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Tyrannosaurus in environment.jpg

Scientific classification

















Tyrannosaurus was a Late Cretaceous theropod, and almost certainly the most popular and famous dinosaur. It was one of the most formidible dinosaurus, capable of catching and killing virtually all dinosaurs of its time. It was one of the biggest land predators of all time. The type and only species, Tyrannosaurus rex, is a fixture in popular culture.


Tyrannosaurus was a bipedal predator. The largest confirmed skeleton nicknamed "Sue", reached 40.35ft long, 12 ft tall at the hip and

Stan the T.rex at Manchester Museum

6.8 t in mass. However, Dr. J. Horner says he has a specimen which is 10% larger than "Sue", nicknamed Celeste. Horner hasnt provided any measurements though if he is right, "Celeste" would be 13.5 m long. However, "Celeste" has not been confirmed by anyone except for Horner, so it is likely an invalid specimen. There is another fragmentary skull, MOR 008, which has been studied but no size estimate has been placed on it as of yet, so "Sue" retains its position as the largest Tyrannosaurus specimen.

Tyrannosaurus had the largest brain compared to it's body size of any large theropod. This enabled it to be a effective hunter. Surprisingly, 65% of that made it's olfactory bulb, in other words, 65% of that made up the organ that enables smelling! This indicates that it was a exellent smeller, picking up scents from miles away. Its jaws were also interesting. Tyrannosaurus teeth were very thick, and spaced close together. This suggests that it had strong, crushing jaws. When feeding, Tyrannosaurus used the sheer force in its jaws to crush the prey, then used its large teeth to rip out chunks of flesh. Tyrannosaurus jaws were capable of tearing out up to 1/4 of a ton of meat in a single bite.

The two largest known specimens of Tyrannosaurus

FMNH PR2081,or 'Sue', holds the record for the longest preserved tooth of any dinosaurs. The largest measured up to a full 12 inches in length. However, at least half of this length was taken up by the root in some theropods (two prime examples are Tyrannosaurus and Spinosaurus) meaning only around 6 inches of the tooth would actually be visible. The teeth themselves were D-shaped in cross section, and very thick. They needed to be so they would be able to survive the tyrannosaurs massive bite force.

Tyrannosaurus lived 68-65 million years ago, in the Northern U.S. and Southern Canada. This means a fairly open, dry, scrubland-like, and somewhat forested enviroment, where the Tyrannosaurus would have competed for food with predators like Nanotyrannus. Tyrannosaurus would likely have hunted primarily hadrosaurids (or more specifically, just Edmontosaurus depending on the synonymony between it and ''Anatotitan), though it may have gone after Triceratops on occasion.

Tyrannosaurus Facts

Pronouciation: tie-RAN-o-SORE-us

Average Length: 36-39 feet (11-12 meters)

Maximum Know Length: 40.35 feet (12.3 meters)

  • Maximum Height: ~12 feet (~3.6 m) at the hips
  • Average Mass: 6 tons
  • Maximum Mass: 9 tons
  • When: 68 to 65 million years ago.
  • Where: Western United States, Southwestern Canada
  • Diet: Carnivore. It hunted and killed the giant herbivores it shared its ecosystem with, and probably took carrion on occasion.

Note* These estimates could all change with recent findings.

Size comparrison of the giant theropods, Tyrannosaurus in blue.

Possilbe large fragmentary specimens

  • UCMP 118742
  • UCMP 137538
  • MOR 1126(C.rex)
  • MOR 1152(F.rex)
  • LACM 23874
  • SMSD 12047

Bite Force

The most recent studies on Tyrannosaurus bite force have put the bite force of this animal at 20-23.5t. If these are correct, Tyrannosaurus would have possesed the most powerful bite of all time. However, this study neglected muscular scaling rules and thus exaggerated the strength of the bite force almost 3-fold. Correcting for this yields an estimate in the region of 8-9t. This is still the largets of any known theropods and one of the highest of any organism ever.

A slightly older study that measured how much force was needed to make the wounds seen in a Triceratops bone got the feeding bite force for Tyrannosaurus at 3t. Its maximum bite would un-doubtably be higher.