Natural sounds are sounds produced by natural sources in their normal soundscape. It is a category whose definition is open for discussion, see the section below. The category includes the sounds of any living organism, from insect larvae to the largest living mammal on the planet, whales, and those generated by natural, non-biological sources. In most respects, the natural habitats from which these acoustic sources emanate, are defined as not heavily impacted by human intervention. The historical background of natural sounds as they have come to be defined, begins with the recording of a single bird, by Ludwig Koch, as early as 1889. Koch’s efforts in the late 19th and early 20th centuries set the stage for the universal audio capture model of single-species—primarily birds at the outset—that subsumed all others during the first half of the 20th century and well into the latter half and into the early 21st, as well. In late 1968, influenced by acoustic efforts in the fields of music and film, this model began to evolve into a much more holistic effort with attention paid to the acoustic experience of entire habitats, inclusive of all the wild animal voices. Expressed as wild soundscapes, these phenomena included sounds primarily from two main sources, non-human and non-domestic wild ones, and non-biological sources in relatively undisturbed habitats. In the early years of the 21st century, the definition of the soundscape was broken down into three components: the geophony, non-biological natural sounds that include the effects of water by a stream or waves at the ocean, the effects of wind in the trees or grasses, and sound generated by the earth, itself, for example, glaciers, avalanches and earthquakes; the biophony, all the non-human, non-domestic sounds that emanate from a relatively undisturbed habitat; and anthrophony, all sound generated by human endeavor, whether music, theatre, or electromechanical.