Tyrannosaurus rex
Pronounced tie-RAN-oh-SORE-us REKS
Coelurosauria ยท Tyrannosauridae
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.
- Bipedal
- Giant
- Apex predator
- Famous specimen
- Movie icon
- Skin impressions known
- Period
- Cretaceousยท Maastrichtian
- Diet
- Carnivore
- Length
- 12.3 mpublished range 12.3โ13 m
- Mass
- 6,000โ9,500 kg
- Location
- Montana, South Dakota, North Dakota, Wyoming, Alberta, Saskatchewan
Quick answers
- How big was Tyrannosaurus rex?
- Tyrannosaurus rex was about 12.3โ13 m long. It stood about 3.6โ4 m tall at the hips. It weighed about 6โ9.5 t. (Brochu 2003; Persons et al. 2020)
- When did Tyrannosaurus rex live?
- Tyrannosaurus rex lived during the Late Cretaceous, about 68โ66 million years ago. (Cohen et al. 2023; Fowler 2017)
- Where have Tyrannosaurus rex fossils been found?
- Fossils of Tyrannosaurus rex have been found in Hell Creek Formation (Montana), Lance Formation (Wyoming), Scollard Formation (Alberta), Frenchman Formation (Saskatchewan), South Dakota, and North Dakota. (Osborn 1905; Brochu 2003)
- What did Tyrannosaurus rex eat?
- Tyrannosaurus rex was a carnivore. (Osborn 1905; Brochu 2003)
- Who named Tyrannosaurus rex, and when?
- Tyrannosaurus rex was described by Henry Fairfield Osborn in 1905. (Osborn 1905)
- Was Tyrannosaurus rex in Jurassic Park?
- Yes. Tyrannosaurus rex appears in 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), and Jurassic World Rebirth (2025). The franchise's signature predator: a huge, scaly, roaring hunter that appears in every film. The first film suggests it cannot see prey that stands still. Skull studies point the other way: T. rex had some of the best binocular vision of any large theropod. (Wikipedia: Dinosaurs in Jurassic Park 2026; Stevens 2006)
On this page
tie-RAN-oh-SORE-us REKS
- Period
- Cretaceous68โ66 Ma
- Diet
- Carnivore
- Length
- 12.3 m
- Mass
- 6โ9.5 t
- Classification
- Coelurosauria ยท Tyrannosauridae
- Described
- 1905, Henry Fairfield Osborn
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).
Biology & evidence
What scientists think about how this animal lived, and how strong the evidence for each idea is.
Locomotion
An adult Tyrannosaurus rex could walk fast but could not truly run.
Evidence level: Moderate evidenceTo run, an animal needs enough leg muscle and bones strong enough for the impact. Models of a 6-9 tonne adult say T. rex had neither for a real run, so estimated top speeds are those of a brisk walk. Juveniles, being lighter, were probably faster.
Evidence for / against ยท 1
Evidence for
Biomechanical model ยท T. rex limb muscle models limit running speed
Models of leg muscle mass needed for fast running (Hutchinson & Garcia 2002) and multibody simulations with bone-stress limits (Sellers et al. 2017) both find that a large adult could not run fast.
Feeding
Tyrannosaurus rex had one of the strongest bites of any land animal and could crush and eat bone.
Evidence level: Strong evidenceThree kinds of evidence agree: bitten bones with deep punctures, droppings full of crushed bone, and computer models of the jaw muscles. Together they show a bite strong enough to shatter bone, unusual among dinosaurs.
Evidence for / against ยท 3
Evidence for
Trace fossil ยท Tooth-marked Triceratops and Edmontosaurus bones
Deep punctures and drag marks attributed to T. rex teeth on a Triceratops pelvis, used to estimate bite force experimentally.
Trace fossil ยท Bone-filled tyrannosaur coprolite (Saskatchewan)
A large coprolite full of crushed bone fragments of a juvenile dinosaur, attributed to T. rex by size and age.
