Tyrannosaurus Rex Claw

• Brown, Barnum. “Field Letter from Barnum Brown to Henry Fairfield Osborn, Aug. 12, 1902.” Field Letter American Museum of Natural History. Accessed 2026. 
• Osborn, Henry Fairfield. Tyrannosaurus and Other Cretaceous Carnivorous Dinosaurs. New York, NY: American Museum of Natural History, 1905. 
• Charlie Roger Scherer, Elizabeth Steell, Paul Upchurch; Drivers and mechanisms of convergent forelimb reduction in non-avian theropod dinosaurs. Proc Biol Sci 1 May 2026; 293 (2071): 20260528. Accessed June 20, 2026. 

THE CLAW OF A TYRANNOSAURUS REX

The first T. rex fossils were unearthed in the Hell Creek Formation in 1902 by Barnum Brown, a paleontologist with the American Museum of Natural History. In 1905, Henry Fairfield Osborn, Barnum Brown’s employer and the President of the American Museum of Natural History, said in reference to one of Brown’s finds: 

"I propose to make this animal the type of the new genus, Tyrannosaurus, in reference to its size, which far exceeds that of any carnivorous land animal hitherto described…This animal is in fact the ne plus ultra of the evolution of the large carnivorous dinosaurs: in brief it is entitled to the royal and high sounding group name which I have applied to it." 

No animal has elicited a combination of fascination, fear, and reverence quite like that of the "tyrant lizard king.” 

In addition to their incredibly lethal teeth and jaws, Tyannosaurus rex were equipped with dagger-like claws to mortally wound their prey in close range. T. rex, dubbed “the prize fighter of antiquity” by the New York Times in 1905, featured two large manus claws on each forelimb and three large claws on each foot, not including a vestigial dewclaw on each foot. 

While their characteristically small arms were also believed by scientists to be vestigial, recent studies suggest smaller arms and thicker, stronger skulls to be examples of convergent evolution. The skull and teeth of the King of the dinosaurs were the primary weapons with which they conquered the food chain. As they hunted other large dinosaurs as their prey, having large forelimbs could potentially have been an unnecessary hindrance. 

Tyrannosaurus rex’s vicious combination of strong build and bone-crushing bite force led T. rex to dominate the western landscape of late Cretaceous North America, hunting virtually every large dinosaur in its environment including Triceratops, Ankylosaurus, Ornithomimus, Pachycephalosaurus, Edmontosaurus, and even other tyrannosaurs.