Biophony (also known as the niche hypothesis) consists of the Greek prefix, bio, meaning life, and the suffix, phon, meaning sound. It specifically refers to the collective sound that vocalizing animals create in each given environment. The term, which refers to one of three components of the soundscape (the others include geophony [non-biological natural sound] and anthrophony [human-induced noise]), was coined by Dr. Bernie Krause. The interrelationship of disciplines informed by natural soundscapes is called soundscape ecology, a further refinement of the older model and term, acoustic ecology.
The study of biophony focuses on the collective impact of all sounds emanating from natural biological origins in a given habitat. The realm of study is focused on the intricate relationships – competitive and/or cooperative – generally between non-human biological sound sources taking into account seasonal variability, weather, and time of day or night, and climate change. It explores new definitions of animal territory as defined by biophony, and addresses changes in density, diversity, and richness of animal populations.
The complete absence of biophony or geophony in a given biome would be expressed as dysphonia (from the Greek meaning the inability to produce a proper collective voice in this case).
The "niche hypothesis", an early version of the term, biophony, describes the acoustic bandwidth partitioning process that occurs in still-wild biomes by which non-human organisms adjust their vocalizations by frequency and time-shifting to compensate for vocal territory occupied by other vocal creatures. Thus each species evolves to establish and maintain its own acoustic bandwidth so that its voice is not masked. For instance, notable examples of clear partitioning and species discrimination can be found in the spectrograms derived from the biophonic recordings made in most uncompromised tropical and subtropical rain forests.