A recent study found that large, plant-eating dinosaurs were already headed for extinction before an asteroid hit Earth 65.5 million years ago. Research indicates that large plant eaters, including hadrosaurs and ceratopsids were declining as a result of changes in the earth’s terrain, including volcanism and sea level changes. Small plant-eaters, carnivorous dinosaurs and huge plant-eaters without advanced chewing abilities all appear to have been prospering before the asteroid.
Read more on Discovery News.