The Bone Wars: How a Bitter Feud Dug Up America’s Dinosaurs

In the spring of 1897, in a pair of joined row houses on Pine Street in Philadelphia, a man of 56 lay dying on a narrow cot in a room crowded with fossils, books and papers. A tortoise and a Gila monster shared the house. The man was Edward Drinker Cope, and he had named more than a thousand species of extinct and living animals. Before he died he made one last arrangement. His skull and brain were to go to science, so that they could be measured. In an age that believed a bigger brain meant a better mind, Cope wanted the figure on record, and he wanted one particular man to try to beat it.

That man was Othniel Charles Marsh of Yale, and he never took up the challenge. By then the two had spent nearly 30 years trying to ruin each other. They had bribed each other’s diggers, hired each other’s workers away, spied on each other’s quarries and, if their own men are to be believed, smashed fossils in the ground rather than let the other side have them. They raced so hard to name new animals that they sometimes named the same one twice, or stuck the wrong head on it. In 1890 they took the fight to the front page of a New York newspaper.

The feud came to be called the Bone Wars, and it was one of the ugliest episodes in the history of American science. It was also one of the most productive. When it started, North America had nine named species of dinosaur. When it ended, Cope and Marsh between them had added 142, among them Stegosaurus, Triceratops, Allosaurus, Diplodocus, Camarasaurus and the most famous misnamed animal of all, Brontosaurus. Many of the skeletons that still anchor museum halls were dug from the ground because two proud men could not bear to lose to each other.

Two Young Men in Berlin

They came from opposite ends of American privilege. Cope was born on July 28, 1840, into a wealthy Quaker family in Philadelphia. He was a prodigy who read natural history the way other boys read adventure stories, and he published his first scientific paper, on salamanders, while still a teenager. He had little formal schooling past 16, but he studied anatomy informally with Joseph Leidy, the great Philadelphia naturalist, and haunted the collections of the city’s Academy of Natural Sciences. Quick, charming, combative and impulsive, he wrote the way he talked, fast and with enormous confidence.

Marsh, born on October 29, 1831, in Lockport, New York, would probably have grown up a poor farmer’s son if not for his mother’s brother. That brother was George Peabody, a Massachusetts-born banker who had made a fortune in London and became one of the great philanthropists of his century. Peabody paid for his nephew’s schooling at Phillips Academy and Yale and then for years of study in Germany. Marsh, in turn, persuaded his uncle to endow a natural history museum at Yale. In 1866 the Peabody Museum of Natural History was founded, and Marsh became Yale’s professor of paleontology, the first in the United States. The post carried no salary, and with his uncle’s money behind him he did not need one. He was slow, methodical, secretive and a lifelong bachelor who preferred to work alone.

The two met in Berlin in the winter of 1863, when Marsh, 32, was studying at the university and Cope, 23, was touring Europe’s museums, partly, it seems, to keep him out of the Civil War. They spent several days together and parted on good terms. Back home, they did what friendly young scientists did. In 1867 Cope named a fossil amphibian after Marsh. Two years later Marsh returned the favor with a sea reptile, Mosasaurus copeanus. It was the last kindness either of them would publish about the other.

Even in the friendly years, the people who knew them could see the trouble coming. Cope backed a version of evolution in which animals passed on traits acquired during their lives, an idea descended from Lamarck. Marsh was a convinced Darwinian. Cope was the better field naturalist and the faster writer. Marsh was the better politician and, thanks to his uncle, the richer man. Even at the best of times, each was inclined to look down on the other.

The Marl Pits of New Jersey

The first real wound was inflicted not in the West but in the farm country of southern New Jersey. The marl pits around Haddonfield, dug for a greenish, mineral-rich clay that farmers spread on their fields, cut into sediments laid down in a shallow sea about 80 million years ago. In 1858 a visitor named William Parker Foulke had dug most of a large skeleton out of one of them. Leidy described it as Hadrosaurus foulkii. It was the first dinosaur known in North America from more than isolated teeth, and it revealed something that shocked the scientists of the day: the animal seemed to have stood on its hind legs.

