mammalogy, scientific study of mammals. Interest in nonhuman mammals dates far back in prehistory, and the modern science of mammalogy has its broad foundation in the knowledge of mammals possessed by primitive peoples. The ancient Greeks were among the first peoples to write systematically on mammalian natural history, and they knew many mammals not native to Greece; Aristotle recognized that whales and dolphins (cetaceans), although fishlike in form, are mammals allied to terrestrial furbearers. Until the late 18th century, much scientific work on mammals was devoted to taxonomy or to the practical matters of animal husbandry. The scientific explorations of the 19th century resulted in large collections of specimens from virtually all parts of the world. Most of the world’s mammal species are believed to be known to science (with the possible exception of a good many rodent and bat species), but the biology of many species is totally unknown. Modern mammalogy is a multidisciplinary field, encompassing specialists in anatomy, paleontology, ecology, behaviour, and many other areas.

Mammalian taxonomy traditionally relied largely on museum collections of preserved skins (with their skulls), but, by the second half of the 20th century, additional information was being gained from other studies—e.g., behaviour, genetics, and biochemistry. In both laboratory and field research, new techniques and instruments have opened avenues of research that had previously been difficult or impossible. The self-contained underwater breathing apparatus (scuba), for example, has been important in many aspects of marine mammalogy. Telemetry, the use of minute radio transmitters to convey information to the researcher from a free-living animal, has been a particularly useful tool, allowing the tracking of the animal in its natural state and the monitoring of physiological information. Video technology also has come into use, while in the laboratory a rapidly increasing array of molecular techniques have changed the way mammalogists determine evolutionary relationships (phylogeny) as well.