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Thursday, April 18, 2002
DINOSAUR PROVINCIAL PARK
Back when the Badlands were lush
By MARK BRAZIL
Drive west from Calgary and rolling foothills dotted with aspen and white spruce rise steadily toward the mighty ridgeback of the Rockies, which dominate the view in this part of Canada's Alberta Province.
Drive east from Calgary, though, and limitless horizons open up -- beyond your window and in your imagination.
A fascinating history lies hidden beneath the vast, rolling prairies. Some hours eastward, the scene becomes monotonous until the road suddenly dips into the valley of the Red Deer River, which winds through the semidesert landscape like a green oasis of tall cottonwood trees. Soft, eroded rock, with rills and hard capstones, form bizarre shapes ranging in color from pale sand to coal black. This is the Badlands of Alberta.
Today, the Badlands are barren. Nocturnal common nighthawks chase erratically, on sharp-pointed wings, any flying insect that dares show itself. There are mule deer here, too -- and coyote, cottontail rabbits, porcupine, prairie rattlesnakes and Richardson's ground squirrels: all tough, adaptable creatures capable of surviving the arid conditions.
Don't be overwhelmed by appearances though, or underwhelmed by the biodiversity. Scratch the surface and you will expose a very different world. There are remnants here that tell a tale of long, long ago.
Where now there are the Badlands, there once were wetlands stretching along the shore of an ancient sea. Fossils and fragments litter the ground (so many that palaeontologists can process only a fraction of them) -- evidence of past lives, past ecosystems and of ancient forests from more than 65 million years ago.
Watch where you tread. That sharp shard of rock may be a sliver of fossilized bone -- dinosaur bone. Looking around at the arid landscape, at vegetation supremely adapted to such dryness, then handling the fossil remnants of ancient lushness, it is impossible not to marvel at the changes the world has undergone since the demise of the dinosaurs at the end of the Cretaceous Period some 65 million years ago.
For much of that period (which began some 70-odd million years before) the Rockies didn't exist and present-day North America was two land masses divided by a broad shallow sea. Called the Bearpaw Sea, this existed for more than 35 million years, and was a zoogeographic barrier separating west from east. To the west, land stretched from what is now Alaska to northern Mexico, and in the east from Greenland to Florida, with those long-gone shallow waters in between.
Where Alberta is now, where the foothills of the Rockies give way to the eastward expanse of the prairies, there used to be vast wetlands, deltas and estuaries. These were home to an array of plants and animals that today appear only in museums as relics of an almost unimaginable era.
Visit Dinosaur Provincial Park in Alberta and the fine dinosaur collection at the Royal Tyrrell Museum at Drumheller. In exhibits here, the modern prairies are wonderfully transformed into the soils, sands and sediments of a coast that supported fantastic and enormous creatures.
The rock here now is soft and crumbly, easily scoured by rain and wind. Strange shapes in the eroded sediment allow the imagination to run riot, though the "Camel" and "Pyramid" rocks in the dinosaur park require little effort -- they really are shaped just like their names. Some of the stone-capped pinnacles have hilarious names, with most known as Hoodoos, a term used widely in the west of the continent for bizarrely eroded, or oddly jumbled piles of rock. But guides will joke and also point out Noodoos, Foodoos and even Hairdoos to the unwary.
Where today the stillness and silence of the Badlands impresses the visitor, slip back 70 or 80 million years in your mind's eye and imagine humid heat, lush vegetation surrounding and growing in warm swamps, marshes, streams and deltas.
There were crocodiles, turtles, rays, salamanders, fish-eating reptiles and, of course, an impressive array of dinosaurs. More than 30 species have been identified from the park area already, evidence of a rich ecosystem complete with grazing herds and voracious predators ranging in size from the immense to the diminutive. Largest of all was a distant cousin of Tyrannosaurus rex -- Albertosaurus. This bipedal beast was 7.5 metres long and is estimated to have weighed in at about 2 tons. It was the nemesis of the grazing herbivores.
Much rarer in the park, but more alarming still, was the 4-ton, 5-meter-tall Daspletosaurus. However, many other predators were considerably smaller, such as the 1.8-meter-long Dromaeosaurus. The skeletal remains of these smaller predators indicate that they relied on speed and agility to tackle their prey.
Many species of herbivorous Hadrosaurids have been found here. These duck-billed dinosaurs, with their enormous hollow crests, are thought to have been social animals, bugling signals to one another via their built-in trumpets. Their dentition, combined with their bulk, gives their diet away. Did they browse on vegetation around the swamp edges, or did they wade out and dine on the semi-submerged aquatic plants much as moose do now?
The most familiar of the remains at the dinosaur park are the Centrosaurs. These "sharp-pointed" lizards grew up to 6 meters long. Like a squat rhinoceros with a heavy drooping tail, the Centrosaurs had forward-pointing nose-horns that might have been used in the same way as modern rhinos use theirs -- to defend their young. Herds of Centrosaurs, and similar Chasmosaurs, roamed the region browsing shrubby vegetation.
The attentions of predators would have weeded out weaker -- or unluckier -- individuals, much as later wolves did among the plains bison. As herds, too, the Centrosaurs sometimes met their end. In 1977, park naturalists stumbled across an astonishing find -- a partly weathered-out bone bed with bones at the center of the exposed area so thickly scattered that there was no bare ground! An initial inspection of the varied skulls and bone sizes indicated that at least six animals had died there, but by 1981 38 individuals had been identified, and by 1994 more than 55.
The bones are disarticulated, jumbled and mixed together, but 90 percent are from animals in the same genus if not the same species, and with as many as 60 bones and fragments per square meter it has been estimated that perhaps up to 400 individuals died there.
Careful analysis of bone beds reveals that most are long-term accumulations that piled up over perhaps thousands of years by being washed into a single area. In other cases -- and the Centrosaur beds seem to be of this type -- a catastrophe seems to have befallen a herd of animals at once.
Just as massed herds of caribou occasionally drown when caught in floods while attempting river crossings, it is surmised that Centrosaurs migrating en masse were caught in a flood and drowned in the melee. Washed downstream until stranded, their carcasses were then eaten (as witnessed by disarticulation, particular types of bone-fractures and tooth- and claw-marked bones). Further floods washed the smaller bones and fragments away and they were lost, but the major bones fetched up in shallows where the current carried them, and there they were buried and lost until a lucky palaeontologist stumbled on them.
While Daspletosaurus and Albertosaurus lorded it over the landscape and terrorized the Centrosaurs, up above another astonishing creature reigned -- the monstrous Pterosaur. Each year brings new discoveries, often new species, and in 1980 the first Pterosaur limb bone was unearthed in the dinosaur park. Measurements revealed that it came from a creature with a likely wingspan of about 12 meters, quite possibly Quetzalcoatlus, a creature somewhat resembling a modern hang-glider, but apparently adept at flight.
The behavior of such a creature is beyond my imagining, but even a short wander in the Dinosaur Provincial Park will surely be sufficient to convince even the least palaeontologically minded visitor that this is an immensely impressive place.
You can contact Mark Brazil by e-mail at: firstname.lastname@example.org