Jack Horner is the paleontologist who discovered that dinosaurs cared for their young and some were social animals, nesting in colonies.
He specializes in researching dinosaur behavior and growth; he has accumulated evidence that many named species of dinosaur are actually immature versions of other dinosaur species: he believes that up to a third of named dinosaur species could ‘disappear’ when the area is fully researched.
His current research is focused on reactivating dormant dinosaur DNA in birds to hatch modern-day dinosaurs.
Horner’s face is familiar to millions because he has starred in many television documentaries about dinosaurs.
John R. Horner was born on June 15, 1946 in Shelby, Montana, USA. His mother was Miriam Whitted, from Virginia, and his father was John Horner, a Montanan. His father had left the Navy when World War 2 finished in 1945 and opened a startup gravel business on the Marias River. Father and son shared the first name John so, to make life easier, the son became Jack.
The newly born Jack Horner spent his first months living in a tent by the river. As the gravel business began to prosper, the family home became a house on a hillside.
School was difficult for Jack, who suffered from undiagnosed dyslexia, making reading and writing difficult. At age eight he found his first dinosaur bone while fossil-hunting with his father. Hunting for dinosaur fossils became a passion for Jack, and his mother took him on frequent searches.
He graduated from high school with low marks and recalls that his English teacher told him he never wanted to see him again. Jack never did see that English teacher again, but playfully sent him a copy of his first book when it was published.
Despite his difficulties with reading and writing, Jack had enormous enthusiasm for practical science, winning high school science fairs.
His senior project, comparing dinosaur fossils from Montana with Alberta wowed the judge so much that he asked Jack if he would like to study geology at Montana State University; the judge was a professor of geology at that institution. So, in 1964 Jack enrolled for a geology degree.
University, Special Forces, and Trucking
University went badly and in 1966 Horner was drafted into the Marines, becoming a special forces operative in Vietnam. There he witnessed atrocities and tried to relieve the tensions of war by polishing a mirror for a telescope he hoped to finish building on his return to America.
In 1968 Horner returned to America. After dropping out of astrophysics at Caltech he returned to the University of Montana to study geology. He did not complete his degree, but did manage to write a geology/paleontology themed thesis which produced three published academic papers.
He moved on from the University of Montana in 1973 and drove trucks for a while. Weekends were reserved for his passion – hunting for dinosaur fossils.
Princeton and Beyond
While making a living driving trucks, Horner never gave up his dream of becoming a paleontologist. He wrote to a large number of museums, and in 1975 he landed his first paid scientific work – a technician’s job at Princeton University’s Natural History Museum.
In 1976 Horner’s dyslexia was diagnosed, allowing him at, the age of 30, to finally understand why he found reading and writing so difficult.
In 1977 he was promoted to research assistant at Princeton’s Museum.
Jack Horner’s Best Known Contributions to Science
Dinosaurs that cared for their young
Marion Brandvold had a rock shop in Bynum, Montana.
Horner, who was doing field-work in Montana with his research partner Bob Makela, called on Marion Brandvold to identify bones she had found.
Horner was shown tiny bone parts. He identified these as a baby duck-billed dinosaur – the smallest he had ever seen. Brandvold then showed him more bones and the site they had come from. Horner excavated the site, finding parts of 15 dinosaur babies.
In 1979 he published a paper about this find in Nature; this paper changed everything, both scientifically and personally:
- it described a new dinosaur genus, which Horner named Maiasaura and a new species Maiasaura peeblesorum.
- it described the first ever discovery of young dinosaur fossils in a nest
- it showed that dinosaurs had cared for their young, which lived in the nest after hatching
- it established Horner as a well-known professional paleontologist, despite the fact that he did not have a degree.
Dinosaurs that nested in colonies
In 1980 Horner was awarded National Science Foundation funding for a fossil-hunting expedition close to the site where Marion Brandvold had found the first tiny Maiasaura bones. The site was near the small town of Choteau, Montana.
This expedition again brought major discoveries:
- the first dinosaur egg clutches in North America
- evidence that dinosaur nests were built around one another, meaning some dinosaurs nested in colonies
- evidence that Maiasaura peeblesorum typically laid about 25 eggs in a nest and the hatchlings were about a foot (30 cm) in length.
The location of these discoveries is now called Egg Mountain!
In 1982 Horner was offered a position at Montana State University’s Museum of the Rockies and returned to live in Montana permanently.
Horner’s discovery of dinosaur colonies led him to conclude that many species of dinosaur were sociable and lived in herds. This contrasted with the previous view that dinosaurs lived solitary lives.
Tyrannosaurus rex – hunter or scavenger?
In his 1993 book The Complete T. Rex, Horner promoted the idea that T. Rex may have been primarily a scavenger.
