Polar Dinos Spotlighted in "Dinosaurs of Darkness" Exhibition
for National Geographic News
|March 29, 2004|
If famed Norwegian explorer Roald Amundsen trekked across Antarctica a few hundred million years earlier, he may never have returned to reveal the details of the world's underside. Cryolophosaurus ellioti might have eaten him for dinner.
The 22-foot-long (7-meter-long) carnivore with an unusual crest on its skull was one of several dinosaurs that thrived in the extreme polar regions of the world. Though the climate was warmer then than it is now, the dinosaurs endured months of darkness and temperatures that plunged below freezing.
For the last two decades a handful of dinosaur hunters have been chipping fossils from the ice in Antarctica, pulling them from mines dug especially to find the bones in Australia, excavating them from streambeds in New Zealand, and digging them out of frozen riverbanks in Alaska and the cold steppes of Patagonia.
These fossils, skeletal reconstructions, and models and paintings of polar dinosaurs' ancient world went on display in the U.S. last Thursday at the Burke Museum in Seattle, Washington. Cryolophosaurus greets visitors with its teeth bared.
"It's ready to eat you up," said Patricia Vickers-Rich, a paleontologist from Monash University in Australia who is the curator of the "Dinosaur of Darkness" exhibition.
Vickers-Rich is at the forefront of the scientific sleuthing into the dinosaurs that thrived in the polar regions. She's pulled together the fossils and research that are painting a picture of dinosaur life at the top and bottom of the world.
"We are getting a good handle on some parts of the dinosaur ecosystem," said William Hammer, a vertebrate paleontologist at Augustana College in Rock Island, Illinois. Hammer discovered Cryolophosaurus ellioti in Antarctica in 1991. "However, dinosaur finds in Antarctica are rare, so we have a limited amount of data."
Vickers-Rich and her colleague and husband Thomas Rich, a paleontologist at Australia's Museum Victoria museum group, have focused their field research in southern Australia. Australia was deep within the South Pole region during the Cretaceous period (140 to 65 million years ago). The National Geographic Society's Committee for Research and Exploration has supported their research with numerous grants over the past 30 years.
Many of the dinosaurs she and colleagues have found are hypsilophodontids, which were small, speedy, plant-eating dinosaurs that ran on two feet.
"They have huge eyes, and we also know they had large optic lobes in their brain," Vickers-Rich said. This suggests that the dinosaurs had eyesight well adapted to operating during the darkest months of the year.
An analysis of the hypsilophodontids' bone growth indicates that they grew year-round. Such clues are evidence that these herbivores did not hibernate during the coldest and darkest months of the year. They were probably warm-blooded dinosaurs, able to control their body temperature.
By examining the sediments and plant fossils associated with their hypsilophodontid finds, the researchers have pieced together a climatological and environmental record of southern Australia during the dinosaurs' reign from about 115 to 105 million years ago.
"Many of the trees didn't slow down to the point of dropping leaves," Vickers-Rich said. "They didn't shut down, so there was food around for the animals. In fact, the climate, other than the light, might well have been like Seattle."
Located in the Pacific Northwest, Seattle is well known as wet, dreary, and mild. Temperate rain forests flourish. Snows blanket the nearby mountains.
Other dinosaurs from southern Australia include Serendipaceratops arthurcclarkei, one of the oldest horned, or frilled, dinosaurs known, which suggests that horned dinosaurs may have originated in the southern polar region.
"That group is most well known from Mongolia, where Protoceratops occurs in the very late Mesozoic/late Cretaceous. The material of Australian origin is early Cretaceous," Vickers-Rich said.
Hammer said Cryolophosaurus ellioti, the 190-million-year-old meat-eating dinosaur he found in Antarctica, "is a very old relative of the well-known Allosaurus from North Americawhich is from the late Jurassic, about 150 million years ago."
Most recently, in December 2003, while Hammer and his colleagues were continuing excavation of the Cryolophosaurus ellioti specimen they found in 1991, their mountain safety guide stumbled upon a sauropod dinosaur. It may turn out to be the largest dinosaur ever found in Antarctica.
The specimen is currently en route to the U.S., where Hammer and colleagues will analyze it later this year.
Since the mid 1980s Roland Gangloff, a paleontologist with the University of Alaska Museum, has uncovered several dinosaurs along Alaska's North Slope. The dinosaurs found there closely resemble the mix of dinosaurs from regions farther south in Alberta, Montana, and Wyoming, with the notable exception of truly cold-blooded reptiles such as lizards and crocodiles.
The lack of cold-blooded reptiles leads Gangloff and others to argue that their dinosaurs may have been neither truly warm nor truly cold blooded, but rather possessed a unique type of metabolism unlike any animals alive today.
Dinosaur hunting in the polar regions is strenuous and expensive work, especially in Antarctica, where Hammer and his colleagues endure temperatures that regularly dip to -25 degrees Fahrenheit (-32 Celsius), live in tents, and melt ice for drinking water.
"The sites are very inaccessible. We are 500 miles [800 kilometers] inland from the coast and about 400 miles [640 kilometers] from the geographic South Pole," Hammer said. "They are also at high altitudethe dino locality on Mount Kirkpatrick [where we found the sauropod] is at about 13,000 feet [4,000 meters]."
In Australia, where today the climate is temperate and most of the continent is accessible, Vickers-Rich and crews had to dangle 300 feet (100 meters) or more off a cliff before tunneling into it to get at the dinosaur bones. "Work in Australia is anything but benign," she said.
The fruits of the dinosaur hunters' labors will be on display at the Burke Museum in Seattle until October 10, 2004.
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