Raymond Lee Ditmars (June 22, 1876 from Newark, New Jersey – May 12, 1942 in New York City) was an American herpetologist.
Ditmars was very interested in animals, (primarily reptiles), obtaining his first snakes at twelve years of age. Only a mediocre student, he much preferred vacations when he could search for new specimens or study them at his house.
In 1893, Ditmars was hired by the Department of Entomology at the American Museum of Natural History as an illustrator. He quit in 1897 to take a better-paying job as a stenographer. In July 1898, he began to report for the New York Times. One of his first pieces led him to discover the newly created New York Zoological Society, which had just built a zoological park in the Bronx. He was soon employed as an assistant conservationist in charge of reptiles in July 1899. He then offered his own collection to the zoo, where it is now a permanent part of the natural history museum. This began a long collaboration between Ditmars and the Bronx Zoo. In 1926 he was placed in charge of the mammals, and in 1940 the insects. His presence helped the Bronx Zoo achieve a world-class status.