# Tyrannosaurus rex

> A giant tyrannosaurid theropod from the very end of the Cretaceous in western North America, and one of the largest land predators known. Adults probably weighed around 6 to 8 tonnes.

- Classification: Dinosauria (clade) > Saurischia (clade) > Theropoda (clade) > Coelurosauria (clade) > Tyrannosauroidea (superfamily) > Tyrannosauridae (family) > Tyrannosaurinae (subfamily) > Tyrannosaurus (genus) > Tyrannosaurus rex (species)
- Length: 12.3–13 m
- Hip height: 3.6–4 m
- Mass: 6–9.5 t
- Age: 68–66 million years ago (Late Cretaceous)
- Fossils found in: Hell Creek Formation (Montana); Lance Formation (Wyoming); Scollard Formation (Alberta); Frenchman Formation (Saskatchewan); South Dakota; North Dakota
- Diet: carnivore
- Described: Henry Fairfield Osborn, 1905
- In films: Jurassic Park (1993), The Lost World: Jurassic Park (1997), Jurassic Park III (2001), Jurassic World (2015), Jurassic World: Fallen Kingdom (2018), Jurassic World Dominion (2022), Jurassic World Rebirth (2025)

Canonical page: https://dinodex.club/dinosaurs/tyrannosaurus-rex
Last updated: 2026-09-27

## Overview

Tyrannosaurus rex lived in western North America during the Maastrichtian, the last age of the Cretaceous, and its fossils come from rock units such as the Hell Creek, Lance, Scollard and Frenchman formations. It was named by Henry Fairfield Osborn in 1905.

It is known from many specimens, including nearly complete skeletons such as FMNH PR 2081 ("Sue") and RSM P2523.8 ("Scotty"). Computer models of mounted skeletons put typical adults at roughly 6 to 8 tonnes, with the largest individuals likely heavier.

Estimates of size vary between studies and between individuals. The figures on this page are given as ranges, each with the study it comes from.

## Name meaning

From Greek tyrannos ("tyrant") and sauros ("lizard"), with Latin rex ("king"): "tyrant lizard king" (Osborn 1905).

## Sources

1. Brochu, C. A. (2003). Osteology of Tyrannosaurus rex: insights from a nearly complete skeleton and high-resolution computed tomographic analysis of the skull. Journal of Vertebrate Paleontology 22 (sup4); Society of Vertebrate Paleontology Memoir 7. https://doi.org/10.1080/02724634.2003.10010947
2. Cohen, K. M., Harper, D. A. T., Gibbard, P. L. & Car, N. (2023). International Chronostratigraphic Chart (v2023/09). International Commission on Stratigraphy. https://stratigraphy.org/ICSchart/ChronostratChart2023-09.pdf
3. Fowler, D. W. (2017). Revised geochronology, correlation, and dinosaur stratigraphic ranges of the Santonian-Maastrichtian (Late Cretaceous) formations of the Western Interior of North America. PLoS ONE 12(11): e0188426. https://doi.org/10.1371/journal.pone.0188426
4. Hutchinson, J. R., Bates, K. T., Molnar, J., Allen, V. & Makovicky, P. J. (2011). A computational analysis of limb and body dimensions in Tyrannosaurus rex with implications for locomotion, ontogeny, and growth. PLoS ONE 6(10): e26037. https://doi.org/10.1371/journal.pone.0026037
5. Osborn, H. F. (1905). Tyrannosaurus and other Cretaceous carnivorous dinosaurs. Bulletin of the American Museum of Natural History 21: 259-265. https://digitallibrary.amnh.org/handle/2246/1464
6. Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.
7. Persons, W. S., Currie, P. J. & Erickson, G. M. (2020). An older and exceptionally large adult specimen of Tyrannosaurus rex. The Anatomical Record 303(4): 656-672. https://doi.org/10.1002/ar.24118

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Cite as: "Tyrannosaurus rex". DinoDex. https://dinodex.club/dinosaurs/tyrannosaurus-rex (updated 2026-09-27).