In 1994 Horner continued to promote this idea at the Dino Fest event held at Indiana University, noting that T. Rex would have been very slow moving. Later research by Thomas Holtz and others, however, contradicted this.
Although the idea of ‘scavenger T. rex‘ resulted in a lot of media interest, Horner has never carried out any serious scientific research in this area. He has used the idea to get people thinking more deeply about dinosaur research and to spur interest in the field.
Most paleontologists believe that T. rex took whatever was on the menu; it would hunt or scavenge according to what was available.
In the movie Jurassic Park, dinosaurs are rescued from extinction when viable DNA is found, allowing scientists to hatch dinosaurs into the modern world.
In the real world, Horner has found that he cannot actually recover dinosaurs from ancient DNA, but he believes he can do the next best thing.
His 2009 book How to Build a Dinosaur: The New Science of Reverse Evolution looks at the possibility of genetically modifying a chicken into a dinosaur: Chickenosaurus. Horner keeps a chicken skeleton at his workplace and says: “If I could just grow those bones a little different, tilt this one way, that another, I’d have a dinosaur skeleton.”
It is now widely accepted that birds are descended from dinosaurs. When one species evolves into another, the DNA also changes – in fact it is the change in the DNA molecule that causes the species transformation.
BUT, the parts of the DNA molecule needed for the old species are not necessarily discarded. They may stay in the DNA molecule of the new species, dormant, waiting for a time when they may be called to action again.
For example, although birds don’t have teeth, the instructions for making dinosaur teeth are present in bird DNA. This was first reported by Dr. Matthew Harris in 2006.
Advances in our ability to manipulate genes and discoveries such as surviving soft tissues of Tyrannosaurus rex have led Horner to believe that a chicken embryo could be grown into an animal which has dinosaur characteristics. Scientists could continue working backwards from this animal, making creatures ever closer to a dinosaur until a real dinosaur could be hatched.
If any of this sounds a little familiar, it’s interesting to bear in mind that Horner was the technical consultant for all four Jurassic Park movies released to date. He was also the real-life scientist that Dr. Alan Grant was modeled on in the movies.
Horner himself makes a cameo appearance in the fourth movie, Jurassic World.
Dinosaur growth, correcting mistakes of the past, juvenile dinosaurs or separate species?
Horner is chiefly interested in the behavior and growth of dinosaurs. From his investigations of dinosaur growth, he has come to the conclusion that mistakes have been made in dinosaur classification.
He thinks dinosaur fossils once thought of as separate species are in fact fossils of the same species at different stages of maturity. Much of Horner’s work in this field has been in cooperation with paleontologist Mark Goodwin, from UC Berkeley Museum of Paleontology.
A good example of a dinosaur that may not have existed is the famous dinosaur Triceratops. Horner and his research student John Scannella published convincing evidence in 2010 that Triceratops is actually an immature Torosaurus.
Horner’s view is that Triceratops is so well-known that its name will stick, while Torosaurus will vanish when the two species are merged into one.
Not all paleontologists are convinced, however, that Triceratops and Torosaurus really are the same species: the issue is yet to be finally decided.
Horner believes that up to a third of named dinosaurs will turn out to be other named dinosaurs at different stages of maturity.
National Geographic’s Dinosaurs Decoded features Horner and Goodwin talking engagingly about this and also about Chickenosaurus.
Horner is currently Curator of Paleontology, Museum of the Rockies and Regent’s Professor, Montana State University. He has one son, Jason, from his marriage to Lee. In 2012 he married Vanessa Shiann Weaver.
Watch Horner Discussing His Research
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"Jack Horner." Famous Scientists. famousscientists.org. 26 Sep. 2015. Web. <www.famousscientists.org/jack-horner/>.
Top photo of Horner, and Horner with bird skeleton by Paolo Sacchi kindly provided by Meet The Media Guru under the Creative Commons Attribution-ShareAlike 2.0 Generic Licence.
Shape-Shifting Dinosaurs from TEDx Vancouver 2010 courtesy of Kris Krüg under the Creative Commons Attribution-ShareAlike 2.0 Generic Licence.
Triceratops by Dmitry Bogdanov under the Creative Commons Attribution 3.0 Unported license.
Torosaurus by Nobu Tamura under the Creative Commons Attribution 3.0 Unported license.
Maiasaura Nest by Drow male under the Creative Commons Attribution-Share Alike 4.0 International license.
Tyrannosaurus rex by Matt Martyniuk under the Creative Commons Attribution-Share Alike 3.0 Unported license.
John R. Horner
“Jack Horner: An Intellectual Autobiography”
The Montana Professor 14.2, Spring 2004
Jack Horner, James Gorman
How to Build a Dinosaur: The New Science of Reverse Evolution
Plume, Feb 23 2010
Jack Horner, Mark Goodwin, Dan Levitt
National Geographic Video, 2010