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Imagining Dinosaurs
HOW THE DINOSAUR AS WE KNOW IT KEEPS CHANGING
By Robert J. Gangewere
"A skeleton is an
idea," says Tom Rea in Bone Wars,
a new book on the dinosaurs at Carnegie Museum of Natural History.
"Meaning gathers up there in the darkness, above the skulls," he
says. When you see a person in a museum gazing at a dinosaur skeleton for
fifteen minutes, then you know that person is trying to imagine the intense
life that once surrounded those bones.
In "Dinosaur
Dreams" (Harpers, October
2001), Tom Witt goes even further.
He says that dinosaurs in America are a metaphor for the anxieties
and worries that afflict the country.
They are icons of our pyschic and social concerns. For instance, if
you thought Andrew Carnegie was interested only in paleontology when he
bought the biggest and best dinosaur fossil of his time for Pittsburgh, you
are wrong. Carnegie was
demonstrating patriotism by suggesting that America rather than Europe had
the greatest example of ancient life, and that American scientists,
including those in his museum in Pittsburgh, were the best in the
world.
When Carnegie was buying
dinosaurs, patriotism was in the air after America's emergence on the world
stage by defeating Spain in the Spanish American War. Carnegie saw himself
as a player on the world stage, and was an advocate for world peace. The passion with which he blended
international politics and science was unique, and he played his Dinosaur
card, so to speak, in a personal effort to secure international cooperation
and peace. He paid the bills to dig
up and display Diplodocus carnegii in
Pittsburgh, and imagined that
sending replicas to nine museums in
capital cities around the world would be understood as a gesture of
American scientific cooperation.
When his museum director, Dr. William Holland (the former Chancellor
of the University of Pittsburgh) wrote him that displaying this monster
"would be the most colossal undertaking of its kind in the
world," Carnegie responded with characteristic enthusiasm: "See
what you can do. I should like to do
the Colossal for the Colossal by the Colossal Lord Chancellor. AC. "
It delighted Carnegie
when King Edward VII of England saw a picture of Diplodocus at Carnegie's Skibo castle in Scotland, and asked
Carnegie if the British Museum could obtain one. Carnegie responded by presenting to the
King the first replica, which stands today in a place of honor.
Spectacular dinosaur
fossils stir the public imagination.
Recently the Chicago Field Museum acquired at a public auction the
large and complete fossil skeleton of a T.
rex discovered in 1990, obtained with financial support from McDonald's
Corporation and Walt Disney World Resort.
In 1997 the museum installed the exhibit at its grand entrance, and
named it "Sue," in honor of fossil hunter Sue Hendrickson who
found it. Carnegie Museum paleontologist Mary Dawson smiles when she says
it could as easily have been named Sioux, in honor of the South Dakota
badlands where it was found. But the
names of new dinosaurs are a very human affair. The second large dinosaur
installed in Pittsburgh was named after Carnegie's wife, Louise: Apatosaurus louisae.
The Popular Imagination
Using dinosaurs as symbols
of human values has been going on a long time. After World War II, the science fiction
fantasies about Godzilla packed
movie theaters for 50 years in 24 different films. The T.
rex-styled monster was an international symbol of global worries about
atomic destruction. It rose up from the depths of the sea and punished
humans with annihilation for the way that scientists tampered with the
mysterious powers of nature.
In the recent film Jurassic Park (1993), director Steven Spielberg
modernized the fear of dinosaurs with the Velociraptor. Writer Tom
Witt believes that the Velociraptor
is actually a metaphor for the1990s Japanese-styled "global business
warrior, physically downsized, entrepreneurially fleet, rapaciously alert, ready
for the dissolution of the nation state." In Jurassic
Park the movie scientist tells us, "it has jugular instincts
('lethal at eight months'), cunning ('problem-solving intelligence') and
strategic adaptability ('they remember')."
While the popular
imagination has made dinosaurs a century-long hit in American culture,
during that time paleontologists have made important discoveries that
change the way we should understand the real dinosaurs that walked the
earth. They no longer believe that giant sauropods such as Diplodocus and Apatosaurus had to live in water so that their weight could be
buoyed up. At the London Museum of Natural History the dinosaur that
Carnegie donated now has a raised tail and a new look.
