There are numerous theories regarding the extinction of the dinosaurs, including the triceratops, at the end of the Cretaceous period. The most prevalent theory describes the sudden destruction of the dinosaurs, and 50 to 75 percent of the planet's flora and other fauna, being due to a huge asteroid impact that dramatically altered the environment. However, despite strong evidence, there is no conclusive proof, explains the Smithsonian Institution.

According to the Smithsonian National Museum of Natural History, the prevalent triceratops and other dinosaur extinction theory is based on evidence of high concentrations of iridium in the crust of the Earth, in a thin layer. Iridium is one of the rarest elements naturally occurring in the Earth's crust, but it is found in high concentration in asteroids; therefore, scientists began to piece together the idea that an asteroid collided with the Earth during the late Cretaceous period, causing major tectonic events that dramatically altered the environment, impacted food sources and changed the climate. It is this event, known as the K-T extinction event, that most scientists believe is responsible for the end of the age of dinosaurs including the triceratops.

The discovery of a huge, round crater in Mexico, covered with millions of years of sediment and debris, which dated to the Cretaceous period supports the theory. The presence of soot, ash and asteroid fragments in the K-T boundary layer also support this theory. The end of the Cretaceous period, from which the planet took over a million years to recover, gave birth to the Age of Mammals or the Tertiary period.