Jack Horner's Coffee Can: The Discovery That Changed Paleontology

Marion and John Brandvold ran a rock shop in Bynum, Montana, a small town on the eastern slope of the Rockies, and in the summer of nineteen seventy-eight they had been picking up unusual small bones from the badlands near their property for years. They did not know what the bones were from. When a young fossil preparator named Jack Horner came through, they showed him a coffee can full of them.

Horner recognized immediately what he was looking at. The bones were from baby hadrosaurs, duck-billed dinosaurs, and they were the first baby dinosaur specimens ever found in North America. More than that: the way the bones clustered, the way they showed up together in the same spot in the same formation, suggested that the animals had not simply died and scattered. They had nested. They had returned to the same site, year after year, in groups. The site near Choteau, Montana, that Horner went back to excavate would later be named Egg Mountain.

What he found there upended a century of thinking about dinosaurs. The evidence of parental care, of communal nesting, of young dinosaurs that stayed at the nest while they grew, was inconsistent with the model of dinosaurs as cold-blooded, solitary, reptile-like creatures. Horner described the species that had nested at Egg Mountain as Maiasaura, meaning good mother lizard. The name stuck.

Horner had struggled badly in school due to undiagnosed dyslexia. He had never finished college. He went on to become the curator of paleontology at the Museum of the Rockies in Bozeman, to describe multiple new dinosaur species, and to serve as the technical advisor for the Jurassic Park films. The Museum of the Rockies now holds more Tyrannosaurus rex specimens than any other institution in the world. It began with a coffee can in a rock shop.