In fact, dinosaurs emerged as the planet’s supreme creatures after the Triassic-Jurassic mass extinction. This event wiped out at least half of all living species approximately 201 million years ago. They then evolved over a period of 177 million years until the Cretaceous-Paleogene extinction event wiped them out too. More than 700 different types of dinosaur have been identified so far, but there are likely to have been lots more.
Indeed, dinosaurs appear to have been a highly diverse group. Some species moved about on two legs, while others used four. Still more were able to do both. Some ate meat. Others only consumed plants. Some had horns. Others evolved spiny armor. And not all dinosaurs were big-boned giants, either. In fact, many species were quite small, such as the 20-inch-long Xixianykus.
Of course, the idea of bringing back dinosaurs was the premise of the best-selling Michael Crichton novel Jurassic Park. After Stephen Spielberg directed a blockbuster adaptation of the book in 1993, a string of sequels and computer games followed. With revenues of more than $5 billion, the Jurassic Park series is in fact one of the most successful entertainment franchises ever established.