Tyrannosaurus rex Discovery: Barnum Brown and the 1902 Find

The discovery of Tyrannosaurus rex began in 1902, when the fossil hunter Barnum Brown of the American Museum of Natural History found a partial skeleton of a huge meat-eating dinosaur in the Hell Creek badlands of eastern Montana. In 1905 the museum’s leading palaeontologist, Henry Fairfield Osborn (later its president), named the animal Tyrannosaurus rex, the “tyrant lizard king”. Later finds, museum displays and films turned it into the most famous dinosaur in the world.

Background: the hunt for Cretaceous giants

By 1900 the great dinosaur discoveries of the American West had mostly come from Jurassic rocks, opened up during the Bone Wars of Edward Drinker Cope and Othniel Charles Marsh. These had produced giant plant-eaters such as Apatosaurus and Diplodocus and the predator Allosaurus. Younger Cretaceous rocks were known to hold horned dinosaurs such as Triceratops, but large Cretaceous predators were poorly understood.

The American Museum of Natural History in New York was then building up its fossil collections under Henry Fairfield Osborn. Wealthy patrons, including the banker J. P. Morgan, supported its expeditions. Osborn wanted spectacular skeletons that would draw the public and rival the collections of Yale and the Carnegie Museum.

Osborn’s star collector was Barnum Brown (1873–1963), born in Carbondale, Kansas, and named after the showman P. T. Barnum. Brown had an extraordinary talent for finding fossils and spent his career travelling the world for the museum, earning the nickname “Mr. Bones”.

What happened in 1902

In 1900 Brown had already found a partial skeleton of a large Cretaceous predator in eastern Wyoming. In 1902 he turned to the remote badlands around Hell Creek, near the small settlement of Jordan in Montana. Reports from the naturalist William T. Hornaday, who had seen large fossils in the area, helped draw the museum’s attention there.

That summer Brown found the bones of an enormous carnivore weathering out of a sandstone hillside. The specimen included parts of the skull and jaws, vertebrae, ribs, part of the pelvis and bones of the hind limbs. The rock was hard, and Brown used dynamite and teams of horses to remove the overlying sandstone, work that continued over more than one field season.

The heavy blocks had to be hauled by horse-drawn wagon across rough, roadless country to the railway, a journey of several days, before shipment to New York. In the museum laboratory, preparators spent months freeing the bones from the rock.

Osborn names Tyrannosaurus

In 1905 Osborn published a short paper in the Bulletin of the American Museum of Natural History describing the Montana skeleton as a new genus and species, Tyrannosaurus rex. In the same paper he named Brown’s 1900 Wyoming skeleton Dynamosaurus imperiosus. Osborn soon recognised that the two were the same kind of animal, and Tyrannosaurus, which appeared first in the paper, became the accepted name.

Osborn described Tyrannosaurus as the largest carnivorous land animal then known. He emphasised its great size and powerful jaws, and he already envisaged it as the ultimate predator of its age.

The 1908 skeleton and the first mount

The 1902 specimen lacked much of the skull. In 1908 Brown found a far better skeleton at Big Dry Creek in Montana, with a nearly complete skull. This specimen, together with casts of missing parts, allowed the museum to build a full skeletal mount.

Osborn and Brown experimented with poses using scale models, and in 1913 Osborn published plates showing reconstructions of the skeleton. The mounted skeleton went on display in New York in 1915 in an upright, kangaroo-like stance, with the tail dragging on the ground. This pose dominated popular images of the animal for decades.

During the Second World War, in 1941, the museum sold the 1902 type specimen to the Carnegie Museum of Natural History in Pittsburgh for $7,000, partly to protect it in case New York was bombed. Brown’s 1900 Wyoming skeleton was later sold to the Natural History Museum in London. The 1908 skeleton was remounted in a horizontal posture in New York in the 1990s, reflecting modern understanding.

Key people

Barnum Brown was associated with the American Museum of Natural History from 1897 until his death in 1963. Besides Tyrannosaurus, he collected a remarkable range of dinosaurs from Montana, Wyoming and the Red Deer River of Alberta, and later searched for fossils in India, Greece, Ethiopia and elsewhere. He was a flamboyant figure who wore a fur coat in the field, and some of his travels were partly funded by oil companies seeking his geological expertise.