In 1868 the English sculptor Benjamin Waterhouse Hawkins, famous for the life-size concrete dinosaurs in the park around London’s Crystal Palace, assembled the Hadrosaurus bones, with plaster stand-ins for the missing parts, at the Academy of Natural Sciences in Philadelphia. It was the first mounted dinosaur skeleton anywhere in the world, and it turned the Academy into a public sensation. A cast of it went back on permanent display at the Academy in July 2025.

Cope had moved his family to Haddonfield to be closer to the pits, and he had already pulled a find of his own out of them: a fierce, two-legged meat-eater he named Laelaps in 1866. In 1868 he showed Marsh around. The two parted amicably, but Marsh had noticed how rich the pits were and how freely the workmen let fossils go. He quietly made an arrangement with the pit operator, Albert Vorhees: from then on, anything Vorhees’s men found would be sent to Marsh in New Haven, not to Cope down the road. When Cope found out, he regarded it as theft from his own backyard.

Marsh had one more way to sting. Laelaps, it turned out, was already the name of a mite. Under the rules of zoological naming, the first use wins, and in 1877 Marsh renamed Cope’s animal Dryptosaurus, “tearing lizard.” The name was legitimate. Cope took it as one more insult.

The Head on the Wrong End

Cope gave Marsh a far better weapon himself. In 1867 Theophilus Turner, an army surgeon at Fort Wallace in western Kansas, found the bones of a huge sea reptile in the chalky badlands near the fort while the Union Pacific was being pushed west. The bones were dug out with picks and shovels, packed in hay and sent east to Philadelphia by military wagon and then rail. Cope described the animal in 1868 as Elasmosaurus platyurus, a plesiosaur with an absurdly long body, and drew a reconstruction for a major paper in the Transactions of the American Philosophical Society.

There was a problem with the drawing. Cope had put the head on the end of the tail. Elasmosaurus had about 72 vertebrae in its neck, which alone ran around 23 feet, and Cope had read the very long neck as a very long tail and the short tail as a stubby neck. Leidy, his old mentor, pointed out the error. By the most colorful account, Leidy simply picked up the skull and walked it to the other end of the skeleton.

Cope tried to recall and destroy the printed copies of the paper and published a corrected version. He also argued, with some justice, that he had been misled by the way Leidy himself had once arranged the backbone of a related animal. But not every copy came back. Marsh kept his, and he brought up the mistake for the rest of his life. Decades later, in the middle of their newspaper war, Marsh claimed that he had been the one to spot the error and that Cope had never forgiven him for it. Historians still argue about who noticed first. Either way, the reversed sea serpent became the emblem of everything Marsh thought was wrong with Cope: brilliant, careless and always in too much of a hurry.

The Elasmosaurus story had a strange coda. Its hip and shoulder bones were apparently lent to Hawkins, who was building a grand Paleozoic Museum in New York’s Central Park. In May 1871 his workshop was smashed and his models broken up and buried. For generations the vandalism was blamed on Boss Tweed’s political machine, but research published in 2023 pinned it on Henry Hilton, a Central Park official with his own grudges. The Elasmosaurus girdles have never been found.

Railroads, Soldiers and the Big Bone Chief

By 1870 both men had seen where the real prizes lay. The transcontinental railroad, finished in 1869, had opened the American West to anyone with a ticket, and its cuts and grades were exposing rock that had been buried since the age of dinosaurs. The army, still fighting the Plains wars, could supply escorts. Marsh moved first, leading the first of four summer expeditions of Yale students into Nebraska, Kansas, Wyoming and Utah in 1870. Their escorts at times included soldiers and the scout William F. Cody, the future Buffalo Bill. The students came back with crates of fossil horses, pterosaurs, toothed birds and mosasaurs.

Cope followed, attaching himself as an unpaid paleontologist to Ferdinand Hayden’s federal survey of the territories. The two soon collided in the fossil beds around Fort Bridger in southwestern Wyoming, where both were digging up the horned, rhinoceros-sized mammals of the Eocene. Each fired off hurried telegrams and short papers back East to establish priority, then argued for years about whose name came first. Between them they named the same few animals so many times, as Uintatherium, Loxolophodon, Eobasileus, Dinoceras and Tinoceras, that later scientists had to untangle a thicket of duplicate names.

