Giant asteroid hit at 'bad' time to kill dinosaurs

If the killer asteroid that wiped out dinosaurs 66 million years ago had hit a few million years earlier or later, dinosaurs probably would have been much better equipped to survive, an interesting study reveals.

Just before a large asteroid slammed into the earth, the diversity of plant-eating dinosaur species declined slightly.

The scarcity of plants would have left them more vulnerable to starvation and population collapse after the impact, with consequences that rippled all the way up the food chain, researchers suggested.

"The asteroid hit at a particularly bad time," said Stephen Brusatte, a palaeontologist at University of Edinburgh.

It is very likely that had the asteroid not hit the earth at that time, we would still have dinosaurs around today, Brusatte claimed.

To explore what dinosaurs were doing when the asteroid hit, the study pulled information from a database on global dinosaur diversity, including hundreds of fossils found in the past decade.

They found most dinosaurs thriving right up until the impact.

"In no sense were dinosaurs doomed to extinction and the asteroid just kind of finished them off," said Richard Butler, a palaeontologist at University of Birmingham.

The extinction set the stage for the modern world.

Although one lineage of dinosaurs survived as modern birds, mammals began their rise only after the dinosaurs were out of the picture.

"That may never have happened if dinosaurs had never gone extinct," Butler added.

The research appeared in the journal Biological Reviews.