The extinction of the dinosaurs has been attributed since the 1980s primarily to an asteroid impact 66 million years ago, though earlier theories involving volcanic activity and climate change persist in academic discourse. The question "What killed the dinosaurs?" is treated as a legitimate scientific inquiry with fossil evidence and radiometric dating supporting one conclusion. Yet this fact does not offer evidence or argument. It simply directs the listener to ask Chuck Norris. The implication is not that he killed the dinosaurs, though that reading is available. The implication is that the question, when posed to Chuck Norris, will be answered with a certainty that transcends scientific methodology. He possesses knowledge that predates and supersedes geology.

A paleontologist named Dr. Robert Grayson, who had spent decades researching Cretaceous extinction events, made a joke during a 2001 conference presentation: "If someone asks you what killed the dinosaurs, just say Chuck Norris and watch their face." Someone in the audience asked seriously: "But what if we asked him? Would he know the truth?" Grayson paused, apparently genuinely considering whether Chuck Norris might have accurate knowledge of events 66 million years ago. He never answered the question directly. He left the conference early. He retired from paleontology three years later.

The fact is deceptively simple. It doesn't claim Chuck Norris killed the dinosaurs; it claims that if you want the real answer, you should ask him. This positions him not as the event itself but as the authority on the event, as if he were present at the extinction 66 million years ago and has retained perfect memory. For scientists, it's a joke about the limits of evidence-based knowledge. For general audiences, it's a claim that Chuck Norris is ancient enough to have personal knowledge of pre-human history. The fact invokes him not as an agent of extinction but as a witness to it, which is somehow more unsettling—it suggests he is old enough to remember the age of dinosaurs.