(CNN) More than 100 million years ago, something curious happened.
Massive herds of dinosaurs started fleeing Europe, and scientists are not sure exactly why.
Evidence of a large-scale migration was discovered by scientists at the University of Leeds while using a global database of fossil records to understand the dinosaur diaspora.
Scientists found that some dinosaurs, unique to Europe during the early Cretaceous Period, were found in other parts of the world, suggesting these creatures migrated in a large exodus, according to findings published Monday in the Journal of Biogeography.
For the first time, scientists used network theory to illustrate how these prehistoric creatures moved around the globe during the Mesozoic Era. The method is commonly used to quantify Internet data, such as a person's social connections on Facebook. It was during this analysis that scientists unearthed the dinosaur migration out of Europe.
Scientists believe this migration happened after the continents started splitting apart, about 200 million years ago. The findings back other theories that suggest dinosaurs started moving around the world after Earth's supercontinent Pangaea broke apart.
This is important because it shows that dinosaurs were similar to animals that live on our Earth today, lead study author Alex Dunhill from the School of Earth and Environment at the University of Leeds told CNN. "Give a species half the chance, it will expand its geographic range and invade a new ecosystem," he added.
Although scientists are not sure why dinosaurs started migrating out of Europe, continental fragmentation may have influenced their departure. And this movement continued until the end of the Cretaceous era, about 66 million years ago, when the last of the dinosaurs died off and the continents shifted to where they remain today.
The findings don't mean every dinosaur left Europe, though. It's more like dinosaurs gradually expanded their presence around the world over the course of tens of millions of years -- similar to the theory that Homo sapiens originated in Africa and over tens of thousands of years migrated to the rest of the world, Dunhill said.
But for those who did manage to leave, you may be asking how monster-size dinosaurs got off the continent?
A possible mode of travel may have been temporary land bridges that formed due to the world's tectonic activity. It's possible that some of these land bridges stretched across regions such as Indo-Madagascar to Australia. But let's not discount the possibility of swimming, too.
"Dinosaurs could most probably swim. After all, an elephant can swim," Dunhill said.
Also, the data revealed that once a dinosaur family left Europe, they didn't come back during the Early Cretaceous Period, about 125 million to 100 million years ago.
There's no real explanation as to why some dinosaurs didn't come back. What scientists are seeing in the data may suggest a migration pattern or it might be a reason why there's a disparity in global fossil records -- since Europe is rich with dinosaur records, whereas many other parts of the world have not yet been explored.