Henry Fairfield Osborn (1857–1935) was a palaeontologist and long-time president of the American Museum of Natural History. He built its vertebrate palaeontology department into one of the most important in the world and published many of its key descriptions. His legacy is mixed: he was also a prominent supporter of eugenics, views that are rejected today.

William T. Hornaday (1854–1937), a naturalist and director of the New York Zoological Park, is best known for his campaign to save the American bison. His reports of fossils in eastern Montana helped point the museum towards Hell Creek.

Behind them stood less famous people: field assistants, cooks, teamsters, ranchers who allowed digging on their land, and preparators in New York whose skilled work turned rough blocks into a scientific specimen.

What kind of animal was T. rex?

Tyrannosaurus rex lived at the very end of the Cretaceous Period, roughly 68 to 66 million years ago, in what is now western North America. Its fossils come mainly from the Hell Creek Formation and related rocks, which also preserve Triceratops, Edmontosaurus and Ankylosaurus.

Large adults are commonly estimated at about 12 metres long and 8 to 9 tonnes, though figures differ between studies. The skull reached about 1.5 metres in length, and the jaws carried thick, serrated teeth suited to crushing bone. Studies of jaw mechanics have produced bite-force estimates in the tens of thousands of newtons, among the highest of any land animal.

Its forelimbs were short, with two functional fingers, but strongly built. Its eyes faced partly forward, giving some overlapping vision, and its brain cavity suggests a keen sense of smell. Patches of fossil skin show scales, while some of its smaller relatives had feathers; whether adult T. rex had any feathers is still debated.

Myths and facts

Myth: T. rex could only see moving objects. This idea, popularised by the 1993 film Jurassic Park, has no basis in the fossils. Studies of the skull suggest T. rex had good, forward-facing vision.

Myth: T. rex stood upright and dragged its tail. That was the early 20th-century reconstruction. Modern studies of the skeleton and of fossil footprints of large theropods show that it held its body roughly horizontal, balanced by the tail.

Debate: hunter or scavenger? In the 1990s some researchers argued that T. rex was mainly a scavenger. Most palaeontologists now see it as an active predator that, like many modern carnivores, would also scavenge. Healed bite marks on plant-eating dinosaurs support active hunting.

Fact: the name is older than some rivals. Cope named two vertebrae Manospondylus gigas in 1892, and they may belong to T. rex. Under naming rules adopted in 2000, a name not used since 1899 cannot displace a widely used later one, so Tyrannosaurus rex stands.

Legacy: from museum hall to pop culture

The New York mount made T. rex a celebrity almost at once. Artists such as Charles R. Knight painted it fighting Triceratops, and it starred in the film King Kong in 1933 and in Walt Disney’s Fantasia in 1940. Later, Jurassic Park in 1993 made it a symbol of dinosaurs for a new generation.

New specimens have transformed scientific knowledge since the 1980s. Several dozen partial skeletons are now known, including the exceptionally complete Sue, found in South Dakota in 1990. They allow scientists to study growth, injuries, disease and variation, making T. rex one of the best understood dinosaurs.

Tyrannosaurus was among the last non-avian dinosaurs. It disappeared in the mass extinction caused by the Chicxulub asteroid impact about 66 million years ago.

By the numbers

Timeline

• 1892: Edward Drinker Cope names Manospondylus gigas from two vertebrae, later linked to T. rex.
• 1900: Barnum Brown finds a partial large theropod skeleton in eastern Wyoming.
• 1902: Brown finds the type specimen of T. rex in the Hell Creek badlands, Montana.
• 1905: Henry Fairfield Osborn names Tyrannosaurus rex and Dynamosaurus imperiosus.
• 1908: Brown finds a more complete skeleton with a skull at Big Dry Creek, Montana.
• 1915: The first mounted T. rex skeleton goes on display in New York.
• 1941: The type specimen is sold to the Carnegie Museum in Pittsburgh.
• 1990: The specimen known as Sue is found in South Dakota.

Why it matters

Barnum Brown’s 1902 find introduced the world to the largest land predator then known and gave it a name that became a household word. T. rex turned dinosaurs into a fixture of museums, films and childhood imagination. Scientifically, the many specimens found since have made it a model for understanding how giant predatory dinosaurs lived, grew and died.