Biomechanical model ยท Bite force simulations for T. rex
Muscle reconstruction and multibody dynamics giving bite forces in the tens of kilonewtons at the back teeth.
Skin & covering
Adult Tyrannosaurus rex had mostly scaly skin; if it had feathers, they were limited.
Evidence level: Moderate evidenceThe only T. rex skin found is scaly, and covers small patches from the neck, hips and tail. Its relative Yutyrannus had long feathers, so feathers on the back of T. rex cannot be ruled out, but a fluffy adult T. rex is not supported.
Evidence for / against ยท 2
Evidence for
Skin impression ยท Scaly skin patches of a T. rex (HMNS / Wyrex)
Small patches of scaly skin from the neck, pelvis and tail of a T. rex, with no trace of feathers.
Evidence against
Feather impression ยท Feathered giant tyrannosauroid Yutyrannus
Long filamentous feathers preserved on a 9 m Early Cretaceous tyrannosauroid from China, showing large tyrannosauroids could be feathered.
Growth
Tyrannosaurus rex grew very fast as a teenager and reached adult size at around 20 years old.
Evidence level: Strong evidenceBones grow in yearly layers, like tree rings. Counting them in T. rex bones shows a growth spurt in the teens, when an individual could gain hundreds of kilograms a year, then a slowdown near 20. Sue is estimated to have died in her late twenties.
Evidence for / against ยท 1
Evidence for
Histology ยท Tyrannosaurid bone histology growth curves
Growth lines counted in thin sections of long bones and ribs of several T. rex individuals, including Sue, fitted to a growth curve with a steep adolescent phase.
Specimen: FMNH PR 2081 โSueโ
Size
- Length
- 12.3 mpublished range 12.3โ13 m
- Height
- 3.9 mpublished range 3.6โ4 m
- Mass
- 6,000โ9,500 kg
(40.4 ft)
Based on FMNH PR 2081 "Sue"
(12.8 ft)
Based on FMNH PR 2081 "Sue" and other large adults
Based on FMNH PR 2081 "Sue" (largest of five mounted skeletons modelled)
Timeline
Periods: Maastrichtian (72.1โ66 Ma), Late Cretaceous (100.5โ66 Ma)
endAgeMa 66.0 = end of the Maastrichtian (ICS 2023/09). startAgeMa left empty: no primary source verified for the first appearance.
Location
Formations
- Hell Creek Formation ยท Montana
- Lance Formation ยท Wyoming
- Scollard Formation ยท Alberta
- Frenchman Formation ยท Saskatchewan
- Tyrannosaurus type locality, Hell Creek, Garfield County, Montana ยท Hell Creek Formation ยท Montana ยท position approximate
- Sue site, Cheyenne River Indian Reservation, near Faith, South Dakota ยท Hell Creek Formation ยท South Dakota ยท position approximate
- Stan site, Harding County, South Dakota ยท Hell Creek Formation ยท South Dakota ยท position approximate
- Scotty site, Frenchman River valley near Eastend, Saskatchewan ยท Frenchman Formation ยท Saskatchewan ยท position approximate
These are the places where fossils have been found, not the full area where the animal lived.
Ecosystem
Lived in: Hell Creek
68โ66 million years ago ยท floodplain, river system, forest, coastal plain
Warm, humid coastal lowlands and river floodplains west of the retreating Western Interior Seaway at the very end of the Cretaceous, with forests of conifers and flowering plants. The ecosystem ends at the Cretaceous-Paleogene extinction.