The tactics turned sharp. Marsh’s collectors kept him informed of Cope’s movements and referred to his rival in their letters by a code name, “Jones.” Each man hired workers away from the other. Each accused the other of claiming his finds. Cope began to see Marsh’s hand in every setback, and Marsh began to treat any bone bed he had visited as his private property.

Marsh’s travels also put him in the middle of one of the great injustices of the period. In 1874 he went to the Red Cloud Agency in Nebraska to dig in the badlands, and the Oglala Lakota leader Red Cloud allowed it on condition that Marsh carry the Lakota’s complaints to Washington. The agency’s rations of beef, flour and blankets were rotten, short or missing, and the people were going hungry. The Lakota called Marsh “Big Bone Chief,” because he was looking for bones rather than gold. Marsh kept his word. In 1875 he took samples of the spoiled rations to President Ulysses S. Grant and the Interior Department and publicly accused the Indian agent and contractors of fraud. A special commission upheld most of his charges, and the scandal led to resignations, though it did little to change government policy toward the Lakota. Some historians think Marsh enjoyed embarrassing an unpopular administration as much as he cared about the Lakota, but the friendship was real. Red Cloud later visited Marsh at his house in New Haven.

Marsh’s science, meanwhile, was winning him the world’s attention. In 1876 Thomas Henry Huxley, Darwin’s fiercest defender, visited New Haven and spent days going through Marsh’s fossil horses, which ran from a small, many-toed animal to the single-hoofed horse of today. Huxley saw at once that the series was a near-perfect demonstration of evolution, and it became one of the most famous examples in every biology textbook. In 1880 Marsh published a monograph on toothed birds from the Kansas chalk, and Darwin wrote to him that his work on the birds and the horses had afforded “the best support to the theory of evolution” in the 20 years since the Origin of Species.

1877: Letters From the West

The dinosaur rush began with a schoolteacher’s letters. In the spring of 1877 Arthur Lakes, a teacher and geologist in Golden, Colorado, was hiking in the hogbacks near the town of Morrison with a friend when they found enormous bones embedded in the rock. Lakes wrote to Marsh and sent samples. When Marsh was slow to answer, Lakes also sent some to Cope. Marsh woke up fast. He sent Lakes $100, urged him to keep quiet and asked him to tell Cope to forward his samples to New Haven. Lakes did, and Marsh published the find. Lakes eventually shipped him some 1,500 pounds of bone. Among the Morrison finds was the first Stegosaurus. The ridge is now a National Natural Landmark called Dinosaur Ridge.

Cope did not stay in second place for long. Weeks later a letter arrived for him from O. W. Lucas, a naturalist collecting plants near Cañon City, Colorado, who had stumbled on even larger bones at a place called Garden Park. From them Cope described Camarasaurus, and later a single, impossibly huge back vertebra he named Amphicoelias fragillimus, which by some estimates came from an animal far longer than any dinosaur known today. The vertebra was soon lost, possibly crumbling to pieces, and only Cope’s drawing survives. Marsh sent his own men to Cañon City, but Lucas would not switch sides. At Morrison, Marsh’s quarry caved in and nearly killed his crew.

Then, later that year, came the most important letter of all. It was signed by two men calling themselves Harlow and Edwards, who said they worked for the Union Pacific Railroad at Como station in southern Wyoming. A long ridge there called Como Bluff, they wrote, was full of giant bones, and others in the area were “looking for such things.” Their real names were William Harlow Reed and William Edwards Carlin. Marsh sent money at once, made out, unhelpfully, to their false names so that they could not cash it, and then his assistant Samuel Wendell Williston to strike a deal. Como Bluff turned out to be one of the richest dinosaur graveyards ever found.

Out of the rock at Como, Morrison and nearby beds came the dinosaurs that most people picture when they hear the word. In late 1877 Marsh named Stegosaurus, Apatosaurus and Allosaurus. Brontosaurus, the “thunder lizard,” followed in 1879, and Diplodocus in 1878. All of them came from the same band of Late Jurassic river and floodplain sediments, about 150 million years old, that geologists named the Morrison Formation after the town where Lakes had first looked. The Morrison remains the single most productive source of dinosaur fossils in North America.

