Books in Animal (sorted alphabetically)
- Mental Life of Monkeys and Apes: A Study of Ideational Behavior Robert Mearns Yerkes
- Metabolic Adaptation to Climate and Distribution of the Raccoon Procyon Lotor and Other Procyonidae John N. Mugaas, John Seidensticker, and Kathleen P. Mahlke-Johnson
- Methods of Destroying Rats David E. Lantz
- Middle American Frogs of the Hyla microcephala Group William Edward Duellman and M. J. Fouquette
- Minds and Manners of Wild Animals: A Book of Personal Observations William T. Hornaday
- Mink Trapping: A Book of Instruction Giving Many Methods of Trapping A. R. Harding
- Monograph on the Sub-class Cirripedia (Volume 1 of 2) Charles Darwin
- Mutineer Robert Shea
- Myology and Serology of the Avian Family Fringillidae: A Taxonomic Study William B. Stallcup
- Natural History in Anecdote
- Natural History of Cottonmouth Moccasin, Agkistrodon piscovorus (Reptilia) Ray D. Burkett
- Natural History of the Bell Vireo, Vireo bellii Audubon Jon C. Barlow
- Natural History of the Brush Mouse (Peromyscus boylii) in Kansas With Description of a New Subspecies Charles Alan Long
- Natural History of the Mammalia of India and Ceylon Robert Armitage Sterndale
- Natural History of the Ornate Box Turtle, Terrapene ornata ornata Agassiz John M. Legler
- Natural History of the Prairie Vole (Mammalian Genus Microtus) E. W. Jameson
- Natural History of the Salamander, Aneides hardii Richard F. Johnston and G. A. Schad
- Neotropical Bats from Western México Sydney Anderson
- Neotropical Hylid Frogs, Genus Smilisca William Edward Duellman and Linda Trueb
- New Bat (Genus Leptonycteris) From Coahuila Howard J. Stains
- New Bat (Genus Pipistrellus) from Northeastern Mexico Rollin H. Baker
- New Bat (Myotis) From Mexico E. Raymond Hall
- New Bog Lemming (Genus Synaptomys) From Nebraska J. Knox Jones
- New Chipmunk (Genus Eutamias) from the Black Hills John A. White
- New Extinct Emydid Turtle from the Lower Pliocene of Oklahoma Edwin C. Galbreath