Fitting for such a rivalry, the two men were about as different as you can get. Born in Lockport, New York, 1831 Marsh was raised by his farmer father and a host of relatives after his mother died when was three. Though quite poor, Marsh studied fossils from a young age, tutored by his mentor Colonel Ezekial Jewett, an engineer who worked on the nearby Erie Canal. Later sponsored by his wealthy uncle, at 20 Marsh attended Phillips Academy Andover, later studying at Yale and across Europe. Though he came late to formal academic training, Marsh quickly proved himself as a paleontologist, receiving an appointment at Yale, one of many alma maters.

While Marsh came late to his studies, Cope was the child prodigy. Like Marsh, his mother died when he was three, but he nevertheless enjoyed a happy childhood. Born in 1840 in Fairfield, Connecticut to a wealthy Quaker family, Cope was writing surprisingly complex notes on a museum’s Ichthyosaur at six. At 18, he published his first scientific paper, while Marsh published his first at 30. Like Marsh, Cope spent some years studying in Europe before returning to the United States to an appointment at Haverford College, though he soon left this post to commit himself to field work.

In the years after the Civil War as Western Expansion kicked into high gear, the ensuing settlements and railroads lead to massive finds of dinosaur specimens, at the cost of displacing the native people already living there. It was in this environment that the men’s rivalry soared, but early on their relationship was amicable. An early meeting in New Jersey in 1868 saw them examining a muddy limestone pit where the Hadrosaurus holotype had been discovered some years before. Though they parted on apparently friendly terms, Marsh secretly bribed the workers at the pit to send all future discoveries to him and not to Cope. The war had begun.

The rivalry quickly grew until it exploded in 1877, when the two men were each sent recently discovered bones from Colorado’s Morrsion formation from the unwitting Arthur Lakes, a fellow paleontologist. Marsh, who had a closer working relationship with Lakes, was furious to find that the new specimen had been shared with his rival. Trying to undo the damage, Lakes sent a letter to Cope asking the bones to be sent along to Marsh, only adding fuel to the fire. Later that year two railroad men reached out to Marsh reporting fossil finds in Como Bluff, a ridge formation in Wyoming. Marsh sent his men to begin excavation, with Cope following suit.

It is here that the story of Cope and Marsh’s fantastic rivalry slips into the realm of the apocryphal. There are some stories of Cope and Marsh’s men encountering each other in Como Bluffs and waging impromptu rock fights, blowing up each other's finds, and even firing weapons upon each other, but evidence of these claims is sparse outside the tales. What is known is that during their time working out west, the two men and their proxies found and identified specimens like Allosaurus, Diplodocus, Stegosaurus and other Late Jurassic genera. Over the next few years the two made numerous discoveries and also formalized methods of encasing fossils, protecting them during excavation and transport.

After years of competition and professional smears, Cope, with his health failing, issued one final challenge to Marsh: he would posthumously donate his brain to the University of Pennsylvania to be measured for size, challenging Marsh to do the same in an attempt to prove himself the smarter man. Marsh declined. Both men were in dire financial straits at the end of their lives in their quest to ruin the other. Although they made many discoveries, their rivalry turned off other paleontologists from field work, hampering paleontological study for years. With the two men hindering their field of study as much as they helped it, one has to wonder what discoveries Cope and Marsh would have made absent their rivalry.