Hey I'm Elliot and this is mental floss on youtube. Today I'm going to talk about some misconceptions about dinosaurs. [Intro Music]
Misconception number 1- Dinosaurs were the first reptiles. Actually, reptiles are older than dinosaurs. Experts believed that the earliest reptiles emerged between 320 and 310 million years ago, during the Carboniferous period. Dinosaurs came about later than that, about 231.4 million years ago, during the Triassic period. One of these early reptiles was the casineria, which was about 15 centimeters long, and had some amphibian characteristics in addition to reptilian ones. Freak.

That brings me to misconception number 2- All ancient reptiles were dinosaurs. [Points at fish tank] Here are some ancient reptiles that are not dinosaurs. There are also a lot of ancient flying reptiles, which many people still believe were dinosaurs, like the Pteranodon. Then of course, I'm sure you've heard of the famous Pterodactyl, which is not a term you will hear dinosaur experts use. In the media the term is used interchangeably with Pterosaur, which is the proper term for the flying reptiles who lived during the Triassic period through the Cretaceous period. But, whatever term you use, they were not dinosaurs.

Famous misconception number 3- "Dinosaur" means "terrible lizard". The term "Dinosaur" was coined by Richard Owen in 1842. Originally he intended it to mean fearfully great lizard. People have simplified it to mean "terrible" over time, but that's not totally accurate. It's also worth noting that dinosaurs are not lizards, they make up their own distinct group, but scientists classify them as reptiles.

Misconception number 4- The T. rex had tiny arms. It might look like the T. rex has small arms in modern depictions, especially compared to its huge body, but since the dinosaur stood about 18 feet tall, that means its arms were around 3 feet long. The publication Popular Science has estimated that the dinosaur could curl 430 pounds, around 195 kilos. A human's absolute maximum is around 260 pounds, or 118 kilos. My maximum is about 25.

Misconception Number 5- The brontosaurus was a dinosaur. Brontosaurus is not the correct name and we can blame this whole misconception on the late 19th century paleontologist named O.C. Marsh. He had been competing with another paleontologist, Edward Drinker Cope, to identify dinosaurs and get those identifications published. So in 1877 when Marsh discovered an incomplete skeleton of an Apatosaurus, he was thrilled and published it. Two years later, his team found a more complete skeleton and he figured a different dinosaur altogether, which he named "Brontosaurus". But because Apatosaurus came first, that is the proper name.

Misconception number 6-Dinosaurs all had scales. So it turns out that dinosaurs might not have looked exactly like the ones in Jurassic Park. I know. It's very disappointing. As of 2014, experts believe that all dinosaurs had feathers or the ability to sprout them. After a group of paleontologists discovered 5 distinct feathered species of dinosaurs in China they published an article claiming that all dinosaurs shared an ancestor that was also feathered. They probably did have scaly skin like we imagined, but that skin was covered in feathers.

Misconception number 7- Dinosaurs all coexisted then died out together. Actually, a lot of time separated different species of dinosaurs, and by "a lot of time", I mean millions of years. According to the National Museum of Natural History, "The distance in time between Tyrannosaurus and Apatosaurus is more than the time between Tyrannosaurus and your parents, about 65 million years. Of the (approximately) 900 named species of Mesozoic dinosaurs, only two or three dozen species faced the final extinction in North America."

Misconception number 8- Dinosaurs did not live amongst mammals. There were proto-mammals long before the dinosaurs showed up. Mammals evolved from those species, and showed up in the late Triassic period, almost simultaneously with dinosaurs. But these early mammals were probably pretty small, like the size of mice.

Speaking of mammals, misconception number 9- Mammals killed the dinosaurs. Some believe that the dinosaurs went extinct because mammals ate all of their eggs. We can't know for sure if this isn't true, but experts don't find the argument very convincing. First of all, if dinosaur eggs were the primary source of early mammals' food, then they would have gone extinct along with the dinosaurs, because they wouldn't have had anything left to eat. Second, there are modern-day mammals that eat eggs daily, but we've never seen another species going extinct because of it. Thirdly, mammals had already been eating dinosaur eggs for millions of years before the dinosaurs went extinct. They probably would have gone extinct earlier if they were the problem.

Misconception number 10- The dinosaurs were killed by an asteroid. Towards the end of the Cretaceous period, an asteroid probably hit the earth, causing an earthquake 1,000 times bigger than anything humans have ever recorded. It's possible that this did cause the extinction of dinosaurs, but paleontologists still aren't sure. A lot of them believe that dinosaurs were already on the decline thanks to a lack of diversity, so the asteroid just moved their already inevitable extinction right along.

Thank you so much for watching Misconceptions on Mental Floss on Youtube, which is made with the help of all these nice people. If you have a topic for an upcoming misconceptions episode that you would like to see, leave it in the comments, and we'll see you next week. Bye! [Outro music]