Smashed Bones and Stolen Crews

Marsh had insisted on secrecy, but Como Bluff did not stay secret long. Reed and Carlin themselves seem to have spread the word, and in April 1878 the Laramie Daily Sentinel reported the finds and wildly exaggerated how much Marsh was paying, perhaps to drive up the price. By that winter Carlin had gone over to Cope, and the bluff became a battlefield.

What followed reads like a frontier novel. Carlin, now working for Cope, locked Reed out of the Como railroad station, so Reed had to haul his bones down the bluff and crate them on the open platform in the freezing cold. Rival crews spied on each other’s quarries. By some accounts they threw rocks. When one of Reed’s quarries ran dry, Marsh told him to clear out the leftover fragments so Cope’s men could not get them, and Reed reported that he had destroyed the remaining bones. Lakes, sent up from Colorado to help, quarreled with Reed, worked through a blizzard and finally quit in 1880 to go back to teaching. Reed left in 1883 to raise sheep, came back to fossils after a brutal winter killed most of his flock, and later worked for the University of Wyoming.

Over roughly a decade, Marsh’s men shipped hundreds of crates of bones east from Como Bluff alone. Many of them were never opened in Marsh’s lifetime. Part of the reason was the sheer scale of the haul. Part was that both men were collecting not only to understand the animals but to keep them away from each other.

A Thunder Lizard With the Wrong Head

Speed came at a price, and it was not only Cope who paid it. In 1877 Marsh named the small, slender sauropod Apatosaurus ajax from bones found at Morrison. Two years later he named Brontosaurus excelsus from a much bigger and more complete skeleton found at Como Bluff. Neither skeleton came with a head. When Marsh published his famous 1883 restoration of Brontosaurus, which he revised in 1896, he gave it a short, boxy skull found at a different quarry in Colorado, one that later scientists concluded came from a different animal altogether, probably Brachiosaurus.

Marsh had his own head-and-tail moments, too. In 1887 he looked at a pair of huge horns sent from Colorado and named them Bison alticornis, an extinct giant bison. Only when more complete skulls arrived did he realize he had been looking at a horned dinosaur, which he named Triceratops in 1889.

Brontosaurus became a story of its own. In 1903 Elmer Riggs of the Field Museum in Chicago concluded that Marsh’s two sauropods were too similar to be separate genera. Under the naming rules, the older name won, so Brontosaurus became Apatosaurus. But the public already loved the thunder lizard. When the American Museum of Natural History put up the first mounted sauropod skeleton in 1905, it labeled it Brontosaurus, and the name lived on in museums, textbooks and, in 1989, a set of U.S. postage stamps. Museums kept the wrong head for most of a century, too. The Carnegie Museum in Pittsburgh did not put a proper Apatosaurus skull on its skeleton until October 20, 1979.

Then, in 2015, a team led by Emanuel Tschopp published an exhaustive analysis of the diplodocid sauropods in the journal PeerJ and concluded that Brontosaurus was distinct enough to be its own genus after all. Marsh’s thunder lizard, sunk for 112 years, was back.

The Feud Goes to the Front Page

By the 1880s Marsh had won the battle that mattered most in Washington. In 1879 Congress consolidated the competing western surveys into a single U.S. Geological Survey, which left Hayden, Cope’s patron, out in the cold. In 1882 John Wesley Powell, the one-armed Civil War veteran and Colorado River explorer who now ran the Survey, made Marsh its vertebrate paleontologist. Marsh got federal money, federal staff and a federal publishing program. In 1883 he was elected president of the National Academy of Sciences. He built an 18-room mansion on a hill above the Peabody Museum.

Cope went the other way. He had poured his inheritance into fossils and into The American Naturalist, a leading science journal he bought in 1877 partly so that he could publish his findings quickly. He published at an astonishing rate, 76 papers in 1879 and 1880 alone. To pay for it all he invested in mines, mostly silver in New Mexico, and by 1886 they had failed. That year he finally took a professor’s job at the University of Pennsylvania. He lived apart from his wife, and the Pine Street houses filled with bones. With a flash of humor, he named one fossil mammal Anisonchus cophater, from “Cope” and “hater.”

