Audubon's fame as a painter of birds often obscures his subsequent work on North American mammals which he published in collaboration with amateur mammalogist, the Reverend John Bachman. Employing a combination of watercolors, oils, pastels, and pencil, Audubon gave his subjects a realistic character. His original drawings were transferred to lithographic stones and printed in the studio of J.W. Bowen in Philadelphia. Lithography proved the perfect medium for conveying the texture of an animal's fur. There were 150 plates printed for the Imperial Folio Quadrupeds, with another five being added to the octavo edition later.