We all know dinosaurs were big or small, strong or fast, terrifying or cute, carnivores or herbivores. But there are things only a few people know. Here’s a list about ten facts you probaly haven’t heard about and maybe wont believe.

1. The tail of a Apatosaurus could break the sound barrier.

According to computer calculations, they could whip their tail so fast that it broke the sound barrier, creating a sonic boom.

2. A Ankylosaurus club tail could break a T-rex’s ankles.

With smaller tails, which were most likely found on younger Ankylosauruses, it would have hit its predators with the same amount of force as a bowling ball. However, bigger tails could have struck blows that were somewhere between 364 and 718 megapascals of impact stress, which is powerful enough to break a T-Rex’s ankle.

3. There has been only 1 case of cannibalism in the time dinosaurs lived

To some people, it may not be shocking that dinosaurs were cannibals. After all, they were carnivorous animals that needed a lot of food to sustain themselves, so one dinosaur eating another dinosaur of the same species must have happened all the time, right? Well, the dinosaurs lived for 65 million years and amazingly, there is only one confirmed case of dinosaur cannibalism. The confirmed case of dinosaur cannibalism involved the Majungasaurus, which lived in Madagascar from 70 to 66 million years ago and they were considered the T-Rex of the southern hemisphere.

4. The smallest pterodactyl was smaller than a pigeon.

The smallest known pterodactyl, the Nemicolopterus crypticus (discovered in 2008), had a wingspan of only 10 inches.

5. There’s only one complete skeleton needed to identify a new species

Only one complete or even partial dinosaur skeleton is needed in order to identify an entirely new species. “Almost half of the 1,200 or so dinosaurs that have been named are known from unique single specimens,” said Mark A. Norell, the American Museum of Natural History’s chairman and curator of the museum’s division of paleontology

6. Birds are the closest to dinosaurs.

“Dinosaurs are not extinct we just call them birds,” Norell said. “In fact, birds are more closely related to dinosaurs like the T.rex than the T.rex is to sauropods like the mamenchisaurus.”

7. A Stegosaurus’ brains were as big as two dense walnuts.

Stegosauruses had an extremely low brain to body mass. Their brain weighed approximately three ounces, was the size of about two dense walnuts, and their body mass was approximately 5 tons, which is heavier than most cars on the road today.

8. The first dinosaur skeleton was found in 1822.

In an attempt to figure out the origins of the iguanodon, an English obstetrician turned paleontologist named Gideon Mantell discovered, before anyone else in all of recorded human history, discovered the first dinosaur fossil.

9. For the last 200 years scientists have no ideo how dinosaurs mated.

Is it as simple as a mommy and daddy dinosaur coming together because they were in love? Probably not. But that theorem is just as good as any other that scientists have presented, as there is nothing even close to a general consensus on how dinosaurs mated. We have no idea how the process of reproduction between dinosaurs occurred, and the debate on how two dinosaurs made a baby dinosaur doesn’t seem like it will ever end.

10. Dinosaurs could reach a age of 300 years.

Scientists estimate, based on bone evidence, that some dinosaurs could have lived to be between 75 and 300 years old.