinger's Pulitzer-prize-winning mural, reproduced that week on the cover of LIFE.

"As soon as I saw it I decided I was going to spend the rest of my life studying dinosaurs," says Bakker, who went on to do just that, becoming a renowned paleontologist and artist in his own right. "That was the first really great color dinosaur mural. It launched an awful lot of careers, including mine."

While many, like C.P. Snow in The Two Cultures, have lamented the growing abyss between science and arts, the two are inexorably merged in paleontology, particularly in the reconstruction of dinosaurs and their habitats and behavior. This union of art and science is what makes ancient bones of long-extinct animals come alive. Paintings and sculptures not only spark the public imagination and inspire new ranks of paleontologists, but for scientists they also are an effective means of communicating ideas and exploring new theories.

"Paleontology s a very visual inquiry," notes Bakker. "All paleontologists scribble on napkins at coffee breaks, making sketches to explain their thinking." If they are not artists themselves, most dinosaur paleontologists work closely with artists, some of whom have published scientific work of their own.

To celebrate a century of these collaborations, the Natural History Museum of Los Angeles County this year unveiled "Dinosaurs Past and Present," a traveling exhibit of dinosaur art. Organized by artist and curator Sylvia Czerkas, the exhibit traces dinosaur reconstruction from its beginnings in the 1800s to the most recent paintings and sculptures. It has just moved to the Denver Museum of Natural History. The show is also scheduled to tour natural history museums in Philadelphia, Washington, D.C., New York City, Albuquerque, Drumheller (Alberta) and Toronto, after which it may be sent to Japan and China.

One purpose of the exhibit is to show how thinking about dinosaurs has evolved since they were first discovered early last century. Dinosaurs in many of the earliest works on display are portrayed as violent, clumsy and slovenly beasts, dressed in drab greys, browns and dark greens and standing by themselves. The newest paintings and sculptures in Czerkas's exhibit project quite a different image of sleeker, more varied and lively animals that lived in socially complex communities and had adapted to almost every ecological niche now occupied by modern mammals and birds. Dinosaurs were "a totally unique form of life that this planet has never seen since," says artist and paleontologist Stephen Czerkas, whose works, along with those of Sylvia Czerkas and many other artists, are featured in the exhibit.

One of the most important changes that has taken place in the portrayal of dinosaurs is in their posture. Until fairly recently, the convention was to draw many large dinosaurs with their front legs splayed out and bent at the elbows, like lizards. But in pictures today, the elbows are straight and the front legs have been pulled under the body, closer to the animal's center of gravity.

The physical appearance of many dinosaurs has changed in other ways as well. Recent studies by Stephen Czerkas, for example, have shown that the Stegosaurus, which had been portrayed with two rows of bony plates down its back for 100 years, really had just one row (SN:8/2/86,p.69). And contemporary illustrators have started to use more vivid colors: mauve, pink, metallic blues and reds. While there is no direct physical evidence to show that dinosaurs were indeed colorful creatures, "this makes a lot of sense," says Bakker, "because dinosaurs are closely related to birds. Colors were undoubtedly used, especially in the mating season."

The reconstruction of dinosaurs has become as sophisticated as forensic science. For his sculptures, Stephen Czerkas often being with resin casts of a real skleton. From muscle scars on bones, which indicate where a muscle or major tendon would attach, and from a knowledge of the anatomy of living animals, Czerkas then "fleshes out" the dinosaur, building up the muscles layer by layer in clay. Sometimes a mummified dinosaur is found with the skin preserved, enabling the artist to sculpt a realistically patterned skin to cover the sculpture. Then the entire piece is cast in a durable material, such as steel-reinforced fiberglass and resin.

Included in the dinosaur exhibit is the first restoration of an animal called Carnotaurus, or "meat-eating bull," because of its unusual bull-like horns. The model, sculpted this year by Stephen Czerkas, was based on the skeleton and skin impression recently discovered by paleontologist Jose Bonaparte at the Museo Argentino de Ciencias Naturales in Buenos Aires, Argentina. This was the first find of skin belonging to a meat-eating dinosaur. Before it was discovered, fossil skin from other types of animals had been used as a reference, says Czerkas. "But that would be like putting the skin of a horse on a lion," he says.