Classification
- cladeDinosauria
- cladeSaurischia
- cladeTheropoda
- cladeCoelurosauria
- superfamilyTyrannosauroidea
- familyTyrannosauridae
- subfamilyTyrannosaurinae
- genusTyrannosaurus
- speciesTyrannosaurus rex
Taxonomic status: Valid
Fossil record
| Catalog number | Status | Institution | Found |
|---|---|---|---|
| CM 9380 | Holotype | Carnegie Museum of Natural History (CM) | 1902 |
| FMNH PR 2081 โSueโ | Referred specimen | Field Museum of Natural History (FMNH) | 1990 |
| BHI 3033 โStanโ | Referred specimen | Black Hills Institute of Geological Research (BHI) | 1987 |
| RSKM P2523.8 โScottyโ | Referred specimen | Royal Saskatchewan Museum (RSKM) | 1991 |
What has been found
Holotype: CM 9380
- Preserved
- Partial
- Reconstructed
- Unknown / not recorded
Holotype: CM 9380
Region by region (table)
| Region | State |
|---|---|
| Skull | Partial |
| Mandible | Partial |
| Teeth | Unknown / not recorded |
| Cervical vertebrae | Unknown / not recorded |
| Dorsal vertebrae | Partial |
| Sacrum | Unknown / not recorded |
| Caudal vertebrae | Unknown / not recorded |
| Ribs | Unknown / not recorded |
| Gastralia | Unknown / not recorded |
| Scapula / shoulder girdle | Unknown / not recorded |
| Humerus | Unknown / not recorded ยท Not reliably known for the holotype. |
| Forearm (radius / ulna) | Unknown / not recorded |
| Hand (manus) | Unknown / not recorded |
| Pelvis | Partial |
| Femur | Preserved |
| Tibia / fibula | Partial |
| Foot (pes) | Unknown / not recorded |
Referred specimen: FMNH PR 2081 โSueโ
Region by region (table)
| Region | State |
|---|---|
| Skull | Preserved |
| Mandible | Preserved |
| Teeth | Preserved |
| Cervical vertebrae | Preserved |
| Dorsal vertebrae | Preserved |
| Sacrum | Preserved |
| Caudal vertebrae | Partial |
| Ribs | Preserved |
| Gastralia | Preserved |
| Scapula / shoulder girdle | Preserved |
| Humerus | Preserved |
| Forearm (radius / ulna) | Preserved |
| Hand (manus) | Partial |
| Pelvis | Preserved |
| Femur | Preserved |
| Tibia / fibula | Preserved |
| Foot (pes) | Partial |
Referred specimen: BHI 3033 โStanโ
Region by region (table)
| Region | State |
|---|---|
| Skull | Preserved ยท One of the best-preserved T. rex skulls. |
| Mandible | Preserved |
| Teeth | Unknown / not recorded |
| Cervical vertebrae | Partial |
| Dorsal vertebrae | Partial |
| Sacrum | Unknown / not recorded |
| Caudal vertebrae | Unknown / not recorded |
| Ribs | Unknown / not recorded |
| Gastralia | Unknown / not recorded |
| Scapula / shoulder girdle | Unknown / not recorded |
| Humerus | Unknown / not recorded |
| Forearm (radius / ulna) | Unknown / not recorded |
| Hand (manus) | Unknown / not recorded |
| Pelvis | Partial |
| Femur | Partial |
| Tibia / fibula | Unknown / not recorded |
| Foot (pes) | Unknown / not recorded |
Referred specimen: RSKM P2523.8 โScottyโ
Region by region (table)
| Region | State |
|---|---|
| Skull | Partial |
| Mandible | Unknown / not recorded |
| Teeth | Unknown / not recorded |
| Cervical vertebrae | Unknown / not recorded |
| Dorsal vertebrae | Partial |
| Sacrum | Unknown / not recorded |
| Caudal vertebrae | Unknown / not recorded |
| Ribs | Unknown / not recorded |
| Gastralia | Unknown / not recorded |
| Scapula / shoulder girdle | Unknown / not recorded |
| Humerus | Unknown / not recorded |
| Forearm (radius / ulna) | Unknown / not recorded |
| Hand (manus) | Unknown / not recorded |
| Pelvis | Partial |
| Femur | Preserved |
| Tibia / fibula | Unknown / not recorded |
| Foot (pes) | Unknown / not recorded |
Gallery
Discovery
- Year described
- 1905
- Described by
- Henry Fairfield Osborn
- Type specimen
- CM 9380 (holotype; originally AMNH 973)
Discovery timeline
1902 ยท First material found
Barnum Brown finds the Tyrannosaurus holotype
Barnum Brown excavates a partial skeleton in the Hell Creek badlands of Montana for the American Museum.
