There is some lively discussion surrounding this question, but the answer is quite straightforward. An asteroid hit. This is firmly established, supported by all sorts of evidence, including a global layer of meteorite ash, and a 100-mile-wide crater. However, there are those who insist that dinosaurs didn’t go extinct but just evolved and changed in many ways. If this theory sounds a little too crazy for you, read this list of 25 Odd And Bizarre Facts About Dinosaurs You Probably Didn’t Know. We promise to shed some light on the topic. They dominated life on earth for 135 to 150 million years, until their demise at the end of the Cretaceous Period. (And we dare to say that we’re the most dominant species in Earth’s history for, what, a few thousand years of human civilization?) It was probably under one meter in length when fully grown, even though we can’t be totally sure as only a fragmentary skeleton has been found. Ichthyosaurs were large marine reptiles and resembled lizards … very big lizards that could swim. The crazy thing about them was that they were born tail-first. Why? Well, if they had been born head-first, they would have drowned before they could reach the water’s surface to take their first breath. A Troodon had a brain the size of a big bird (which was huge for dinosaur standards). It also had grasping hands and stereoscopic vision. For the record, smaller fossils than that of the Lesothosaurus have been found, but they belonged to baby dinosaurs. While scientists do not fully understand the function of these massive plates, they speculate that the Stegosaurus could control its body temperature by regulating blood flow through them. A Stegosaurus may have also been able to control its skin color this way, to either attract a mate or scare predators. Scientists call this color change “blushing.” The Ornithomimus is considered to be the fastest dinosaur to ever live as it could run up 70 km/h. In case you’re wondering how scientists can estimate such things, we’ve got the answer for you. They guess how fast a dinosaur walked or ran by looking at the gaps between its footprints. Kind of a cool scientific method, isn’t it? As for the toothiest dinosaur ever? The Hadrosaur had around 1,000 teeth and it continually grew new ones (during its youth). The dinosaur with the thickest skull was the Pachycephalosaurus. Its skull grew up to 8 inches thick It looked like a shark, but it was about three times bigger and much more aggressive and mean than our modern sharks. Interestingly, Sauropods are considered the tallest animals to ever walk on earth. Some of them were twice as tall as a giraffe. It weighed eight times more than a modern crocodile. Can you picture that? Even Gustave – the deadliest crocodile of our times – would look like a dwarf compared to a Deinosuchus. A T. Rex ate up to 22 tons of meat a year. The funny thing is that it had jagged teeth six inches long and thus couldn’t chew very well. As a result of this, it swallowed its food in large chunks. Yep, several kids of dinosaurs often swallowed large rocks. Why? For functional purposes, mainly. See, these rocks stayed in a dinosaur’s stomach and helped them grind up food. On the other hand, most “vegan” dinosaurs walked on four feet to carry their heavy bodies more comfortably. Some plant eaters could balance on two feet for a short time. For the record, the first dinosaurs were carnivores. The “vegans” and omnivores appeared later. The herds ranged from just a few adults and their young to as many as thousands of animals. The Stegosaurus has the smallest brain for its body size of any known dinosaur. Its body was roughly the size of a van, but it had a brain the size of a walnut. To get an idea of how small they are, they could literally fit inside an ordinary shopping bag like the ones you get in a supermarket. The blue whale is bigger than any dinosaur in history, as this whale can grow to as long as 108 feet (33 meters). When the bone was discovered, however, people were not aware of dinosaurs yet. So, originally, the Chinese thought that the remains belonged to dragons. Some experts suggest that there are many still undiscovered dinosaurs; in fact, there may be as many as 1,850 different kinds of dinosaurs. However, some scientists speculate that some dinosaurs lived for as long as 200 years. The Eoraptor was carnivorous and was roughly the size of a Belgian Shepherd dog. The first skeleton of this dinosaur’s kind was found in Argentina back in 1991. Rather than implying that dinosaurs were fearsome, Owen used the term to refer to their majesty and size. How exactly dinosaurs shrank and became birds must be a true miracle of Mother Nature, but some respected scientists believe that a long series of evolutionary changes could have made the transformation possible.