"This suggests that for tens of millions of years before their ultimate demise, dinosaurs were beginning to lose their edge as the dominant species on Earth," said Sakamoto.
But theropods, the group that includes the iconic, meat-eating Tyrannosaurus rex, were disappearing at a more gradual pace.
Factors in their struggle likely included the break-up of continental land masses and sustained volcanic activity, the study said.
Even more, the research offers a look into the future. With many species already struggling due to human-driven climate change, those on the edge may be completely wiped out in the event of a disaster.
"Our study strongly indicates that if a group of animals is experiencing a fast pace of extinction more so than they can replace, then they are prone to annihilation once a major catastrophe occurs," Sakamoto said.
"This has huge implications for our current and future biodiversity, given the unprecedented speed at which species are going extinct owing to the ongoing human-caused climate change."
Then, a giant asteroid collided in Mexico with the Earth -- known as the Chicxulub impact -- 66 million years ago, causing a massive dust storm that blocked the Sun and led to a period of global cooling and widespread plant death.
Without trees and vegetation, an important food and shelter source disappeared, and so did the dinosaurs.
But theropods, the group that includes the iconic, meat-eating Tyrannosaurus rex, were disappearing at a more gradual pace.
Factors in their struggle likely included the break-up of continental land masses and sustained volcanic activity, the study said.
Even more, the research offers a look into the future. With many species already struggling due to human-driven climate change, those on the edge may be completely wiped out in the event of a disaster.
"Our study strongly indicates that if a group of animals is experiencing a fast pace of extinction more so than they can replace, then they are prone to annihilation once a major catastrophe occurs," Sakamoto said.
"This has huge implications for our current and future biodiversity, given the unprecedented speed at which species are going extinct owing to the ongoing human-caused climate change."
Then, a giant asteroid collided in Mexico with the Earth -- known as the Chicxulub impact -- 66 million years ago, causing a massive dust storm that blocked the Sun and led to a period of global cooling and widespread plant death.
Without trees and vegetation, an important food and shelter source disappeared, and so did the dinosaurs.