For years Cope kept a journal of every mistake, misdeed and act of plagiarism he believed Marsh and Powell had committed, and stored it in the bottom drawer of his desk. At the end of the 1880s Powell gave him a reason to use it. At Marsh’s urging, the Survey pressed Cope to hand over specimens he had dug up while working for the old government surveys, on the grounds that they belonged to the government. Cope had paid for much of that work out of his own pocket as an unpaid volunteer. To him, it looked like Marsh trying to take the last thing he had.

Cope’s answer arrived on January 12, 1890, in the New York Herald, under the headline SCIENTISTS WAGE BITTER WARFARE. The reporter, William Hosea Ballou, a New York newspaperman and Cope ally, laid out Cope’s charges: that Marsh had plagiarized the work of others, made gross errors, misused government funds and passed off his assistants’ work as his own. Ballou gave Marsh and Powell space to reply, and Marsh did so with relish, dragging out the Elasmosaurus head once again. New York papers had been selling astonishment to their readers since the Sun’s Great Moon Hoax of 1835. This time the astonishing claims came from two of the most eminent scientists in the country. Marsh kept the story alive with a fiery rebuttal, and the Philadelphia Inquirer suggested that Penn’s trustees might ask Cope to step down unless he could prove his charges. By the end of January the papers had moved on. No hearing was ever held, and nobody was punished.

Neither man came out of it well. Some of Marsh’s former assistants backed Cope’s charge that the professor took credit for their work. Cope’s charges, for their part, were tangled up with his own grudges. To readers, the spectacle was of America’s leading scientists calling each other liars in print. Science has seen bitter rivalries before and since, like the one between Thomas Young and Jean-François Champollion over who cracked the Rosetta Stone, or the clockmaker John Harrison’s long war with the astronomer Nevil Maskelyne over the longitude prize. Few have been fought so publicly or so personally.

The damage to Marsh came slowly, and then all at once. In 1892 Congressional critics of the Survey’s spending cut its paleontology funding, and Powell sent Marsh a curt telegram asking for his resignation. Marsh’s allies were retiring or dying. His spending had caught up with him, too. Within a few years he had to mortgage his mansion and, for the first time, ask Yale for a salary.

Two Ruined Men

Cope’s luck turned for a while. In 1889 he took over Leidy’s chair as professor of zoology at Penn, and in the early 1890s he was elected president of the American Association for the Advancement of Science. But his health was failing, and his money was gone. To make ends meet he sold parts of the collection he had spent his life building. The American Museum of Natural History, where the young paleontologist Henry Fairfield Osborn was building a fossil hall, bought part of it for $32,000, raised from New York society donors. Cope rented out one of his houses and went on working from the other, sleeping on a cot among his specimens.

In his last years he found an unlikely collaborator. Osborn had begun commissioning a young artist named Charles R. Knight to paint prehistoric animals as living creatures for the museum, and in 1897 Osborn sent him to Cope. Cope, already ill, talked him through how his animals might have stood, moved and fought, and he died not long after their meetings. Knight’s “Leaping Laelaps,” with one dinosaur hurtling through the air onto another, was one result. It looked nothing like the slow, tail-dragging monsters of earlier art, and a century later scientists came back to Cope’s view of agile, active dinosaurs.

Even in a fever Cope kept lecturing from his bed. He died on April 12, 1897, 16 weeks short of his 57th birthday. Osborn and a few friends sat with his coffin among the fossils and the pets for what Osborn called “a perfect Quaker silence.” His brain, as he had asked, was measured and is still preserved in alcohol at the Wistar Institute in Philadelphia. His skull is at the Penn Museum. Marsh never offered his own brain for comparison. In 1993 the photographer Louie Psihoyos borrowed Cope’s skull and took it on a road trip across America, photographing it at dinosaur sites for his book Hunting Dinosaurs. Cope, who never liked staying home, might have enjoyed that.

