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Click here to find out how the life-sized replica of
Diplodocus carnegii was made.
 

Dippy's Anniversary

By R. Jay Gangewere 

The World will see a new version of the famous dinosaur Diplodocus carnegii (popularly called "Dippy") when Carnegie Museum of Natural History celebrates the 100th anniversary of its discovery with a life-size replica. 

 
There is no better story about dinosaurs and America than the rich brew of science, personal ego, and international politics that made Diplodocus carnegii an international star 150 million years after it died. Andrew Carnegie reached his prime as a big spender for scientific research just as the Golden Age of dinosaur paleontology flowered--from the 1890s to the 1920s. Carnegie wanted his own Museum of Natural History fossil hunters to be in the field, bringing back to Pittsburgh exciting discoveries to rival or surpass those of other great museums, such as the American Museum of Natural History in New York. 

Personally, Carnegie liked to boast that his Carnegie Institute in working class Pittsburgh was leading the world in paleontology. His interest supposedly began in 1898 when he read in his New York newspaper about "The most colossal animal ever on earth" being found in Wyoming. Legend has it that he sent the clipping with a $10,000 check to his museum director to "bring this back to Pittsburgh." The truth, says collection manager Elizabeth Hill of the Carnegie Museumís Vertebrate Paleontology department, is that the check came later. First came a tug-of-war between the University of Wyoming and Carnegie's agents over the right to remove the fossils. After no more Diplodocus bones were actually found at the site, Carnegie's bone hunters moved to a new location and uncovered the remains of two more creatures. The Diplodocus which went on display in Pittsburgh in 1907 is largely made of bones discovered north of Medicine Bow, Wyoming. 

Carnegie took personal pleasure in giving a replica of Diplodocus to King Edward VII of England, for the British Museum in 1905. It gave the feisty 5-foot, 2-inch Carnegie, once a poor immigrant boy, a patriotic thrill to proclaim that American paleontologists had uncovered in America the largest animal ever to walk the earth. It also tells you about Carnegie's salesmanship that he managed to get the British Museum replica on display two years before the original was erected in Pittsburgh, where Carnegie Institute was being expanded to hold it, in 1907. 

Carnegieís personal presentation of a Diplodocus cast to the British Museum triggered requests for replicas from European presidents, kings and emperors. This entrée to the ruling class of Europe took museum director Dr.William Holland across Europe, gathering honors for Carnegie Museum of Natural History wherever he went to supervise the assembly and make presentations. Casts were installed in the capital cities of Germany, France, Austria and Italy. After the first five, Holland authorized four more replicas, which went to Russia, Spain, Argentina and Mexico. 

It was a sign of the times that after receiving new medals for the museumís research from European rulers, Holland would paint each new medal with his own hand on an existing portrait of himself in Pittsburgh. This was more than personal vanity. European scientists still condescended to American science. Holland, like Carnegie, had an agenda to promote America's scientific honor. A distinguished scientist, Holland spent two decades aggressively promoting Carnegie Museum of Natural History as "the Home of the Dinosaurs." 

In 1910 he defended in The American Naturalist his view of how to assemble Diplodocus bones (with the legs directly below the torso, like a horse), rather than spread to the sides (like an alligator) as proposed by European critics. He ridiculed his critics as "broomcloset naturalists," calling their analogy between Diplodocus and living lizards false. If this dinosaur had been like an alligator its belly would always be moving in a trough while the feet were employed for locomotion along the banks. This would explain the creature's early extinction, said Holland, since (and here he scores against the Europeans), "It is physically and mentally bad to 'get into a rut.'" 

Holland became a national spokesperson for paleontological research, and was embroiled in the political fight to preserve for science the fossil-rich lands where Diplodocus and other dinosaur fossils were found. He helped to modify the federal Homesteading Act, which would have turned over fossil-rich dinosaur lands in the west to speculators. In 1915 President Woodrow Wilson signed a bill preserving 80 acres around the old Carnegie Quarry in Utah as Dinosaur National Monument Park. 

A lawn mower, not a giraffe 

Scientists still debate vigorously the best way to interpret dinosaurs to the public. Holland's decision about the morphology or shape of Diplodocus was validated by modern evidence in "trackways," or fossil footprints, which confirm that its legs were straight down and it had a narrow gait. 

