Dinsoaurs were a victim of their own success, new study suggests

Dinosaurs may have been so successful at world domination that it ended up contributing to their own demise, a new scientific theory suggests.

Numbers of the enormous reptiles were in already in decline even before the killer asteroid hit 65 million years ago, according to a study by UK researchers published in the journal, Nature Ecology and Evolution.

That is because the dinosaurs had run out of space on Earth after colonising every corner of the planet.

From their beginnings in South America, dinosaurs migrated “in a frenzy of movement” across the globe.

The reptiles had arrived hot on the heels of the world's largest extinction event, known as the Great Dying, which left a blank canvas for them to fill.

"They burst on to the scene and really quickly moved to all parts of the Earth," said Dr Chris Venditti of the University of Reading, a co-researcher on the study.

The study uses statistics to map the spread of dinosaurs in their great variety of species, from the T. rex to the gigantic long-necked Diplodocus.

Over the next 150 million years the reptiles evolved, but then a lack of new habitats to fill may have slowed their evolutionary progress.

“This honeymoon period could not last forever, and the dinosaurs eventually filled every available habitat on Earth,” lead author Ciara O'Donovan said.

“There was nowhere new for species to move to, which may have prevented new species from arising, contributing to the dinosaurs' pre-asteroid decline.

'In essence, they were perhaps too successful for their own good.”