By studying the mass and distribution of muscles, the mechanics of limbs, fossilized footprints and the newly characterized posture of the dinosaurs, some scientists have concluded that the animals could move at greater speeds than once thought. Bakker, in particular, has championed the idea that dinosaurs were much nimbler than earlier paleontologists believed. His 1969 drawing of a running Deinonychus (or "terrible claw," for the lethal, sickle-shaped claws on its feet) shows a "very sleek, fast-moving animal," says Sylvia Czerkas. "It started people thinking in a whole different way about dinosaurs. It's probably one of the most viewed and reproduced modern drawings."

At a symposium held in Los Angeles last February in conjunction with the exhibit, Bakker presented evidence, based on the stride and leg lengths of some dinosaurs, that their walking speed averaged about 3 miles per hour -- about four times as fast as that of present-day lizards and turtles, and comparable to the speeds of moose, deer, bulls and other warm-blood animals. Because the average cruising speed reflects an animal's metablism, Bakker argues that many dinosaurs were warm-blooded.

"When I went to school [in the 1960s] it was indeed a heresy to think of dinosaurs as warm-blooded and light-footed," he says. "And in 1979, the last time there was a major dinosaur symposium, a lot of people still viewed these ideas as heresy. But at the L.A. meeting one could definitely see movement toward quick-footedness."

Another perception that has evolved dramatically is that of the social behavior of dinosaurs, which palentologists have inferred from various kinds of physical evidence. These clues -- such as bone beds, created when a group of animals was killed en masse by a flood, volcano or other catastrophe, and fossilized trackways -- suggest that both predators and prey traveled in packs or herds. One painting in the exhibit, by Baltimore artist Gregory Paul, illustrates that the prey were by no means defenseless: A Herbivorous Diplodocus is rearing up like an elephant to protect the rest of its herd against a carnivorous Allosaurus, and is swinging a thick, very lethal, whip-like tail. Trackways also show that some dinosaurs walked side by side as they traveled. Other tracks indicate that meat-eating dinosaurs could swim, leaving the herbivores little chance of escaping in the water, as some scientists had once believed they could.

There is also growing evidence that dinosaurs, like present-day crocodiles, cared for their young after they hatched. Dinosaur eggs were first discovered in the 1920s in the Gobi deset, but it wasn't until a few years ago that communal nesting grounds were found. Paleontologist John Horner of the Museum of the Rockies in Bozeman, Mont., discovered a series of nests in Choteau, Mont., tht had belonged to duckbilled Maiasaura. Because young Maiasaura of different ages and sizes were found in nests, some ages and sizes were found in nests, some scientists have concluded that parents were protecting and feeding thrir young until they were large enough to fend for themselves.

"These arenht the stereotypic dinosaurs, portrayed in the movies as always killing each other," says Sylvia Czerkas. "There were a lot of tender and gentle moments."

Dinosaur reconstructions enable scientists to envision not only how life used to be, but also what it might have become. Perhaps the most intriguing piece in the exhibit is a somewhat eerie sculpture by Canadian artist Ron Seguin of a very human-like "dinosauroid." This creature is what paleontologist Dale Russell speculates a small meat-eating dinosaur called Stenonychosaurus might have eventually evolved into, had it survived the mass extinction of the dinosaur 65 million years ago. Russell, who works with Seguin at the National Museum of Natural Sciences in Ottawa, chose the two-legged Stenonychosaurus as an ancestor of the dinosauroid because it had a relatively large brain (comparable to that of a large modern bird), opposable fingers and big stereoscopic eyes.

The dinosauroid is a clear favorite among the younger visitors at the exhibit. Watching a few delighted children ogle this magical world, Stephen Czerkas asks, "Who knows how many paleontologists we're stimulating [with this exhibit]?" adds Sylvia Czerkas, pointing across the room at a child, "That could be a baby Bob Bakker right over there."