John "Jack" R. Horner (born June 15, 1946) is an American paleontologist who discovered and named Maiasaura, providing the first clear evidence that some dinosaurs cared for their young. He is one of the best-known paleontologists in the United States. In addition to his many paleontological discoveries, Horner served as the technical advisor for all of the Jurassic Park films, and even served as partial inspiration for the movie's lead character, Dr. Alan Grant.