John Bell Hatcher (October 11, 1861[1]: 3  – July 3, 1904[2]) was an American paleontologist and fossil hunter known as the "king of collectors"[1][2] and best known for discovering Torosaurus and Triceratops, two genera of dinosaurs described by Othniel Charles Marsh.

[1]: 4 [3] He first took an interest in paleontology and geology while working as a coal miner to save money for school[2] and discovering fossils of ancient organisms.

Before graduating, he showed his coal mines collection of Carboniferous fossils to George Jarvis Brush, professor of metallurgy and director of the Sheffield Scientific School, who then introduced him to the paleontologist Othniel C.

[1]: 32  Hatcher, with his formal education and training from Marsh, proved to be careful worker and was skilled in excavating fossils with less damage than other collectors inflicted.

[1]: 125  However, in 1892, funding of the United States Geological Survey was dramatically cut by Congress, and Marsh could no longer pay Hatcher to collect for him in the West.

[1]: 263  In the 1896 expedition he was joined by his brother-in-law Olaf A. Peterson whom he hired away from the American Museum of Natural History to the dissatisfaction of Osborn.

[1]: 239 [3] For the third expedition, a young Barnum Brown of the American Museum of Natural History accompanied Hatcher,[3] owing to Osborn's arrangement with Scott.

[1]: 290–291  Hatcher supervised William Harlow Reed and hired Charles Whitney Gilmore during his time at the Carnegie Museum.

[1]: 306–307  In addition to supervising field expeditions and excavations, he was responsible for the scientific investigation and display of Diplodocus carnegii, a species named by Hatcher for his patron Andrew Carnegie (1835–1919), the Scottish-American industrialist.

Finished in 1907, casts of "Dippy" were sent to museums in the United Kingdom, Germany, France, Austria, Italy, Russia, Spain, Argentina, and Mexico.

[1]: 410  Hatcher's monograph on the find was published in 1901 as Diplodocus Marsh: Its Osteology, Taxonomy, and Probable Habits, with a Restoration of the Skeleton.