The dinosaurs may have died with a gasp rather than a bang, a Notre Dame paleontologist told a gathering of peers and students Thursday at Mendenhall Laboratory. “The evidence just doesn’t add up to a catastrophic, knife-edge extinction,” said J. Keith Rigby, professor. Contrary to most paleontologists, Rigby said the extinction of dinosaurs occurred at a much slower rate. The popular theory holds that dinosaurs were alive and well, dominating the earth, when suddenly an asteroid struck the Earth and wiped out the entire species.”There was an impact of some kind, but I don’t think it was large enough to cause total extinction,” Rigby said. “If it’s dark, and everything is supposed to be starving to death why are reptiles and small mammals not being affected, and dinosaurs are in the cross hairs.”There is evidence that dinosaurs in North America became extinct much sooner than those in other parts of the world, specifically southern China, Rigby said. This could show the extinction of dinosaurs was not a sudden occurrence, he said.The fossil record also indicates that about two-thirds of the dinosaur population would have already died when a sizable asteroid hit, Rigby said.More compelling evidence against the singular asteroid theory is if it hit during that time and was big enough to vaporize 25 percent of the earth, “you would think that it would at least singe the fur of a few mammals,” Rigby said.Rigby believes a loss of oxygen played a role in the extinction of dinosaurs in that it would be enough to make them too tired to reproduce, he said.”There may have been something going on in the atmosphere that would cause a slower rate of extinction,” Rigby said. Geological Sciences Professor Emeritus Walter Sweet agrees with Rigby that the asteroid theory did not cause dinosaur extinction.”There certainly has been asteroid impact that’s been pretty well documented. I just don’t believe the asteroid extinction theory,” Sweet said.Loren Babcock from the Department of Geological Sciences at OSU said “He (Rigby) has a lot of interesting things to say on the subject, and we’re very excited to have him here at Ohio State.”Rigby finds the subject fascinating and challenging.”The more we study the situation, we come up with more riddles than answers,” Rigby said. “The complexity of the riddle is what I consider fun.”