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 t... More »

According to the most popular theory, the Brachiosaurus dinosaur became extinct during the end of the Cretaceous period due to the impact of a meteor on Earth's surface. More »

Ammonites went extinct 65 million years ago along with the dinosaurs. The shells of ammonites are often used to date other fossils that are found. More »

www.reference.com Science Biology Zoology

According to the most popular theory, the Brachiosaurus dinosaur became extinct during the end of the Cretaceous period due to the impact of a meteor on Earth's surface. More »

There is not sufficient proof as to why dinosaurs went extinct, but experts believe it is related to geological events, diseases, climate change and lack of plant life for sustenance. The last known dinosaurs, according ... More »

www.reference.com Pets & Animals Dinosaurs

The ankylosaurus became extinct with the other great dinosaurs during the Cretaceous-Paleogene extinction event that occurred about 66 million years ago. While some questions remain about what caused this extinction, geo... More »

The velociraptor became extinct at the end of the Cretaceous Period due to an asteroid strike at the Yucatan Peninsula that occurred roughly 65 million years ago. This extinction event, known as the K-T boundary, also ki... More »