Peter Lars Larson (born 1952) is an American fossil expert and president of the Black Hills Institute of Geological Research. He led the team that excavated "Sue", one of the largest and most complete specimen of Tyrannosaurus rex found to date, and has published numerous scientific and popular works on dinosaur paleontology. He is criticized by paleontologists for his commercial enterprises and support of private collections. Early life and education Peter Larson grew up on a ranch near Mission, South Dakota. He began rock hunting at the age of four on his parents' ranch. He attended the South Dakota School of Mines to study paleontology. He graduated with a bachelor's degree in 1974. Shortly after graduating college he started Black Hills Minerals. Career Larson founded what eventually became the Black Hills Institute in 1974. Partners Robert Farrar and (Larson's brother) Neal Larson later joined the company. In 1990, Larson led the excavation of the Tyrannosaurus rex skeleton later named "Sue". With only a bachelor's degree in geology, Larson has written and co-authored numerous publications on dinosaurs, has excavated more T. rex skeletons than any paleontologist, and his organization's work on excavation and preparation of fossils has been recognized by paleontologists Robert Bakker, Philip Currie, Phillip Manning, and Jack Horner for its quality. He was one of the first to work with T. rex bone pathologies, has worked to uncover sexual dimorphism in the chevron length of T. rex, and argues that several juvenile T. rex skeletons actually represent a distinct genus, Nanotyrannus. In 1992, Larson's team helped to discover second largest Tyrannosaurus rex Stan. Larson, along with paleontologist Kenneth Carpenter, edited the scholarly text Tyrannosaurus Rex, the Tyrant King. Larson and his ex-wife Kristin Donnan wrote the book Rex Appeal, which relates the story of how the U.S. Government took possession of the "Sue" T. rex skeleton following its excavation, as well as the scientific work Larson was doing at the time. The pair also wrote Bones Rock!, an acclaimed children's book about the history of paleontology and requirements on how to become a paleontologist. In 2013 Larson and colleagues began excavating at a site located in Wyoming, US containing the remnants of three nearly complete skeletons of Triceratops. They have been involved in many excavations of notable fossils, and their work—both real skeletons and casts—are mounted and displayed in museums on several continents. Federal lands dispute In 1992, an