--- title: Tyrannosaurus rex: what we really know, from teeth and dung to tiny arms — a lesson of Mova's school · trees and pragmatics description: «Tyrannosaurus rex: what we really know, from teeth and dung to tiny arms», a lesson of the biology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Tyrannosaurus rex lived about 68 to 66 million years ago in western North America, and a grown on --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/) / Tyrannosaurus rex: what we really know… # Tyrannosaurus rex: what we really know, from teeth and dung to tiny arms Lesson 265 of the biology course of Mova's primary school: 14 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/0/) — Tyrannosaurus rex lived about 68 to 66 million years ago in western North America, and a grown one was about 12 metres long and as tall at the hips as a double-decker bus. - [1](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/1/) — Nobody ever saw a living T. rex, so everything we know comes from clues: bones, teeth, footprints, skin prints and even fossil dung full of crushed bone. - [2](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/2/) — Its teeth were as long as a banana and thick like a railway spike, made to crush bone, and its bite was one of the strongest of any land animal that ever lived. - [3](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/3/) — Films like to show a T. rex racing a jeep and missing you if you stand still, but its heavy legs could not sprint, and its big forward-facing eyes and keen nose would have found you easily. - [4](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/4/) — Bones even have growth lines like the rings in a tree, and they tell us a T. rex grew up fast as a teenager and lived to about 28 to 30 years. - [6](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/6/) — A grown T. rex was about 12 metres long; its biggest teeth, root included, were about 30 centimetres long and kept being replaced all its life. - [8](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/8/) — Fossil dung is called a coprolite; one T. rex coprolite, as big as a loaf of bread, was full of crushed bone from a plant-eater. - [9](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/9/) — T. rex arms were short, about as long as a man's arm, but strong, with two fingers; scientists still argue what they were for. - [10](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/10/) — A grown T. rex probably could not truly run fast, perhaps 15 to 25 kilometres an hour, because its legs would have broken under its weight; young ones were slimmer and faster. - [12](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/12/) — Nobody knows what T. rex sounded like, because sounds do not fossilise; its relatives, birds and crocodiles, boom and rumble with closed mouths, so it may have rumbled rather than roared. - [13](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/13/) — Sue, found in South Dakota in 1990, is one of the most complete T. rex skeletons, with about 90 percent of the bones, a treasure because most dinosaurs are known only from a few bones; nobody knows whether Sue was male or female. - [14](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/14/) — Skin prints show small scales on parts of T. rex, while some smaller relatives such as Yutyrannus had feathers; babies may have been fluffy, but this is not known for sure. - [15](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/15/) — Stegosaurus lived about 150 million years ago, so more time separates Stegosaurus from T. rex than separates T. rex from us. - [16](https://md.mova.elamur.ai/free/en/corpora/school/biology/265-tyrannosaurus-rex-teeth-dung-and-tiny-arms/16/) — Growth lines in T. rex bones show it lived to about 28 to 30 years, and as a teenager it gained up to two kilograms a day. - ← previous: [How scientists find out: naturalists, Darwin, the microscope and wildlife filming](https://md.mova.elamur.ai/free/en/corpora/school/biology/264-how-scientists-find-out-naturalists-darwin-the-microscope-and-wildlife-filming/) - next →: [The long-necked giants: Diplodocus, Brachiosaurus, Argentinosaurus and Brontosaurus](https://md.mova.elamur.ai/free/en/corpora/school/biology/266-the-long-necked-giants-sauropods/) - ↑ back to [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/)