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New Dinosaur Exhibit at the Field Museum



It's exhibits like this which make putting up with
Chicago winters a whole lot easier... :-)

Guy Leahy
--------------------------------------------------
Field dinosaur exhibit teaches, debunks myths
By Michelle S. Keller
Chicago Tribune staff reporter

March 27, 2007, 8:31 PM CDT

Thanks to Hollywood, the image of an aggressive
Tyrannosaurus rex snapping its massive jaw as it
barrels through the landscape at high speed is a
familiar one.

But it is also likely wrong.

Recent research suggests T. rex more likely moved at
speeds of 10 to 25 m.p.h.?faster than its prey, but
probably not as fast as the speeding jeep in "Jurassic
Park." Though the 5- to-7-ton dinosaur had massive leg
muscles, the effort required to move those huge limbs
likely slowed the animal down.

The speed of T. rex is one of the myths debunked at
the Field Museum's newest temporary exhibit,
"Dinosaurs: Ancient Fossils, New Discoveries," which
opens Friday and was organized in cooperation with
four other natural history museums.

The Field has long been known for its collection of
dinosaur specimens, including Sue, the largest, most
complete T. rex skeleton ever recovered. The new
exhibition aims to complement the museum's permanent
"Evolving Planet" exhibit by moving beyond what
fossils tell us about evolution.

One focus is scientists' efforts to learn about
dinosaur behavior. Researchers are now applying
technology such as computer animation and CT scans to
the known morphology, or anatomy, of the giant beasts.

"Based on their skeletons, we know a lot about how
dinosaurs looked, but we wanted to look more at how
they moved, what they ate, how they lived," said
Hilary Hansen, project manager of exhibitions at the
museum.

Upon entering the exhibit, visitors are greeted by a
fierce-looking T. rex and invited to play with a
computer simulation of its movement based on research
by John Hutchinson at the Royal Veterinary College in
London.

By manipulating the T. rex's leg muscle mass, posture
and center of gravity, visitors can make the dinosaur
move faster or slower, learning about the biomechanics
of movement along the way. Straighter legs and a more
upright posture, for instance, likely made for a
slower dinosaur.

The exhibit also touches on how researching modern-day
animals, including ostriches and elephants, can
increase our understanding of how large creatures
move, said Peter Makovicky, curator of dinosaurs at
the Field Museum.

"In order to have a good understanding of extinct
animals, you need to have a good understanding of
large, living animals," Makovicky said. "Amazingly, we
don't have much information" on the movement of these
living creatures," he said.

Makovicky cautioned that comparisons to modern-day
animals can be tricky. Sauropods, gentle giants with
long eel-like necks, were often thought to move like
giraffes, reaching their necks high to snap leaves
from trees. The idea was so widespread that museum
exhibits used to display dinosaur skeletons in such
poses.

Computer simulation research by Kent Stevens at the
University of Oregon, however, shows that sauropods
could not have craned their necks upward; their
vertebrae simply didn't allow it.

Makovicky's own research is represented in a colorful,
lifelike diorama depicting a marshy shore in China's
Liaoning province 130 million years ago. Thin ash beds
in the region preserved soft tissues such as feathers
and fur, as well as plants and insects, making for a
treasure trove of paleontological research.

"This is probably the best snapshot we have of this
era," he said of the Liaoning site.

He pointed out a cat-size mammal featured in the
diorama whose fossilized innards were so
well-preserved that scientists were able to determine
it once ate baby dinosaurs. "You get the entire animal
in three dimensions."

Ideas abound on why dinosaurs became extinct, with the
meteor hypothesis holding the most sway, but the
exhibit also presents two possibilities related to
climate change. Massive volcanic activity in what is
now India or receding shallow sea levels could have
changed the global climate so significantly as to
wholly disrupt life for dinosaurs.

The truth, Makovicky said, is scientists don't really
know what happened. Each hypothesis on its own
"doesn't fit the pattern very well. Was extinction
gradual or sudden? The lack of data doesn't allow us
to answer the question."

mkeller@tribune.com