People: Barnum Brown
1905 ยท Formally described
Osborn names Tyrannosaurus rex (and Dynamosaurus imperiosus)
In the same paper Osborn also names Dynamosaurus imperiosus from another skeleton; he synonymized it with T. rex a year later.
People: Henry Fairfield Osborn
1941 ยท Revision
Holotype sold to the Carnegie Museum
The AMNH sells the type specimen to the Carnegie Museum in Pittsburgh, reportedly to keep it safe from wartime bombing.
1990 ยท Specimen recovered
Sue found by Sue Hendrickson
The largest and most complete T. rex known at the time is found near Faith, South Dakota.
People: Sue Hendrickson
2003 ยท Major study
Brochu publishes the osteology of Sue
The first full monograph of a nearly complete T. rex skeleton, with CT scans of the skull.
2020 ยท Major study
Scotty described as the largest known T. rex
Persons, Currie and Erickson describe Scotty as an old adult with an estimated mass above that of Sue.
In Jurassic Park & Jurassic World
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)
On screen
The franchise's signature predator: a huge, scaly, roaring hunter that appears in every film.
Film vs fossils
- The first film suggests it cannot see prey that stands still. Skull studies point the other way: T. rex had some of the best binocular vision of any large theropod.
- The films show it keeping pace with a speeding jeep. Biomechanical models make an adult T. rex a fast walker, not a sprinter.
- The scaly skin is broadly consistent with the fossils: skin impressions from tyrannosaurids show scales.
Film titles are used for identification only. DinoDex is not affiliated with or endorsed by the Jurassic Park / Jurassic World franchise. All dinosaurs seen in the films
Sources
- (2026). Wikipedia: Dinosaurs in Jurassic Park. Wikipedia. https://en.wikipedia.org/wiki/Dinosaurs_in_Jurassic_Park (opens in a new tab)
- (2026). Wikipedia: Jurassic World Rebirth. Wikipedia. https://en.wikipedia.org/wiki/Jurassic_World_Rebirth (opens in a new tab)
- Bell, P. R., Campione, N. E., Persons, W. S., Currie, P. J., Larson, P. L., Tanke, D. H. & Bakker, R. T. (2017). Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution. Biology Letters 13: 20170092. doi:10.1098/rsbl.2017.0092 (opens in a new tab)
- 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. doi:10.1080/02724634.2003.10010947 (opens in a new tab)
- 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 (opens in a new tab)
- 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. doi:10.1371/journal.pone.0188426 (opens in a new tab)
- Hutchinson, J. R. & Garcia, M. (2002). Tyrannosaurus was not a fast runner. Nature 415: 1018-1021. doi:10.1038/4151018a (opens in a new tab)
- 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. doi:10.1371/journal.pone.0026037 (opens in a new tab)
- 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 (opens in a new tab)
- Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.
- 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. doi:10.1002/ar.24118 (opens in a new tab)
- Sellers, W. I., Pond, S. B., Brassey, C. A., Manning, P. L. & Bates, K. T. (2017). Investigating the running abilities of Tyrannosaurus rex using stress-constrained multibody dynamic analysis. PeerJ 5: e3420. doi:10.7717/peerj.3420 (opens in a new tab)
- Stevens, K. A. (2006). Binocular vision in theropod dinosaurs. Journal of Vertebrate Paleontology. doi:10.1671/0272-4634(2006)26[321:BVITD]2.0.CO;2 (opens in a new tab)