Marsh outlived him by less than two years. In December 1897 the French Academy of Sciences gave him the Cuvier Prize, one of the highest honors in his field. He was also nearly broke. He caught a cold on a winter train trip from Washington and died of pneumonia in New Haven in March 1899, at 67. By one account he had $186 in the bank. He left his collections, the core of today’s Peabody Museum, to Yale.

Who Won?

It depends on what you count. By the usual tally, Marsh named 80 new dinosaur species and Cope 56. Marsh’s tally also included most of the famous names, so in the public imagination he won. Cope wrote more than 1,400 papers and named over 1,000 vertebrate species of all kinds, a record few naturalists have matched, and he left behind more than 13,000 specimens. Marsh’s collection was far bigger and was valued at more than a million dollars. Both men left boxes of fossils that their museums were still opening decades later.

The cost was real, too. Europe’s scientists watched the newspaper war with dismay, and American paleontology’s reputation suffered for a generation. Leidy, the quiet founder of the field in America, was driven out of western vertebrate paleontology by the competition, unwilling to fight two rich men who were buying up everything. Some of the names the rivals rushed into print described the same animals over and over, and later scientists spent careers sorting them out. Fossils were lost, damaged in hurried excavations or, by their own collectors’ accounts, deliberately destroyed.

And yet the fossils that survived built modern paleontology. The rival collections filled the Peabody, the American Museum of Natural History and the Smithsonian, and Marsh’s insight that birds were related to dinosaurs, drawn partly from his toothed birds, is now textbook science. The public appetite the feud created helped push industrialists like Andrew Carnegie into the dinosaur business. Many of the classic species the two men named are still valid, and their quarries, at Como Bluff, Garden Park and Dinosaur Ridge, are still producing fossils and visitors.

Their monument is in New Haven. When the Yale Peabody Museum reopened on March 26, 2024, after a four-year renovation, its Brontosaurus, the skeleton dug from Como Bluff in 1879, stood remounted in a livelier pose, its neck curved and its tail lifted off the floor to match modern thinking about how sauropods carried themselves. The rebuild added 27 vertebrae to the skeleton. Admission is now free.

The Bone Rush Never Ended

The two men’s quarries left odd legacies. Near Como Bluff, a homesteader named Thomas Boylan spent years gathering fragments of dinosaur bone from the surrounding hills, and in 1932 he built a small cabin out of them to serve as a roadside stop on U.S. Highway 30. It used 5,796 bones weighing 102,116 pounds. In 1938 Ripley’s Believe It or Not billed it as “The World’s Oldest Cabin.” The Fossil Cabin is on the National Register of Historic Places.

The commercial side of the Bone Wars never went away either. Cope and Marsh paid ranchers, railroad workers and schoolteachers for bones. Today fossils found on private land in the United States can be bought and sold, and the prices have reached heights the rivals never imagined. In May 2022 a commercial paleontologist found a Stegosaurus near the town of Dinosaur, Colorado, in the same Morrison rocks Lakes had first spotted at Morrison. Nicknamed Apex, it had about 254 of its roughly 320 bones. On July 17, 2024, Sotheby’s sold it for $44.6 million, at the time a record for a fossil, to the hedge fund billionaire Kenneth Griffin, who lent it to the American Museum of Natural History. It went on view there in December 2024 and now stands at the entrance to the museum’s fossil halls, where scientists are sampling one of its thighbones to learn how stegosaurs grew. Many paleontologists warn that prices like that push important specimens into private hands and out of science, an argument Cope and Marsh would have recognized.

The story keeps finding new audiences. Michael Crichton’s Dragon Teeth, a novel found among his papers after his death and published in 2017, drops a fictional Yale student into the middle of the feud in 1876. The cartoonist Jim Ottaviani told it as a graphic novel, Bone Sharps, Cowboys, and Thunder Lizards. And in the summer of 2026, a musical called Bone Wars ran off-Broadway at the Players Theatre in New York, which means the two men’s feud has now been fought in field quarries, scientific journals, a New York newspaper and, at last, in song.

Marsh would probably have hated the musical. Cope might have loved it, and then demanded a bigger part. In a museum in Philadelphia his skull is still waiting for a reply.

Further reading