← Rex's Notes
Tyrannosaurus rex
The one everyone draws first.
Said: tie-RAN-uh-SOR-us REX
Era: Cretaceous · 68 to 66 million years ago
Diet: Carnivore
Habitat: Forested river plains of western North America
Size: about as long as a school bus, and as tall as a giraffe.
What it was like
T. rex had teeth the size of bananas and a bite strong enough to crunch through bone. Its arms were so short it couldn't clap. Babies had a soft fluff of feathers, like fuzzy chicks the size of a turkey.
What we know now
Recent biomechanical modeling suggests adult T. rex topped out around 12 mph, well below the 25+ mph of older popular-science estimates; bone stress at higher speeds would have been catastrophic. Skin impressions confirm scales on the flanks and tail, but close relatives preserve filamentous protofeathers, so a downy juvenile is now the consensus reconstruction. The famous tiny arms were not vestigial; they could lift roughly 200 kg.
Notes
- Sue, the most complete T. rex skeleton, lived to about 28 and shows healed injuries that imply other rexes attacked her.
- Its binocular field was wider than a hawk's, with sharp depth perception.
- Recent papers suggest it had lips that covered its teeth at rest.