Dino hunters hit mother lode

Three summers ago, when a team of dinosaur hunters first stumbled upon a bevy of Tyrannosaurus rex skeletons, they could have practiced old-school paleontology: piecing together the life stories of prehistoric creatures, one bone at a time.

Instead, as Jack Horner's crew jackhammered deeper into the Hell Creek geological formation, unearthing a diverse assemblage of ancient creatures and plants along the way, Mr. Horner says a larger vision began to take shape.

The traditional practice of tagging and cataloguing individual specimens for museum display – "butterfly collecting," as Mr. Horner dubs it – became less important than connecting the dots between different species.

Now, the distinguished team is applying an "ecosystem approach" to their discoveries in an effort to reveal what the late Cretaceous period looked like 68 million years ago, just prior to end of the dinosaur age. The five-year "megaproject" is intended to create a visual image that might also illuminate the imminent effects of modern global warming.

"[The dig] is allowing us to look at patterns in evolution through time to see how environmental change affected life back then," Horner explains. "This work could help provide better insight into how plants and animals adapt to ecological change today."

In the process, scientists are asking themselves what relationship T. rex bones have to nearby duckbills and triceratops bones, and, in turn, how these fossilized specimens can shed light on the lives of mammals, mollusks, and plants.

The affable Horner, who oversees the department of paleontology at the Museum of the Rockies in Bozeman, Mont., is a shy man, yet he invariably attracts a lot of attention. After all, he is the closest thing paleontology has to a rock star. The protagonist in the film "Jurassic Park" was modeled after him. In scientific circles, he is renowned for his discovery of 20,000 duck bill dinosaurs at Egg Mountain and his recent theory that the T. rex was more like a scavenging vulture than a predatory lion.

Yet, despite his reputation, the bearded dinosaur detective initially had difficulty finding any funding for the dig. Conventional wisdom suggested that Hell Creek had been picked over by a century's worth of other famous prospectors. Indeed, the National Science Foundation rejected Horner's grant proposal because he could not guarantee that significant finds could be made.

It wasn't going to be a cheap, small-scale operation. For starters, the tent encampment is large enough to be, in effect, the second-largest town in Garfield County. Adding to the cost: The slow nature of the dig. To reach the isolated excavation site the group makes a daily seven-mile trek upriver by speedboat and then hikes two miles in – the last mile across vertical terrain best suited for mountain goats.

"It's rare that you have a paleontology project at this scale, but thinking bold has paid off," says physicist Nathan Myhrvold, the retired founder of research at Microsoft who is one a few individuals funding the project.

So far, eight T. rexes and a mother lode of other valuable specimens. To put that into perspective, that accounts for one-third of all known T. rex skeletons. The crew's haul also boasts two dozen triceratops skeletons, several edmontosauruses, and potentially the largest Duckbill dinosaur skeleton yet discovered, measuring between 45 and 50 feet long.

However, it is the diversity of other smaller fossils – such as elaborately ornate snails, fossilized fruit, and long-nosed fish – that most excites Horner and colleagues like mammalogist Bill Clemens and botanist Nan Arens from the Museum of Paleontology at the University of California-Berkeley.

"If you just see a certain percentage of diversity coming out of the ground, and focus on single species, you're glazing over a lot of things," adds Joseph Hartman, a malacologist from the University of North Dakota who specializes in ancient clams and snails.

Along with these creatures, scientists say it's significant that more T. rexes have been found than prey species such as duckbills. "T. rex appears to have been much more common than we thought," says Horner.

The paleontologist has a hunch that, prior to a cataclysmic event such as a meteor crash around 65 million years ago, other changes were occurring in the environment. Around 75 million years ago, Horner says, a trend toward extinction of many taxa of dinosaurs was underway.

"We are seeing evidence of ecological instability. The question is why?" Mr. Hartman asks.

Contorted plant fronds and fresh-water mollusk shells indicate stressful environmental conditions that provide potential clues on how earth changes were affecting different kinds of life.

According to Mr. Myhrvold, who once found one of the biggest T. rexes ever unearthed, the issues being addressed by paleontology are remarkably timely. Learning about climate change in previous ages can help experts better anticipate how the biota will respond to changing weather patterns in the decades ahead.

Thus far, it appears that common species fared far better in a changing environment than the organisms with specific adaptations – not dissimilar from endemic creatures that end up on the endangered species list.

"Dinosaur paleontology might seem like one of the least-applied sciences in the 21st century," Myhrvold says, "but I believe the knowledge it is giving us might some day help us save our world."