WASHINGTON — New research pinpoints how the torch passed from one dominant creature on Earth to another, from the brutish dinosaur to the crafty mammal.
Two studies published Thursday in the journal Science better explain the Earth-shaking consequences of a catastrophic cosmic collision 66 million years ago when a comet or asteroid smashed into the Gulf of Mexico.
The crash seemed to end the reign of the dinosaurs. And it gave way to the age of mammals that probably started with a cute squirrel-like critter and eventually led to us, the researchers report.
"I think it's fair to say, without the dinosaurs having gone extinct, we would not be here," said Paul Renne, director of the Berkeley Geochronology Center, who led the research on the dinosaurs and cosmic crash. The dinosaurs' disappearance "essentially releases the little timid mammals to become the big guys."
Renne demonstrated how the timing of the cosmic crash exquisitely matches the disappearance of the slow-footed dinosaurs of Jurassic Park fame. His findings provide more evidence for the theory that an extraterrestrial crash was most responsible for the extinction of dinosaurs.
Scientists have long thought that there were 200,000 years between the big crash and the end of the dinosaurs, but Renne's more detailed examination of fossils and soil at Hell Creek in northeast Montana puts the two events within 32,000 years of each other. That strengthens the case for the space crash as the "straw that broke the camel's back" and killed off the dinosaurs, said Renne.
He said other environmental factors, such as a changing climate from volcanic eruptions, also had made life harder for the dinosaurs, but that the big final dagger was the giant collision that caused a now-filled crater more than 100 miles wide at Chicxulub, on the coast of the Yucatan peninsula.