The imposing figure of Tyrannosaurus rex has captured public imagination, standing as a symbol of prehistoric power. Its immense size and predatory reputation make it one of the most recognized dinosaurs, fueling widespread curiosity about how much we truly know about this creature. A common question arises: how many of these magnificent “tyrant lizard kings” have actually been brought to light by paleontologists?
Defining a T. Rex Find
The number of Tyrannosaurus rex specimens discovered is nuanced, as finds range from isolated bone fragments to nearly complete skeletons. Paleontologists estimate fewer than 100 individual T. rex specimens have been identified globally. Approximately 32 relatively well-preserved individuals are housed in public museums. A “complete” skeleton typically refers to one where over 40% of the bones have been recovered. Beyond public collections, at least 43 additional specimens are known to be in private or commercial hands, complicating a precise count of scientifically accessible material.
Notable T. Rex Specimens
Several T. rex fossils stand out. “Sue” is the most complete T. rex skeleton found to date, with approximately 85-90% of its bones recovered. Discovered in 1990 in South Dakota, Sue measures about 12.3-12.4 meters (40-41 feet) long and stood 3.66-3.96 meters (12-13 feet) tall at the hips. Studies indicate Sue lived to be around 28 years old, the longest estimated lifespan for a T. rex.
“Scotty,” discovered in Saskatchewan, Canada, in 1991, is another notable specimen. Scotty is considered a contender for the largest T. rex by mass, reaching up to 13 meters (43 feet) in length, and is about 65% complete. This individual was over 30 years old at the time of its death, making it the oldest known T. rex specimen. “Stan” is another significant find, boasting 199 recovered bones, making it 70% complete with a well-preserved skull.
Geographic Discovery Hotspots
All known Tyrannosaurus rex fossils have been found only in western North America, an area that was once an island continent called Laramidia during the Late Cretaceous period. The primary source of these discoveries is the Hell Creek Formation, a geological division spanning parts of eastern Montana, North Dakota, South Dakota, and Wyoming. This formation was deposited from 72.7 to 66 million years ago. Specific finds within this region include the first partial skeleton unearthed by Barnum Brown in eastern Wyoming in 1900, followed by another significant discovery in Hell Creek, Montana, in 1902. Other notable fossil sites for T. rex include the Lance Formation in Wyoming and the Frenchman Formation in Saskatchewan.