Large numbers of dinosaurs migrated out of Europe approximately 125 million years ago. This mass exodus of dinosaurs was probably the Europe's original migration crisis and paleontologists have yet to know why.

A team of researchers mapped out dinosaur movements during the Mesozoic Era. They found that between 225 million to 65 million years ago, a bizarre mass exodus of dinosaurs happened in the middle.

For the migration computer model, the Leeds University researchers used the Paleobiology Database. This collection includes all the documented dinosaur fossils around the globe.

Compared to other parts of the world, Europe has an extensive dinosaur fossil record due to widespread digs.

For the migration map, the researchers filtered the database by focusing on the earliest time a dinosaur lineage moved from one continent to another.

What they found was strange: all the Early Cretaceous movements between Europe and the other continents were out-going. This means that 125 to 100 million years ago, dinosaurs were moving out of Europe.

For approximately 25 million years, there were no new dinosaur families moving into Europe until the species began to make their way back later.

"This is a curious result that has no concrete explanation. It might be a real migratory pattern or it may be an artefact of the incomplete and sporadic nature of the dinosaur fossil record," said lead study author Dr. Alex Dunhill from the University of Leeds' School of Earth and Environment.

The recent study, which was released in the Journal of Biogeography on April 25 supports past research wherein scientists found that dinosaur families continued moving to various parts of the world post the splitting of the "supercontinent" Pangaea.

The researchers presumed that the changes in the sea levels resulted in the formation of temporary land bridges. These massive structures reconnected the continent and supported continued migration.

For example, these massive "temporary land bridges" connected Australia to the Indo-Madagascar. In the span of tens of millions of years, the researchers theorized that the tectonic activity produced the right conditions for the formation of these land bridges that enabled further movement of the dinosaur families.

Photo: Yosuke Shimizu | Flickr