Numerous Dinosaur Footprints Discovered in Remote Alaskan Peninsula

Researchers have identified numerous dinosaur tracks in the Alaskan Peninsula—a strip of land which extends for about 500 miles from the southwest part of the state.

A team led by Anthony Fiorillo from the Perot Museum of Nature and Science in Texas documented the footprints in the remote Aniakchak National Monument nature preserve, around 420 miles southwest of Anchorage, the state's largest city.

According to a study published in the open-access journal PLOS ONE, the tracks were found preserved in the so-called Chignik Formation—a series of coastal sediment deposits approximately 1,650 to 2,000 feet thick which dates back to the Late Cretaceous Period (100.5-66 million years ago.)

The researchers conducted investigations of the site between 2001-2002 and 2016-2018, identifying more than 75 dinosaur track sites which included dozens of footprints.

"The first tracks were found in the last two hours of a week-long white-water rafting trip," Fiorillo told Newsweek. "While some of the team broke down the rafts, I ran down the beach to look around one more corner. And turning that last corner is where I found the tracks. When we returned in 2016, I took the new team to where the first tracks were found and almost immediately we started finding more footprints."

The discovery is significant, the team say, because while dinosaur fossils have been found across Alaska—particularly in places such as Denali National Park and the North Slope—there are very few records of these ancient animals in the Alaskan Peninsula.

The researchers analyzed the prints that they found, identifying two belonging to armored dinosaurs, one from a carnivorous tyrannosaur, and several others which were likely made by two types of birds. Birds are essentially avian dinosaurs given that they were the only dinosaur lineage to survive the mass extinction event which occurred at the end of the Cretaceous Period, 66 million years ago.

dinosaur footprints, Alaskan Peninsula
Hadrosaur footprints documented in the Alaskan Peninsula. Fiorillo et al, 2019

However, the vast majority of the trackways (93 percent) belonged to a group of herbivorous duck-billed dinosaurs known as "hadrosaurs"—which means "bulky lizards."

These animals—which ranged in length from around 10 to 65 feet—were highly successful before going extinct and scientists think that they were the most common dinosaurs living in regions located in Earth's higher latitudes.

The researchers say that the abundance of hadrosaur tracks suggests that these animals in this part of Alaska preferred coastal habitats—a conclusion which mirrors similar findings from previous research in the north of Alaska.

"Our study shows us something about habitat preferences for some dinosaurs and also that duck-billed dinosaurs were incredibly abundant," Fiorillo said in a statement. "Duck-billed dinosaurs were as commonplace as cows, though given we are working in Alaska, perhaps it is better to consider them the caribou of the Cretaceous."

The authors of the study conclude that understanding more about the habitat preferences of hadrosaurs could help to shed light on how ecosystems changed through time by looking at the migration patterns of these animals.

This article was updated to include additional comments from Anthony Fiorillo.