In all, he dedicated nearly half-a-century to the study. Crampton taught as a professor at Columbia University and Barnard College from 1904 to 1943. He also worked as a curator at the American Museum of Natural History.
Throughout his career, he spent nearly five decades studying his subject. Crampton taught as a professor at Columbia University and Barnard College from 1904 to 1943, while also serving as a curator at the American Museum of Natural History.