Theropods (THER-oh-pods) were fast-running, meat-eating dinosaurs of various sizes, with sharp, serrated teeth. They are thought to have hunted in packs or social groups. They walked on two legs. Theropods found so far are grouped into three families:

7 – Albertosaurus (Al-BERT-to-SORE-us): up to 10 feet tall, 15 to 17 feet long, isolated teeth and rare bones found in Alaska.

8 – Tyrannosaurus (Tie-RAN-oh-SORE-us): under 15 feet tall, 10 to 15 feet long, species not known; a single tooth found in Alaska.

Troodontids (Troo-DON-tids) had relatively large brains. Their large eyes were likely better adapted for hunting during twilight or at high latitudes:

9 – Troodon (TROH-oh-don): small, lightly built, 6 feet tall, 8 feet long, weighed several hundred pounds; teeth and skull fragments found in Alaska.

Dromaeosaurids (Droh-MAY-oh-SORE-ids) were possibly the fastest, fiercest predators of any kind:

10 – Dromaeosarus (DROH-may-oh-SORE-us): small, lightly built, around 4 feet tall, 6 feet long, 100 pounds; a cousin to the Velociraptor made famous in the movie “Jurassic Park’; isolated teeth and a single tail vertebra found in Alaska.

11 – Saurornitholestes (Sore-OR-nith-oh-LES-teez): very similar to Dromaeosaurus, 4 feet tall, 6 feet long, 100 pounds; isolated teeth and vertebrae found in Alaska.

Hypsilophodontids (HIP-sil-oh-fo-DON-tids) were small, swift-running, plant-eating dinosaurs that walked on two legs:

12 – Thescelosaurus (Thes-keloh-SORE-us): less than 5 feet tall, 11 feet long, 200 pounds; teeth and toe bone found in Alaska.

Two Areas, Two Finds

Fiorillo and his colleagues are focusing on two areas of Alaska: the North Slope and Denali National Park and Preserve. On the North Slope, the scientists have found a huge number of dinosaur bone fossils, leading them to conclude it might have been a seasonal killing field. The dense concentration of the bones and fine river sediment suggests the dinosaurs were caught in a flash flood and swept to their deaths.

“Given the unique geography of high mountains next to a warm coastal plain in a polar world, there was a greater probability of getting clocked by a flood than places farther south,” Fiorillo said.

Most of the dinosaurs appear to be juveniles, which further supports the idea of a flood or unexpected runoff. The scientists theorize the taller, more able, adult dinosaurs might have been able to cross the flood channels.

In Denali National Park, Fiorillo and his team have found thousands of tracks made by dinosaurs and prehistoric birds. “The North Slope bones tell us who was at the party and Denali tells us what the dance was,” he said.

The dance includes unprecedented information about the full polar ecosystem. In addition to prehistoric bird tracks and plant- and meat-eating dinosaur tracks, there is a wealth of trace fossils including fish, worms and crayfish. All of this points to significant biodiversity during the Late Cretaceous period.

“It’s all here,” Fiorillo said. “It is just phenomenal.”

A Pachyrhinosaurus perotorum skull fossil is one of the most exciting discoveries to date by Tony Fiorillo and his team, who also discovered two prehistoric birds.

Dinosaur Lessons

In a world moving as fast as this one, why are we still so fascinated with how dinosaurs lived and died? Fiorillo thinks the study of dinosaurs opens a broader discussion about life today.

“I think what our work has shown is that during the Cretaceous, the ancient Arctic was an area with a rich, warmer terrestrial ecosystem,” he said. “And as a result of that, in addition to questions about biodiversity through time, we can begin to ask meaningful questions about what a warm Arctic may mean to a society currently concerned with global warming.”

Addressing the challenges of global warming by looking to our ancient past is a big part of answering the question of why we study dinosaurs, and why Alaska is so important in the search for clues to how they lived and died. But there are larger reasons.

“There is one history of past life on the planet—the fossil record—and in order to understand the world today we need to know how we got here,” Fiorillo said. By understanding as much as we can about the lives of dinosaurs, perhaps we gain an understanding of our own place in history.

Plus, they could just be the coolest things, ever.

Barb Cooper is a freelance writer based in New York. 

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