March 24, 2020

Canadian dinosaurs stayed put for the winter, new study shows

Study of isotopes in dinosaur teeth confirm that Late Cretaceous hadrosaurs were non-migratory

Were Canadian dinosaurs snowbirds or locals? Until now, no techniques had been developed that could conclusively answer if Canadian dinosaurs were migratory. 

Dinosaur migration has been debated by paleontologists for decades, as similar species of dinosaurs can be found from Montana up to Alaska. As a significant amount of that area would have experienced near-total darkness during the winters, some researchers have suggested that some dinosaur species may have migrated south from Alaska and the Yukon for the winter in search of a better climate, while others have maintained that dinosaurs could tough out the Cretaceous arctic winters.

A new study by David Terrill (pictured above), PhD student in the Department of Geoscience, found that — while some dinosaurs were indeed migratory — the brave creatures likely did not migrate to escape winter conditions. The study, published in the journal Biology Letters, part of the Royal Society, details part of Terrill’s thesis studying dinosaur migration, and represents the first attempt to use strontium isotopes to study dinosaur migration.  

New application of strontium isotopes key to solving mystery

Along with his supervisors and co-authors, Dr. Charles Henderson, PhD, and  Dr. Jason S. Anderson, PhD, Terrill studied the chemistry of tooth enamel of a single duckbill dinosaur. The researchers focused on a particular element, strontium, which substitutes for calcium in teeth. Strontium is an element with multiple isotopes (atoms of different masses that are otherwise identical), and these isotopes occur in different concentrations in different locations. This means that every location can have its own strontium ‘signature,’ which enters the body of animals through their food and water before becoming part of their bones and teeth.

Close-up of dinosaur fossil in dirt

Researchers compared samples of strontium signatures in teeth to arrive at results.

To figure out the unique signatures of different places in Cretaceous Alberta, the researchers measured the strontium signatures from non-migrating animals, such as crocodiles and freshwater fish, from four different fossil sites in Alberta. They compared those strontium signatures to what they found in the teeth of the duckbill dinosaur. 

The study also details the probable movement range of an individual dinosaur. These results suggest that hadrosaurs were not likely to be long-range migrators, and is in agreement with past work suggesting these dinosaurs likely did not migrate to escape winter conditions. 

“The results suggest our dinosaur did migrate, though only for a short distance, and lived in an area between Dinosaur Provincial Park and Medicine Hat, a range like what can be seen in modern elephant populations,” Terrill explains.

This dinosaur was a local, through and through!

While strontium isotopes have been previously used in migration studies in archaeological materials, they have never been used to study dinosaur migration. This study represents the first of its kind to be published in a major journal, and suggests that this technique could be applied to the study of migration in other dinosaur species. Migration is an important process for animals in modern environments; having the tools to properly study migration is therefore also of great importance in paleoecology.

Funding for the research was provided by an NSERC grant to Henderson, as well as a grant from the Dinosaur Research Institute. Most of the lab work was performed in the Department of Physics and Astronomy in Dr. Michael Wieser's stable isotope lab, with some specimens provided by the Royal Tyrrell Museum in Drumheller.