In the latest chapter of clues left by dinosaurs, it turns out that they migrated out of Europe en masse some 100 million years ago.

New information published in the Journal of Biogeography Tuesday reveals that during the Early Cretaceous period, dinosaur families left significant information about their departure from certain parts of Europe; indicating that while many families left the territory, none entered it.

Researchers from Department of Biology & Biochemistry at the University of Bath and the University of Leeds in the U.K. undertook the project. They determined this information using a method known as “network theory,” which is often used in physics, or to quantify internet data, like one’s friends on Facebook.

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In order to solidify their findings, the researchers turned to the Paleogeology Database, a catalog containing every documented and accessible fossil across the globe. Records from different dinosaur families in different parts of the world were then mapped, and a filter was applied to only count family connections between different continents once.

The information further reveals that dinosaurs continued to migrate to other territories using temporary land bridges following the split of the subcontinent Pangea.

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On the University of Bath website, Dr. Alex Dunhill from the University of Leeds said, “We presume that temporary land bridges formed due to changes in sea levels, temporarily reconnecting the continents.”