A classic example is the
change is that of the skull of Apatosaurus
at Carnegie Museum of Natural History, which was made in 1979. Since this animal is the "type"
specimen which defines the species, all other exhibits of this same animal
had to change their heads as well. Carnegie Museum curator David Berman was
one of the investigators who demonstrated that the first skull, made up of
fossil pieces found 50 and 500 miles distant from the existing skeleton of
the body, was simply a mistake in judgment.
Rival paleontologists of the past were themselves divided on which
head should go on this body (which was excavated at the site without the
skull). It turned out that the
wrongly installed skull belonged to a different species, a Camarasaurus.
The Scientific Imagination
What is required during
the reconstruction of fossil
skeletons is a scientific imagination, since the animals are often
incomplete, and mixed in a jumble with bones from many different
animals. Did they all die at the
same time, or were their bodies deposited later at one location by flowing
waters? Removing fossilized bones
from the hard "matrix" of rock and completely reconstructing one
or more animals is a delicate puzzle in species identification.
But science corrects
past misconceptions, and modern technology has made that process more
exciting. Investigators can now
study the bones and go inside the skulls of extinct animals with CAT scans,
and use computer simulations to reconstruct the anatomies and physical
behavior of long-dead animals. Such
analysis has indicated that the tails of some great lizards served as
posterior balancing weights for their long necks and heads, thus new museum
displays now raise the tails of some exhibited specimens off the
ground. The Diplodocus replica outside Carnegie Museum of Natural History
installed in 1999 has the correct posture, but the "type"
specimen itself inside the museum was mounted in 1907, and still shows the
old concept that the creature's tail was dragged on the ground.
Computer-assisted
studies of dinosaur trackways use physics and mechanical engineering to
recreate the way dinosaurs really moved. It is clear now that T. rex and many dinosaurs moved
bird-like, in a horizontal posture on two legs, rather than by standing
erect and as humans do. Pittsburgh's
popularly remembered mural of a Godzilla-like T. rex from the1950s, at one time on the wall behind the type
specimen of the real T. rex, was
scientifically misleading--which is why scientists had it removed several
years ago. The new T. rex replica in the museum's
entrance hall has the new posture, but the T. rex mount in the Hall of Dinosaurs still displays the old
posture.
Studies now indicate
that T. rex probably moved at a
speed no greater than 20 miles per hour, and that if an adult fell down at
that speed it could easily fracture its skull and die. T.
rex had small arms completely useless for grabbing prey or for getting
itself up, but its olfactory powers were so great (based on CAT scans of
its skull) that it could smell carrion five miles away. T.
rex may have been a hyena-like scavenger of dead meat and not the
fleet-footed predator of live prey the public imagines.
There are also trends in
scientific interpretation. In the
1970s fossil hunter Jack Horner discovered dinosaur eggs, and named a new
species "Good Mother Lizard," or Maiasaura. This
feminizing trend continues in the latest museum exhibits, like the one at
the American Museum of Natural
History in New York, where a dinosaur mother protects her babies against a
fierce predator, although whether lizards protected their young the way
mammals do is debatable.
Recent discoveries in
China and elsewhere have revealed that some dinosaurs probably evolved into
birds, causing some to imagine that in an evolutionary sense the dinosaurs
are still with us.
All this new information
has led Director Bill DeWalt of Carnegie Museum of Natural History, along
with Curator Mary Dawson and other staff paleontologists, to examine the
ways that other museums display their dinosaur fossils.
Which museum has the
best dinosaur exhibit of dinosaurs from the Jurassic Age? DeWalt
points out that the answer depends upon what you are looking for,
and "there is no simple measurement but based on the quantity and
quality of our specimens, we have arguably the best collection."
Carnegie Museum of
Natural History has many outstanding specimens that it never had space to
exhibit. In addition, it is amazing
to imagine that the T. rex in
Dinosaur Hall is in fact closer to us in time, some 65 million years ago,
than it is in time to the Diplodocus and
Apatosaurus specimens standing in
front of it. These two animals stand
only fifteen feet away in the Hall of Dinosaurs, but the distance is meant
to suggest more than 65 million years in evolutionary time.
When asked what is in
the future for the Hall of Dinosaurs, DeWalt says, “our priority now is to
bring our exhibits up to the standards merited by the quality of our
collections. Our vision is of an exhibit that shows dinosaurs in the full
context of their own times, including mammals, plants, insects, and the
rest of the environment of the dinosaurs--all areas that are part of the
scientific collections of Carnegie Museum of Natural History."
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