But new evidence has surfaced in the 20th century about its behavior. Modern studies of the head, neck and tail reveal that the neck was carried low and forward, says curator of Vertebrate Paleontology Mary Dawson. It was not like a giraffe with an erect neck, chewing on the leaves of high trees. Anatomical studies during the past 30 years point out that the shoulder and neck of Diplodocus would not support great vertical weight, says Carnegie paleontologist Chris Beard, although other sauropods like Camarasaurus were equipped to feed on trees. Diplodocus probably fed like a widespread, horizontal mowing machine, moving its head and neck in wide swaths while its body could remain stationary. 

Science also now confirms that the tail was probably raised off the ground, unlike early reconstructions (including the one at Carnegie Museum) that show a tail being dragged behind. Trackways provide no evidence of a dragging tail and not many animals slow themselves down by dragging an extremely long tail behind them. But as a flexible, balancing counterweight to the extended neck at the front, the long tail has a dynamic function. The 1999 reconstruction has a raised tail. 

Curator Dawson rejects for Diplodocus the latest whiplash theory that its tail was used as a defensive weapon. For a big sauropod with a shorter tail, like Apatosaurus, that might work, she says. But if the extremely long Diplodocus tail reached such whiplash speeds, it could have snapped off its own end. 

Delicate teeth and high nostrils 

Dippy must have been an eating machine, because the small head and long neck supplied food to an immense body. The long and narrow skull has protruding peg-like and delicate teeth--not equipment for chopping up and chewing the high-fiber vegetation of trees. Perhaps Diplodocus was a water feeder, browsing on algae and aquatic plants, or on tender vegetation close to the ground such as ferns. 

Its nostrils are located high on its head above the eyes, suggesting that it could look for food under the water surface when it browsed. If its head was poked straight down into thick succulent vegetation, its nostrils were well positioned above its eyes for breathing. Many scientists now believe Diplodocus was primarily terrestrial, and not an aquatic monster as portrayed in early 20th century illustrations. 

More toes than claws 

Carnegie Museum paleontologist David Berman says that research has changed the arrangement of this dinosaur's feet. A century ago it was known that the dinosaur had five digits on each of its front and hind feet, but the lack of fossil claws for each digit was written off by field researchers as a failure in the fossil record. Now trackways evidence of footprints, and new fossils, indicate that there was only one claw on the front foot, and three claws on the rear feet. The new model has the new feet. 

Making an accurate model 

Arranging fossil bones in the form of a living creature was always a challenge. Carnegie scientist Arthur S. Coggeshall solved the problem for his time a century ago by using a framework of structural steel. This specimen was mounted so its vertebral column had the position we now know, with the tail along the ground. 

But with new structural materials come new possibilities. In 1957 the Utah Field House of Natural History in Vernal, Utah, used the deteriorating original Carnegie molds for the last time in constructing a replica made of lighter weight cement and cinder bones. The material deteriorated, and in 1989 these cast bones were used to recreate molds for new bones. This time Diplodocus was given a more dynamic shape, its neck curled in one direction while its tail curled in the opposite direction. 

A fleshed-in-version over 80 feet long was created in the 1960s for West Yellowstone National Park. In 1977 it was moved to the "Dinosaur Garden" at the Utah Field House. Through the years this dinosaur has had different colors, going from elephant color grey with a green belly, to a more recent tan and brown. Dinosaur colors, like dinosaur sounds,  are not in the fossil record and will probably always be a mystery to scientists. 

Making an accurate model of an animal that became extinct 150 million years ago requires both guesswork and hard evidence. Paleontologist David Berman remarks that Ford cars did not become extinct when Henry Ford stopped making the Model T.--the Ford car simply evolved into new models, and is still with us today. Artist Michael Skrepnick, who is making a dramatic new mural of Diplodocus for Dinosaur Hall, is ready to argue the theory that dinosaurs are still with us--in the form of birds. 

"Science is a successive approximation of the truth, not a set of facts," says paleontologist Chris Beard. All it takes, says curator Mary Dawson, is one convincing new fossil discovery--one trackways sign that Dippy did drag his tail--to send scientists back to their evidence for a new, more accurate interpretation. 

 

 
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